505,926 research outputs found
'It'll get worse before it gets better': Local experiences of living in a regeneration area
The negative consequences of living in deprived neighbourhoods for residentsâ quality of life are well documented. Area-based regeneration initiatives are invariably concerned with improving local quality of life over the long term. The process of regeneration, however, can itself directly result in immediate and potentially lasting negative effects for local communities. This paper discusses some of the ways in which living in an area undergoing regeneration can adversely affect inhabitantsâ quality of life, including problems associated with voids, relocation, demolitions, environmental quality, complexity, funding issues, uncertainty, frustration, fear for the future and consultation fatigue. A case study approach draws examples from a deprived neighbourhood in the North East of England. The conclusion discusses some of the possible implications for future regeneration policy, including: the importance of ongoing communication between professionals and communities; the need to value local peopleâs experience, judgement and the contribution they can make to local decision-making processes; recognition that successful regeneration can take many years; and the implications of current UK government policy
A study on communication optimization of distributed gradient descent algorithms based on large-scale machine learning
In recent years, the rapid development of new generation information technology has resulted in an unprecedented expansion
of information capacity. Machine learning algorithms are also increasingly used to compute information sets and build information systems
to solve problems whose complexity makes algorithmic solutions infeasible. Examples include autonomous vehicles, speech recognition
or user determination (recommendation systems). The complexity of the machine learning model, combined with the larger amount of data
collected, makes it much more expensive to use the model on a single machine, or even impossible to train. Using the computing power of
distributed systems is a straightforward, simple solution to the problem. Today, powerful computer clusters are used to train complex deep
neural networks on large data sets. However, in large-scale clustered environments, the commonly used distributed synchronous stochastic
gradient descent algorithms require frequent node communication to ensure consistency of the gradients (parameters). This has led to the
communication bandwidth being a key constraint for distributed machine learning systems
Information Cost Tradeoffs for Augmented Index and Streaming Language Recognition
This paper makes three main contributions to the theory of communication
complexity and stream computation. First, we present new bounds on the
information complexity of AUGMENTED-INDEX. In contrast to analogous results for
INDEX by Jain, Radhakrishnan and Sen [J. ACM, 2009], we have to overcome the
significant technical challenge that protocols for AUGMENTED-INDEX may violate
the "rectangle property" due to the inherent input sharing. Second, we use
these bounds to resolve an open problem of Magniez, Mathieu and Nayak [STOC,
2010] that asked about the multi-pass complexity of recognizing Dyck languages.
This results in a natural separation between the standard multi-pass model and
the multi-pass model that permits reverse passes. Third, we present the first
passive memory checkers that verify the interaction transcripts of priority
queues, stacks, and double-ended queues. We obtain tight upper and lower bounds
for these problems, thereby addressing an important sub-class of the memory
checking framework of Blum et al. [Algorithmica, 1994]
Privacy-Aware Processing of Biometric Templates by Means of Secure Two-Party Computation
The use of biometric data for person identification and access control is gaining more and more popularity. Handling biometric data, however, requires particular care, since biometric data is indissolubly tied to the identity of the owner hence raising important security and privacy issues. This chapter focuses on the latter, presenting an innovative approach that, by relying on tools borrowed from Secure Two Party Computation (STPC) theory, permits to process the biometric data in encrypted form, thus eliminating any risk that private biometric information is leaked during an identification process. The basic concepts behind STPC are reviewed together with the basic cryptographic primitives needed to achieve privacy-aware processing of biometric data in a STPC context. The two main approaches proposed so far, namely homomorphic encryption and garbled circuits, are discussed and the way such techniques can be used to develop a full biometric matching protocol described. Some general guidelines to be used in the design of a privacy-aware biometric system are given, so as to allow the reader to choose the most appropriate tools depending on the application at hand
Communication Theoretic Data Analytics
Widespread use of the Internet and social networks invokes the generation of
big data, which is proving to be useful in a number of applications. To deal
with explosively growing amounts of data, data analytics has emerged as a
critical technology related to computing, signal processing, and information
networking. In this paper, a formalism is considered in which data is modeled
as a generalized social network and communication theory and information theory
are thereby extended to data analytics. First, the creation of an equalizer to
optimize information transfer between two data variables is considered, and
financial data is used to demonstrate the advantages. Then, an information
coupling approach based on information geometry is applied for dimensionality
reduction, with a pattern recognition example to illustrate the effectiveness.
These initial trials suggest the potential of communication theoretic data
analytics for a wide range of applications.Comment: Published in IEEE Journal on Selected Areas in Communications, Jan.
201
Streaming algorithms for language recognition problems
We study the complexity of the following problems in the streaming model.
Membership testing for \DLIN We show that every language in \DLIN\ can be
recognised by a randomized one-pass space algorithm with inverse
polynomial one-sided error, and by a deterministic p-pass space
algorithm. We show that these algorithms are optimal.
Membership testing for \LL For languages generated by \LL grammars
with a bound of on the number of nonterminals at any stage in the left-most
derivation, we show that membership can be tested by a randomized one-pass
space algorithm with inverse polynomial (in ) one-sided error.
Membership testing for \DCFL We show that randomized algorithms as efficient
as the ones described above for \DLIN\ and \LL(k) (which are subclasses of
\DCFL) cannot exist for all of \DCFL: there is a language in \VPL\ (a subclass
of \DCFL) for which any randomized p-pass algorithm with error bounded by
must use space.
Degree sequence problem We study the problem of determining, given a sequence
and a graph , whether the degree sequence of is
precisely . We give a randomized one-pass space
algorithm with inverse polynomial one-sided error probability. We show that our
algorithms are optimal.
Our randomized algorithms are based on the recent work of Magniez et al.
\cite{MMN09}; our lower bounds are obtained by considering related
communication complexity problems
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