Unified reliability estimation and management of NoC based chip multiprocessors

We present a new architecture level unified reliability evaluation methodology for chip multiprocessors (CMPs). The proposed reliability estimation (REST) is based on a Monte Carlo algorithm. What distinguishes REST from the previous work is that both the computational and communication components are considered in a unified manner to compute the reliability of the CMP. We utilize REST tool to develop a new dynamic reliability management (DRM) scheme to address time-dependent dielectric breakdown and negative-bias temperature instability aging mechanisms in network-on-chip (NoC) based CMPs. Designed as a control loop, the proposed DRM scheme uses an effective neural network based reliability estimation module. The neural-network predictor is trained using the REST tool. We investigate how system’s lifetime changes when the NoC as the communication unit of the CMP is considered or not during the reliability evaluation process and find that differences can be as high as 60%. Full-system based simulations using a customized GEM5 simulator show that reliability can be improved by up to 52% using the proposed DRM scheme in a best-effort scenario with 2–9% performance penalty (using a user set target lifetime of 7 years) over the case when no DRM is employed.     

CPSDebug: Automatic failure explanation in CPS models

International Journal on Software Tools for Technology Transfer - Debugging cyber-physical system (CPS) models is a cumbersome and costly activity. CPS models combine continuous and discrete...     

Bistable Piezoelectric Flutter Energy Harvesting with Uncertainty

The analytical formulation of piezoelectric flutter energy harvesting using a bistable material, while considering uncertainties in the model is presented in this paper. Bistable laminates provide the advantage of large deflection due to the nonlinear snap-through characteristics when exposed to external loading, and can therefore provide a suitable base for piezoelectric material in energy harvesting applications. A piezoelectric material that is bounded on the surface of bistable laminates, subjected to external loading, generates large strains and hence relatively higher electrical output energy, in comparison with the case where piezoelectric material is bonded on a regular surface, with analogous loading conditions. Although information regarding the external loading, material characteristics of the bistable laminate and the piezoelectric material, boundary conditions, and overall electrical circuit efficiency can be defined for analytical purposes, the exact model of the system is not readily accessible. The unavoidable uncertainties in the material, loading, and efficiency of a complex system call for a probabilistic approach. Hence, this paper provides a formulation that considers uncertainty bounds in obtaining a realistic model. Optimal Uncertainty Quantification (OUQ) is used in this paper, which takes into account uncertainty measures with optimal bounds and incomplete information about the system, as a well-defined optimization problem according to maximum probabilities, subjected to the imposed constraints. The OUQ allows the inspection of the solution for a span of uncertain input parameters, as a reliable and realistic model.     

On new sequences converging towards the Euler–Mascheroni constant

We propose new sequences containing a modified logarithmic term which converge to the Euler–Mascheroni constant faster than sequences known from the literature.     

Use of atrial and ventricular electrograms from a dual chamber implantable cardioverter defibrillator to elucidate a complex dysrhythmia

Stored intracardiac electrograms provided by third-generation ICDs have proved their use in the analysis of the mechanism of tachydysrhythmic events. There are cases in which the analysis of ventricular electrograms is insufficient for the elucidation of certain dysrhythmias. The availability of atrial electrograms provided by dual chamber ICDs improves the diagnostic capability of electrogram analysis and could prove most useful especially in complex dysrhythmias.     

The synthesis of MMA-S copolymer starting from PMMA and elemental sulfur

Summary The synthesis of methylmethacrylat (MMA) — sulfur copolymer has been completed by starting from a mixture of Polymethylmethacrylat (PMMA) temperature (360°C) by using a specially designed reaction vessel. The formation of copolymer is spontaneous and is due to the presence of active species (free biradical of MMA and S) generated through the decomposition of PMMA and polysulfur under extreme conditions.The resulted copolymer has been characterized by using elemental analysis, IR, NMR and MS spectroscopy.     

A class of integral approximations for the factorial function

We introduce Stirling’s formula in a more general class of approximation formulas to extend the integral representation of Liu [Z. Liu, A new version of the Stirling formula, Tamsui Oxf. J. Math. Sci. 23 (4) (2007) 389–392]. Finally, an accurate approximation for the factorial function is established.     

Improved asymptotic formulas for the gamma function

The aim of this paper is to improve the Ramanujan formula for approximation the gamma function. A fast asymptotic series is constructed.     

Specifying and detecting temporal patterns with shape expressions

International Journal on Software Tools for Technology Transfer - Modern cyber-physical systems (CPS) and the Internet of things (IoT) are data factories generating, measuring and recording huge...