31 research outputs found
Camera calibration by evolutionary algorithms
Práce se zabývá vývojem a zhodnocením programu pro výpočet vnitrních a vnějších parametrů kamery, pomocí evolučních algoritmů resp. pomocí algoritmu diferenciální evoluce. Zároveň popisuje možnost využití grafické karty pro paralelní výpočet.This paper describes the possibility of using evolutionary algorithms (specifically the differential evolution) to figure out interior and exterior parameters of camera. It is an easy and an effective way to solve this problem. Also describe possibility of using graphics processor unit to parallel computing.
Authentication with RFID tags
Bakalářská práce se zabývá problematikou RFID prvků autentizačních systémů využívající prvky RFID a čipové karty. Jsou popsány základní rozdíly mezi aktivními a pasivními RFID prvky. Jsou popsány základní útoky, jakými se dá ohrozit komunikace mezi čtečkou a RFID zařízením v bezdrátovém prostředí. V práci je zahrnuto měření jednotlivých pasivních RFID tagů. Výsledky měření jsou zaznamenány pomocí tabulek a grafů. Hlavní cíl práce se zaměřuje na realizaci autentizačního protokolu, který je určen pro procesorové karty. Díky procesoru zde můžou být nasazeny protokoly využívající kryptografii, kde je vyžadován určitý výpočetní výkon. S využitím procesoru je možné zajistit bezpečný přenos dat a autentizaci. Práce popisuje 2 návrhy protokolů, které byly modifikovány pro BasicCard prostředí. V prvním schématu je představena autentizace klienta vůči terminálu, využívající zabezpečený přenos dat pomocí AES 256 bit a ověřovatel je strana terminálu. Ve druhém schématu je strana karty jako ověřovatel, kde karta generuje takové údaje, aby mohla ověřit, že druhá strana je schopná se autentizovat.The bachaleror thesis deals with issue of RFID elements and authentication systems used by elements of RFID and chip cards. The basic differences between active and passive RIFD tags are decsribed. The thesis describes basic attacks which can threat communication between reader and RFID device in wireless comunication. In the thessis is included measuring of passive RFID tags. Results of the measurement are presented by tables and graphs. Main goal of this thesis aims at the implementation of the authentication protocol which is mainly for processor cards. Because of the processor we can use cryptography where is neccessary computing power. We can ensure secure data transfer and authentication. The thesis describes 2 schemes of one authentication protocol, which were modificated for BasicCard Enviroment. In the first scheme client(card) authenticate to the terminal using secure AES 256 bit data transfer and verifier is the terminal side. Data which needs to be exchanged is secured by AES 256 bit. In the second scheme the card side is a verifier and the card generates such data to verify that the other party is able to authenticate.
Data Acquisition and Processing in the 2D and 3D SLAM Tasks of Navigation in Robotics
Tato práce se zabývá návrhem a implementací algoritmu SLAM pro sebelokalizaci a mapování v interiéru budov s využitím dat z laserového scaneru. Návrh je tvořen pro 2D variantu SLAMu, ale je záměrně realizován tak, aby byl principiálně použitelný i pro 3D SLAM, což je v závěru práce demonstrováno.This paper describe design and implementation of SLAM algorithm for selflocalization and mapping in indoor environment using data from laser scanner. Design is focused on 2D variant of SLAM, but parts is purposely reliazed to be usable in 3D SLAM. This ability is demonstrated at the end of paper.
Comparison Of Different Approaches To Adaptation Of Unscented Kalman Filter For Non-Odometry Slam
This paper is aimed at utilizing of an Unscented Kalman filter (UKF) for application on non-odometry SLAM problem. Non-odometry SLAM problem lacks state transitions function for part of state vector so theoretical part of the paper describes the derivation of three proposed modifications. The experimental part then shows experiments which evaluate modifications performance in reference to Extended Kalman filter. Experiments are based on simulation of monocular photogrammetry reconstruction problem
Network communication monitoring probe
Diplomová práce se zabývá analýzou jednodeskových počítačů, které využívají systém Linux jako operační systém. Dále jsou zkoumaný jednotlivé NIDS systémy a jejich vlastnosti za účelem výběru vhodného kandidáta pro jednodeskový počítač, který má být využit jako síťová sonda sloužící pro analýzu, filtraci a logování síťového provozu. Část práce je zaměřena na vývoj rozhraní, které slouží ke konfiguraci síťové sondy přes webový prohlížeč. Rozhraní umožňuje vykonávat základní operace nad síťovou sondu, která ovlivňují datový provoz nebo specifikují, jaké informace mají být zaznamenány. Následně, došlo k implementaci parserů pro síťové protokoly pomocí knihovny Scappy. Závěr práce obsahuje realizaci krycího obalu pro zařízení dle požadavků IP54.Master thesis deals with analysis of single board PC which use Linux as operation system. Analysis of individual NIDS systems and examined their properties for choosing right candidate for single board computer which shall be used as network probe for analysis, filtering and logging of network traffic. Part of the work is aimed on development of a interface which is used for configuration of network probe through the web browser. Web interface allows perform basic operations over network probe which influence network traffic or specify, which information shall be logged. Subsequently network parsers were implemented for network protocols using the Scappy library. The conclusion of the thesis contains the design of the security cover for the device according to the IP54 requirements.
A new line-shape asymmetry model for wavelength modulation spectroscopy in gaseous flows
This communication reports technical notes on the development and application of an automated line-shape fitting procedure for wavelength modulation spectroscopy (WMS). Near-infrared transitions of carbon dioxide (CO2) around 1573 nm were measured in vertical cold (non-reacting) flow of CO2 at atmospheric pressure using WMS with demodulation at second harmonic frequency. Semi-empirical model based on the set of so-called Gabor functions was developed and parameters of Lorentzian line-shape profile and its asymmetry resulting from simultaneous frequency and amplitude response of the current-modulated semiconductor laser were determined. Nonlinear least-square fitting procedure employing differential evolution algorithm was successfully utilized for performing this task. Line-shape fitting procedure enabling efficient signal de-noising and background subtraction of wavelength modulation spectra was implemented into an open-source code.Web of Science18416115
General concepts of multi-sensor data-fusion based SLAM
This paper is approaching a problem of Simultaneous Localization and Mapping (SLAM) algorithms focused specically on processing of data from a heterogeneous set of sensors concurrently. Sensors are considered to be different in a sense of measured physical quantity and so the problem of effective data-fusion is discussed. A special extension of the standard probabilistic approach to SLAM algorithms is presented. This extension is composed of two parts. Firstly is presented general perspective multiple-sensors based SLAM and then thee archetypical special cases are discuses. One archetype provisionally designated as ”partially collective mapping” has been analyzed also in a practical perspective because it implies a promising options for implicit map-level data-fusion
MECHANICAL PROPERTIES OF FORGED TUNGSTEN HEAVY ALLOYS
Tungsten heavy alloys are composite materials containing spherical tungsten particles embedded in binder matrix. Their excellent mechanical properties can be further improved by rotary forging. This paper aims to gain deeper understanding of the forging process by investigating the local elastic modulus, hardness, and residual stress of individual phases in W6Ni3Co pseudo-alloy. The resulting global properties of the composite material such as stress-strain behavior, fracture toughness and fatigue crack growth rate behavior are also studied. The results show that sintered and quenched material consists of highly textured matrix containing nearly perfect single crystal spheres of pure W. The rotary forging leads to significant lattice deformations destroying the texture and significantly increasing the hardness of both WNiCo matrix and W particles and making residual stresses in W particles anisotropic with increased compression along the longitudinal axis of the forged part
Changing pollinator communities along a disturbance gradient in the Sundarbans mangrove forest: A case study on Acanthus ilicifolius and Avicennia officinalis
The role of species traits in predator-prey interactions and food web structure
This thesis deals with the role of species traits in predator-prey interactions and food web structure. I conducted laboratory experiments with predatory aquatic insects and their prey to reveal the traits determining who eats whom in small standing waters. I also focused on the possibility of incorporating the observed dependence of predator-prey interactions on body mass into existing food web models. Further, I developed a simple simulation model to explore the consequences of body mass dependent feeding and dispersal for food web assembly. Last, I show that four common methods for sampling aquatic insects differ in their selectivity, especially on the basis of body mass of sampled insects. In conclusion, I combined laboratory experiments, field work and mathematical models to evaluate the importance of body mass and other species traits, such as foraging behaviour and microhabitat selectivity, in predator-prey interactions and explored selected food web level consequences