Negotiating Reality

Our understanding of research through design is demonstrated by a close examination of the methods used in the project lifeClipper2. This design research project investigates the applicability of immersive outdoor Augmented Reality (AR). lifeClipper2 offers an audiovisual walking experience in a virtually extended public space and focuses on audiovisual perception as well as on the development of the appropriate technology. The project involves contributions of partners from different fields of research. Thus, lifeClipper2 is able to test the potential of AR for visualizing architecture and archaeological information and to challenge our understanding of perception and interaction. Using examples from our research, the paper reflects on how scenario design contributes to the production of design knowledge and explores the possibilities and variations of AR. Finally, the paper drafts our approach to design research. The three tenets of our work are: the use of scenarios as a tool of interdisciplinary research, the experimental exploration of media and the intention to make design knowledge explicit. Keywords: augmented reality; locative media; hybrid environment; immersion; perception; experience design; research through design; scenario design</p

Empirical processes for recurrent and transient random walks in random scenery

In this paper, we are interested in the asymptotic behaviour of the sequence of processes $(W_n(s,t))_{s,t\in[0,1]}$ with \begin{equation*} W_n(s,t):=\sum_{k=1}^{\lfloor nt\rfloor}\big(1_{\{\xi_{S_k}\leq s\}}-s\big) \end{equation*} where $(\xi_x, x\in\mathbb{Z}^d)$ is a sequence of independent random variables uniformly distributed on $[0,1]$ and $(S_n)_{n\in\mathbb N}$ is a random walk evolving in $\mathbb{Z}^d$, independent of the $\xi$'s. In Wendler (2016), the case where $(S_n)_{n\in\mathbb N}$ is a recurrent random walk in $\mathbb{Z}$ such that $(n^{-\frac 1\alpha}S_n)_{n\geq 1}$ converges in distribution to a stable distribution of index $\alpha$, with $\alpha\in(1,2]$, has been investigated. Here, we consider the cases where $(S_n)_{n\in\mathbb N}$ is either: a) a transient random walk in $\mathbb{Z}^d$, b) a recurrent random walk in $\mathbb{Z}^d$ such that $(n^{-\frac 1d}S_n)_{n\geq 1}$ converges in distribution to a stable distribution of index $d\in\{1,2\}$

KAStrion project: a new concept for the condition monitoring of wind turbines

International audienceKAStrion was a project entitled “Current and vibration analysis for preventive and predictive condition-based maintenance in wind farms”. It was fund by the KIC InnoEnergy from 2012 to 2014. The aim of this paper is to sum up and highlight the main results of the project. KAStrion goals were to maximize the production time of wind turbine farms by delivering a complete solution build upon a stand-alone analysis system which delivers a continuous on-site pre-diagnostic of the machine based on a multi-modal spectral monitoring technology. This embedded system located in the nacelle is connected to a tailored diagnostic center which delivers a periodic reporting on technical state of each machine of the farm. The strong innovation of KAStrion was to develop firstly a data-driven signal processing, referred to as AStrion, to automatically analyze, detect, classify all the spectral structures (harmonics and sidebands) of vibration signals, and secondly an original approach, referred to as SMESA, to process polyphase electrical signals. Contrary to existing systems, the coupling with the system kinematics is done after the analysis. KAStrion system has been tested on a specific test bench designed as a wind turbine at a smaller scale with load units on the main bearing, the planetary gear box and the output bearing in order to generate defects within an endurance test program. When compared with standard condition monitoring features, KAStrion shows its ability to characterize the start and the stage of the fault without the need of a historical data base. KAStrion system is also continuously tested on 2 two wind turbines in Arfons windfarm in Franc

An electrochemical and surface analytical study of the formation of nanoporous oxides on niobium

In the present paper, the anodization of Nb in mixed sulphate + fluoride electrolytes resulting in the formation of a nanoporous oxide film has been studied. Chronoamperometry and electrochemical impedance spectroscopy have been employed to characterise in situ the kinetics of the oxidation process. In addition, the evolution of the layer structure and morphology has been followed by ex situ scanning electron microscopy. Particularly, local electrochemical impedance spectroscopy has been used to discern between the mesoscopic 2D and 3D distributions of time constants at the electrode surface. The similarity between local and global impedance spectra during anodic oxidation of Nb demonstrates the presence of an inherent 3D distribution of the high-frequency time constant, which is interpreted as in-depth variation of the steady state conductivity of the passive film. The experimental and calculational results are discussed in relation to the micro- and nanoscopic structure of the formed oxide

Microlunatus parietis sp. nov., isolated from an indoor wall

A Gram-positive, coccoid, non-endospore-forming actinobacterium (strain 12-Be-011T) was isolated from indoor wall material. Based on 16S rRNA gene sequence comparisons, strain 12-Be-011T was clearly shown to belong to the genus Microlunatus and was most closely related to Microlunatus panaciterrae Gsoil 954T (95.7 %), Microlunatus soli CC-12602T (94.9 %), Microlunatus ginsengisoli Gsoil 633T (94.8 %), Microlunatus aurantiacus YIM 45721T (95.5 %) and Microlunatus phosphovorus DSM 10555T (94.7 %). The cell-wall peptidoglycan contained ll-diaminopimelic acid as the diagnostic diamino acid. Mycolic acids were absent. The major menaquinone was MK-9(H4). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unknown phospholipids and one unknown glycolipid. The major fatty acids of iso-C15:0, anteiso-C15:0 and iso-C16:0 supported the affiliation of strain 12-Be-011T to the genus Microlunatus. Physiological and biochemical test results allowed a clear phenotypic differentiation of strain 12-Be-011T from all other species of the genus Microlunatus. Hence, strain 12-Be-011T can be regarded as a representative of a novel species, for which the name Microlunatus parietis sp. nov. is proposed, with the type strain 12-Be-011T (=DSM 22083T=CCM 7636T)

Stochastic superspace phenomenology at the Large Hadron Collider

We analyse restrictions on the stochastic superspace parameter space arising from 1 fb$^{-1}$ of LHC data, and bounds on sparticle masses, cold dark matter relic density and the branching ratio of the process $B_s \rightarrow \mu^+ \mu^-$. A region of parameter space consistent with these limits is found where the stochasticity parameter, \xi, takes values in the range -2200 GeV < \xi < -900 GeV, provided the cutoff scale is $\mathcal{O}(10^{18})$ GeV.Comment: 9 pages, 13 figure

Computing earliest arrival flows with multiple sources

Earliest arrival flows are motivated by applications related to evacuation. Given a network with capacities and transit times on the arcs, a subset of source nodes with supplies and a sink node, the task is to send the given supplies from the sources to the sink "as quickly as possible". The latter requirement is made more precise by the earliest arrival property which requires that the total amount of flow that has arrived at the sink is maximal for all points in time simultaneously. It is a classical result from the 1970s that, for the special case of a single source node, earliest arrival flows do exist and can be computed by essentially applying the Successive Shortest Path Algorithm for min-cost flow computations. While it has previously been observed that an earliest arrival flow still exists for multiple sources, the problem of computing one efficiently has been open. We present an exact algorithm for this problem whose running time is strongly polynomial in the input plus output size of the problem

Extraction of Pertinent Subsets from Time-Frequency Representations for Detection and Recognition Purposes

International audienceA time-frequency representation can highlight non-stationarities in a signal. We propose to extract subsets from the Time-Frequency Representation (TFR) for classification or recognition purposes. We developed two approaches. The first one is developed for TFRs obtained from the Short Time Fourier Transform or the gliding Minimum Variance method. The extraction of compact subsets is viewed as a segmentation of the TFR, which is performed by morphological filtering and Watershed segmentation. The second approach is developed when the TFR has been obtained using parametric estimators. We consider a hybrid estimator, the ARCAP method, and use a Kalman filter trajectory tracker to extract spectral lines. The proposed methods are illustrated by examples on natural signals : dolphin whistle acoustical signals, cavitation signals and seismic signals produced by snow avalanches