Search results for "NETWORKS"
showing 10 items of 3260 documents
Generalized person-by-person optimization in team problems with binary decisions
2008
In this paper, we extend the notion of person by person optimization to binary decision spaces. The novelty of our approach is the adaptation to a dynamic team context of notions borrowed from the pseudo-boolean optimization field as completely local-global or unimodal functions and sub- modularity. We also generalize the concept of pbp optimization to the case where the decision makers (DMs) make decisions sequentially in groups of m, we call it mbm optimization. The main contribution are certain sufficient conditions, verifiable in polynomial time, under which a pbp or an mbm optimization algorithm leads to the team-optimum. We also show that there exists a subclass of sub-modular team pr…
Virtual Resource Allocation for Wireless Virtualized Heterogeneous Network with Hybrid Energy Supply
2022
In this work, two novel virtual user association and resource allocation algorithms are introduced for a wireless virtualized heterogeneous network with hybrid energy supply. In the considered system, macro base stations (MBSs) are supplied by the grid power and small base stations (SBSs) have the energy harvesting capability in addition to the grid power supplement. Multiple infrastructure providers (InPs) own the physical resources, i.e., BSs and radio resources. The Mobile Virtual Network Operators (MVNOs) are able to recent these resources from the InPs and operate the virtualized resources for providing services to different users. In particular, aiming to maximize the overall utility …
Structural Dynamics and Intentional Governance in Strategic Interorganizational Network Evolution: A Multilevel Approach
2016
This article aims to shed light on the drivers underlying the role and scope of intentional governance of the structural dynamics of whole interorganizational networks. Prior research has distinguished networks that are emergent from networks that are orchestrated. While empirical studies have shown situations in which the role and scope of intentional governance of whole interorganizational networks has changed in time, and there is a growing interest regarding the endogenous drivers of network dynamics, the dimensions that influence intentional governance of network structure dynamics and the way this is carried out remain still to be elucidated. In order to pinpoint these drivers, we le…
Correlation, hierarchies, and networks in financial markets
2010
We discuss some methods to quantitatively investigate the properties of correlation matrices. Correlation matrices play an important role in portfolio optimization and in several other quantitative descriptions of asset price dynamics in financial markets. Specifically, we discuss how to define and obtain hierarchical trees, correlation based trees and networks from a correlation matrix. The hierarchical clustering and other procedures performed on the correlation matrix to detect statistically reliable aspects of the correlation matrix are seen as filtering procedures of the correlation matrix. We also discuss a method to associate a hierarchically nested factor model to a hierarchical tre…
How individual characteristics shape the structure of social networks
2015
Abstract We study how students’ social networks emerge by documenting systematic patterns in the process of friendship formation of incoming students; these students all start out in a new environment and thus jointly create a new social network. As a specific novelty, we consider cooperativeness, time and risk preferences – elicited experimentally – together with factors like socioeconomic and personality characteristics. We find a number of robust predictors of link formation and of the position within the social network (local and global network centrality). In particular, cooperativeness has a complex association with link formation. We also find evidence for homophily along several dim…
A 16QAM super-orthogonal space-frequency code for broadband mobile communication systems with two transmit antennas
2010
We combine our previously designed 32-state super-orthogonal space-time trellis code (SOSTTC) with orthogonal frequency division multiplexing (OFDM) to build a broadband mobile communication system having a spectral efficiency that amounts to 4 bits/s/Hz depending on the length of the cyclic prefix used to avoid interframe interference. The transmitter is equipped with two antennas, where the OFDM frames they transmit are not independent, as they carry the same information in an orthogonal form. The 2N OFDM tones are grouped in N pairs of tones. Each group of two tones transmits the entries of a 2×2 orthogonal matrix. In our case, the entries are symbols taken from the rectangular 16-point …
An OFDM Receiver Exploiting Multipath Diversity
2008
We propose a novel receiver structure, to be employed with standard Orthogonal Frequency Division Multiplexing transmitters, capable of exploiting the multipath diversity of wireless channels. The proposed technique is based on cancellation of inter-block interference arising in the guard interval and linear detection techniques. It features a low implementation complexity and is easily generalized to MIMO systems and non-linear detection techniques.
Multimodal disinformation about otherness on the internet : the spread of racist, xenophobic and Islamophobic fake news in 2020
2021
This work studies the use of disinformation to construct an image of otherness through the internet. We applied a content analysis methodology to the 161 racist, xenophobic or Islamophobic fake news pieces that were discredited in 2020 by the four Spanish information verification media entities accredited by the International Fact-Checking Network: Maldita.es , Newtral , Efe Verifica and Verificat . The results show that the most commonly used formats were image and video, that disinformation was most often based on taking information out of context and deception, and that the source could not be identified. The most shared characteristics associated otherness with receiving aid, violence a…
Privacy-Preserving Overgrid: Secure Data Collection for the Smart Grid
2020
In this paper, we present a privacy-preserving scheme for Overgrid, a fully distributed peer-to-peer (P2P) architecture designed to automatically control and implement distributed Demand Response (DR) schemes in a community of smart buildings with energy generation and storage capabilities. To monitor the power consumption of the buildings, while respecting the privacy of the users, we extend our previous Overgrid algorithms to provide privacy preserving data aggregation (PP-Overgrid). This new technique combines a distributed data aggregation scheme with the Secure Multi-Party Computation paradigm. First, we use the energy profiles of hundreds of buildings, classifying the amount of &ldquo
DiDuSoNet: A P2P architecture for Ditributed Dunbar-based Social Networks,
2015
Online Social Networks (OSNs) are becoming more and more popular on the Web. Distributed Online Social Networks (DOSNs) are OSNs which do not exploit a central server for storing users data and enable users to have more control on their profile content, ensuring a higher level of privacy. In a DOSN there are some technical challenges to face. One of the most important challenges is the data availability problem when a user is offline. In this paper we propose DiDuSoNet, a novel P2P Distributed Online Social Network where users can exercise full access control on their data. Our system exploits trust relationships for providing a set of important social services, such as trustness, informati…