17,200 research outputs found
Themed issue: Optofluidics
The term optofluidics defines a growing
research area that integrates optics and
microfluidics in ways that enable unique
strengths and advantages for a broad range
of applications. The First International
Conference on Optofluidics (Optofluidics-
2011) organized by Xi’an Jiaotong
University and Lab on a Chip on 11–12
December 2011 featured work in this field,
with an exciting two-day program of presentations
and discussions. We are happy
that Lab on a Chip, a major publication
destination for optofluidic research, has
scheduled this themed issue on Optofluidics.
We are especially heartened that the optofluidics
community has responded enthusiastically
with a large number of excellent
manuscript submissions
Self-Learning Hot Data Prediction: Where Echo State Network Meets NAND Flash Memories
© 2019 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.Well understanding the access behavior of hot data is significant for NAND flash memory due to its crucial impact on the efficiency of garbage collection (GC) and wear leveling (WL), which respectively dominate the performance and life span of SSD. Generally, both GC and WL rely greatly on the recognition accuracy of hot data identification (HDI). However, in this paper, the first time we propose a novel concept of hot data prediction (HDP), where the conventional HDI becomes unnecessary. First, we develop a hybrid optimized echo state network (HOESN), where sufficiently unbiased and continuously shrunk output weights are learnt by a sparse regression based on L2 and L1/2 regularization. Second, quantum-behaved particle swarm optimization (QPSO) is employed to compute reservoir parameters (i.e., global scaling factor, reservoir size, scaling coefficient and sparsity degree) for further improving prediction accuracy and reliability. Third, in the test on a chaotic benchmark (Rossler), the HOESN performs better than those of six recent state-of-the-art methods. Finally, simulation results about six typical metrics tested on five real disk workloads and on-chip experiment outcomes verified from an actual SSD prototype indicate that our HOESN-based HDP can reliably promote the access performance and endurance of NAND flash memories.Peer reviewe
Aperiodic conductivity oscillations in quasi-ballistic graphene heterojunctions
We observe conductivity oscillations with aperiodic spacing to only one side
of the tunneling current in a dual-gated graphene field effect transistor with
an n-p-n type potential barrier. The spacing and width of these oscillatoins
were found to be inconsistent with pure Farbry-Perot-type interferences, but
are in quantitative agreement with theoretical predictions that attribute them
to resonant tunneling through quasi-bound impurity states. This observation may
be understood as another signature of Klein tunneling in graphene
heterojunctions and is of importance for future development and modeling of
graphene based nanoelectronic devices.Comment: 3 pages, 3 figure
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