1,221 research outputs found
Multi-layered Spiking Neural Network with Target Timestamp Threshold Adaptation and STDP
Spiking neural networks (SNNs) are good candidates to produce
ultra-energy-efficient hardware. However, the performance of these models is
currently behind traditional methods. Introducing multi-layered SNNs is a
promising way to reduce this gap. We propose in this paper a new threshold
adaptation system which uses a timestamp objective at which neurons should
fire. We show that our method leads to state-of-the-art classification rates on
the MNIST dataset (98.60%) and the Faces/Motorbikes dataset (99.46%) with an
unsupervised SNN followed by a linear SVM. We also investigate the sparsity
level of the network by testing different inhibition policies and STDP rules
Muppet: MapReduce-Style Processing of Fast Data
MapReduce has emerged as a popular method to process big data. In the past
few years, however, not just big data, but fast data has also exploded in
volume and availability. Examples of such data include sensor data streams, the
Twitter Firehose, and Facebook updates. Numerous applications must process fast
data. Can we provide a MapReduce-style framework so that developers can quickly
write such applications and execute them over a cluster of machines, to achieve
low latency and high scalability? In this paper we report on our investigation
of this question, as carried out at Kosmix and WalmartLabs. We describe
MapUpdate, a framework like MapReduce, but specifically developed for fast
data. We describe Muppet, our implementation of MapUpdate. Throughout the
description we highlight the key challenges, argue why MapReduce is not well
suited to address them, and briefly describe our current solutions. Finally, we
describe our experience and lessons learned with Muppet, which has been used
extensively at Kosmix and WalmartLabs to power a broad range of applications in
social media and e-commerce.Comment: VLDB201
FAIR: Forwarding Accountability for Internet Reputability
This paper presents FAIR, a forwarding accountability mechanism that
incentivizes ISPs to apply stricter security policies to their customers. The
Autonomous System (AS) of the receiver specifies a traffic profile that the
sender AS must adhere to. Transit ASes on the path mark packets. In case of
traffic profile violations, the marked packets are used as a proof of
misbehavior.
FAIR introduces low bandwidth overhead and requires no per-packet and no
per-flow state for forwarding. We describe integration with IP and demonstrate
a software switch running on commodity hardware that can switch packets at a
line rate of 120 Gbps, and can forward 140M minimum-sized packets per second,
limited by the hardware I/O subsystem.
Moreover, this paper proposes a "suspicious bit" for packet headers - an
application that builds on top of FAIR's proofs of misbehavior and flags
packets to warn other entities in the network.Comment: 16 pages, 12 figure
Unsupervised Visual Feature Learning with Spike-timing-dependent Plasticity: How Far are we from Traditional Feature Learning Approaches?
Spiking neural networks (SNNs) equipped with latency coding and spike-timing
dependent plasticity rules offer an alternative to solve the data and energy
bottlenecks of standard computer vision approaches: they can learn visual
features without supervision and can be implemented by ultra-low power hardware
architectures. However, their performance in image classification has never
been evaluated on recent image datasets. In this paper, we compare SNNs to
auto-encoders on three visual recognition datasets, and extend the use of SNNs
to color images. The analysis of the results helps us identify some bottlenecks
of SNNs: the limits of on-center/off-center coding, especially for color
images, and the ineffectiveness of current inhibition mechanisms. These issues
should be addressed to build effective SNNs for image recognition
Analysis of distributed multi-periodic systems to achieve consistent data matching
International audienceDistributed real-time architecture of an embedded system is often described as a set of communicating components. Such a system is data flow (for its description) and time-triggered (for its execution). This work fits in with these problematics and focuses on the control of the time compatibility of a set of interdependent data used by the system components. The architecture of a component-based system forms a graph of communicating components, where more than one path can link two components. These paths may have different timing characteristics but the flows of information which transit on these paths may need to be adequately matched, so that a component uses inputs which all (directly or indirectly) depend on the same production step. In this paper, we define this temporal datamatching property, we show how to analyze the architecture to detect situations that cause data matching inconsistencies, and we describe an approach to manage data matching that uses queues to delay too fast paths and timestamps to recognize consistent data
Bounded variability of metric temporal logic
Deciding validity of Metric Temporal Logic (MTL) formulas is generally very complex and even undecidable over dense time domains; bounded variability is one of the several restrictions that have been proposed to bring decidability back. A temporal model has bounded variability if no more than v events occur over any time interval of length V, for constant parameters v and V. Previous work has shown that MTL validity over models with bounded variability is less complex—and often decidable—than MTL validity over unconstrained models. This paper studies the related problem of deciding whether an MTL formula has intrinsic bounded variability, that is whether it is satisfied only by models with bounded variability. The results of the paper are mainly negative: over dense time domains, the problem is mostly undecidable (even if with an undecidability degree that is typically lower than deciding validity); over discrete time domains, it is decidable with the same complexity as deciding validity. As a partial complement to these negative results, the paper also identifies MTL fragments where deciding bounded variability is simpler than validity, which may provide for a reduction in complexity in some practical cases
JaxNet: Scalable Blockchain Network
Today's world is organized based on merit and value. A single global currency
that's decentralized is needed for a global economy. Bitcoin is a partial
solution to this need, however it suffers from scalability problems which
prevent it from being mass-adopted. Also, the deflationary nature of bitcoin
motivates people to hoard and speculate on them instead of using them for day
to day transactions. We propose a scalable, decentralized cryptocurrency that
is based on Proof of Work.The solution involves having parallel chains in a
closed network using a mechanism which rewards miners proportional to their
effort in maintaining the network.The proposed design introduces a novel
approach for solving scalability problem in blockchain network based on merged
mining.Comment: 55 pages. 10 figure
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