135 research outputs found
Understanding Soft Errors in Uncore Components
The effects of soft errors in processor cores have been widely studied.
However, little has been published about soft errors in uncore components, such
as memory subsystem and I/O controllers, of a System-on-a-Chip (SoC). In this
work, we study how soft errors in uncore components affect system-level
behaviors. We have created a new mixed-mode simulation platform that combines
simulators at two different levels of abstraction, and achieves 20,000x speedup
over RTL-only simulation. Using this platform, we present the first study of
the system-level impact of soft errors inside various uncore components of a
large-scale, multi-core SoC using the industrial-grade, open-source OpenSPARC
T2 SoC design. Our results show that soft errors in uncore components can
significantly impact system-level reliability. We also demonstrate that uncore
soft errors can create major challenges for traditional system-level checkpoint
recovery techniques. To overcome such recovery challenges, we present a new
replay recovery technique for uncore components belonging to the memory
subsystem. For the L2 cache controller and the DRAM controller components of
OpenSPARC T2, our new technique reduces the probability that an application run
fails to produce correct results due to soft errors by more than 100x with
3.32% and 6.09% chip-level area and power impact, respectively.Comment: to be published in Proceedings of the 52nd Annual Design Automation
Conferenc
Morphometric analysis of fossil bumble bees (Hymenoptera, Apidae, Bombini) reveals their taxonomic affinities
This work is licensed under a Creative Commons Attribution 4.0 International License.Bumble bees (Bombus spp.) are a widespread corbiculate lineage (Apinae: Corbiculata: Bombini), mostly found among temperate and alpine ecosystems. Approximately 260 species have been recognized and grouped recently into a simplified system of 15 subgenera. Most of the species are nest-building and primitively eusocial. Species of Bombus have been more intensely studied than any other lineages of bees with the exception of the honey bees. However, most bumble bee fossils are poorly described and documented, making their placement relative to other Bombus uncertain. A large portion of the known and presumed bumble bee fossils were re-examined in an attempt to better understand their affinities with extant Bombini. The taxonomic affinities of fossil specimens were re-assessed based on morphological features and previous descriptions, and for 13 specimens based on geometric morphometrics of forewing shape. None of the specimens coming from Eocene and Oligocene deposits were assigned within the contemporary shape space of any subgenus of Bombus. It is shown that Calyptapis florissantensis Cockerell, 1906 (Eocene-Oligocene boundary, Florissant shale, Colorado, USA) and Oligobombus cuspidatus Antropov, 2014 (Late Eocene, Bembridge Marls) likely belong to stem-group Bombini. Bombus anacolus Zhang, 1994, B. dilectus Zhang, 1994, B. luianus Zhang, 1990 (Middle Miocene, Shanwang Formation), as well as B. vetustus Rasnitsyn & Michener, 1991 (Miocene, Botchi Formation) are considered as species inquirenda. In the Miocene, affinities of fossils with derived subgenera of Bombus s. l. increased, and some are included in the shape space of contemporary subgenera: Cullumanobombus (i.e., B. pristinus Unger, 1867, B. randeckensis Wappler & Engel, 2012, and B. trophonius Prokop, Dehon, Michez & Engel, 2017), Melanobombus (i.e., B. cerdanyensis Dehon, De Meulemeester & Engel, 2014), and Mendacibombus (i.e., B. beskonakensis (Nel & PetruleviÄŤius, 2003), new combination), agreeing with previous estimates of diversification
Ion-Induced Dipole Interactions and Fragmentation Times : C -C Chromophore Bond Dissociation Channel
The fragmentation times corresponding to the loss of the chromophore
(C-- C bond dissociation channel) after photoexcitation at 263
nm have been investigated for several small peptides containing tryptophan or
tyrosine. For tryptophan-containing peptides, the aromatic chromophore is lost
as an ionic fragment (m/z 130), and the fragmentation time increases with the
mass of the neutral fragment. In contrast, for tyrosine-containing peptides the
aromatic chromophore is always lost as a neutral fragment (mass = 107 amu) and
the fragmentation time is found to be fast (\textless{}20 ns). These different
behaviors are explained by the role of the postfragmentation interaction in the
complex formed after the C--C bond cleavage
Reliable Circuit Design with Nanowire Arrays
The emergence of different fabrication techniques of silicon nanowires (SiNWs) raises the question of finding a suitable architectural organization of circuits based on them. Despite the possibility of building conventional CMOS circuits with SiNWs, the ability to arrange them into regular arrays, called crossbars, offers the opportunity to achieve higher integration densities. In such arrays, molecular switches or phase-change materials are grafted at the crosspoints, i.e., the crossing nanowires, in order to perform computation or storage. Given the fact that the technology is not mature, a hybridization of CMOS circuits with nanowire arrays seems to be the most promising approach. This chapter addresses the impact of variability on the nanowires in circuit designs based on the hybrid CMOS-SiNW crossbar approach
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