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To facilitate a functional analysis of neuronal connectivity in a mammalian nervous system that is tightly packed with billions of cells, we developed a new technique that uses inducible genetic manipulations in fluorescently labeled single neurons in mice. Our technique, single-neuron labeling with inducible Cre-mediated knockout (SLICK), is achieved by(More)
—The simulation models of wireless networks rapidly increase in complexity to accurately model wireless channel characteristics and the properties of advanced transmission technologies. Such detailed models typically lead to a high computational load per simulation event that accumulates to extensive simulation runtimes. Reducing runtimes through(More)
— OFDM systems are known to overcome the impairment of the wireless channel by splitting the given system bandwidth into parallel sub-carriers, on which data symbols can be transmitted simultaneously. This enables the possibility of enhancing the system's performance by deploying adaptive (dynamic) mechanisms, namely power and modulation adaption and(More)
Recently, a lot of research effort has been spent on cross-layer system design. It has been shown that cross-layer mechanisms (i.e., policies) potentially provide significant performance gains for various systems. In this article we review several aspects of cross-layer system optimization regarding wireless OFDM systems. We discuss basic optimization(More)
In this paper, we study the performance of a combined link-and physical-layer approach for the downlink of a dynamic OFDM-FDMA transmission system delivering MPEG-4 video streams. The approach consists of three different mechanisms — queue management, resource allocation, and subcarrier assignment — which can be used separately as well as in combination.(More)
Within the last decade the OFDM transmission scheme has become part of several standards for wireless systems. Today, OFDM is even a candidate for 4G wireless systems. It is well known that dynamic OFDMA systems potentially increase the spectral efficiency. They exploit diversity effects in time, space, and frequency by assigning system resources(More)
—Soft frequency reuse is a strong tool for co-channel interference mitigation in cellular OFDMA/LTE networks. The performance of such networks significantly depends on the configuration of the power masks that implement the soft frequency reuse patterns. In this paper, we investigate the performance of different power mask configurations against the optimal(More)
Wireless multi carrier approaches can support the simultaneous transmissions to several wireless terminals , each one getting only some of the available sub-carriers. Judiciously assigning subcarriers to terminals can be used to, e.g., increase the capacity of a wireless cell; however, the resulting assignment problem is difficult. The first subproblem is(More)
In wireless local area networks often a station can potentially associate with more than one access point. Therefore, a relevant question is which access point to select " best " from a list of candidate ones. In IEEE 802.11, the user simply associates to the access point with the strongest received signal strength. However, this may result in a significant(More)
Efficiently scheduling and synchronizing parallel event execution constitutes the fundamental challenge in parallel discrete event simulation. Existing synchronization algorithms typically do not analyze event interactions within the simulation model – mainly to minimize runtime overhead and complexity. However, we argue that disregarding event interactions(More)