Algorithm for Dynamic Fingerprinting Radio Map Creation Using IMU Measurements

While a vast number of location-based services appeared lately, indoor positioning solutions are developed to provide reliable position information in environments where traditionally used satellite-based positioning systems cannot provide access to accurate position estimates. Indoor positioning systems can be based on many technologies; however, radio networks and more precisely Wi-Fi networks seem to attract the attention of a majority of the research teams. The most widely used localization approach used in Wi-Fi-based systems is based on fingerprinting framework. Fingerprinting algorithms, however, require a radio map for position estimation. This paper will describe a solution for dynamic radio map creation, which is aimed to reduce the time required to build a radio map. The proposed solution is using measurements from IMUs (Inertial Measurement Units), which are processed with a particle filter dead reckoning algorithm. Reference points (RPs) generated by the implemented dead reckoning algorithm are then processed by the proposed reference point merging algorithm, in order to optimize the radio map size and merge similar RPs. The proposed solution was tested in a real-world environment and evaluated by the implementation of deterministic fingerprinting positioning algorithms, and the achieved results were compared with results achieved with a static radio map. The achieved results presented in the paper show that positioning algorithms achieved similar accuracy even with a dynamic map with a low density of reference points

Dielectric Properties and Breakdown of the Gate Oxide in the MOS Structure

The article treats the methodology of measuring the breakdown voltage on Si-based MOS structures. Identification of defects in the thin gate oxide is performed using the Weibull statistical analysis. By comparing the current and capacitance measurements on MOS structures we determined the influence of the defect charge in the oxide upon the parameters characterizing the breakdown. A higher occurrence of defects was correlated with elevated values of the flat band voltages. This verifies the hypothesis of an increased destruction of MOS structures caused by electrically active defects arising in the course of thermic oxidation and pre-oxidation treatment of the surface of silicon