Information technology is now an indispensable pillar of a modern-day society, thanks to the proliferation of digital platforms in the past several decades. While demand for computing is increasing at unprecedented levels, the digital platforms (i.e., servers and datacenters) that form the backbone of IT have hit an energy “wall”. In the past decades, as chip densities increased, individual transistors also become more energy-efficient, enabling designers to exploit the increase in transistors to enhance chip functionality and perceived performance. While chip densities are projected to continue to scale well into the next decade, transistor energy efficiency has slowed down, resulting in a paradigm shift in computing to “dark silicon” where only a fraction of a chip’s transistors can be powered up at any given time. In this talk, I will present evidence to motivate this paradigm shift, and describe its implications on computing.
Communications
The presentation of the communications of the CHIST-ERA Conference 2012 (keynote and short talks, posters) will be continuously updated in the course of June.
Babak Falsafi is a Professor in the School of Computer and Communication Sciences at EPFL (http://ic.epfl.ch/page-5735-en.html), and an Adjunct Professor of Electrical & Computer Engineering and Computer Science at Carnegie Mellon. He is the founding director of the EcoCloud research center at EPFL (http://www.ecocloud.ch/) innovating future energy-efficient and environmentally friendly cloud technologies. His research targets design for dark silicon, architectural support for parallel programming, resilient systems, architectures to break the memory wall, and analytic and simulation tools for computer system performance evaluation.
Keynote talk
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 Presentation Babak Falsafi.pdf | 22.41 MB |
Prof. Clivia M. Sotomayor Torres is full-time ICREA Research Professor at the Catalan Institute of Nanotechnology (ICN - http://www.nanocat.org/) where she set up the Phononic and Photonic Nanostructures group. Prior to joining ICN, she was research professor at the University College Cork, Tyndall National Institute, Ireland. Her research interests are in the field of science and engineering of optical nanostructures, especially novel lithography methods for their realisation, such as nanoimprint lithography. More recently she has been working on inorganic nanotubes and confined phonons in silicon-on-insulator thin films.
To get as close as possible to zero power electronics, the understanding of phonons and fluctuations in IT device-relevant materials is essential. Lattice vibrations or phonons are at the heart of heat generation, transport and storage starting at the atomic scale. In nanoscience we have learnt that the characteristics of excitations in solids are strongly modified as dimensions are reduced and become commensurate with their de Broglie wavelength. The dispersion relations determining their interactions are strongly modified and this impacts the way that, for example, phonons interact with electrons, spins, photons and plasmons. Therein exists a major opportunity to understand and modify the heat transport by phonons in nanoelectronics. The theoretical descriptions are in general classical, however, once quantised electrons come into play, quantum mechanics needs to be considered.
Viewing fluctuations as low frequency phonons helps us in our understanding of noise and energy harvesting. The descriptions in these cases are firmly based in statistical mechanics highlighting the need for a stronger interaction with that area of research. Quantum processes in photosynthesis, noise generation and transmission of information below KT are some of the examples demonstrating the need to bring together currently separate bodies of knowledge.
Our research is focused on confined acoustic phonons, which have been invoked in the explanation of thermal conductance in condensed matter in attempts to explain experimental results in, eg., Si and metals both bulk and microstructures. The predictions of Hicks and Dresselhaus of the dominant role of dimensionality in the thermoelectric figure of merit ZT spun renewed interest in the study of confined acoustic phonons. The theoretical background on the origin of these modes triggered inelastic light scattering studies. Perhaps the most unambiguous observations of confined acoustic phonons in Si nanostructures were those in sub 40 nm thick SOI membranes which showed acoustic phonons in low frequency Raman scattering, the frequencies of which increased with decreasing membrane thickness.
We will discuss progress in our understanding of confined phonons since, its impact on thermal transport and outstanding scientific questions.
Keynote talk
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| Presentation Clivia M. Sotomayor Torres.pdf | 2.89 MB |
Giorgos Fagas is a Researcher at Tyndall National Institute in Ireland. He is the coordinator of the project SiNAPS (http://www.sinaps-fet.eu) in the initiative on Towards Zero Power ICT of the EU's FET programme and is participating in the FET coordination action so-called ZEROPOWER (http://www.zero-power.eu/). His expertise is in transport and quantum effects in nanomaterials and low dimensional structures and has been developing simulation tools that constitute part of Tyndall’s IP portfolio on software.
In a world of increasing global energy demand, ICT and consumer electronics account for one of the fastest growing sectors of energy consumption. It is projected that by 2030 the global energy use by just residential electronic gadgets could rise to 1,700TWh, greater than the current electricity generation capacity of the third largest producer in the world. On the other hand, miniaturised electronic systems applied in ambient intelligence, point-of-care diagnostics, supply-chain control and chemical warfare can potentially achieve large cost/energy savings with additional huge societal impact. The major challenges also come in dual form, namely: (i) energy needs to be harvested from sustainable ambient sources and (ii) the use of energy needs to be optimised.
Recent advances in ICT have been enabled by materials design and fabrication at the nanoscale. In this talk, I will provide examples of how nanotechnology and design at the smallest scales can enhance the efficiency of energy harvesters and the properties of