Refine
Year of publication
Document Type
- Master's Thesis (8)
- Article (7)
- Bachelor Thesis (6)
- Preprint (2)
- Working Paper (2)
- Study Thesis (1)
Has Fulltext
- yes (26)
Keywords
- XML (4)
- FPGA (3)
- Field programmable gate array (3)
- Autonomer Roboter (2)
- Dienstgüte (2)
- Mobile Telekommunikation (2)
- Multimedia (2)
- RTLIL (2)
- Rechnernetz (2)
- Smartphone (2)
Faculty
- Fakultät 07 / Institut für Nachrichtentechnik (26) (remove)
The objective of this paper is to implement a baseband OFDM transceiver on FPGA hardware. The design uses 8-point SLT/ISLT (Slantlet/Inverse Slantlet) for the processing module with processing block of 8 inputs data wide. All modules are designed and implemented using VHDL programming language. Software tools used in this work includes Altera Quartus II 7.2 and ModelSim Altera 6.1g, to assist the design process and downloading process into FPGA board while Cyclone III board EP3C120F780C7 is used to realize the designed module.
This paper presents the design procedure and implementation results of a proposed software defined radio (SDR) using Altera Cyclone II family board. The implementation uses Matlab/SimulinkTM, Embedded MatlabTM blocks, and Cyclone II development and educational board. The design has first implemented in Matlab/SimulinkTM environment. It is then converted to VHDL level using Simulink HDL coder. The design is synthesized and fitted with Quartus II 9.0 Web Edition® software, and downloaded to Altera Cyclone II board. The results show that it is easy to develop and understand the implementation of SDR using programmable logic tools. The paper also presents an efficient design flow of the procedure followed to obtain VHDL netlists that can be downloaded to FPGA boards.
High-quality rendering of spatial sound fields in real-time is becoming increasingly important with the steadily growing interest in virtual and augmented reality technologies. Typically, a spherical microphone array (SMA) is used to capture a spatial sound field. The captured sound field can be reproduced over headphones in real-time using binaural rendering, virtually placing a single listener in the sound field. Common methods for binaural rendering first spatially encode the sound field by transforming it to the spherical harmonics domain and then decode the sound field binaurally by combining it with head-related transfer functions (HRTFs). However, these rendering methods are computationally demanding, especially for high-order SMAs, and require implementing quite sophisticated real-time signal processing. This paper presents a computationally more efficient method for real-time binaural rendering of SMA signals by linear filtering. The proposed method allows representing any common rendering chain as a set of precomputed finite impulse response filters, which are then applied to the SMA signals in real-time using fast convolution to produce the binaural signals. Results of the technical evaluation show that the presented approach is equivalent to conventional rendering methods while being computationally less demanding and easier to implement using any real-time convolution system. However, the lower computational complexity goes along with lower flexibility. On the one hand, encoding and decoding are no longer decoupled, and on the other hand, sound field transformations in the SH domain can no longer be performed. Consequently, in the proposed method, a filter set must be precomputed and stored for each possible head orientation of the listener, leading to higher memory requirements than the conventional methods. As such, the approach is particularly well suited for efficient real-time binaural rendering of SMA signals in a fixed setup where usually a limited range of head orientations is sufficient, such as live concert streaming or VR teleconferencing.
Conventional individual head-related transfer function (HRTF) measurements are demanding in terms of measurement time and equipment. For more flexibility, free body movement (FBM) measurement systems provide an easy-to-use way to measure full-spherical HRTF datasets with less effort. However, having no fixed measurement installation implies that the HRTFs are not sampled on a predefined regular grid but rely on the individual movements of the subject. Furthermore, depending on the measurement effort, a rather small number of measurements can be expected, ranging, for example, from 50 to 150 sampling points. Spherical harmonics (SH) interpolation has been extensively studied recently as one method to obtain full-spherical datasets from such sparse measurements, but previous studies primarily focused on regular full-spherical sampling grids. For irregular grids, it remains unclear up to which spatial order meaningful SH coefficients can be calculated and how the resulting interpolation error compares to regular grids. This study investigates SH interpolation of selected irregular grids obtained from HRTF measurements with an FBM system. Intending to derive general constraints for SH interpolation of irregular grids, the study analyzes how the variation of the SH order affects the interpolation results. Moreover, the study demonstrates the importance of Tikhonov regularization for SH interpolation, which is popular for solving ill-posed numerical problems associated with such irregular grids. As a key result, the study shows that the optimal SH order that minimizes the interpolation error depends mainly on the grid and the regularization strength but is almost independent of the selected HRTF set. Based on these results, the study proposes to determine the optimal SH order by minimizing the interpolation error of a reference HRTF set sampled on the sparse and irregular FBM grid. Finally, the study verifies the proposed method for estimating the optimal SH order by comparing interpolation results of irregular and equivalent regular grids, showing that the differences are small when the SH interpolation is optimally parameterized.
Die Grundlage für diese Arbeit ist das opensource Roboterkettenfahrzeug SRV1 der Firma Surveyor [www-surveyor]. Im Auslieferungszustand ist es möglich, das Fahrzeug über ein Steuerungsprogramm fernzusteuern. Dies entspricht dem Funktionsumfang eines normalen ferngesteuerten Fahrzeugs, erweitert um eine Kamera, jedoch ohne jegliche Autonomie oder Intelligenz. Da das Fahrzeug auf einem embedded Board aufgebaut ist, welches über eine WLAN Verbindung verfügt, bietet es einen guten Ausgangspunkt für Erweiterungen. Ziel dieser Arbeit ist es eine Grundlage für autonome Fahrten zu schaffen. Als Betriebssystem wird uClinux, ein Linux für embedded Plattformen genutzt. Das Fahrzeug soll um einen zur Orientierung dienenden Kompass erweitert werden. Außerdem kommt ein RFID-Reader zum Einsatz, mit dessen Hilfe werden RFID-Transponder auf einer Teststrecke als künstliche Landmarken zur Positionsbestimmung genutzt. Es wird eine Software für autonome Fahrten entwickelt, die es ermöglicht, durch Verwendung der erweiterten Hardware, den Roboter eigenständig Punkte der Teststrecke anfahren zu lassen. Hierzu ist es erst notwendig alle Hardware im Betriebssystem, beispielsweise durch Treiber verfügbar zu machen.
This project was done in collaboration with CERN and is part of the detector control system of the ATLAS experiment. The primary goal foresaw the development and testing of the FPGA card for the MOPS-HUB crate with the focus on radiation tolerance. This was accomplished with the approach of designing two different PCBs. The first PCB was created as a fast prototype with the use of a commercial SOM-board. This was also beneficial for confirming that the chosen FPGA is suitable for the MOPS-HUB application. After the successful assembly and test, a second, more complex and foremost radiation tolerant PCB was designed. This was achieved by solely using components of the CERN radiation database.
The second part of this thesis focuses on increasing the distance of TMR registers with a Python script. A method was created for extracting and later parsing a design’s placement
information from Vivado. Furthermore, were system designed and implemented to recognize TMR cells, to find and validate free cells and to finally create a new placement for import into Vivado. These algorithms were tested with a multitude of configurations and the quality, based on the maximum possible frequency of a design, determined.
In this paper we describe traffic sign recognition with neural networks in the frequency domain. Traffic signs exist in all countries to regulate the traffic of vehicles and pedestrians. Each country has its own set of traffic signs that are more or less similar. They consist of a set of abstract forms, symbols, numbers and letters, which are combined into different signs. Automatic traffic sign recognition is important for driver assistance systems and for autonomous driving. Traffic sign recognition is a subtype of image recognition. The traffic signs are usually recorded by a camera and must be recognized in real time, i.e. assigned to a class. We use neural networks for traffic sign recognition. The special feature of our method is that the traffic sign recognition does not take place in the spatial domain but in the frequency domain. This has advantages because it is possible to significantly reduce the number of neurons and thus the computing effort of the neural network compared to a conventional neural network.
Das für diese Masterthesis realisiertes Softwaresystem verwendet als Teilkomponente die Softwarelösung IPEE (Internet Pattern Extrakt Engine), die von M.Sc. Andreas Frey entwickelt und in der ursprünglichen Fassung dokumentiert wurde. Diese Kapitel sind aus Gründen des Copyrights, die auf der Software IPEE liegen, nicht in der veröffentlichten Fassung (der Masterthesis) enthalten. Eingeleitet wird die Arbeit mit Aspekten des Entwicklungsstandes des Semantik Web (Web3.0). Es folgt die Begriffsdefinition der Semantik und der semantisch orientierten Verarbeitung. Für die Ablage (Archivierung) und Verarbeitung von Daten für semantisch orientierte verarbeitende Systeme eignet sich die Konzeption der semistrukturierten Daten, die darauf folgend definiert und mit den anderen Konzeptionen - wie strukturiert und nicht strukturiert - in Beziehung gesetzt wird. In den folgenden Kapiteln werden die Komponenten erklärt, die für die Realisierung eines Prototypen zur semantisch orientierten Verarbeitung verantwortlich sind und hauptsächlich auf Aspekte der semantisch orientierten Verarbeitung von Verben fokussiert sind. Von Relevanz sind hierbei Komponenten zur Wort- und Phrasen-Analyse und zur automatischen Recherche von Wörtern aus dem Internet. Da diese Komponenten auf die Realisierung von Pattern-Extraktionsverfahren basieren, wurde die spezielle Softwarelösung IPEE verwendet. Des weiteren werden Komponenten für die Generierung des semantischen Graphen und die Visualisierung anhand von hyperbolischen Bäumen mit Hilfe einer Open Source Software Treebolic Browser beschrieben. Auch wird eine GUI für die Eingabe und Verarbeitung von Sätzen der deutschen Sprache und die Verwaltung eines Bedeutungswörterbuches erklärt. Abschließend erfolgt eine experimentelle Auswertung der semantisch orientierten Verarbeitung.
A level graph G = (V,E,λ) is a graph with a mapping λ : V → {1,...,k}, k ≥ 1, that partitions the vertex set V as V = V1 ∪...∪ Vk, Vj = λ-1(j), Vi ∩ Vj = ∅ for i ≠ j, such that λ(v) = λ(u) + 1 for each edge (u, v) ∈ E. Thus a level planar graph can be drawn with the vertices of every Vj, 1 ≤ j ≤ k, placed on a horizontal line, representing the level lj , and without crossings of edges, which can be drawn as straight line segments between the levels. Healy, Kuusik and Leipert gave a complete characterization of minimal forbidden subgraphs for level planar graphs (MLNP patterns) for hierarchies [4]. Minimal in terms of deleting an ar- bitrary edge leads to level planarity. A radial graph partitions the vertex set on radii, which can be pictured as concentric circles, instead of levels, lj = (j cos(α), j sin(α)), α ∈ [0,2π), mapped around a shared center, where j, 1 ≤ j ≤ k indicates the concentric circles’ radius. Comparing embeddings of radial graphs with that of level graphs we gain a further possibility to place an edge and eventually avoid edge crossings which we wish to prevent for planarity reasons. This offers a new set of minimal radial non planar subgraphs (MRNP patterns). Some of the MLNP pat- terns can be adopted as MRNP patterns while some turn out to be radial planar. But based on the radial planar MLNP patterns and the use of augmentation we can build additional MRNP patterns that did not occur in the level case. Furthermore we point out a new upper bound for the number of edges of radial planar graphs. It depends on the subgraphs in- duced between two radii. Because of the MRNP patterns these subgraphs can either consist of a forest or a cycle with several branches. Applying the bound we are able to characterize extremal radial planar graphs. Keywords: radial graphs, minimal non-planarity, extremal radial planar