Rewriting toward trace coverage analysis of symmetric systems

Innovations in Systems and Software Engineering - Verification coverage is an important metric in any hardware verification effort. Coverage models are proposed as a set of events the hardware may...     

Synthesis and Structure−Activity Relationships of Imidazopyridine/Pyrimidine- and Furopyridine-Based Anti-infective Agents against Trypanosomiases

Neglected tropical diseases remain among the most critical public health concerns in Africa and South America. The drug treatments for these diseases are limited, which invariably leads to fatal cases. Hence, there is an urgent need for new antitrypanosomal drugs. To address this issue, a large number of diverse heterocyclic compounds were prepared. Straightforward synthetic approaches tolerated pre-functionalized structures, giving rise to a structurally diverse set of analogs. We report on a set of 57 heterocyclic compounds with selective activity potential against kinetoplastid parasites. In general, 29 and 19 compounds of the total set could be defined as active against Trypanosoma cruzi and T. brucei brucei, respectively (antitrypanosomal activities <10 μM). The present work discusses the structure−activity relationships of new fused-ring scaffolds based on imidazopyridine/pyrimidine and furopyridine cores. This library of compounds shows significant potential for anti-trypanosomiases drug discovery.     

Landsat 8 OLI satellite data for mapping of the Posidonia oceanica and benthic habitats of coastal ecosystems

The benthic seabeds and seagrass ecosystems, in particular the vulnerable Posidonia oceanica (PO), are increasingly threatened by climate change and other anthropogenic pressures. Along the 8000 km coastline of Italy, they are often poorly mapped and monitored to properly evaluate their health status. Thus to support these monitoring needs, the improved capabilities of the Landsat 8 Operational Land Imager (OLI) Earth Observation (EO) satellite system were tested for PO mapping by coupling its atmospherically corrected multispectral data with near-synchronous sea truth information. Two different approaches for the necessary atmospheric correction were exploited focusing on the Aerosol Optical Depth (AOD) and adjacency noise effects, which typically occur at land–sea interfaces. The general achievements demonstrated the effectiveness of High Resolution (HR) spectral responses captured by OLI sensor, for monitoring seagrass and sea beds in the optically complex Tyrrhenian shallow waters, with performance level dependent on the type of applied atmospheric pre-processing. The distribution of the PO leaf area index (LAI) on different substrates has been most effectively modelled using on purpose developed spectral indices. They were based on the coastal and blue-green OLI bands, atmospherically corrected using a recently introduced method for AOD retrieval, based on the Short Wave Infrared (SWIR) reflectance. The alternative correction method including a less effective AOD assessment but the removal of adjacency effects has proven its efficacy for improving the thematic discriminability of the seabed types characterized by different PO cover–substrate combinations.     

Preliminary Mechanical Characterization of Thermal Filters for the X-IFU Instrument on Athena

The X-ray Integral Field Unit (X-IFU) is one of the two instruments of the Athena astrophysics space mission approved by ESA in the Cosmic Vision Science Program. The X-IFU consists of a large array of TES microcalorimeters that will operate at?~?50 mK inside a sophisticated cryostat. A set of thin filters, highly transparent to X-rays, will be mounted on the cryostat thermal shields in order to attenuate the IR radiative load, to attenuate RF electromagnetic interferences, and to protect the detector from contamination. In this paper, we present the current thermal filters design, describe the filter samples developed/procured so far, and present preliminary results from the ongoing characterization tests.     

Nickel–palladium electrocatalysts for methanol,ethanol, and glycerol oxidation reactions

Carbon-supported Pd and PdNi electrocatalysts with different Ni contents were prepared by metal ion chemical reduction with borohydride. XRF analyses showed that the actual compositions of the materials were close to the nominal compositions. XRD measurements revealed that the materials were crystalline, with small peak displacements when Ni and Pd ions were reduced on carbon support, and suggested a segregated phase and not a Ni incorporation into the Pd lattice. HRTEM micrographs showed homogeneous particle distributions on the carbon, with a narrow particle size distribution and few agglomerations of nanoparticles. All the materials presented electrochemical activity for the oxidation of methanol, ethanol, and glycerol in KOH, and the oxidation current peak increased as a function of the Ni content in the catalyst.     

A method to compensate the influence of speech codec in speaker recognition

The recognition of a person by his voice or “speaker recognition”, is a biometric specialty increasingly used in electronic commerce and electronic banking transactions and forensic investigations, among others. Speaker recognition is supported by the discriminative information contained in the speech of a person and its main challenge is the variability that exists between different speech samples of the same person, used for training and evaluation, or “session variability”. When a speech communication is transmitted over the internet, for example, the coding–decoding process “codec” of the speech causes loss of such information and affects the effectiveness of the speaker recognition. Some methods have been proposed to mitigate this effect. This work makes a study of the degree of affectation of this information for some commonly used codec types and proposes our own solution, to compensate the session variability provoked by the codec. The influence of some types of codec in the quality of the sample was evaluated first with a set of synthesized speech samples. Later, experiments were carried out with speech samples of international competitions, retransmitted over two different codecs, and the effect on the speaker recognition effectiveness was checked. Finally, the variability compensation was applied, with an improvement of the recognition effectiveness, measured by the equal error rate, of 20.8% for the g.722 codec and 27.8% for the gsm 6.20 codec.     

Kinetic models analysis

This paper introduces a freeware program for models analysis, which implements a robust method for parameter estimation of nonlinear models, able to detect outliers. A new class of criteria is proposed in order to achieve an optimal experimental design. Finally a strategy for model discrimination is presented. Since this is a critical point, the correct meaning of statistical tests and regions of confidence is proposed. At last, it is explained why it is better to avoid any approach that makes use of probability to discriminate among models.     

Control of bidirectional physical human–robot interaction based on the human intention

This paper presents a control strategy for human–robot interaction with physical contact, recognizing the human intention to control the movement of a non-holonomic mobile robot. The human intention is modeled by mechanical impedance, sensing the human-desired force intensity and the human-desired force direction to guide the robot through unstructured environments. Robot dynamics is included to improve the interaction performance. Stability analysis of the proposed control system is proved by using Lyapunov theory. Real experiments of the human–robot interaction show the performance of the proposed controllers.     

RF-MEMS switch design optimization for long-term reliability

This contribution presents an optimization strategy for the mechanical and geometrical characteristics of clamped–clamped dielectric-less RF-MEMS switches in order to enhance their reliability performances both in terms of switch properties control and long-term actuation behavior. The modifications mainly affect the switch membrane, which is made more robust, and the stopping pillar dimensions, while the switch dimensions are practically unaffected. In the case of the proposed ohmic switch, also the mobile contact region was redesigned in order to increase the contact force. Experimental measurements have demonstrated that the optimized version of the capacitive switch investigated shows an improved resistance to high bias voltages (up to 90 V), while the optimized ohmic switch shows a lower, more stable and more reproducible contact resistance. Long-term actuation measurements are analyzed in detail, proposing a model to evaluate the switch lifetime, which was found of the order of few years in the more conservative estimate in the case of capacitive switches. The lifetime estimates are less precise in the case of ohmic switches, mainly because the contact instability sums up with the charging contribution. In spite of the improved switch general properties, lifetime is however not increased with optimization. The most likely explanation is that the optimization strategy was aimed at reducing charge injection and charge non-uniformity, but other effects can be important in lifetime determination.