Evaluation of the Suitability of NEON SIMD Microprocessor Extensions Under Proton Irradiation

This paper analyzes the suitability of single-instruction multiple data (SIMD) extensions of current microprocessors under radiation environments. SIMD extensions are intended for software acceleration, focusing mostly in applications that require high computational effort, which are common in many fields such as computer vision. SIMD extensions use a dedicated coprocessor that makes possible packing several instructions in one single extended instruction. Applications that require high performance could benefit from the use of SIMD coprocessors, but their reliability needs to be studied. In this paper, NEON, the SIMD coprocessor of ARM microprocessors, has been selected as a case study to explore the behavior of SIMD extensions under radiation. Radiation experiments of ARM CORTEX-A9 microprocessors have been accomplished with the objective of determining how the use of this kind of coprocessor can affect the system reliability

Online error detection through trace infrastructure in ARM microprocessors

This paper presents a solution for error detection in ARM microprocessors based on the use of the trace infrastructure. This approach uses the Program and Instrumentation Trace Macrocells that are part of ARM's CoreSight architecture to detect control-flow and data-flow errors, respectively. The proposed approach has been tested with low-energy protons. Experimental results demonstrate high accuracy with up to 95% of observed errors detected in a commercial microprocessor with no hardware modification. In addition, it is shown how the proposed approach can be useful for further analysis and diagnosis of the cause of errors

Processes with Multiple Entries and Exits Modulo Isomorphism and Modulo Bisimulation

This paper is an attempt to integrate the algebra of communicating processes (ACP) and the algebra of flownomials (AF). Basically, this means to combine axiomatized parallel and looping operators. To this end we introduce a model of process graphs with multiple entries and exits. In this model the usual operations of both algebras are defined, e.g. alternative composition (this covers both the sum of ACP and the disjoint sum of AF), sequential composition, feedback, parallel composition, left merge, communication merge, encapsulation, etc. 1 The main results consist of correct and complete axiomatisations of process graphs modulo isomorphism and modulo bisimulation. Key words & Phrases: process algebra, feedback, flowchart theories. 1 Introduction This paper is an attempt to integrate the algebra of communicating processes (ACP) and the algebra of flownomials (AF). Basically, this means to combine axiomatized parallel and looping operators. There are three axiomatized looping opera..

Oligodendrocytes in brain and optic nerve express the β3 subunit isoform of Na,K-ATPase

The Na,K-ATPase, which catalyzes the active transport of Na+ and K+, has two principal subunits (α and β) that have several genetically distinct isoforms. Most of these isoforms are expressed in the nervous system, but certain ones are preferentially expressed in glia and others in neurons. Of the β isoforms, β1 predominates in neurons and β2 in astrocytes, although there are some exceptions. Here we demonstrate that β3 is expressed in rat and mouse white matter oligodendrocytes. Immunofluorescence microscopy identified β3 in oligodendrocytes of rat brain white matter in typical linear arrays of cell bodies between fascicles of axons. The intensity of stain peaked at 20 postnatal days. β3 was identified in cortical oligodendrocytes grown in culture, where it was expressed in processes and colocalized with antibody to galactocerebroside. In the mouse and rat optic nerve, β3 stain was seen in oligodendrocytes, where it colocalized with carbonic anhydrase II. For comparison, optic nerve was stained for the β1 and β2 subunits, showing distinct patterns of labelling of axons (β1) and astrocytes (β2). The C6 glioma cell line was also found to express the β3 isoform preferentially. Since β3 was not found at detectable levels in astrocytes, this suggests that C6 is closer to oligodendrocytes than astrocytes in the glial cell lineage. (C) 2000 Wiley-Liss, Inc.Peer Reviewe

General Purpose Transistor Characterized as Dosimetry Sensor of Proton Beams

A commercial pMOS transistor (MOSFET), 3N163 from Vishay (USA), has been characterized as a low-energy proton beam dosimeter. The top of the samples’ housing has been removed to guarantee that protons reached the sensitive area, that is, the silicon die. Irradiations took place at the National Accelerator Centre (Seville, Spain). During irradiations, the transistors were biased to improve the sensitivity, and the silicon temperature was monitored activating the parasitic diode of the MOSFET. Bias voltages of 0, 1, 5, and 10 V were applied to four sets of three transistors, obtaining an averaged sensitivity that was linearly dependent on this voltage. In addition, the short-fading effect was studied, and the uncertainty of this effect was obtained. The bias voltage that provided an acceptable sensitivity, (11.4 ± 0.9) mV/Gy, minimizing the uncertainty due to the fading effect (−0.09 ± 0.11) Gy was 1 V for a total absorbed dose of 40 Gy. Therefore, this off-the-shelf electronic device presents promising characteristics as a dosimeter sensor for proton beams

Direct Ionization Impact on Accelerator Mixed-Field Soft Error Rate

We investigate, through measurements and simulations, the possible direct ionization impact in the accelerator soft error rate, not considered in standard qualification approaches. Results show that, for a broad variety of state-of-the art commercial components considered in the 65 nm to 16 nm technological range, indirect ionization is still expected to dominate the overall soft-error rate in the accelerator mixed-field. However, the derived critical charges of the most sensitive parts, corresponding to ∼0.7 fC, are expected to be at the limit of rapid direct ionization dominance and soft-error increase.peerReviewe