Mittweida, Germany
Mittweida, Germany

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Huebelt J.,Hochschule Mittweida | Lindemann J.,Hochschule Mittweida | Wolf S.,Wolf Strassen und Tiefbau GmbH | Wellner F.,TU Dresden
Civil Engineering and Urban Planning IV - Proceedings of the 4th International Conference on Civil Engineering and Urban Planning, CEUP 2015 | Year: 2016

Among others, the long term durability of road pavements is influenced by the time gap between the laying process and the opening to traffic. Here, in this project a rather simple method for the estimation of the time for opening the pavement to traffic after the laying process is discussed. Therefore in the first part of the paper a technique for the measurement of the mechanical input impedance is introduced. On the basis of this measurement the Young’s modulus is estimated at 5 Hz and 20 °C by use of the temperature/frequency equivalence. In the second part of the project the method has been applied to five new built German pavements. Moreover, by applying a first rough assumption for the setting of asphalts the time for opening the pavements to traffic has been estimated. © 2016 Taylor & Francis Group, London.

Zimmer K.,Leibniz Institute fur Oberflachenmodifizierung E.V. | Ehrhardt M.,Leibniz Institute fur Oberflachenmodifizierung E.V. | Lorenz P.,Leibniz Institute fur Oberflachenmodifizierung E.V. | Stephan T.,Leibniz Institute fur Oberflachenmodifizierung E.V. | And 2 more authors.
Optics and Laser Technology | Year: 2013

The joining of micron devices by bonding of thin films is required for the electrical or mechanical connection of thin film components. Current developments of flexible electronics call for advanced micron interconnection technologies. For the joining of thin film devices on flexible polymer substrates a novel technique called laser microriveting (LMR) is introduced and demonstrated which enables the bonding of two thin metal layers of different materials for mechanical and electrical connections. In this approach the mechanical and electrical connections are achieved by geometrical interlocking of the thin film materials as a consequence of pulsed laser irradiation. Imaging by SEM and EDX shows clearly that a hollow rivet of copper is formed interlocking the copper layer with the overlaying molybdenum film. The copper hollow rivet formation is the result of highly-dynamic laser-driven processes of melting, evaporation, recoil pressure formation, material transport processes, and resolidification of the molten copper within a single laser pulse. A contact resistance of less than 100 mΩ for one rivet of approximately 20 μm size was measured. This new approach provides a solution for current problems of joining very dissimilar materials. © 2013 Elsevier Ltd.

Muller R.,Norwegian University of Science and Technology | Lampe A.,Hochschule Mittweida
AEU - International Journal of Electronics and Communications | Year: 2011

This paper studies the spectral efficiency of code-division multiple access with constant envelope modulation in the large system limit. Despite the fact that continuous phase modulation is hit by a severe drawback in spectral efficiency as compared to quadrature amplitude modulation on a single user communication link, the gap in terms of spectral efficiency is found to be negligible when employed on a multiple access channel with the CDMA protocol. Accounting for the efficiency of the transmit amplifier, the latter comparison becomes even favorable for constant envelope modulation. © 2011 Elsevier GmbH. All rights reserved.

Huebelt J.,Hochschule Mittweida | Lindemann J.,TU Dresden | Zander U.,University of Siegen | Wellner F.,TU Dresden
42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life | Year: 2013

The long term durability of road pavements plays an important role when calculating the expenses of road construction. Among others, this durability is influenced by the conditions during the laying process of the pavement. Here, as important factors, the environmental temperature and the time duration between the laying process and the opening for traffic has to be mentioned. In Germany, for constructing a double layer, the required duration time is about 36 hours. During this time, the road has to be remaining closed. This can lead to big traffic jams, not only in urban areas. To shorten this time gap accurate information about the properties of the asphalt during and after the laying process are required. An indicator for the durability of the pavement could be the mechanical input impedance. Therefore, in the paper, the convenience of the use of the measurement of the mechanical input impedance for predicting the durability of the pavement will be discussed. Copyright© (2013) by Austrian Noise Abatement Association (OAL).

Gay M.,Hochschule Mittweida | Lampe A.,Hochschule Mittweida | Breiling M.,Fraunhofer Institute for Integrated Circuits
Proceedings of 2013 9th International ITG Conference on Systems, Communication and Coding, SCC 2013 | Year: 2013

Several contributions have been made on using Compressed Sensing (CS) for sparse channel estimation in wireless communications. Therein the focus is mainly set on designing transmission systems towards the application of CS channel estimation, which includes for example the proposal for random pilot patterns in OFDM systems. However, most state of the art OFDM transmission systems are using regular pilot patterns, which is beneficial for classical MMSE channel estimators. This constrains a CS-based channel estimator in its ability to choose frequency measurements at random. With the aim of using CS-based OFDM channel estimation for existing standards we examine the effect of these constraints, and we give some necessary conditions for the existence of a unique solution and good reconstruction properties. In particular, we study the effects at the example of the DVB-T standard, where we will see that it is possible to obtain reconstruction performance comparable to using random pilot patterns.

Dohmen K.,Hochschule Mittweida | Tittmann P.,Hochschule Mittweida
Electronic Journal of Combinatorics | Year: 2012

In this paper, we propose a new network reliability measure for some particular kind of service networks, which we refer to as domination reliability. We relate this new reliability measure to the domination polynomial of a graph and the coverage probability of a hypergraph. We derive explicit and recursive formulæ for domination reliability and its associated domination reliability polynomial, deduce an analogue of Whitney's broken circuit theorem, and prove that computing domination reliability is NP-hard.

Gay M.,Hochschule Mittweida | Lampe A.,Hochschule Mittweida | Breiling M.,Fraunhofer Institute for Integrated Circuits
Proceedings of the International Symposium on Wireless Communication Systems | Year: 2013

In mobile systems it is essential to estimate the channel response at the receiver. Since the multipath structure of the radio channel is generally sparse, this has recently proven in OFDM systems to be an application where insights from the theory of Compressed Sensing (CS) can be beneficial. Classical methods apply for example digital MMSE filters, exploiting correlation in time and frequency to estimate the channel in frequency domain, whereas CS methods exploit sparsity in time domain. Many contributions have been made on this topic with the focus on designing transmission systems that support CS-based channel estimation. In this paper we study the applicability of CS-based channel estimation for the next generation digital video broadcasting standards DVBT2 and DVB-NGH, where the pilot patterns were designed for conventional linear estimation methods, rather than for CS. Based on the mutual coherence of the resulting sensing matrices for different configurations, we give statements on the expected reconstruction performance when using CS methods and verify the results by numerical simulations. We focus on the probability of correct support detection and the mean squared error in the noise free case and give an outlook on the estimation error for varying noise level. © VDE Verlag GMBH.

Lindemann J.,Hochschule Mittweida | Hubelt J.,Hochschule Mittweida
42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life | Year: 2013

The use of laser treatment processes allow to achieve parts in a very high precision and therefore, miniature components can be produced. But to save time, money and especially material, an online process monitoring for fault detection is necessary. Therefore optical measurement methods have been established for the monitoring of the laser welding and cutting procedures. They are based, for example, on the detection of the process-dependent plasma. However, the reliability and validity of the error detection during the process can be increased by use of a combination of different sensors. Therefore, both optical and acoustic sensors, such as microphones and accelerometers, where used in the presented study. Copyright© (2013) by Austrian Noise Abatement Association (OAL).

Delmdahl R.,Coherent GmbH | Weissmantel S.,Hochschule Mittweida | Reisse G.,Hochschule Mittweida
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

Super-hard functional coatings are obtained by high power excimer laser based PLD. Diamond-like, tetrahedral amorphous carbon (ta-C) is grown on substrates moderately heated to below 90°C inside a vacuum chamber upon ablating a graphite target by means of a high pulse energy excimer laser at a wavelength of 248 nm. The fast evaporation of the target material induced by the high photon energy of 5 eV, the short temporal width of 30 ns and the high fluence of the excimer laser pulses generates plume species with a high degree of ionisation and high kinetic energies. As a consequence, the kinetic energies resulting from excimer based PLD are significantly higher than those associated with the thermal evaporation and the ion sputtering deposition methods. In fact, the mean kinetic energy of the atoms and ions in the plume are in the range of 30 eV to 80 eV for fluencies of 5 J/cm2 to 20 J/cm2. Such large ontarget UV fluences are easily provided by high energy excimer lasers such as the Coherent LPXpro and by LSX laser models which can operate at output energies up to 1 J and average output powers up to 540 W. © 2010 Copyright SPIE - The International Society for Optical Engineering.

This article is designed to the currently heated debate of an amendment to the German psychotherapist law and the connected factional dispute wether psychotherapy education will be strong adapted to the biomedical paradigm or will prefer the biopsychosocial paradigm (public health).

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