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Building a visual overview of temporal event sequences with an optimal level-of-detail (i.e. simplified but informative) is an ongoing challenge - expecting the user to zoom into every important aspect of the overview can lead to missing insights. We propose a technique to build a multilevel overview of event sequences, whose granularity can be transformed across sequence clusters (vertical level-of-detail) or longitudinally (horizontal level-of-detail), using hierarchical aggregation and a novel cluster data representation Align-Score-Simplify. By default, the overview shows an optimal number of sequence clusters obtained through the average silhouette width metric - then users are able to explore alternative optimal sequence clusterings. The vertical level-of-detail of the overview changes along with the number of clusters, whilst the horizontal level-of-detail refers to the level of summarization applied to each cluster representation. The proposed technique has been implemented into a visualization system called Sequence Cluster Explorer (Sequen-C) that allows multilevel and detail-on-demand exploration through three coordinated views, and the inspection of data attributes at cluster, unique sequence, and individual sequence level. We present two case studies using real-world datasets in the healthcare domain: CUREd and MIMIC-III; which demonstrate how the technique can aid users to obtain a summary of common and deviating pathways, and explore data attributes for selected patterns. [ABSTRACT FROM AUTHOR]

Additional evidence is presented and discussed on the mechanism for the subthreshold leakage currents induced in power MOSFETs by single nucleon and ion interactions. The new evidence excludes microdose in gate oxides and instead points to microdose in field/edge oxides. [ABSTRACT FROM AUTHOR]

During neutron irradiation of 4-Mb SRAMs, large-scale multiple cell upsets (MCUs) were observed. These were observed in 90-nm devices at accelerated test facilities providing fission, fusion, and spallation neutron environments. The MCUs are shown to manifest themselves in 2-D patterns encompassing scores of cells, which, even with bit interleaving, lead to uncorrectable multiple bit upsets (MBU) in the same word. The mechanism behind the MCU appears to be micro-latching within blocks of the memory array that are powered up sequentially during the read cycle of the device. [ABSTRACT FROM AUTHOR]

Eight commercially available n-channel power MOSFETs were exposed to high energy spallation neutrons and thermal neutrons in separate experiments. Single event burnout (SEB) was observed in several of the devices in both environments. Measurements of SEB at derated drain-source voltages show very strong reductions in burnout cross-sections, but suggest that current recommendations for safe operation of devices may need updating for high voltage devices. In one device a different failure mode was observed, with subsequent investigations suggesting that single event gate rupture (SEGR) was responsible. This first observation of SEGR in accelerated neutron testing of power MOSFETs represents a new consideration for designers of high voltage control systems. [ABSTRACT FROM PUBLISHER]

Various SRAM and MOSFET devices were exposed to 3 MeV and 14 MeV neutrons at a fusion facility and to a fission neutron spectrum with a californium-252 source. Single event burnout (SEB) was observed in several of the MOSFETs in all three environments—the first time this phenomenon has been observed at neutron energies below 10 MeV. In addition to observing single event upsets (SEU) and single event latchup (SEL) in the SRAMs, two devices experienced significant multiple cell upset (MCU) effects which dominated the upset rate. The physical mechanisms underlying these phenomena and the consequences for various radiation environments are discussed. [ABSTRACT FROM AUTHOR]

New radiation monitors based on solid-state detectors have been developed to perform wide-ranging measurements of the atmospheric environment and provide warnings of sudden increases during solar particle events. Results have been obtained during the current deep solar minimum across the full range of latitudes and from sea level to 13 km altitude. Results for ambient dose equivalent agree very closely with Tissue Equivalent Proportional Counters carried on the same flights. Values of 10 μSv/hr are being reached at 12km altitude and high latitude. Comparisons are made with the QinetiQ Atmospheric Radiation Model and the need to include cosmic-ray heavy ions is demonstrated. [ABSTRACT FROM AUTHOR]

The Galileo global navigation system will employ an array of satellites in medium Earth orbit (MEO). Internal charging is one of the primary hazards for any spacecraft in MEO, and accordingly, the Galileo test satellite, Giove-A, carries a detector, SURF, to undertake the measurement of internal charging currents at three different shielding depths. The currents are due to electrons stopped in three aluminum plates: the first plate is 0.5 mm thick and located under 0.5-mm Al-equivalent shielding, the second is 0.5 mm thick and located underneath the first plate, and the third is 1.0 mm thick and located underneath the second plate. Giove-A was successfully launched on December 28, 2005 into a 23300-km circular 56° inclination orbit. In this paper, we provide data on the internal charging currents observed in 2006, with particular emphasis on two large charging events, one in mid-April and one in mid-December. Comparisons are made to predictions using the DICTAT internal charging tool and the FLUMIC "worst case" trapped electron belt model. In general, the charging currents observed are safely within the standard DICTAT 3.5/FLUMIC 3.0 predictions but are exceeded in the most shielded plate on five calendar days during December 2006. The December event was unique in 2006 in that it was triggered by the arrival of a coronal mass ejection (CME) rather than being due to the effects of a fast solar wind stream flowing from a coronal hole. The currents measured in the December event were, however, an order of magnitude lower than those predicted using the "anomalously large event" supplement to FLUMIC which models the most extreme electron enhancements associated with CMEs. [ABSTRACT FROM AUTHOR]

Discusses issues arising from the use of the Mixed Initiative Activity Plan Generator (MAPGEN) as an activity tool in the U.S. National Aeronautics & Space Administration's Mars Exploration Rover mission. Activity planning tool and planning and scheduling system combined under MAPGEN; Mission objectives; MAPGEN system design and functionality; Application in tactical planning.