Evaluating indoor positioning systems in a shopping mall : the lessons learned from the IPIN 2018 competition

The Indoor Positioning and Indoor Navigation (IPIN) conference holds an annual competition in which indoor localization systems from different research groups worldwide are evaluated empirically. The objective of this competition is to establish a systematic evaluation methodology with rigorous metrics both for real-time (on-site) and post-processing (off-site) situations, in a realistic environment unfamiliar to the prototype developers. For the IPIN 2018 conference, this competition was held on September 22nd, 2018, in Atlantis, a large shopping mall in Nantes (France). Four competition tracks (two on-site and two off-site) were designed. They consisted of several 1 km routes traversing several floors of the mall. Along these paths, 180 points were topographically surveyed with a 10 cm accuracy, to serve as ground truth landmarks, combining theodolite measurements, differential global navigation satellite system (GNSS) and 3D scanner systems. 34 teams effectively competed. The accuracy score corresponds to the third quartile (75th percentile) of an error metric that combines the horizontal positioning error and the floor detection. The best results for the on-site tracks showed an accuracy score of 11.70 m (Track 1) and 5.50 m (Track 2), while the best results for the off-site tracks showed an accuracy score of 0.90 m (Track 3) and 1.30 m (Track 4). These results showed that it is possible to obtain high accuracy indoor positioning solutions in large, realistic environments using wearable light-weight sensors without deploying any beacon. This paper describes the organization work of the tracks, analyzes the methodology used to quantify the results, reviews the lessons learned from the competition and discusses its future

Synthesis of Cyclic N-Acyl Amidines by [3 + 2] Cycloaddition of N-Silyl Enamines and Activated Acyl Azides

In this study, we describe the synthesis of cyclic N-acyl amidines from readily available N-heteroarenes. The synthetic methodology utilized the versatile N-silyl enamine intermediates from the hydrosilylation of N-heteroarenes for the [3 + 2] cycloaddition reaction step. We evaluated various acyl azides and selected an electronically activated acyl azide, thereby achieving a reasonable yield of cyclic N-acyl amidines. We analyzed the relationship between the reactivity of each step and the electronic nature of substrates using in situ nuclear magnetic resonance spectroscopy. In addition, we demonstrated gram-scale synthesis using the proposed methodology

Micro/nano‐wrinkled elastomeric electrodes enabling high energy storage performance and various form factors

Abstract Stretchable elastomer‐based electrodes are considered promising energy storage electrodes for next‐generation wearable/flexible electronics requiring various shape designs. However, these elastomeric electrodes suffer from the limited electrical conductivity of current collectors, low charge storage capacities, poor interfacial interactions between elastomers and conductive/active materials, and lack of shape controllability. In this study, we report hierarchically micro/nano‐wrinkle‐structured elastomeric electrodes with notably high energy storage performance and good mechanical/electrochemical stabilities, simultaneously allowing various form factors. For this study, a swelling/deswelling‐involved metal nanoparticle (NP) assembly is first performed on thiol‐functionalized polydimethylsiloxane (PDMS) elastomers, generating a micro‐wrinkled structure and a conductive seed layer for subsequent electrodeposition. After the assembly of metal NPs, the conformal electrodeposition of Ni and NiCo layered double hydroxides layers with a homogeneous nanostructure on the micro‐wrinkled PDMS induces the formation of a micro/nano‐wrinkled surface morphology with a large active surface area and high electrical conductivity. Based on this unique approach, the formed elastomeric electrodes show higher areal capacity and superior rate capability than conventional elastomeric electrodes while maintaining their electrical/electrochemical properties under external mechanical deformation. This notable mechanical/electrochemical performance can be further enhanced by using spiral‐structured PDMS (stretchability of ~500%) and porous‐structured PDMS (areal capacity of ~280 μAh cm−2)

Determination of twisting angle of electrospun nanofiber bundle for continuous electrospinning system

Electrospinning continuously produced twisted nanofibers with a convergence coil and a rotating ring collector. The positively charged nozzle was used in the electrospinning process to deposit electrospun fibers of polyacrylonitrile onto a rotating ring collector. By withdrawing the electrospun fibers from the rotating ring collector, it was possible to spin the electrospun fibers yarn. In this study, theoretical approaches and numerical simulations were used to determine the twisting angle of the yarn. Using the equations developed in this study, we performed numerical simulations and compared the experimental results with the numerical simulation results. Mechanical properties of the fiber bundle were analyzed for twisting angle. It was confirmed the relationship among the winding drum, the ring collector, and flux of the fibers mass per time during electrospinning in the developed system. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 4552