2,873 research outputs found
Nonlinear Control of a DC MicroGrid for the Integration of Photovoltaic Panels
New connection constraints for the power network (Grid Codes) require more
flexible and reliable systems, with robust solutions to cope with uncertainties
and intermittence from renewable energy sources (renewables), such as
photovoltaic arrays. The interconnection of such renewables with storage
systems through a Direct Current (DC) MicroGrid can fulfill these requirements.
A "Plug and Play" approach based on the "System of Systems" philosophy using
distributed control methodologies is developed in the present work. This
approach allows to interconnect a number of elements to a DC MicroGrid as power
sources like photovoltaic arrays, storage systems in different time scales like
batteries and supercapacitors, and loads like electric vehicles and the main AC
grid. The proposed scheme can easily be scalable to a much larger number of
elements.Comment: arXiv admin note: text overlap with arXiv:1607.0848
Nonlinear Control of an AC-connected DC MicroGrid
New connection constraints for the power network (Grid Codes) require more
flexible and reliable systems, with robust solutions to cope with uncertainties
and intermittence from renewable energy sources (renewables), such as
photovoltaic arrays. A solution for interconnecting such renewables to the main
grid is to use storage systems and a Direct Current (DC) MicroGrid. A "Plug and
Play" approach based on the "System of Systems" philosophy using distributed
control methodologies is developed in the present work. This approach allows to
interconnect a number of elements to a DC MicroGrid as power sources like
photovoltaic arrays, storage systems in different time scales like batteries
and supercapacitors, and loads like electric vehicles and the main AC grid. The
proposed scheme can easily be scalable to a much larger number of elements.Comment: IEEE IECON 2016, the 42nd Annual Conference of IEEE Industrial
Electronics Society, October 24-27, 201
String Stability of a Vehicular Platoon with the use of Macroscopic Information
We investigate the possibility to use macroscopic information to improve
control performance of a vehicular platoon composed of autonomous vehicles. A
general mesoscopic traffic modeling is described, and a closed loop String
Stability analysis is performed using Input-to-State Stability (ISS) results.
Examples of mesoscopic control laws are provided and shown to ensure String
Stability properties. Simulations are implementedin order to validate the
control laws and to show the efficacy of the proposed approach.Comment: arXiv admin note: substantial text overlap with arXiv:2003.1252
An International Survey on Taking Up a Career in Cardiovascular Research: Opportunities and Biases toward Would-Be Physician-Scientists
Background
Cardiovascular research is the main shaper of clinical evidence underpinning decision making, with its cyclic progression of junior researchers to mature faculty members. Despite efforts at improving cardiovascular research training, several unmet needs persist. We aimed to appraise current perceptions on cardiovascular research training with an international survey.
Methods and Results
We administered a 20-closed-question survey to mentors and mentees belonging to different international institutions. A total of 247 (12%) surveys were available (out of 2,000 invitations). Overall, mentees and mentors were reasonably satisfied with the educational and research resources. Significant differences were found analyzing results according to gender, geographic area, training and full-time researcher status. Specifically, women proved significantly less satisfied than men, disclosed access to fewer resources and less support from mentors (all P
Conclusions
Several potential biases appear to be present in the way training in cardiovascular research is provided worldwide, including one against women. If confirmed, these data require proactive measures to decrease discriminations and improve the cardiovascular research training quality
Efficacy of 1998 <i>vs</i> 2006 first-line antiretroviral regimens for HIV infection: an ordinary clinics retrospective investigation
Purpose: The evidence suggesting increased HAART efficacy over time comes from randomized trials or cohort
studies. This retrospective multicenter survey aimed to assess the variation over time in the efficacy and tolerability of first-line HAART regimens in unselected patients treated in ordinary clinical settings.
Methods: Retrospective analysis of data of all patients starting first-line HAART regimens in 1998 and 2006 at adhering centers in the Italian CISAI group.
Results: For the 543 patients included, mean age was 39.1 ± 9.8y in 1998 and 41.0 ± 10.7y in 2006 (p=0.03),
with a similar proportion of males. Baseline mean log10 HIV-RNA was 4.56 ± 0.97 copies/mL in 1998 vs 4.91 ± 0.96
copies/mL in 2006 (p<0.001); baseline mean CD4 T-cell counts were 343 ± 314/mm3 in 1998 vs 244 ± 174/mm3 in
2006 (p<0.001). The following outcomes were significantly improved at 48w in 2006: proportion with undetectable HIV-RNA (86.3% vs 58.0%; p<0.001); mean increase in CD4 T-cells count (252 ± 225 vs 173 ± 246; p<0.001); HAART modification (20.1% vs 29.2%; p=0.02); HAART interruption (7.3% vs 14.6%; p=0.01); proportion reporting optimal adherence (92.2% vs 82.7%, p=0.03). No differences were observed in the prevalence of grade 3-4 WHO toxicities (26.4% vs 26.6%; p=0.9). Multivariate logistic regression showed that being treated in 1998 remained an independent predictor of virological failure after several adjustments, including adherence.
Conclusions: Our data from patients not included in clinical trials or cohort studies provide an additional
line of evidence that the effectiveness of HAART significantly improved in 2006. Treated patients, however, were significantly older and more frequently late HIV presenters in 2006 than in 1998.</br
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