6,654 research outputs found
Neural Distributed Autoassociative Memories: A Survey
Introduction. Neural network models of autoassociative, distributed memory
allow storage and retrieval of many items (vectors) where the number of stored
items can exceed the vector dimension (the number of neurons in the network).
This opens the possibility of a sublinear time search (in the number of stored
items) for approximate nearest neighbors among vectors of high dimension. The
purpose of this paper is to review models of autoassociative, distributed
memory that can be naturally implemented by neural networks (mainly with local
learning rules and iterative dynamics based on information locally available to
neurons). Scope. The survey is focused mainly on the networks of Hopfield,
Willshaw and Potts, that have connections between pairs of neurons and operate
on sparse binary vectors. We discuss not only autoassociative memory, but also
the generalization properties of these networks. We also consider neural
networks with higher-order connections and networks with a bipartite graph
structure for non-binary data with linear constraints. Conclusions. In
conclusion we discuss the relations to similarity search, advantages and
drawbacks of these techniques, and topics for further research. An interesting
and still not completely resolved question is whether neural autoassociative
memories can search for approximate nearest neighbors faster than other index
structures for similarity search, in particular for the case of very high
dimensional vectors.Comment: 31 page
Optimizing Associative Information Transfer within Content-addressable Memory
Original article can be found at: http://www.oldcitypublishing.com/IJUC/IJUC.htmlPeer reviewe
Hypersparse Neural Network Analysis of Large-Scale Internet Traffic
The Internet is transforming our society, necessitating a quantitative
understanding of Internet traffic. Our team collects and curates the largest
publicly available Internet traffic data containing 50 billion packets.
Utilizing a novel hypersparse neural network analysis of "video" streams of
this traffic using 10,000 processors in the MIT SuperCloud reveals a new
phenomena: the importance of otherwise unseen leaf nodes and isolated links in
Internet traffic. Our neural network approach further shows that a
two-parameter modified Zipf-Mandelbrot distribution accurately describes a wide
variety of source/destination statistics on moving sample windows ranging from
100,000 to 100,000,000 packets over collections that span years and continents.
The inferred model parameters distinguish different network streams and the
model leaf parameter strongly correlates with the fraction of the traffic in
different underlying network topologies. The hypersparse neural network
pipeline is highly adaptable and different network statistics and training
models can be incorporated with simple changes to the image filter functions.Comment: 11 pages, 10 figures, 3 tables, 60 citations; to appear in IEEE High
Performance Extreme Computing (HPEC) 201
A study of pattern recovery in recurrent correlation associative memories
In this paper, we analyze the recurrent correlation associative memory (RCAM) model of Chiueh and Goodman. This is an associative memory in which stored binary memory patterns are recalled via an iterative update rule. The update of the individual pattern-bits is controlled by an excitation function, which takes as its arguement the inner product between the stored memory patterns and the input patterns. Our contribution is to analyze the dynamics of pattern recall when the input patterns are corrupted by noise of a relatively unrestricted class. We make three contributions. First, we show how to identify the excitation function which maximizes the separation (the Fisher discriminant) between the uncorrupted realization of the noisy input pattern and the remaining patterns residing in the memory. Moreover, we show that the excitation function which gives maximum separation is exponential when the input bit-errors follow a binomial distribution. Our second contribution is to develop an expression for the expectation value of bit-error probability on the input pattern after one iteration. We show how to identify the excitation function which minimizes the bit-error probability. However, there is no closed-form solution and the excitation function must be recovered numerically. The relationship between the excitation functions which result from the two different approaches is examined for a binomial distribution of bit-errors. The final contribution is to develop a semiempirical approach to the modeling of the dynamics of the RCAM. This provides us with a numerical means of predicting the recall error rate of the memory. It also allows us to develop an expression for the storage capacity for a given recall error rate
Multitasking associative networks
We introduce a bipartite, diluted and frustrated, network as a sparse
restricted Boltzman machine and we show its thermodynamical equivalence to an
associative working memory able to retrieve multiple patterns in parallel
without falling into spurious states typical of classical neural networks. We
focus on systems processing in parallel a finite (up to logarithmic growth in
the volume) amount of patterns, mirroring the low-level storage of standard
Amit-Gutfreund-Sompolinsky theory. Results obtained trough statistical
mechanics, signal-to-noise technique and Monte Carlo simulations are overall in
perfect agreement and carry interesting biological insights. Indeed, these
associative networks pave new perspectives in the understanding of multitasking
features expressed by complex systems, e.g. neural and immune networks.Comment: to appear on Phys.Rev.Let
SoK: Cryptographically Protected Database Search
Protected database search systems cryptographically isolate the roles of
reading from, writing to, and administering the database. This separation
limits unnecessary administrator access and protects data in the case of system
breaches. Since protected search was introduced in 2000, the area has grown
rapidly; systems are offered by academia, start-ups, and established companies.
However, there is no best protected search system or set of techniques.
Design of such systems is a balancing act between security, functionality,
performance, and usability. This challenge is made more difficult by ongoing
database specialization, as some users will want the functionality of SQL,
NoSQL, or NewSQL databases. This database evolution will continue, and the
protected search community should be able to quickly provide functionality
consistent with newly invented databases.
At the same time, the community must accurately and clearly characterize the
tradeoffs between different approaches. To address these challenges, we provide
the following contributions:
1) An identification of the important primitive operations across database
paradigms. We find there are a small number of base operations that can be used
and combined to support a large number of database paradigms.
2) An evaluation of the current state of protected search systems in
implementing these base operations. This evaluation describes the main
approaches and tradeoffs for each base operation. Furthermore, it puts
protected search in the context of unprotected search, identifying key gaps in
functionality.
3) An analysis of attacks against protected search for different base
queries.
4) A roadmap and tools for transforming a protected search system into a
protected database, including an open-source performance evaluation platform
and initial user opinions of protected search.Comment: 20 pages, to appear to IEEE Security and Privac
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