410 research outputs found
Crusade for Justice and the Question of Authenticity in African American Autobiography
This article aims at investigating the concept of authenticity and its connections with authority
and cultural dominance in Ida B. Wells\ub4s Crusade for Justice. Set in the Reconstruction period, Wells\u2019s
autobiography incorporates authenticating strategies typical of slave narratives and post-Emancipation
political memoirs, therefore it can be analyzed as a work of transition that embodies the profound shift in
authenticating issues occurring after Emancipation
Learning-Based Constraint Satisfaction With Sensing Restrictions
In this paper we consider graph-coloring problems, an important subset of
general constraint satisfaction problems that arise in wireless resource
allocation. We constructively establish the existence of fully decentralized
learning-based algorithms that are able to find a proper coloring even in the
presence of strong sensing restrictions, in particular sensing asymmetry of the
type encountered when hidden terminals are present. Our main analytic
contribution is to establish sufficient conditions on the sensing behaviour to
ensure that the solvers find satisfying assignments with probability one. These
conditions take the form of connectivity requirements on the induced sensing
graph. These requirements are mild, and we demonstrate that they are commonly
satisfied in wireless allocation tasks. We argue that our results are of
considerable practical importance in view of the prevalence of both
communication and sensing restrictions in wireless resource allocation
problems. The class of algorithms analysed here requires no message-passing
whatsoever between wireless devices, and we show that they continue to perform
well even when devices are only able to carry out constrained sensing of the
surrounding radio environment
Synchronization in random networks with given expected degree sequences
Synchronization in random networks with given expected degree sequences is studied. We also investigate in details the synchronization in networks whose topology is described by classical random graphs, power-law random graphs and hybrid graphs when N goes to infinity. In particular, we show that random graphs almost surely synchronize. We also show that adding small number of global edges to a local graph makes the corresponding hybrid graph to synchroniz
Equilibrium analysis of cellular neural networks
Cellular neural networks are dynamical systems, described by a large set of coupled nonlinear differential equations. The equilibrium point analysis is an important step for understanding the global dynamics and for providing design rules. We yield a set of sufficient conditions (and a simple algorithm for checking them) ensuring the existence of at least one stable equilibrium point. Such conditions give rise to simple constraints, that extend the class of CNN, for which the existence of a stable equilibrium point is rigorously proved. In addition, they are suitable for design and easy to check, because they are directly expressed in term of the template elements
Synchronization in Networks of Hindmarsh-Rose Neurons
Synchronization is deemed to play an important role in information processing in many neuronal systems. In this work, using a well known technique due to Pecora and Carroll, we investigate the existence of a synchronous state and the bifurcation diagram of a network of synaptically coupled neurons described by the Hindmarsh-Rose model. Through the analysis of the bifurcation diagram, the different dynamics of the possible synchronous states are evidenced. Furthermore, the influence of the topology on the synchronization properties of the network is shown through an exampl
Decentralised Algorithms for Wireless Networks.
Designing and managing wireless networks is challenging for many
reasons. Two of the most crucial in 802.11 wireless networks are:
(a) variable per-user channel quality and (b) unplanned, ad-hoc deployment
of the Access Points (APs). Regarding (a), a typical consequence
is the selection, for each user, of a different bit-rate, based on
the channel quality. This in turn causes the so-called performance
“anomaly”, where the users with lower bit-rate transmit for most of
the time, causing the higher bit-rate users to receive less time for
transmission (air time). Regarding (b), an important issue is managing
interference. This can be mitigated by selecting different channels
for neighbouring APs, but needs to be carried out in a decentralised
way because often APs belong to different administrative domains, or
communication between APs is unfeasible. Tools for managing unplanned
deployment are also becoming important for other small cell
networks, such as femtocell networks, where decentralised allocation
of scrambling codes is a key task
Fast, responsive decentralized graph coloring
Graph coloring problem arises in numerous networking applications. We solve it in a fully decentralized way (ı.e., with no message passing). We propose a novel algorithm that is automatically responsive to topology changes, and we prove that it converges to a proper coloring in O(NlogN) time with high probability for generic graphs, when the number of available colors is greater than Δ , the maximum degree of the graph, and in O(logN) time if Δ=O(1) . We believe the proof techniques used in this paper are of independent interest and provide new insight into the properties required to ensure fast convergence of decentralized algorithms
All That Glitters is Gold -- An Attack Scheme on Gold Questions in Crowdsourcing
One of the most popular quality assurance mechanisms in paid micro-task crowdsourcing is based on gold questions: the use of a small set of tasks of which the requester knows the correct answer and, thus, is able to directly assess crowd work quality. In this paper, we show that such mechanism is prone to an attack carried out by a group of colluding crowd workers that is easy to implement and deploy: the inherent size limit of the gold set can be exploited by building an inferential system to detect which parts of the job are more likely to be gold questions. The described attack is robust to various forms of randomisation and programmatic generation of gold questions. We present the architecture of the proposed system, composed of a browser plug-in and an external server used to share information, and briefly introduce its potential evolution to a decentralised implementation. We implement and experimentally validate the gold detection system, using real-world data from a popular crowdsourcing platform. Finally, we discuss the economic and sociological implications of this kind of attack
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