Search results for "NETWORKS"

Model-Based Transfer Entropy Analysis of Brain-Body Interactions with Penalized regression techniques

2020

The human body can be seen as a functional network depicting the dynamical interactions between different organ systems. This exchange of information is often evaluated with information-theoretic approaches which comprise the use of vector autoregressive (VAR) and state space (SS) models, normally identified with the Ordinary Least Squares (OLS). However, the number of time series to be included in the model is strictly related to the length of data recorded thus limiting the use of the classical approach. In this work, a new method based on penalized regressions, the so-called LASSO, was compared with OLS on physiological time-series extracted from 18 subjects during different stress condi…

Assessing movie similarity using a multilayer network model

2021

International audience; This work investigates the movie similarity issue. A multilayer network model capturing various aspects of the story is built from movie scripts. Based on this representation, movies are compared not from summary or actors but using their storyboard. We rely on the "Portrait divergence" to quantify distances between graph characteristics. We illustrate the effectiveness of this approach in comparing movie series.

Dynamic packet scheduling performance in UTRA Long Term Evolution downlink

2008

In this paper we evaluate the performance of dynamic Packet Scheduling (PS) of 3GPP UTRAN Long Term Evolution (LTE) Downlink. Packet scheduling is of utmost importance in 3G LTE, because all traffic types with different Quality of Service requirements are competing of the resources. We present a decoupled time and frequency domain packet scheduling framework for LTE downlink. Simulation results with three basic packet scheduler combinations with different amount of fairness are presented in four different 3GPP macro simulation cases to show the both extremes in tradeoff between fairness and spectral efficiency. In addition, the effect of multiuser diversity on packet scheduling performance …

Feasibility of FPGA accelerated IPsec on cloud

2018

Abstract Hardware acceleration for famous VPN solution, IPsec, has been widely researched already. Still it is not fully covered and the increasing latency, throughput, and feature requirements need further evaluation. We propose an IPsec accelerator architecture in an FPGA and explain the details that need to be considered for a production ready design. This research considers the IPsec packet processing without IKE to be offloaded on an FPGA in an SDN network. Related work performance rates in 64 byte packet size for throughput is 1–2 Gbps with 0.2 ms latency in software, and 1–4 Gbps with unknown latencies for hardware solutions. Our proposed architecture is capable to host 1000 concurre…

On the role of symmetry in solving maximum lifetime problem in two-dimensional sensor networks

2016

We analyze a continuous and discrete symmetries of the maximum lifetime problem in two dimensional sensor networks. We show, how a symmetry of the network and invariance of the problem under a given transformation group $G$ can be utilized to simplify its solution. We prove, that for a $G$-invariant maximum lifetime problem there exists a $G$-invariant solution. Constrains which follow from the $G$-invariance allow to reduce the problem and its solution to a subset, an optimal fundamental region of the sensor network. We analyze in detail solutions of the maximum lifetime problem invariant under a group of isometry transformations of a two dimensional Euclidean plane.

Efficient Steering Mechanism for Mobile Network-Enabled UAVs

2022

HTTP Adaptive Streaming (HAS) is becoming the de-facto video delivery technology over best-effort networks nowadays, thanks to the myriad advantages it brings. However, many studies have shown that HAS suffers from many Quality of Experience (QoE)-related issues in the presence of competing players. This is mainly caused by the selfishness of the players resulting from the decentralized intelligence given to the player. Another limitation is the bottleneck link that could happen at any time during the streaming session and anywhere in the network. These issues may result in wobbling bandwidth perception by the players and could lead to missing the deadline for chunk downloads, which result …

Downlink channel access performance of NR-U: Impact of numerology and mini-slots on coexistence with Wi-Fi in the 5 GHz band

2020

Coexistence between cellular systems and Wi-Fi gained the attention of the research community when LTE License Assisted Access (LAA) entered the unlicensed band. The recent introduction of NR-U as part of 5G introduces new coexistence opportunities because it implements scalable numerology (flexible subcarrier spacing and OFDM symbol lengths), and non-slot based scheduling (mini-slots), which considerably impact channel access. This paper analyzes the impact of NR-U settings on its coexistence with Wi-Fi networks and compares it with LAA operation using simulations and experiments. First, we propose a downlink channel access simulation model, which addresses the problem of the dependency an…

Il paradigma della Smart Land nell’arcipelago Sicano

2017

Le Aree Interne, caratterizzate da poli rurali-urbani disconnessi tra loro, possono essere interpretate come arcipelaghi territoriali che, a differenza dei consolidati sistemi metropolitani, rappresentano ‘isole di eccellenza’, territori fertili non-gravitazionali su cui sperimentare nuove centralità, con specializzazioni funzionali che valorizzino le identità locali (uniche e non riproducibili) in forme innovative e attivare azioni di networking per produrre attrattività e competere nel contesto sovralocale. La ricerca presentata, che si inserisce nell’ambito dell’interesse ministeriale sulle Aree Interne, è finalizzata alla individuazione di sistemi rurali/urbani locali per ri-attivare il…

Air Transport Network: a short review

2013

La proposta di Direttiva Bolkestein fra nuove esigenze e paure di innovazione

2006

By the beginning of this year, EU institutions are approving a proposal of directive on the internal market services liberalization. It is probably the last important step along the path of european economic integration, started in 1957 with the Treaty of Rome. The proposal has not yet an easy pattern, above all for the "country of origin principle". This principle is seen by the supporters as an important tool to speed up the process, but by the opponents as a way to favour possible bottom races for social standards, due to a competition based exclusively upon the employment factor. A basic question is what it will remain at the end of the day, after revisions, corrections, integrations th…