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See detailDuplicate Suppression for Efficient Floating Car Data Collection in Heterogeneous LTE-DSRC Vehicular Networks
Turcanu, Ion UL; Klingler, Florian; Sommer, Christoph et al

in Computer Communications (2018), 123

Collecting data from a large number of agents scattered over a region of interest is becoming an increasingly appealing paradigm to feed big data archives that lay the ground for a vast array of ... [more ▼]

Collecting data from a large number of agents scattered over a region of interest is becoming an increasingly appealing paradigm to feed big data archives that lay the ground for a vast array of applications. Vehicular Floating Car Data (FCD) collection is a major representative of this paradigm. Massive data collection from floating vehicles is the key to Intelligent Transportation Systems. We address the design and performance evaluation of a data collection protocol for the use case of periodic data collection. We target robustness, optimizing the amount of data and the value of the collection period, keeping in mind the goals of autonomous node operation and minimal coordination effort. From a system point of view, we believe that best solutions should jointly exploit the Long Term Evolution (LTE) cellular access network and the Dedicated Short-Range Communication (DSRC) based Vehicular Ad Hoc Network (VANET). Through a detailed comparative analysis, we show that such a hybrid approach offers superior performance, especially as for offloading the cellular radio access. A lightweight signaling procedure is designed, based on the DSRC VANET, which is able to avoid most of the duplicated data records, even if a distributed operation approach is pursued. The impact of the proposed protocol on the VANET load is evaluated and proved to be quite small, so that it does not interfere with other VANET-specific messages. [less ▲]

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See detailPick the Right Guy: CQI-Based LTE Forwarder Selection in VANETs
Turcanu, Ion UL; Sommer, Christoph; Baiocchi, Andrea et al

in 8th IEEE Vehicular Networking Conference (VNC 2016) (2016, December)

Periodical collection of data from vehicles inside a target area is of interest for many applications in the context of Intelligent Transportation Systems (ITS). Long Term Evolution (LTE) has been ... [more ▼]

Periodical collection of data from vehicles inside a target area is of interest for many applications in the context of Intelligent Transportation Systems (ITS). Long Term Evolution (LTE) has been identified as a good candidate technology for supporting such type of applications - particularly for the non-safety domain. However, a high number of vehicles intermittently reporting their information via LTE can introduce a very high load on the LTE access network. In this context, the use of heterogeneous networking technologies can yield significant offloading of LTE - here, WLAN and Dedicated Short-Range Communication (DSRC) technology can support local data aggregation. In this paper, we propose an on-the-fly distributed clustering algorithm that uses both LTE and DSRC networks in the forwarder selection process. Our results clearly indicate that it is crucial to consider parameters drawn from both networking platforms for selecting the right forwarders. In particular, we show for the first time that relying on the Channel Quality Indicator (CQI) has a substantial impact. We demonstrate that our solution is able to significantly reduce the LTE channel utilization with respect to other state of the art approaches. [less ▲]

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See detailFrom experimental setup to bioinformatics: An RNAi screening platform to identify host factors involved in HIV-1 replication
Boerner, Kathleen; Hermle, Johannes; Sommer, Christoph et al

in Biotechnology Journal (2010), 5(1), 39-49

RNA interference (RNAi) has emerged as a powerful technique for studying loss-of-function phenotypes by specific down-regulation of gene expression, allowing the investigation of virus-host interactions ... [more ▼]

RNA interference (RNAi) has emerged as a powerful technique for studying loss-of-function phenotypes by specific down-regulation of gene expression, allowing the investigation of virus-host interactions by large-scale high-throughput RNAi screens. Here we present a robust and sensitive small interfering RNA screening platform consisting of an experimental setup, single-cell image and statistical analysis as well as bioinformatics. The workflow has been established to elucidate host gene functions exploited by viruses, monitoring both suppression and enhancement of viral replication simultaneously by fluorescence microscopy. The platform comprises a two-stage procedure in which potential host factors are first identified in a primary screen and afterwards re-tested in a validation screen to confirm true positive hits. Subsequent bioinformatics allows the identification of cellular genes participating in metabolic pathways and cellular networks utilised by viruses for efficient infection. Our workflow has been used to investigate host factor usage by the human immunodeficiency virus-1 (HIV-1), but can also be adapted to other viruses. Importantly, we expect that the description of the platform will guide further screening approaches for virus-host interactions. The ViroQuant-Cell Networks RNAi Screening core facility is an integral part of the recently founded BioQuant centre for systems biology at the University of Heidelberg and will provide service to external users in the near future. [less ▲]

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