Building memristor applications: from device model to circuit design

Since the memristor was first built in 2008 at HP Labs, no end of devices and models have been presented. Also, new applications appear frequently. However, the integration of the device at the circuit level is not straightforward, because available models are still immature and/or suppose high computational loads, making their simulation long and cumbersome. This study assists circuit/systems designers in the integration of memristors in their applications, while aiding model developers in the validation of their proposals. We introduce the use of a memristor application framework to support the work of both the model developer and the circuit designer. First, the framework includes a library with the best-known memristor models, being easily extensible with upcoming models. Systematic modifications have been applied to these models to provide better convergence and significant simulations speedups. Second, a quick device simulator allows the study of the response of the models under different scenarios, helping the designer with the stimuli and operation time selection. Third, fine tuning of the device including parameters variations and threshold determination is also supported. Finally, SPICE/Spectre subcircuit generation is provided to ease the integration of the devices in application circuits. The framework provides the designer with total control overconvergence, computational load, and the evolution of system variables, overcoming usual problems in the integration of memristive devices

A tool for the automatic analysis of single events effects on electronic circuits

Nowadays integrated circuit reliability is challenged by both variability and working conditions. Environmental radiation has become a major issue when ensuring the circuit correct behavior. The required radiation and later analysis performed to the circuit boards is both fund and time expensive. The lack of tools which support pre-manufacturing radiation hardness analysis hinders circuit designers tasks. This paper describes an extensively customizable simulation tool for the characterization of radiation effects on electronic systems. The proposed tool can produce an in depth analysis of a complete circuit in almost any kind of radiation environment in affordable computation times

Four-injector variability modeling of FinFET predictive technology models

The usual way of modeling variability using threshold voltage shift and drain current amplification is becoming inaccurate as new sources of variability appear in sub-22nm devices. In this work we apply the four-injector approach for variability modeling to the simulation of SRAMs with predictive technology models from 20nm down to 7nm nodes. We show that the SRAMs, designed following ITRS roadmap, present stability metrics higher by at least 20% compared to a classical variability modeling approach. Speed estimation is also pessimistic, whereas leakage is underestimated if sub-threshold slope and DIBL mismatch and their correlations with threshold voltage are not considered

Integrated Photogrammetric-Acoustic Technique for Qualitative Analysis of the Performance of Acoustic Screens in Sandy Soils

[EN] In this work, we present an integrated photogrammetric-acoustic technique that, together with the construction of a scaled wind tunnel, allows us to experimentally analyze the permeability behavior of a new type of acoustic screen based on a material called sonic crystal. Acoustic screens are devices used to reduce noise, mostly due to communication infrastructures, in its transmission phase from the source to the receiver. The main constructive difference between these new screens and the classic ones is that the first ones are formed by arrays of acoustic scatterers while the second ones are formed by continuous walls. This implies that, due to their geometry, screens based on sonic crystals are permeable to wind and water, unlike the classic ones. This fact may allow the use of these new screens in sandy soils, where sand would pass through the screen, avoiding the formation of sand dunes that are formed in classic screens and drastically reducing their acoustic performance. In this work, the movement of the sand and the resulting acoustic attenuation in these new screens are analyzed qualitatively, comparing the results with those obtained with the classic ones, and obtaining interesting results from the acoustic point of view.Bravo, JM.; Buchón Moragues, FF.; Redondo, J.; Ferri García, M.; Sánchez Pérez, JV. (2019). Integrated Photogrammetric-Acoustic Technique for Qualitative Analysis of the Performance of Acoustic Screens in Sandy Soils. Sensors. 19(22):1-17. https://doi.org/10.3390/s19224881S1171922Castiñeira-Ibañez, S., Rubio, C., & Sánchez-Pérez, J. V. (2015). Environmental noise control during its transmission phase to protect buildings. Design model for acoustic barriers based on arrays of isolated scatterers. Building and Environment, 93, 179-185. doi:10.1016/j.buildenv.2015.07.002Fredianelli, L., Del Pizzo, A., & Licitra, G. (2019). Recent Developments in Sonic Crystals as Barriers for Road Traffic Noise Mitigation. 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Journal of Archaeological Science, 36(1), 19-24. doi:10.1016/j.jas.2008.06.028Bruno, F., Bianco, G., Muzzupappa, M., Barone, S., & Razionale, A. V. (2011). Experimentation of structured light and stereo vision for underwater 3D reconstruction. ISPRS Journal of Photogrammetry and Remote Sensing, 66(4), 508-518. doi:10.1016/j.isprsjprs.2011.02.009Bertani, D. (1995). High-resolution optical topography applied to ancient painting diagnostics. Optical Engineering, 34(4), 1219. doi:10.1117/12.196545Buchón-Moragues, F., Bravo, J., Ferri, M., Redondo, J., & Sánchez-Pérez, J. (2016). Application of Structured Light System Technique for Authentication of Wooden Panel Paintings. Sensors, 16(6), 881. doi:10.3390/s16060881Arias, P., Herráez, J., Lorenzo, H., & Ordóñez, C. (2005). Control of structural problems in cultural heritage monuments using close-range photogrammetry and computer methods. Computers & Structures, 83(21-22), 1754-1766. doi:10.1016/j.compstruc.2005.02.018Rocchini, C., Cignoni, P., Montani, C., Pingi, P., & Scopigno, R. (2001). A low cost 3D scanner based on structured light. Computer Graphics Forum, 20(3), 299-308. doi:10.1111/1467-8659.00522Bianchi, M. G., Casula, G., Cuccuru, F., Fais, S., Ligas, P., & Ferrara, C. (2018). Three-dimensional imaging from laser scanner, photogrammetric and acoustic non-destructive techniques in the characterization of stone building materials. Advances in Geosciences, 45, 57-62. doi:10.5194/adgeo-45-57-2018Alvarez, L., Moreno, H., Segales, A., Pham, T., Pillar-Little, E., & Chilson, P. (2018). Merging Unmanned Aerial Systems (UAS) Imagery and Echo Soundings with an Adaptive Sampling Technique for Bathymetric Surveys. Remote Sensing, 10(9), 1362. doi:10.3390/rs10091362Miller, B. S., Wotherspoon, S., Rankin, S., Calderan, S., Leaper, R., & Keating, J. L. (2018). Estimating drift of directional sonobuoys from acoustic bearings. The Journal of the Acoustical Society of America, 143(1), EL25-EL30. doi:10.1121/1.5020621Zhang, D., Li, S., Bai, X., Yang, Y., & Chu, Y. (2019). Experimental Study on Mechanical Properties, Energy Dissipation Characteristics and Acoustic Emission Parameters of Compression Failure of Sandstone Specimens Containing En Echelon Flaws. Applied Sciences, 9(3), 596. doi:10.3390/app9030596Hartley, R. I., & Schaffalitzky, F. (2009). Reconstruction from Projections Using Grassmann Tensors. International Journal of Computer Vision, 83(3), 274-293. doi:10.1007/s11263-009-0225-1Ahmadabadian, A. H., Robson, S., Boehm, J., Shortis, M., Wenzel, K., & Fritsch, D. (2013). A comparison of dense matching algorithms for scaled surface reconstruction using stereo camera rigs. ISPRS Journal of Photogrammetry and Remote Sensing, 78, 157-167. doi:10.1016/j.isprsjprs.2013.01.015Olague, G., & Dunn, E. (2007). 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Análisis térmico en la obtención de aceros y fundiciones

El análisis térmico consiste en determinar las temperaturas de las transformaciones alotrópicas (puntos críticos) que se originan al calentar o enfriar un metal o aleación. Con ellas se puede trazar la gráfica de las funciones entre tiempo y temperatura. Los puntos de inflexión o tramos horizontales de las curvas indican las temperaturas de las transformaciones alotrópicas que van acompañadas de un desprendimiento de calor (en el calentamiento). Para efectos prácticos, el análisis térmico solo es factible cuando las transformaciones en el metal ocurren con un efecto térmico lo suficientemente considerable como para que sea detectable y medible con instrumentos de medida industriales. En este trabajo el estudio se ha concretado en la faceta que interesa al fundidor, cual es la del enfriamiento desde el estado líquido hasta la solidificación total. El análisis de las transformaciones y puntos de inflexión permite predecir la composición, estructura y propiedades que tendrán las piezas que se cuelen en esa aleación líquida y aplicar a tiempo las correcciones pertinentes y necesarias para satisfacer las características exigidas a esas piezas. Es decir, hay dos pasos u objetivos en el análisis térmico: el primero es conocer que metal tenemos en el horno; el segundo es, basándose en ese conocimiento, determinar las adiciones correctoras que hay que introducir en el horno o cuchara para satisfacer las demandas del acero y fundición especificados. En este trabajo el estudio se ha concretado en la faceta que interesa al fundidor, cual es la del enfriamiento desde el estado líquido hasta la solidificación total. El análisis de las transformaciones y puntos de inflexión permite predecir la composición, estructura y propiedades que tendrán las piezas que se cuelen en esa aleación líquida y aplicar a tiempo las correcciones pertinentes y necesarias para satisfacer las características exigidas a esas piezas. Es decir, hay dos pasos u objetivos en el análisis térmico: el primero es conocer que metal tenemos en el horno; el segundo es, basándose en ese conocimiento, determinar las adiciones correctoras que hay que introducir en el horno o cuchara para satisfacer las demandas del acero y fundición especificados

Phisically based modelling of induction lamps: aplication to the improvement of energy efficiency in the lighting system of a University building. Poster

To manage efforts in energy efficiency, the Polytechnic University of Cartagena (UPCT) decided in 2003 to develop an ambitious project to reduce energy use intensity and costs during the period 2003-2008. To accomplish this objective in lighting end-use demand -one of the two main electrical uses together with space cooling/heating-, the UPCT joins, in July 2002, the U.E. GreenLight program as a partner. This paper describes the University experience in the second year (2003/04) of partnership in this UE initiative. The objectives were: to manage the demand, to improve the quality of lighting, working and environmental conditions, and reduce significantly energy and O&M expenses. Basically, the work developed in this year is focused in the change of conventional High Intensity Discharge (HID) lighting systems in classrooms (2000 m2) through the evaluation of advantages and drawbacks of different alternatives. The most promising one, the change to a new technology -165W induction lamps-, will be analyzed in detail in the paper

Reconfigurable writing architecture for reliable RRAM operation in wide temperature ranges

Resistive switching memories [resistive RAM (RRAM)] are an attractive alternative to nonvolatile storage and nonconventional computing systems, but their behavior strongly depends on the cell features, driver circuit, and working conditions. In particular, the circuit temperature and writing voltage schemes become critical issues, determining resistive switching memories performance. These dependencies usually force a design time tradeoff among reliability, device endurance, and power consumption, thereby imposing nonflexible functioning schemes and limiting the system performance. In this paper, we present a writing architecture that ensures the correct operation no matter the working temperature and allows the dynamic load of application-oriented writing profiles. Thus, taking advantage of more efficient configurations, the system can be dynamically adapted to overcome RRAM intrinsic challenges. Several profiles are analyzed regarding power consumption, temperature-variations protection, and operation speed, showing speedups near 700x compared with other published drivers

The validity and reliability of a new instrumented device for measuring ankle dorsiflexion range of motion

PURPOSE/BACKGROUND: A restriction in ankle dorsiflexion range of motion (ROM) has been linked to several clinical manifestations such as metatarsalgia, heel pain, nerve entrapment, ankle joint equinus, patellar and ankle injuries. The purpose of the present study was to examine the validity and reliability of the Leg Motion system for measuring ankle dorsiflexion ROM. STUDY DESIGN: Descriptive repeated-measures study. METHODS: Twenty-six healthy male university students were recruited to test the reliability of the Leg Motion system, which is a portable tool used for assessment of ankle dorsiflexion during the weight-bearing lunge test. The participants were tested two times separated by two weeks and measurements were performed at the same time of the day by the same single rater. To test the validity of the Leg Motion system, other maximal ankle dorsiflexion ROM assessments (goniometer, inclinometer and measuring tape) were measured in a single session (i.e., the first test session) during the weight-bearing lunge position using a standard goniometer, a digital inclinometer and a measuring tape measure with the ability to measure to the nearest 0.1 cm. RESULTS: Paired t-tests showed the absence of significant differences between right and left limb measurements of dorsiflexion in all tests. Mean values ± standard deviations were as follows: Leg Motion test (left 11.6cm±3.9; right 11.9cm ±4.0), tape measure (left 11.6cm±4.0; right 11.8cm±4.2), goniometer (left 40.6º±5.2; right 40.6º±5.2), and digital inclinometer (left 40.0º±5.8; right 39.9º±5.6). The Leg Motion composite values (i.e., average of the two legs) showed a significant (p<0.05) positive correlation with the tape measure (r=0.99), with the goniometer (r=0.66), and with the digital inclinometer (r=0.72). CONCLUSIONS: The results of the present study provide evidence to support the use of the Leg Motion system as a valid, portable, and easy to use alternative to the weight-bearing lunge test to assess ankle dorsiflexion ROM in healthy participants