Search results for "Computer network"
showing 10 items of 1634 documents
System times and channel availability analyses in multi-channel cognitive radio networks
2014
Channel accessibility by a secondary user (SU) in cognitive radio networks (CRNs) depends on the availability of the spectrum based on primary user and other SU activities. A new SU request may be blocked and an ongoing SU service may also be discarded if no sufficient spectrum is available. So far, little work has been done to analyze the reliability and availability aspects of CRNs from the perspective of the dependability theory. In this paper, we introduce the concept of availability for spectrum access in multi-channel CRNs, which is defined as the fraction of time that a CRN can allocate at least the minimum number of required channels for a new SU request. Through a proposed continuo…
Combining social media affordances for organising collective action
2020
Swarming Models for Facilitating Collaborative Decisions
2010
The paper highlights the computational power of swarming models (i.e., stigmergic mechanisms) to build collaborative support systems for complex cognitive tasks such as facilitation of group decision processes (GDP) in e-meetings. Unlike traditional approaches that minimize the cognitive complexity by incorporating the facilitation knowledge into the system, stigmergic coordination mechanisms minimize the complexity by providing the system with emergent functionalities that are shaped by the environment itself through the possibility to structure it in terms of high-level cognitive artefacts. This is illustrated by conducting a socio-simulation experiment for an envisioned collaborative sof…
XPL the Extensible Presentation Language
2009
The last decade has witnessed a growing interest in the development of web interfaces enabling both multiple ways to access contents and, at the same time, fruition by multiple modalities of interaction (point-and-click, contents reading, voice commands, gestures, etc.). In this paper we describe a framework aimed at streamlining the design process of multi-channel, multimodal interfaces enabling full reuse of software components. This framework is called the eXtensible Presentation architecture and Language (XPL), a presentation language based on design pattern paradigm that keeps separated the presentation layer from the underlying programming logic. The language supplies a methodology to…
Mobile social networking in theory and practice
2008
Mobile social networks have gained the attention of the media, academy and mobile market. Despite of the robust tradition of network and community studies, mobile social networks are often addressed improperly. This paper presents a theoretical framework to study mobile social networking and examines the design implications of results of an exploratory study conducted with a group of 18 young adults in Finland. The findings of this study indicate that the quality of mobile applications offering social networking could be greatly increased by integrating the knowledge of two traditions that so far developed in parallel, namely the mathematical as well as social approaches to social networks.
Learning with belief levels
2008
AbstractWe study learning of predicate logics formulas from “elementary facts,” i.e. from the values of the predicates in the given model. Several models of learning are considered, but most of our attention is paid to learning with belief levels. We propose an axiom system which describes what we consider to be a human scientist's natural behavior when trying to explore these elementary facts. It is proved that no such system can be complete. However we believe that our axiom system is “practically” complete. Theorems presented in the paper in some sense confirm our hypothesis.
Incremental Generalized Discriminative Common Vectors for Image Classification.
2015
Subspace-based methods have become popular due to their ability to appropriately represent complex data in such a way that both dimensionality is reduced and discriminativeness is enhanced. Several recent works have concentrated on the discriminative common vector (DCV) method and other closely related algorithms also based on the concept of null space. In this paper, we present a generalized incremental formulation of the DCV methods, which allows the update of a given model by considering the addition of new examples even from unseen classes. Having efficient incremental formulations of well-behaved batch algorithms allows us to conveniently adapt previously trained classifiers without th…
A Guaranteed performance of a green data center based on the contribution of vital nodes
2016
International audience; In order to satisfy the need for the critical computing resources, many data center architectures proposed to house a huge number of network devices. These devices are used to achieve the highest performance in case of full utilization of the network. However, the peak capacity of the network is rarely reached. Consequently, many devices are set into idle state and cause a huge energy waste leading to a non-proportionality between the network load and the energy consumed. In this paper, we propose a power-aware routing algorithm that saves energy consumption with a negligible trade-off on the performance of the network. The idea is to keep active only the source and …
Achieving energy efficiency in data centers with a performance-guaranteed power aware routing
2017
Nowadays, data centers are designed to offer the highest performance in case of high traffic load and peak utilisation of the network. However, in a realistic data center environment, the peak capacity of the network is rarely reached and the average utilisation of devices varies between 5% and 25% which results into a huge loss of energy since most of the time links and servers are idle or under-utilized. The high impact of this wasted power on environmental effects, energy needs and electricity costs raised the concerns to seek for an efficient solution to make data centers more power effective while keeping the desired quality of service. In this paper, we propose a power-aware routing a…