The Triangle Metric: Fast Link Quality Estimation for Mobile Wireless Sensor Networks (Invited Paper)

ReSensesuppleCONE

Controllable radio interference for experimental and testing purposes in wireless sensor networks

Abstract—We address the problem of generating customized, controlled interference for experimental and testing purposes in Wireless Sensor Networks. The known coexistence problems between electronic devices sharing the same ISM radio band drive the design of new solutions to minimize interference. The validation of these techniques and the assessment of protocols under external interference require the creation of reproducible and well-controlled interference patterns on real nodes, a nontrivial and time-consuming task. In this paper, we study methods to generate a precisely adjustable level of interference on a specific channel, with lowcost equipment and rapid calibration. We focus our work on the platforms carrying the CC2420 radio chip and we show that, by setting such transceiver in special mode, we can quickly and easily generate repeatable and precise patterns of interference. We show how this tool can be extremely useful for researchers to quickly investigate the behaviour of sensor network protocols and applications under different patterns of interference, and we further evaluate its performance

Demo Abstract: Generation of Controllable Radio Interference for Protocol Testing in Wireless Sensor Networks

GINSENGCONETReSens

Anwendung des mikrobiellen Wundversiegelers InteguSeal® in der Herzchirurgie - Klinisch prospektive Vergleichsstudie bei isolierter Bypasschirurgie

Anwendung des mikrobiellen Wundversiegelers InteguSeal® in der Herzchirurgie- Klinisch prospektive Vergleichsstudie bei isolierter Bypasschirurgie – 2016 – 68 Bl.: 37 Abb., 4 Tab. An der Herzchirurgischen Klinik der Sana Herzchirurgie Stuttgart GmbH wurden im Jahr 2009 397 Patienten mit einem aortocoronaren Bypass versorgt. Davon wurden 89 Patienten mit dem mikrobiellen Wundversiegeler InteguSeal® behandelt, während die anderen 308 Patienten mit der Anwendung einer herkömmlichen Inzisionsfolie operiert wurden. Ziel dieses mikrobiellen Wundversiegelers soll die Minimierung des Auftretens von postoperativen Wundinfektionen sein. Die hier vorliegende Arbeit vergleicht die Ergebnisse der Anwendung des mikrobiellen Wundversiegelers InteguSeal® mit denen der Anwendung einer herkömmlichen Inzisionsfolie. Dazu wurden prospektiv randomisiert 89 bzw. 308 Patienten jeweils den verschiedenen Patientengruppen zugeordnet. Die entsprechenden präoperativen, intraoperativen und postoperativen Daten wurden hierzu verglichen. Die Untersuchung der präoperativen Risikofaktoren ergab einen signifikanten Unterschied in beiden Gruppen beim Auftreten eines Diabetes mellitus, welcher sich auch in dieser Studie als Hauptrisikofaktor für das Auftreten von postoperativen Wundinfektionen herausstellte. Aus diesem Grund wurde im Anschluss ein Matchvergleich durchgeführt, um zwei gleich große Patientengruppen mit ähnlichem Risikoprofil für postoperative Wundinfektion zu erhalten. Der Einfluss von Diabetes mellitus als Risikofaktor für postoperative Wundinfektionen wurde damit in der Matchgruppe ausgeschlossen. Im Matchvergleich zeigte sich keine signifikante Reduktion in Bezug auf das Auftreten von postoperativen Wundinfektionen durch die Anwendung des mikrobiellen Wundversiegelers InteguSeal®. Bei aufgetretenen Wundinfektionen zeigte sich kein signifikanter Unterschied in der Behandlung bzw. der chirurgischen Revisionsrate in beiden Gruppen. Aufgrund meiner erhobenen Daten ist eine Wirksamkeit von InteguSeal® daher zu verneinen. Es kann aber nur bedingt eine Aussage getroffen werden aufgrund der eher geringen Anzahl von 178 Patienten im Matchvergleich. Daher sind weitere Studien zu dieser Fragestellung nötig

Using a Drone Formation with Sectored Antennas in Search-And-Rescue: Heuristics for Orienting Drones and Moving the Formation

Recently there has been interest in using drones/unmanned aerial vehicles in search-and-rescue applications. Here we apply a formation of drones equipped with sectorised antennae to navigate to a transmitter using Direction of Arrival (DoA) estimation to navigate. We present results indicating that the error of the DoA estimate is dependent on the DoA and evaluate a mitigation technique, finding that incrementally changing the drone orientation across the formation reduces the DoA estimation error. Further, we investigate a “dumbbell” formation in which the two “weights” generate independent DoA estimates, the difference between which are used to broadly classify the distance to the transmitter. We found that the choice of distance thresholds and relative direction of the transmitter substantially changes the performance of this distance heuristic

Constraints on mantle evolution from Ce-Nd-Hf isotope systematics

Mantle evolution is governed by continuous depletion by partial melting and replenishment by recycling oceanic and continental crust. Several important unknowns remain, however, such as the extent of compositional variability of the residual depleted mantle, the timescale, mass flux and composition of recycled oceanic and continental crust. Here, we investigate the Ce-Nd-Hf isotope systematics in a globally representative spectrum of mid ocean ridge and ocean island basalts. Using a Monte Carlo approach for reproducing the observed Ce-Nd-Hf isotope variation shows that the type and age of depleted mantle and recycled crust have the dominant influence on the slope, scatter, and extent of the modeled Ce-Nd-Hf isotope array. The model results suggest a relatively young (Peer reviewe

An Information-Motivated Exploration Agent to Locate Stationary Persons with Wireless Transmitters in Unknown Environments

Unmanned Aerial Vehicles (UAVs) show promise in a variety of applications and recently were explored in the area of Search and Rescue (SAR) for finding victims. In this paper we consider the problem of finding multiple unknown stationary transmitters in a discrete simulated unknown environment, where the goal is to locate all transmitters in as short a time as possible. Existing solutions in the UAV search space typically search for a single target, assume a simple environment, assume target properties are known or have other unrealistic assumptions. We simulate large, complex environments with limited a priori information about the environment and transmitter properties. We propose a Bayesian search algorithm, Information Exploration Behaviour (IEB), that maximizes predicted information gain at each search step, incorporating information from multiple sensors whilst making minimal assumptions about the scenario. This search method is inspired by the information theory concept of empowerment. Our algorithm shows significant speed-up compared to baseline algorithms, being orders of magnitude faster than a random agent and 10 times faster than a lawnmower strategy, even in complex scenarios. The IEB agent is able to make use of received transmitter signals from unknown sources and incorporate both an exploration and search strategy

Demersal Fish Assemblages and Spatial Diversity Patterns in the Arctic-Atlantic Transition Zone in the Barents Sea

Direct and indirect effects of global warming are expected to be pronounced and fast in the Arctic, impacting terrestrial, freshwater and marine ecosystems. The Barents Sea is a high latitude shelf Sea and a boundary area between arctic and boreal faunas. These faunas are likely to respond differently to changes in climate. In addition, the Barents Sea is highly impacted by fisheries and other human activities. This strong human presence places great demands on scientific investigation and advisory capacity. In order to identify basic community structures against which future climate related or other human induced changes could be evaluated, we analyzed species composition and diversity of demersal fish in the Barents Sea. We found six main assemblages that were separated along depth and temperature gradients. There are indications that climate driven changes have already taken place, since boreal species were found in large parts of the Barents Sea shelf, including also the northern Arctic area. When modelling diversity as a function of depth and temperature, we found that two of the assemblages in the eastern Barents Sea showed lower diversity than expected from their depth and temperature. This is probably caused by low habitat complexity and the distance to the pool of boreal species in the western Barents Sea. In contrast coastal assemblages in south western Barents Sea and along Novaya Zemlya archipelago in the Eastern Barents Sea can be described as diversity “hotspots”; the South-western area had high density of species, abundance and biomass, and here some species have their northern distribution limit, whereas the Novaya Zemlya area has unique fauna of Arctic, coastal demersal fish. (see Information S1 for abstract in Russian)