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The Global ETD Search service is a free service for researchers
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Showing 31 to 40 of 59 (0.069 seconds)Spelling suggestions: "subject:"energieeffizienz""
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Secure degrees of freedom on widely linear instantaneous relay-assisted interference channelHo, Zuleita K.-M., Jorswieck, Eduard January 2013 (has links)
The number of secure data streams a relay-assisted interference channel can support has been an intriguing problem. The problem is not solved even for a fundamental scenario with a single antenna at each transmitter, receiver and relay. In this paper, we study the achievable secure degrees of freedom of instantaneous relay-assisted interference channels with real and complex coefficients. The study of secure degrees of freedom with complex coefficients is not a trivial multiuser extension of the scenarios with real channel coefficients as in the case for the degrees of freedom, due to secrecy constraints. We tackle this challenge by jointly designing the improper transmit signals and widely-linear relay processing strategies.
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Interference Leakage Neutralization in Two-Hop Wiretap Channels with Partial CSIEngelmann, Sabrina, Ho, Zuleita K.-M., Jorswieck, Eduard A. January 2013 (has links)
In this paper, we analyze the four-node relay wiretap channel, where the relay performs amplify-and-forward. There is no direct link between transmitter and receiver available. The transmitter has multiple antennas, which assist in securing the transmission over both phases. In case of full channel state information (CSI), the transmitter can apply information leakage neutralization in order to prevent the eavesdropper from obtaining any information about the signal sent. This gets more challenging, if the transmitter has only an outdated estimate of the channel from the relay to the eavesdropper. For this case, we optimize the worst case secrecy rate by choosing intelligently the beamforming vectors and the power allocation at the transmitter and the relay.
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HAEC NewsJanuary 2013 (has links)
No description available.
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Automatisierte Herstellungstechnologie zur Fertigung von dünnwandigen 3D-geformten Verbundelementen für nachhaltige energieeffiziente Fassadenlösungen – „GreenFACE“Schönfelder, Daniel, Funke, Henrik, Gelbrich, Sandra, Kroll, Lothar 21 July 2022 (has links)
Zielstellung des Forschungsprojektes war die Entwicklung eines montagefertigen Verbundsystems aus vorgefertigten Elementen, Verankerungen und Unterkonstruktion zur Umsetzung nachhaltiger Fassadenlösungen. Dabei wurde ein neuer mineralischer Materialverbund mit textiler Verstärkung eingesetzt, der die Fertigung extrem dünnwandiger 3D-geformter Elemente mit hoher Passgenauigkeit gestattet. Das somit eröffnete sehr große Leichtbaupotential geht mit einer starken Gewichtsreduktion einher und ermöglicht damit erhebliche Ressourcen- und Energieeinsparungen. ... / The aim of the research project was the development of an assembly working system consisting of careful elements, anchors and substructure for the development of leading facade solutions. Has become a new mineral composite material with a textile ef ect, which allows the production of extremely narrow-walled 3D high-performance elements with a high degree of accuracy. This means that there is a very great potential for lightweight construction, with a strong weight reduction and thus enables what it is to do. ...
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| 35 |
HAEC News06 September 2013 (has links) (PDF)
No description available.
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| 36 |
HAEC News06 September 2013 (has links) (PDF)
No description available.
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Non-regenerative Two-Hop Wiretap Channels using Interference NeutralizationGerbracht, Sabrina, Jorswieck, Eduard A., Zheng, Gan, Ottersten, Björn 23 May 2013 (has links) (PDF)
In this paper, we analyze the achievable secrecy rates in the two-hop wiretap channel with four nodes, where the transmitter and the receiver have multiple antennas while the relay and the eavesdropper have only a single antenna each. The relay is operating in amplify-and-forward mode and all the channels between the nodes are known perfectly by the transmitter. We discuss different transmission and protection schemes like artificial noise (AN). Furthermore, we introduce interference neutralization (IN) as a new protection scheme. We compare the different schemes regarding the high-SNR slope and the high-SNR power offset and illustrate the performance by simulation results. It is shown analytically as well as by numerical simulations that the high SNR performance of the proposed IN scheme is better than the one of AN.
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Comparison of LDPC Block and LDPC Convolutional Codes based on their Decoding LatencyHassan, Najeeb ul, Lentmaier, Michael, Fettweis, Gerhard P. 11 February 2013 (has links) (PDF)
We compare LDPC block and LDPC convolutional codes with respect to their decoding performance under low decoding latencies. Protograph based regular LDPC codes are considered with rather small lifting factors. LDPC block and convolutional codes are decoded using belief propagation. For LDPC convolutional codes, a sliding window decoder with different window sizes is applied to continuously decode the input symbols. We show the required Eb/N0 to achieve a bit error rate of 10 -5 for the LDPC block and LDPC convolutional codes for the decoding latency of up to approximately 550 information bits. It has been observed that LDPC convolutional codes perform better than the block codes from which they are derived even at low latency. We demonstrate the trade off between complexity and performance in terms of lifting factor and window size for a fixed value of latency. Furthermore, the two codes are also compared in terms of their complexity as a function of Eb/N0. Convolutional codes with Viterbi decoding are also compared with the two above mentioned codes.
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Communications with 1-Bit Quantization and Oversampling at the Receiver: Benefiting from Inter-Symbol-InterferenceKrone, Stefan, Fettweis, Gerhard 25 January 2013 (has links) (PDF)
1-bit analog-to-digital conversion is very attractive for low-complexity communications receivers. A major drawback is, however, the small spectral efficiency when sampling at symbol rate. This can be improved through oversampling by exploiting the signal distortion caused by the transmission channel. This paper analyzes the achievable data rate of band-limited communications channels that are subject to additive noise and inter-symbol-interference with 1-bit quantization and oversampling at the receiver. It is shown that not only the channel noise but also the inter-symbol-interference can be exploited to benefit from oversampling.
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Static Partial Order Reduction for Probabilistic Concurrent SystemsFernández-Díaz, Álvaro, Baier, Christel, Benac-Earle, Clara, Fredlund, Lars-Åke 10 September 2013 (has links) (PDF)
Sound criteria for partial order reduction for probabilistic concurrent systems have been presented in the literature. Their realization relies on a depth-first search-based approach for generating the reduced model. The drawback of this dynamic approach is that it can hardly be combined with other techniques to tackle the state explosion problem, e.g., symbolic probabilistic model checking with multi-terminal variants of binary decision diagrams. Following the approach presented by Kurshan et al. for non-probabilistic systems, we study partial order reduction techniques for probabilistic concurrent systems that can be realized by a static analysis. The idea is to inject the reduction criteria into the control flow graphs of the processes of the system to be analyzed. We provide the theoretical foundations of static partial order reduction for probabilistic concurrent systems and present algorithms to realize them. Finally, we report on some experimental results.
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