3,952 research outputs found
MV-algebras freely generated by finite Kleene algebras
If V and W are varieties of algebras such that any V-algebra A has a reduct
U(A) in W, there is a forgetful functor U: V->W that acts by A |-> U(A) on
objects, and identically on homomorphisms. This functor U always has a left
adjoint F: W->V by general considerations. One calls F(B) the V-algebra freely
generated by the W-algebra B. Two problems arise naturally in this broad
setting. The description problem is to describe the structure of the V-algebra
F(B) as explicitly as possible in terms of the structure of the W-algebra B.
The recognition problem is to find conditions on the structure of a given
V-algebra A that are necessary and sufficient for the existence of a W-algebra
B such that F(B) is isomorphic to A. Building on and extending previous work on
MV-algebras freely generated by finite distributive lattices, in this paper we
provide solutions to the description and recognition problems in case V is the
variety of MV-algebras, W is the variety of Kleene algebras, and B is finitely
generated--equivalently, finite. The proofs rely heavily on the Davey-Werner
natural duality for Kleene algebras, on the representation of finitely
presented MV-algebras by compact rational polyhedra, and on the theory of bases
of MV-algebras.Comment: 27 pages, 8 figures. Submitted to Algebra Universali
Microwave Active Filter Design
A simplified method for the project and design of microwave active filters is presented here. The presented design is based on the use of an active inductor that emulates an inductor behavior by implementing a passive variable phase- and amplitude-compensating network and amplifiers, forming a gyrator-C architecture. This method can be applied with success for the design of bandpass filters with very high performances in terms of integration and application from a few hundreds of MHz to tens of GHs with filter high dynamic range and frequency tuning capability
An IC architecture for RF Energy Harvesting systems
In this work we present an IC architecture for RF energy harvesting. The system has been designed with a 0.18ÎŒm CMOS SMIC technology and optimized at 900MHz. Simulation results have confirmed that the integrated system handles an incoming power typically ranging from -25 dBm to 20 dBm by rectifying the variable input signals into a DC voltage source with an overall efficiency up to 50%. The chip area estimation for the proposed system is as low as 3x3mm2
A GPU based multidimensional amplitude analysis to search for tetraquark candidates
The demand for computational resources is steadily increasing in experimental
high energy physics as the current collider experiments continue to accumulate
huge amounts of data and physicists indulge in more complex and ambitious
analysis strategies. This is especially true in the fields of hadron
spectroscopy and flavour physics where the analyses often depend on complex
multidimensional unbinned maximum-likelihood fits, with several dozens of free
parameters, with an aim to study the internal structure of hadrons.
Graphics processing units (GPUs) represent one of the most sophisticated and
versatile parallel computing architectures that are becoming popular toolkits
for high energy physicists to meet their computational demands. GooFit is an
upcoming open-source tool interfacing ROOT/RooFit to the CUDA platform on
NVIDIA GPUs that acts as a bridge between the MINUIT minimization algorithm and
a parallel processor, allowing probability density functions to be estimated on
multiple cores simultaneously.
In this article, a full-fledged amplitude analysis framework developed using
GooFit is tested for its speed and reliability. The four-dimensional fitter
framework, one of the firsts of its kind to be built on GooFit, is geared
towards the search for exotic tetraquark states in the decays and can also be seamlessly adapted for other similar analyses.
The GooFit fitter, running on GPUs, shows a remarkable improvement in the
computing speed compared to a ROOT/RooFit implementation of the same analysis
running on multi-core CPU clusters. Furthermore, it shows sensitivity to
components with small contributions to the overall fit. It has the potential to
be a powerful tool for sensitive and computationally intensive physics
analyses.Comment: Replaced with the published version. Added the journal reference and
the DO
Enhancing selectivity in photocatalytic formation of p-anisaldehyde in aqueous suspension under solar light irradiation via TiO2 N-doping
The photocatalytic partial oxidation of 4-methoxybenzyl alcohol to the corresponding aldehyde (p-anisaldehyde) was performed under simulated solar irradiation by using home prepared N-doped TiO2 catalysts. The photocatalysts were prepared by a solâgel method, using TiCl4 as TiO2 precursor and NH4Cl, urea or NH4OH as N-doping sources. A commercial TiO2 (Degussa P25) was also used for comparison aims. The prepared catalysts were characterized by BET
specific surface area, XRD, ESEM and UV-vis spectroscopy. The reactivity results show that (i) the doped catalysts are predominantly amorphous, and they show selectivity values far higher than those of the corresponding undoped ones and of well crystallized catalysts â even if the last ones show a higher activity â and (ii) exploitation of solar light significantly increases the reaction selectivity. In addition, different light sources were also used in order to investigate the effect of radiation wavelength ranges on the reactivity and selectivity to aldehyde
Electronic Interface for Lidar System and Smart Cities Applications
This work deals with the design of a new readoutelectronics for silicon photomultipliers sensors. The so-calledSiPMs sensors are an emerging technology currentlydiffusing in many applications and, among them, in thedefinition of a new generation of LIDAR systems. Thelatter, nowadays have a primary role in the evolutionprocess that is involving Smart Cities, being an enablingtechnology in different fields. The solution here proposed isrealized at electronic level with a 150 nm technology processfrom LFoundry and results provide a feasibledemonstration of the capability of the proposed designapproach to be employed in practical application
Noise analysis and optimization of VCII-based SiPM interface circuit
AbstractRecently, second generation voltage conveyor (VCII)-based transimpedance amplifiers (TIAs) have begun to find their way in different applications, among which, silicon photomultipliers (SiPMs) interfacing circuitry. There are many advantages which make VCII-based TIAs attractive over conventional circuits: the intrinsic low impedance at VCII current input Y port is very helpful to mitigate the effect of high value sensor capacitance and provides fast response time; the achieved bandwidth is high and due to current mode operation; the circuits enjoy the low-voltage low-power features. As signal-to-noise ratio is a crucial parameter in SiPMs interface circuit applications, here we consider the noise specifications and optimization of VCII-based SiPM interface circuits. The noise model of VCII is introduced and equivalent noise of a VCII-based interface circuit is derived. Methods to optimize trade-offs existing between key parameters including power consumption, gain and noise performance are discussed. Simulation results are also provided showing a considerable reduction of two orders of magnitude in most of the noise performances when compared to the previous work while preserving other performance parameters
Advanced Computational Methods for Oncological Image Analysis.
The Special Issue "Advanced Computational Methods for Oncological Image Analysis", published for the Journal of Imaging, covered original research papers about state-of-the-art and novel algorithms and methodologies, as well as applications of computational methods for oncological image analysis, ranging from radiogenomics to deep learning [...]
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