Search results for "working"
showing 10 items of 2747 documents
The Urban Theory
2014
Il paradigma della rete è sempre più utilizzato per spiegare i processi dell’economia globalizzata e della cooperazione internazionale, e le dinamiche con cui i soggetti intercettano flussi materiali e immateriali e costruiscono relazioni. A seguito di una rassegna della letteratura internazionale sulle diverse teorie delle reti, la ricerca, da cui questo articolo è estratto, approfondisce la Urban Theory, che analizza la rete come quella forma relazionale che rilevando i flussi, reali o potenziali, connette i centri urbani. L’attenzione è posta sulle dinamiche urbane, in termini di competizione e coesione, che sono spiegate alla luce dei flussi e delle relazioni tra gli attori urbani, valu…
Analysis of Users Behaviour from a Movie Preferences Perspective
2018
Despite their tremendous popularity, Online Social Networks (OSNs) have several issues related to the privacy of social users. These issues have motivated researchers to develop OSN services that take advantage of the decentralized platforms (such as P2P systems or opportunistic networks). Decentralized Online Social Networks (DOSNs) need specific approaches to manage the decentralization of social data. In particular, data availability is one of the main issues and current proposals exploit properties of the social relationships to manage it. At the best of our knowledge, there are no proposals which exploit similarity between users, expressed with the term homophily. Homophily has been we…
Exploiting community detection to recommend privacy policies in decentralized online social networks
2018
The usage of Online Social Networks (OSNs) has become a daily activity for billions of people that share their contents and personal information with the other users. Regardless of the platform exploited to provide the OSNs’ services, these contents’ sharing could expose the OSNs’ users to a number of privacy risks if proper privacy-preserving mechanisms are not provided. Indeed, users must be able to define its own privacy policies that are exploited by the OSN to regulate access to the shared contents. To reduce such users’ privacy risks, we propose a Privacy Policies Recommended System (PPRS) that assists the users in defining their own privacy policies. Besides suggesting the most appro…
Restoration of Vertical Line Scratches with a Distributed Genetic Algorithm
2006
This contribution approaches the problem of scratch restoration in old movies as a optimisation's problem. The functional based on the statistical properties of the image around the scratch is optimised using an ad-hoc genetic algorithm. Given the large amount of the computational time needed by genetic algorithms, a network of standard workstations with heterogeneous operating systems has been used. Each workstation in the network works on each scratch to perform the restoration, and a specific machine works as root node with the task of distributing jobs on the network and adding the outputted restored scratches back into the image.
Effect of residual stresses and their redistribution on the fatigue crack growth in cold-worked holes
2009
The cold-expansion process is widely used to enhance the fatigue life of structures with fastener holes. Various studies assert that the cold-expansion improves the fatigue strength of fastener holes; however, the improvement of fatigue life is difficult to quantify. The influence on fatigue life of cold-worked hole in a 6061-T6 alluminum allosy was studied by numerical and experimental tests. Fatigue crack growth tests were carried out to find the crack length and growth rates of crack propagating from hole edge. Thus, the cold-expansion process was modeled with a Lagrangian implicit code for metal forming to obtain the residual stress field. Progressive crack growth along the observed fat…
How firms are using networking decisions to achieve strategic objectives: Building theories from four case studies
2011
Many research studies in OM literature have investigated how different kinds of focal firm decisions regarding business vertical relationships (i.e. with both suppliers and buyers) can positively affect firm’s operations performance and thus improve its competitive position. In this paper we extend this genre of study by also considering business horizontal relationships (i.e with competitors and firms that own complementary capabilities) and by considering the impact of business relationships not only on focal firm’s operations performance but also on its resources endowment. We present four cases that describe what are the strategic manager intents (in term of operations performance and r…
Realizing airtime allocations in multi-hop Wi-Fi networks: A stability and convergence study with testbed evaluation
2019
Abstract REACT is a distributed resource allocation protocol used to negotiate a max–min allocation of airtime for multi-hop ad hoc wireless networks. Two approaches are proposed for a node to realize its REACT allocation in a contention-based MAC protocol. This is achieved by tuning its contention window to a value that corresponds to its allocation. Only a change in the allocation, due to a change in local traffic requirements or local network views, results in re-tuning. The approaches for tuning are implemented in commercial Wi-Fi devices and their stability and convergence are studied experimentally in the w-iLab.t wireless network testbed. These properties are also studied analyticall…
Coexistence between IEEE802.15.4 and IEEE802.11 through cross-technology signaling
2017
When different technologies use the same frequency bands in close proximity, the resulting interference typically results in performance degradation. Coexistence methods exist, but these are often technology specific and requiring technology specific interference detection methods. To remove the root cause of the performance degradation, devices should be able to negotiate medium access even when using different technologies. To this end, this paper proposes an architecture that allows crosstechnology medium access by means of a Time Division Multiple Access (TDMA) scheme. In order to achieve cross-technology synchronization, which is required for the TDMA solution, an energy pattern beacon…
Cross-Technology WiFi/ZigBee Communications: Dealing With Channel Insertions and Deletions
2016
In this letter, we show how cross-technology interference can be exploited to set up a low-rate bidirectional communication channel between heterogeneous WiFi and ZigBee networks. Because of the environment noise and receivers' implementation, the cross-technology channel can be severely affected by insertions and deletions of symbols, whose effects need to be taken into account by the coding scheme and communication protocol.
MAC design on real 802.11 devices: From exponential to Moderated Backoff
2016
In this paper we describe how a novel backoff mechanism called Moderated Backoff (MB), recently proposed as a standard extension for 802.11 networks, has been prototyped and experimentally validated on a commercial 802.11 card before being ratified. Indeed, for performance reasons, the time critical operations of MAC protocols, such as the backoff mechanism, are implemented into the card hardware/firmware and cannot be arbitrarily changed by third parties or by manufacturers only for experimental reasons. Our validation has been possible thanks to the availability of the so called Wireless MAC Processor (WMP), a prototype of a novel wireless card architecture in which MAC protocols can be p…