I. Azcarate

Type testing of a highly accurate illuminance flickermeter

The standard IEC 61000-4-15 establishes the design specifications to measure the annoyance produced by flicker. This instrument is based on the working principles and the response to input voltage variations of an incandescent lamp, which was taken as the reference lamp for the design. However, nowadays new lighting technologies are being adopted worldwide and the incandescent lamp has fallen into disuse. With the purpose of characterizing the sensitivity to voltage fluctuations of new modern lamps an adapted flickermeter has been designed. This tool uses as input the illuminance signals registered from the different lighting technologies. This paper describes the implementation of an illuminance flickermeter as well as its functional verification according to the type tests described in the new edition of the IEC 61000-4-15 standard.

Sensitivity to flicker of dimmable and non-dimmable lamps

In the last years, modern lighting technologies are being adopted worldwide. However, in terms of flicker, the incandescent lamp was the one used as the reference lamp in the design of the standards. Due to their different working principles, the new lamps may have quite a different response to input voltage variations than the response of the incandescent lamp. This paper describes the results of the study of the sensitivity of some modern lamps by means of objective tests.

Case study: Flicker emission and 3P power oscillations on fixed-speed wind turbines

This paper studies the influence that the power oscillations due to the tower shadow effect and the wind shear have on the flicker emission of fixed-speed wind turbines. For three-bladed wind turbines, the frequency of this characteristic fluctuation of power is 3 times the blade rotational frequency, and it is known as 3P oscillation. This work aims to analyse real measurement data from an experimental wind farm in Northern Spain in order to extract time-frequency features related to the 3P oscillation. In the same way, the algorithm that measures the generated flicker during continuous operation of wind turbines is applied to the recorded data. Using the instantaneous flicker sensation and the short-time flicker severity, the correlation between the 3P oscillation and the flicker characteristic of a wind turbine is presented. The results demonstrate that monitoring 3P power oscillation allows obtaining an estimation of the flicker emission on wind turbines.

Monitoring chest compression quality during cardiopulmonary resuscitation: Proof-of-concept of a single accelerometer-based feedback algorithm

Background The use of real-time feedback systems to guide rescuers during cardiopulmonary resuscitation (CPR) significantly contributes to improve adherence to published resuscitation guidelines. Recently, we designed a novel method for computing depth and rate of chest compressions relying solely on the spectral analysis of chest acceleration. That method was extensively tested in a simulated manikin scenario. The purpose of this study is to report the results of this method as tested in human out-of-hospital cardiac arrest (OHCA) cases. Materials and methods The algorithm was evaluated retrospectively with seventy five OHCA episodes recorded by monitor-defibrillators equipped with a CPR feedback device. The acceleration signal and the compression signal computed by the CPR feedback device were stored in each episode. The algorithm was continuously applied to the acceleration signals. The depth and rate values estimated every 2-s from the acceleration data were compared to the reference values obtained from the compression signal. The performance of the algorithm was assesed in terms of the sensitivity and positive predictive value (PPV) for detecting compressions and in terms of its accuracy through the analysis of measurement error. Results The algorithm reported a global sensitivity and PPV of 99.98% and 99.79%, respectively. The median (P75) unsigned error in depth and rate was 0.9 (1.7) mm and 1.0 (1.7) cpm, respectively. In 95% of the analyzed 2-s windows the error was below 3.5 mm and 3.1 cpm, respectively. Conclusions The CPR feedback algorithm proved to be reliable and accurate when tested retrospectively with human OHCA episodes. A new CPR feedback device based on this algorithm could be helpful in the resuscitation field.