RRAM variability and its mitigation schemes

Emerging technologies such as RRAMs are attracting significant attention due to their tempting characteristics such as high scalability, CMOS compatibility and non-volatility to replace the current conventional memories. However, critical causes of hardware reliability failures, such as process variation due to their nano-scale structure have gained considerable importance for acceptable memory yields. Such vulnerabilities make it essential to investigate new robust design strategies at the circuit system level. In this paper we have analyzed the RRAM variability phenomenon, its impact and variation tolerant techniques at the circuit level. Finally a variation-monitoring circuit is presented that discerns the reliable memory cells affected by process variability.Peer ReviewedPostprint (author's final draft

Social responsibility and social security: The foundation of caja de pensiones para la vejez y de ahorros

The concept of Corporate Social Responsibility (CSR) is not new. Over the course of time, many entrepreneurs have created and developed companies, with a strong sense of ethical and social responsibility. This paper presents an example of how CSR was conceived and put into practice when Caja de Pensiones para la Vejez y de Ahorros was created in Barcelona in 1905, following the life and ideas of its founder, Francesc Moragas, a lawyer with a deep commitment to social action and a successful conception of the technical and economic dimensions of a financial and social institution.savings bank; corporate social responsibility; social security; welfare state;

Corporate social responsibility in the first years of Caja de Pensiones para la Vejez y de Ahorros

When Caja de Pensiones para la Vejez y de Ahorros, 'la Caixa', was created in 1905, it was not just a transient response to a serious social, political, and economic problem; it also provided a permanent solution by creating a long-lasting social welfare institution. In addition, its founder understood the responsibility of social welfare institutions not as an isolated responsibility for each institution, but as part of a harmonious whole that is a true moral entity, with a socio-economic character, independence and unity of nature, purpose and form. The purpose of this article is to show how the conception of corporate social responsibility of Francesc Moragas, the founder of 'la Caixa,' informed the activities of the new institution in a variety of dimensions, including its service to its customers, its economic strengths, its social welfare work and its participation in the creation of Spain's public social security system.savings bank; corporate social responsibility; social security; welfare state;

Experimental study of artificial neural networks using a digital memristor simulator

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper presents a fully digital implementation of a memristor hardware simulator, as the core of an emulator, based on a behavioral model of voltage-controlled threshold-type bipolar memristors. Compared to other analog solutions, the proposed digital design is compact, easily reconfigurable, demonstrates very good matching with the mathematical model on which it is based, and complies with all the required features for memristor emulators. We validated its functionality using Altera Quartus II and ModelSim tools targeting low-cost yet powerful field programmable gate array (FPGA) families. We tested its suitability for complex memristive circuits as well as its synapse functioning in artificial neural networks (ANNs), implementing examples of associative memory and unsupervised learning of spatio-temporal correlations in parallel input streams using a simplified STDP. We provide the full circuit schematics of all our digital circuit designs and comment on the required hardware resources and their scaling trends, thus presenting a design framework for applications based on our hardware simulator.Peer ReviewedPostprint (author's final draft

Assessment of the Accuracy of a Multi-Beam LED Scanner Sensor for Measuring Olive Canopies

MDPI. CC BYCanopy characterization has become important when trying to optimize any kind of agricultural operation in high-growing crops, such as olive. Many sensors and techniques have reported satisfactory results in these approaches and in this work a 2D laser scanner was explored for measuring canopy trees in real-time conditions. The sensor was tested in both laboratory and field conditions to check its accuracy, its cone width, and its ability to characterize olive canopies in situ. The sensor was mounted on a mast and tested in laboratory conditions to check: (i) its accuracy at different measurement distances; (ii) its measurement cone width with different reflectivity targets; and (iii) the influence of the target’s density on its accuracy. The field tests involved both isolated and hedgerow orchards, in which the measurements were taken manually and with the sensor. The canopy volume was estimated with a methodology consisting of revolving or extruding the canopy contour. The sensor showed high accuracy in the laboratory test, except for the measurements performed at 1.0 m distance, with 60 mm error (6%). Otherwise, error remained below 20 mm (1% relative error). The cone width depended on the target reflectivity. The accuracy decreased with the target density

Statistical analysis and comparison of 2T and 3T1D e-DRAM minimum energy operation

Bio-medical wearable devices restricted to their small-capacity embedded-battery require energy-efficiency of the highest order. However, minimum-energy point (MEP) at sub-threshold voltages is unattainable with SRAM memory, which fails to hold below 0.3V because of its vanishing noise margins. This paper examines the minimum-energy operation point of 2T and 3T1D e-DRAM gain cells at the 32-nm technology node with different design points: up-sizing transistors, using high- V th transistors, read/write wordline assists; as well as operating conditions (i.e., temperature). First, the e-DRAM cells are evaluated without considering any process variations. Then, a full-factorial statistical analysis of e-DRAM cells is performed in the presence of threshold voltage variations and the effect of upsizing on mean MEP is reported. Finally, it is shown that the product of the read and write lengths provides a knob to tradeoff energy-efficiency for reliable MEP energy operation.Peer ReviewedPostprint (author's final draft

Analysis of the impact of the Asset Health Index in a Maintenance Strategy

Hosted by the Johannes Kepler University, Linz, Austria. May 23-24, 2019 - European Safety, Reliability & Data Association (ESReDA)During many years, asset management methodologies used in industry were focused on knowing and analysing the operational control of the daily work and the impact of the maintenance on the availability. Later, the costs turn into the priority, and strategies were focused on assesses a longer lifecycle and optimizing processes and contracts. Finally, recent normative have included concepts as “knowing and managing the risks” and the target is to prioritize the maintenance tasks to the critical assets. However, taking a balanced asset management model for the operational environment, quite a lot of facilities of Oil & Gas sector are reaching the end of their initially estimated lifecycle. New challenges are related to extend the life of the main items of the facilities or at least, to find the optimal replacement moment that guarantees that the maintenance strategy is being optimized. Asset Health Index methodology considers a theoretical lifecycle of an item, in which depending on the proximity to the end of the useful life, the probability of failure increases. But take this theoretical lifecycle as a base, different operation location factors or O&M aspects can modify this period. All these factor are quantified and permit us to calculate a new theoretical profile. This paper is about assess the impact of the AHI into the maintenance strategy optimisation. AHI enables us to compare future alternative cost profiles and assess the impact in the failure probability of the item. As a result, we are able to know the risk that is taken when we enlarge the operation of an item, and the impact in the operational costs