8,680 research outputs found
Towards formal models and languages for verifiable Multi-Robot Systems
Incorrect operations of a Multi-Robot System (MRS) may not only lead to
unsatisfactory results, but can also cause economic losses and threats to
safety. These threats may not always be apparent, since they may arise as
unforeseen consequences of the interactions between elements of the system.
This call for tools and techniques that can help in providing guarantees about
MRSs behaviour. We think that, whenever possible, these guarantees should be
backed up by formal proofs to complement traditional approaches based on
testing and simulation.
We believe that tailored linguistic support to specify MRSs is a major step
towards this goal. In particular, reducing the gap between typical features of
an MRS and the level of abstraction of the linguistic primitives would simplify
both the specification of these systems and the verification of their
properties. In this work, we review different agent-oriented languages and
their features; we then consider a selection of case studies of interest and
implement them useing the surveyed languages. We also evaluate and compare
effectiveness of the proposed solution, considering, in particular, easiness of
expressing non-trivial behaviour.Comment: Changed formattin
Blind user detection in doubly-dispersive DS/CDMA channels
In this work, we consider the problem of detecting the presence of a new user
in a direct-sequence/code-division-multiple-access (DS/CDMA) system with a
doubly-dispersive fading channel, and we propose a novel blind detection
strategy which only requires knowledge of the spreading code of the user to be
detected, but no prior information as to the time-varying channel impulse
response and the structure of the multiaccess interference. The proposed
detector has a bounded constant false alarm rate (CFAR) under the design
assumptions, while providing satisfactory detection performance even in the
presence of strong cochannel interference and high user mobility.Comment: Accepted for publication on IEEE Transactions on Signal Processin
A Dual Hybrid Virtual Element Method for Plane Elasticity Problems
A dual hybrid Virtual Element scheme for plane linear elastic problems is
presented and analysed. In particular, stability and convergence results have
been established. The method, which is first order convergent, has been
numerically tested on two benchmarks with closed form solution, and on a
typical microelectromechanical system. The numerical outcomes have proved that
the dual hybrid scheme represents a valid alternative to the more classical
low-order displacement-based Virtual Element Method
Third molar maturity index by measurements of open apices in a Libyan sample of living subjects
In most countries, forensic age estimation in living subjects has become increasingly important in the last few years. In addition, as the age of legal majority ranges from 14 to 18 in many countries, and in Libya it is 18 years, radiographic assessment of the degree of third molar development is essential for forensic age estimation of adolescents and young adults. The aim of this paper is to assess the accuracy of the cut-off value of 0.08, by measurements of third molar index (I3M), in determining if a subject is adult or not in Libyan population. Digital panoramic radiographs of 307 healthy subjects (163 girls, 144 boys), aged between 14 and 22, were analysed. The I3M, the age and the sex of the subjects were used as predictive variable for age estimation. Using a cut-off of 0.08, the sensitivity of the test for boys was 90.9% and the specificity 100%. The proportion of correctly classified individuals was 95.1% (95% CI: 91.5–98.7%). The sensitivity for girls was 90.6% and the specificity 100%. The proportion of correctly classified individuals was 94.5% (95% CI: 90.9–98.1%). Estimated post-test probability in boys and girls was 100%. Further analyses, performed using a cut-off of 0.09, do not affect the specificity (100%) while they improve the sensitivity for both boys and girls
Accuracy and precision of an intraoral scanner in complex prosthetic rehabilitations: an in vitro study
The main purpose of this study is to measure the accuracy and the precision of the intraoral
optical scanner CS3500® (Carestream Dental LLC, Atlanta, USA) in complex clinical situations as
full arch rehabilitations on impl
ants.
50 scans of the acrylic resin model were performed by using CS3500® (Carestream Dental
LLC, Atlanta, USA) scanner. Each scan was compared with the virtual model derived from scanning
with the laboratory scanner Dscan3® (Enhanced Geometry Soluti
on, Bologna, Italy) to measure a
possible misalignment.
The alignment error was found to be 79,6 (
±
12,87)
m. The measurement was taken at the
level of 2 distal scan
-
abutments. The scanner's precision ranges from 24 to 52
m , depending on
the dist
ance between scan
-
abutment.
CS3500® (Carestream Dental LLC, Atlanta, USA) intraoral scanner has detected a valid device
in the execution of complex rehabilitations on implants. His accuracy and precision values fall within
the range established in li
terature to define acceptable the prosthetic fitting on full arch implant
rehabilitation
Strong unique continuation and local asymptotics at the boundary for fractional elliptic equations
We study local asymptotics of solutions to fractional elliptic equations at
boundary points, under some outer homogeneous Dirichlet boundary condition. Our
analysis is based on a blow-up procedure which involves some Almgren type
monotonicity formulae and provides a classification of all possible homogeneity
degrees of limiting entire profiles. As a consequence, we establish a strong
unique continuation principle from boundary points.Comment: 40 pages, 2 figure
Mating behaviour and dual mode communication of Pear Psylla CACOPSYLLA PYRI
Cacopsylla pyri (L.) (Hemiptera, Psyllidae) is one of the most important pests of European pear, and its management generally depends on the use
of chemical insecticides, but C. pyri outbreaks are sometime observed. Ecological control strategies should be desirable and the knowledge of mating behavior is crucial to develop new ones. A multi-approaches research aimed to acquire knowledges about C. pyri mate finding. Electroantennographic (EAG) analyses and olfactometric bioassays were used to evaluate the activity of intraspecific semiochemicals on C. pyri. The EAG amplitudes revealed that volatile compounds, present in female cuticular extracts, elicited dose-dependent responses in males, indicating that these compounds were able to stimulate the male olfactory system. In behavioral bioassays, living females and female cuticular extracts, attracted summerform males in a highly significant manner. Gas chromatography-mass spectrometry revealed that 13-methylheptacosane, 11,13-dimethylheptacosane, 2-methylheptacosane and 3-methylheptacosane were found in larger amounts in female extracts than in male ones, which suggests their role in male attraction. In addition, a laser vibrometer device was used to detect a male-female substrate-born vibrations pattern during pre-copulatory period. The female vibrational signal was recorded as mp3 and conveyed, in loop using a minishaker, on pear shoots with C. pyri virgin pairs to interfere with the mating by masking the natural communications
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