Search results for "reliability"
showing 10 items of 1563 documents
Terahertz electrical writing speed in an antiferromagnetic memory
2018
The speed of writing of state-of-the-art ferromagnetic memories is physically limited by an intrinsic gigahertz threshold. Recently, realization of memory devices based on antiferromagnets, in which spin directions periodically alternate from one atomic lattice site to the next has moved research in an alternative direction. We experimentally demonstrate at room temperature that the speed of reversible electrical writing in a memory device can be scaled up to terahertz using an antiferromagnet. A current-induced spin-torque mechanism is responsible for the switching in our memory devices throughout the 12-order-of-magnitude range of writing speeds from hertz to terahertz. Our work opens the…
Statistical analysis of RaptorQ failure probability applied to a data recovery software
2014
In this work, we have implemented a data recovery software integrating the most recent rateless codes, i.e., RaptorQ codes. Thanks to the above-mentioned software, it is possible to recover data loss occurring on several kinds of network conditions. We have performed a statistical analysis of failure probabilities at several configurations of RaptorQ parameters. We have found a good agreement with the theoretical values of a random linear fountain code over Galois Field GF(256). Moreover, we have shown that the probability of having a certain number of failed decoded source blocks - when sending a fixed size file - follows a Poisson distribution.
The SCIA Questionnaire: standards for communities for children and adolescents – a tool for the evaluation of good practices
2019
Purpose The purpose of this paper is to present the Italian validation of the standards for communities for children and adolescents (SCIA) Questionnaire, an evaluation tool of communities quality standards, based on the “Service Standards for Therapeutic Communities for Children and Young People – 2nd edition” of the Community of Communities (2009), that enables an empirical, multidimensional and complex evaluation of the therapeutic community (TC) “system”. It is a self-report that sets out and measures variables that allow to get an overview of organisational models and the possible development areas to improve the effectiveness of the protection of child and adolescents in community tr…
Estimating the occurrence of traffic accidents near school locations: A case study from Valencia (Spain) including several approaches
2019
Traffic safety around school locations is a topic of particular interest given the large number of vulnerable users, such as pedestrians or cyclists, that commute to them at certain times of the day. A dataset of traffic accidents recorded in Valencia (Spain) during 2014 and 2015 is analyzed in order to estimate the effects that school locations produce on traffic risk within their surroundings. The four typologies of school in this city according to the academic levels they offer (All-level, Preschool, Primary, Secondary) are distinguished and taken into consideration for the analysis. Two time windows comprising the starting time in the morning and the evening time once day school has end…
Mixed Harmonic Elimination Control for a Single-Phase 9 Level Grid-Connected Inverter
2018
The power quality requirements are increasingly stringent, due to the continuous growth of devices connected to the grid that introduce harmonics. These devices include DC to AC energy conversion systems, i.e. grid connected inverters. The design, control and operation of these systems must take into account the rules of interconnection to the electricity grid. To improve the quality of the output waveform of the grid-connected inverter, Multilevel Converters (MC) with selective harmonic elimination modulation technique can be used. This paper presents a single-phase nine level grid-connected inverter with DC/DC input stages. The obtained switching angles for THD minimization are independen…
The International Measurement Evaluation Programme (IMEP) IMEP-6: "Trace elements in water"
1998
The sixth round of the International Measurement Evaluation Programme (IMEP) is presented. The programme offers reference values, established by primary methods of measurement, against which participating laboratories can evaluate their performance. The degree of comparability is thus established against the most objective references available at present. In IMEP-6, reference values for total concentrations of 14 trace elements in a synthetic and a natural water were established mainly by isotope dilution mass spectrometry (IDMS). For the majority of the measurands, results traceable to the international system of units (SI) and having expanded uncertainties, U (k=2), of 2% could be establi…
The Technologies of Architectural Survey: A New Comparison Based on the Tower of Sotillo de la Ribera, Burgos
2017
The paper offers an original research about the analysis and the comparison of different techniques of survey concerning the architectural field – image-based and range-based – throughout the development of the theory of errors in order to evaluate reliability and precision of the results. In particular, this analysis will be focused on the tower of the parochial Church of Santa Águeda, a building located in the small village of Sotillo de la Ribera, within the province of Burgos (Spain). The first part of this work, therefore, has been submitted to the implementation of different methodologies, from the direct survey used as a basis, to the procedure to represent graphically the results (e…
Testing experimental designs in liquid chromatography (II): Influence of the design geometry on the prediction performance of retention models.
2021
Abstract In liquid chromatography, the reliability of predictions carried out with retention models depends critically on the quality of the training experimental design. The search of the best design is more complex when gradient runs are used instead of isocratic experiments. In Part I of this work (JCA 1624 (2020) 461180), a general methodology based on the error propagation theory was developed and validated for assessing the quality of training designs involving gradients. The treatment relates the mathematical properties of a retention model with the geometry of the training designs and their subsequent predictions. In that work, only five usual designs were considered. Part II invest…
A Compact SPICE Model for Organic TFTs and Applications to Logic Circuit Design
2016
This work introduces a compact DC model developed for organic thin film transistors (OTFTs) and its SPICE implementation. The model relies on a modified version of the gradual channel approximation that takes into account the contact effects, occurring at nonohmic metal/organic semiconductor junctions, modeling them as reverse biased Schottky diodes. The model also comprises channel length modulation and scalability of drain current with respect to channel length. To show the suitability of the model, we used it to design an inverter and a ring oscillator circuit. Furthermore, an experimental validation of the OTFTs has been done at the level of the single device as well as with a discrete-…
Reliability of Data Transmission of UAVs
2018
Drones have been recently an interesting subject of research due to their roles in accomplishing missions. Flying in a formation fleet, they form a cooperative communication system in order to improve the efficiency of the mission. For this reason, the reliability of the communication is essential to guarantee the overall performance of the fleet although the link conditions, the external factors and the hardware failures of a drone. The drones capture several images or videos of the geographical area of the mission and send them to other drones in the fleet or to the Ground Station Control (GSC). The importance is to ensure that all the data transmitted is received. In this article, we aim…