Automatic Generation of Scanning Positions for Sheet Metal Parts Digitization

Práce se zabývá návrhem metodiky pro automatické generování pozic optického skeneru pro digitalizaci plechových dílů na základě počítačového modelu měřeného dílu. Výroba a s tím související inspekce plechových dílů jsou velmi úzce spojeny s automobilním průmyslem. Kvůli obecným zvyšujícím se nárokům na přesnost je v sériové výrobě kladen požadavek na přesnou kontrolu vyráběných dílů. K tomu se stále častěji začínají využívat optické 3D skenery a průmyslové roboty. V případě zavedení výroby nového dílu a jeho automatické kontroly v procesu sériové výroby je nutné připravit pozice měření, ze kterých dojde k přesné a rychlé digitalizaci dílu pro následnou inspekci. Příprava těchto pozic probíhá nejčastěji ručním uvedením robota do daných pozic a jejich uložením. Navržená metodika řeší přípravu pozic automaticky. V práci je představena metodika návrhu pozic měření, jejich simulace na skutečnou viditelnost části dílu pomocí osvětlovacího modelu a simulace vygenerovaných pozic na dostupnost robota. Metodika byla zpracována jako plugin pro software Rhinoceros. Na základě experimentálního ověření bylo zjištěno, že dojde ke značné časové úspoře v přípravě pozic měření v porovnání s jejich ruční přípravou.This thesis deals with the development of a new methodology for automatic generation of scanning positions based on a computer model of the part for digitization of sheet metal parts. Manufacture and related inspection of sheet metal parts are closely connected to automotive industry. Based on increasing general requirements on accuracy, there is also a requirement for accurate inspection of manufactured parts in serial-line production. Optical 3D scanners and industrial robots are used more often for that purpose. Measuring positions for accurate and fast digitization of a part need to be prepared as the manufacturing of the new part begins. Planning of such positions is done manually by positioning of the industrial robot and saving the positions. The planning of positions proposed by this methodology is done automatically. A methodology of positions planning, their simulation for true visibility of the part elements using reflectance model and a simulation of the positions for robot reachability is presented in this thesis. The entire methodology is implemented as a plug-in for the Rhinoceros software. High reduction of time in positions planning compared to the manual approach was observed in the performed experiments.

Simplified Algorithmic Metatheorems Beyond MSO: Treewidth and Neighborhood Diversity

This paper settles the computational complexity of model checking of several extensions of the monadic second order (MSO) logic on two classes of graphs: graphs of bounded treewidth and graphs of bounded neighborhood diversity. A classical theorem of Courcelle states that any graph property definable in MSO is decidable in linear time on graphs of bounded treewidth. Algorithmic metatheorems like Courcelle's serve to generalize known positive results on various graph classes. We explore and extend three previously studied MSO extensions: global and local cardinality constraints (CardMSO and MSO-LCC) and optimizing the fair objective function (fairMSO). First, we show how these extensions of MSO relate to each other in their expressive power. Furthermore, we highlight a certain "linearity" of some of the newly introduced extensions which turns out to play an important role. Second, we provide parameterized algorithm for the aforementioned structural parameters. On the side of neighborhood diversity, we show that combining the linear variants of local and global cardinality constraints is possible while keeping the linear (FPT) runtime but removing linearity of either makes this impossible. Moreover, we provide a polynomial time (XP) algorithm for the most powerful of studied extensions, i.e. the combination of global and local constraints. Furthermore, we show a polynomial time (XP) algorithm on graphs of bounded treewidth for the same extension. In addition, we propose a general procedure of deriving XP algorithms on graphs on bounded treewidth via formulation as Constraint Satisfaction Problems (CSP). This shows an alternate approach as compared to standard dynamic programming formulations

Comparison of Sublimation 3D Scanning Sprays in Terms of Their Effect on the Resulting 3D Scan, Thickness, and Sublimation Time

This study compared eight sublimation scanning sprays in terms of their effect on 3D scanning results, coating thickness, and sublimation time. The work used an automated spraying system to ensure the same deposition conditions for all tested materials. All experiments were performed under the same environmental conditions to exclude the influence of the ambient environment on the coatings. All tested scanning sprays created coatings with thicknesses in the order of tens of micrometers that were detectable by the 3D scanner Atos III Triple Scan. The coatings must be applied carefully when accurate measurements are required. All used materials enabled the capture of the highly reflective surface of the Si-wafer. However, the differences between some sprays were significant. Sublimation time measurements showed that all coatings disappeared from the Si-wafer surface completely. Nevertheless, all coatings left visible traces on the mirror-like surface. They were easily wiped off with a cloth

Mechanics of screw joints solved as beams placed in a tangential elastic foundation

This article deals with a new original analytical solution of deformation, force and stress states in wood screw joints up to the limit values of pulling out/breaking the screw. The screws are under tension. The wood-to-screw interaction is effectively simplified by introducing several physical model variants using a tangential elastic non-linear foundation. The experimental verification of the proposed models using pull-out tests (i.e., pulling out screws from dry spruce wood in laboratory conditions) confirms the correctness of the proposed models of the elastic linear/non-linear foundation. The validity of the model is also analytically and experimentally verified in the biomechanical model of pulling out screws from the femur of a bovine/human cadaver, which confirms and expands the validity of newly designed screw joint models outside the timber structure area.Web of Science1112art. no. 561

<scp>ReSurveyEurope</scp>: A database of resurveyed vegetation plots in Europe

AbstractAimsWe introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions.ResultsReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun‐Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020.ConclusionsReSurveyEurope is a new resource to address a wide range of research questions on fine‐scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well‐established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.</jats:sec

Certification IPv6 for the software and devices

Bachelor thesis on certification IPv6 for the software and devices describes how the proces of device certification works, what is the reason for the product certification is and who performs it. The project also focuses on the basic requirements which the producer has to meet. It compares single certification organizations and describes their role. In the practical part, applications and operating systems are tested. Testing of the operating systems is marginally tested according to the test profile IPv6 Ready and by single applications connectivity to the IPv6 World is tested

Design of lower-limb prostheses

Cílem této bakalářské práce je podat přehled současného stavu v oblasti protéz dolních končetin po amputaci mezi kyčlí a kolenem. Práce se zabývá otázkou lidské chůze, její analýzou a odchylkami v případě chůze s protézou. Dále popisuje základní rozdělení protéz dolních končetin. Hlavní částí je pak popis konstrukce těchto protéz a především jejich jednotlivých komponent a základní přehled dostupných typů těchto komponent.The goal of this bachelor's thesis is to give an overview of the current state of lower limb prostheses after amputation between the hip and the knee. It deals with the human gait, its analysis and with deviations in gait with the prosthesis. It also describes basic division of lower limb prostheses. The main part is the description of these prostheses designs and especially the design of main components and general overview of available types.

Automation of optical measuring via TRITOP optical coordinate system

Cílem této diplomové práce je automatizace fotogrammetrického měřícího systému TRITOP. Rešeršní část práce obsahuje rozdělení digitalizačních metod a jejich popis. Dále popisuje funkci fotogrammetrického systému TRITOP. Vlastní práce se zabývá metodikou automatizace procesu měření systémem TRITOP a vyhodnocení tohoto měření. Řešení je následně ověřeno na vybraném příkladu z praxe.The goal of this diploma thesis is to automate photogrammetric measuring system TRITOP. In the literature retrieval part there is a review of digitizing methods and its description. Further it contains a description of the photogrammetric system TRITOP role. The practical part of the thesis deals with methodology of the TRITOP measurement and evaluation process automation. Automation is then verified on a practical example.