Assessing the impact of multi-channel BLE beacons on fingerprint-based positioning

Bluetooth Low Energy (BLE) beacons are attractive for indoor location due to their ease of deployment, wide support on consumer devices and low cost. Co-ordinate location can be estimated using radio fingerprinting techniques applied to Received Signal Strength (RSS) values from BLE beacons. Earlier work on BLE fingerprinting has noted that the separate BLE advertising channels can exhibit different RSS values, although modern consumer devices do not provide channel information and therefore report a composite RSS with artificially inflated variance that can lead to reduced positioning accuracy. In this work we quantify how often this channel dispersion occurs in typical environments, what the extent of the dispersion is, and what impact it has on positioning. Furthermore we explore how to obtain channel information when using today's consumer devices. We find that the dispersion is both common and significant and leads to significantly reduced positioning accuracy; in our experiments only 10% of composite variances were within 1 dBm of an individual channel's variance, and 40% of composite variances were at least 4 dBm greater. We also show that the behaviour of the channels is sufficiently distinct that a fingerprinting scheme that uses a signal map for each achieves significantly increased positioning accuracy (up to 3 m)

Proposal for creating a centre for research in solar-terrestrial physics as an interdepartmental activity during IHY at Shivaji University, Kolhapur (16.40°N, 74.15°E)

This note describes teaching and R & D activities presently being carried out in the solar-terrestrial Physics at the Space Science laboratory, Department of Physics, Shivaji University, Kolhapur. A variety of solar and geophysical ground based experiments are available, which can be operated on a regular basis during IHY, with financial help from the government funding agencies in India. The main purpose of this note is to briefly describe our experimental research facilities of relevance to IHY

Photoelectrochemical properties of mesoporous NiOx deposited on technical FTO via nanopowder sintering in conventional and plasma atmospheres

Nanoporous nickel oxide (NiO x ) has been deposited with two different procedures of sintering (CS and RDS). Both samples display solid state oxidation at about 3.1 V vs Li+/Li. Upon sensitization of CS/RDS NiO x with erythrosine b (ERY), nickel oxide oxidation occurs at the same potential. Impedance spectroscopy revealed a higher charge transfer resistance for ERY-sensitized RDS NiO x with respect to sensitized CS NiO x . This was due to the chemisorption of a larger amount of ERY on RDS with respect to CS NiO x . Upon illumination the photoinduced charge transfer between ERY layer and NiO x could be observed only with oxidized CS. Photoelectrochemical effects of sensitized RDS NiO x were evidenced upon oxide reduction. With the addition of iodine RDS NiOx electrodes could give the reduction iodine → iodide in addition to the reduction of RDS NiO x . p-type dye sensitized solar cells were assembled with RDS NiO x photocathodes sensitized either by ERY or Fast Green. Resulting overall efficiencies ranged between 0.02 and 0.04 % upon irradiation with solar spectrum simulator (Iin : 0.1 W cm −2 )

Increasing p-type dye sensitised solar cell photovoltages using polyoxometalates

Lindqvist polyoxometalate (POM) additives increase VOC in p-type DSSCs by up to 140%, yielding substantial efficiency gains for poorly matched dyes and redox mediators. For better dye/electrolyte combinations, these gains are typically outweighed by losses in JSC. Charge lifetime and transient IR measurements show that this is due to retardation of both recombination and electron transfer to the mediator, and a positive shift in the NiO valence band edge. The POMs also show their own, limited sensitizing effect

Buckling and free vibrations behaviour through differential quadrature method for foamed composites

The current work focuses on predicting the buckling and free vibration frequencies (fn) of cenosphere reinforced epoxy based syntactic foam beam under varying loads. Critical buckling loads (Ncr) and fn are predicted using the differential quadrature method (DQM). Ncr and fn have been calculated for beams of varying cenosphere volume fractions subjected to axial load under clamped-clamped (CC), clamped-simply (CS), simply-simply (SS), and clamped-free (CF) boundary conditions (BC′s). Upon increasing the cenosphere volume fraction, Ncr and fn of syntactic foam composites increases. These numerical outcomes are compared with the theoretical values evaluated through the Euler-Bernoulli hypothesis and further compared with experimental outcomes. Results are observed to be in precise agreement. The results of the DQM numerical analysis are given out for the different BC′s, aspect ratios, cenosphere volume fractions, and varying loads. It is perceived that depending on the BC′s, the type of axial varying loads and aspect ratios has a substantial effect on the Ncr and fn behaviour of the syntactic foam beams. A comparative study of the obtained results showed that the beam subjected to parabolic load under CC boundary conditions exhibited a higher buckling load. © 2023 The Author