The growing diffusion of distributed generation and its impact on voltage profiles increases the need for regulating voltage also in low-voltage (LV) networks, particularly at active user's premise. ...The quality of voltages should be ensured by devices that are fast-acting, economical, compact and easy to be installed, without a negative impact on the reliability of the network and its users. With this aim, a new simple, cheap and compact device for supporting voltage control at LV active users' premises has recently been proposed; it is based on a transformer that is able to change its winding configuration by static switches. In this paper, the design of the static-commutated device is described and analyzed; various laboratory tests for validating the control structure are presented. The results show the effectiveness of the control strategy to ensure an adequate voltage quality at LV active users' premises.
Two procedures are suggested to select a representative subset from a large data set. The first is based on the use of the estimate of the multivariate probability density distribution by means of ...the potential functions technique. The first object selected for the subset is that for which the probability density is larger. Then, the distribution is corrected, by subtraction of the contribution of the selected object multiplied by a selection factor. The second procedure uses genetic algorithms to individuate the subset that reproduces the variance–covariance matrix with the minimum error. Both methods meet the requirement to obtain a representative subset, but the results obtained with the method based on potential functions are generally more satisfactory in the case when the original set is not a random sample from an infinite population, but is the finite population itself. Several examples show how the extraction of a representative subset from a large data set can give some advantages in the use of representation techniques (i.e., eigenvector projection, non-linear maps, Kohonen maps) and in class modelling techniques.
The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) flew on May 13\(^{\text{th}}\) and 14\(^{\text{th}}\) of 2023. Consisting of two novel optical telescopes, the payload ...utilized next-generation instrumentation for the observations of extensive air showers from near space. One instrument, the fluorescence telescope (FT) searched for Ultra-High Energy Cosmic Rays (UHECRs) by recording the atmosphere below the balloon in the near-UV with a 1~\(\mu\)s time resolution using 108 multi-anode photomultiplier tubes with a total of 6,912 channels. Validated by pre-flight measurements during a field campaign, the energy threshold was estimated around 2~EeV with an expected event rate of approximately 1 event per 10 hours of observation. Based on the limited time afloat, the expected number of UHECR observations throughout the flight is between 0 and 2. Consistent with this expectation, no UHECR candidate events have been found. The majority of events appear to be detector artifacts that were not rejected properly due to a shortened commissioning phase. Despite the earlier-than-expected termination of the flight, data were recorded which provide insights into the detectors stability in the near-space environment as well as the diffuse ultraviolet emissivity of the atmosphere, both of which are impactful to future experiments.
We compare two different formalisms for modeling the energy deposition of macroscopically sized/massive quark nuggets (a.k.a. macros) in the Earth's atmosphere. We show that for a reference mass of 1 ...g, there is a discrepancy in the macro luminosity of about 14 orders of magnitude between the predictions of the two formalisms. Armed with our finding we estimate the sensitivity for macro detection at space-based (Mini-EUSO and POEMMA) and suborbital (EUSO-SPB2) experiments.
A computer assisted toolholder, integrated with an anatomical graphic 3-D rendering programme, is presented. Stereotactic neuroanatomical images are acquired, and the same reference system is ...employed to represent the position of the toolholder on the monitor. The surgeon can check the orientation of different approach trajectories, moving the toolholder in a situation of virtual reality. Angular values expressed by high precision encoders on the five joints of the toolholder modify "on line" the representation of the configuration of the toolholder within the three dimensional representation of the patient's anatomy.
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