3,559 research outputs found
Adaptive service discovery on service-oriented and spontaneous sensor systems
Service-oriented architecture, Spontaneous networks, Self-organisation, Self-configuration, Sensor systems, Social patternsNatural and man-made disasters can significantly impact both people and environments. Enhanced effect can be achieved through dynamic networking of people, systems and procedures and seamless integration of them to fulfil mission objectives with service-oriented sensor systems. However, the benefits of integration of services will not be realised unless we have a dependable method to discover all required services in dynamic environments. In this paper, we propose an Adaptive and Efficient Peer-to-peer Search (AEPS) approach for dependable service integration on service-oriented architecture based on a number of social behaviour patterns. In the AEPS network, the networked nodes can autonomously support and co-operate with each other in a peer-to-peer (P2P) manner to quickly discover and self-configure any services available on the disaster area and deliver a real-time capability by self-organising themselves in spontaneous groups to provide higher flexibility and adaptability for disaster monitoring and relief
Open education: common(s), commonism and the new common wealth
Open Education, and specifically the Open Education Resources movement, seeks to provide universal access to knowledge, undermining the historical enclosure and increasing privatisation of the public education system. An important aspect of this movement is a reinvigoration of the concept of âthe commonsâ. The paper examines this aspiration by submitting the implicit theoretical assumptions of Open Education and the underlying notion of âthe commonsâ to the test of critical political economy. The paper acknowledges the radical possibility of the idea of âthe commonsâ, but argues that its radical potentiality can be undermined by a preoccupation with âthe freedom of things rather than with the freedom of labourâ. The paper presents an interpretation of âthe commonsâ based on the concept of âliving knowledgeâ and âautonomous institutionalityâ (Roggero, 2011), and offers the Social Science Centre in the UK, as an example of an âinstitution of the commonâ1. The paper concludes by arguing the most radical revision of the concept of âthe commonâ involves a fundamental reappraisal of what constitutes social or common wealth
Stochastic Analysis of a Churn-Tolerant Structured Peer-to-Peer Scheme
We present and analyze a simple and general scheme to build a churn
(fault)-tolerant structured Peer-to-Peer (P2P) network. Our scheme shows how to
"convert" a static network into a dynamic distributed hash table(DHT)-based P2P
network such that all the good properties of the static network are guaranteed
with high probability (w.h.p). Applying our scheme to a cube-connected cycles
network, for example, yields a degree connected network, in which
every search succeeds in hops w.h.p., using messages,
where is the expected stable network size. Our scheme has an constant
storage overhead (the number of nodes responsible for servicing a data item)
and an overhead (messages and time) per insertion and essentially
no overhead for deletions. All these bounds are essentially optimal. While DHT
schemes with similar guarantees are already known in the literature, this work
is new in the following aspects:
(1) It presents a rigorous mathematical analysis of the scheme under a
general stochastic model of churn and shows the above guarantees;
(2) The theoretical analysis is complemented by a simulation-based analysis
that validates the asymptotic bounds even in moderately sized networks and also
studies performance under changing stable network size;
(3) The presented scheme seems especially suitable for maintaining dynamic
structures under churn efficiently. In particular, we show that a spanning tree
of low diameter can be efficiently maintained in constant time and logarithmic
number of messages per insertion or deletion w.h.p.
Keywords: P2P Network, DHT Scheme, Churn, Dynamic Spanning Tree, Stochastic
Analysis
Analysis of current middleware used in peer-to-peer and grid implementations for enhancement by catallactic mechanisms
This deliverable describes the work done in task 3.1, Middleware analysis: Analysis of current middleware used in peer-to-peer and grid implementations for enhancement by catallactic mechanisms from work package 3, Middleware Implementation. The document is divided in four parts: The introduction with application scenarios and middleware requirements, Catnets middleware architecture, evaluation of existing middleware toolkits, and conclusions. -- Die Arbeit definiert Anforderungen an Grid und Peer-to-Peer Middleware Architekturen und analysiert diese auf ihre Eignung fĂŒr die prototypische Umsetzung der Katallaxie. Eine Middleware-Architektur fĂŒr die Umsetzung der Katallaxie in Application Layer Netzwerken wird vorgestellt.Grid Computing
Specifying and analysing reputation systems with coordination languages
Reputation systems are nowadays widely used to support decision making in networked systems. Parties in such systems rate each other and use shared ratings to compute reputation scores that drive their interactions. The existence of reputation systems with remarkable differences calls for formal approaches to their analysis. We present a verification methodology for reputation systems that is based on the use of the coordination language Klaim and related analysis tools. First, we define a parametric Klaim specification of a reputation system that can be instantiated with different reputation models. Then, we consider stochastic specification obtained by considering actions with random (exponentially distributed) duration. The resulting specification enables quantitative analysis of properties of the considered system. Feasibility and effectiveness of our proposal is demonstrated by reporting on the analysis of two reputation models
Framing the collaborative economy - Voices of contestation
Within the context of multiple crises and change, a range of practices discussed under the umbrella term of collaborative (or sharing) economy have been gaining considerable attention. Supporters build an idealistic vision of collaborative societies. Critics have been stripping the concept of its visionary potential, questioning its revolutionary nature. In the study, these debates are brought down to the local level in search for common perceptions among the co-creators of the concept in Vienna, Austria. Towards this aim a Q study is conducted, i.e. a mixed method enabling analyses of subjective perceptions on socially contested topics. Four framings are identified: Visionary Supporters, Market Optimists, Visionary Critics, and Skeptics, each bringing their values, visions, and practical goals characteristic of different understanding of the collaborative economy. The study questions the need for building a globally-applicable definition of the concept, calls for more context-sensitivity, exploratory studies, and city-level multi-stakeholder dialogues
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Conversations on a probable future: interview with Beatrice Fazi
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