1,720,966 research outputs found
Reliable design for MPPT management through the SMP technique
No full textOperation of a S/C power system based on the SMP technique for Maximum Power Point Tracking management is the subject of the present work. 12Improvements both in transient behaviour and EMC are reported and experimental results are analysed with reference to specific design solutions. Particular design techniques are then presented, specifically developed to avoid that the increased circuit complexity could negatively affect the system reliability, especially in the cases where Commercial Off The Shelf components are used. Basically, the circuits for fundamental operation, designed on the basis of classical and very reliable schemes, are separated from those dedicated to the SMP control, based on digital integrated circuits, with an higher failure rate. Then, the interfaces between the two blocks are designed so that the SMP control circuit can only affect (positively) the system operation when it is correctly operating, while its interactions with the basic circuit are blocked if errors are detected. ©2009 IEEE
On the Reliability of Modular Power conversion Systems for Small Spacecraft
No full textModular power conversion systems for space application, thanks to their flexibility, can be easily adapted with minor changes to missions with different power requirements. 12In the perspective of an application to low-cost satellite, based on Commercial Off The Shelf components, the main design drivers are efficiency and reliability. We will focus our attention to spacecrafts with body-mounted solar cells. Thus, trade-off between the opposite requirements, efficiency and reliability, have been discussed through the analysis of several redundancy schemes. Reliability calculation of circuits will be performed on the basis of MIL-HDBK-217F. The aim of this work is to demonstrate that specific design efforts allow to increase the reliability of COTS-based power systems to levels comparable to classical systems based on space-qualified components. ©2009 IEEE
Sentinel Node detection with Imaging Probe.
No full textTumori. 2002 May-Jun;88(3):S32-5.
Sentinel node detection with imaging probe.
Schillaci O, D'Errico G, Scafè R, Soluri A, Burgio N, Santagata A, Spanu A, Mangano AM, David V, Schiaratura A, Scopinaro F.
SourceTor Vergata University, Rome, Italy.
Abstract
A once-square-inch-field-of-view mini gamma camera, whose first prototype was built by us in 1998 and given the name imaging probe (IP), was initially employed in sentinel lymph node (SLN) detection. This is probably the best way of learning how to use it. In the present work IP was used for SLN localization by a medical team that, after having been trained by the group of nuclear physicians of "La Sapienza" University who designed and first used the detector, used IP at their own hospital to 1) acquire experience for future use during surgery (a cooperative project on IP-radioguided orthopedic surgery is ongoing) and 2) start multicenter trials with IP. The SLN was identified and localized with IP and a non-imaging probe, Neoprobe 2000, in six patients with breast cancer who underwent lymphoscintigraphy for SLN biopsy. The operators who used Neoprobe and IP were blinded to each other's findings and to the results obtained with the large-field-of-view Anger camera that was used for lymphoscintigraphy. The Anger camera, IP and Neoprobe detected seven SLNs in six patients. The mean detection time was 2 mins 6 s (standard deviation (SD) 26 s) with IP, and 2 mins 18 s (SD 47 s) with Neoprobe 2000. The SLN that was most difficult to find was detected in 2 mins 56 s with IP and 3 mins 45 s with Neoprobe. The operators' subjective impression of having detected the SLN was "absolutely sure" for 7/7 nodes with IP and "absolutely sure" for 5/7 nodes with Neoprobe.
PMID:12365381[PubMed - indexed for MEDLINE
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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