Availability-based persistence in reti sociali P2P

Le Distributed Online Social Networks (DOSNs) sono una sottoclasse delle OSNs che garantiscono un alto livello di autonomia e privacy. Questa tesi propone un approccio dinamico e totalmente distribuito al problema della persistenza dei dati nelle DOSNs che, basandosi sulla availability dei peer e sul concetto di trust tra utenti, garantisce un alto grado di disponibilità dei dati all’interno della rete. La persistenza dei dati nel sistema viene garantita attraverso l’elezione di un insieme di punti di memorizzazione, detti social cache, per i dati degli utenti. Le social cache, scelte in base alla loro centralità nella rete e alla loro disponibilità nel sistema, memorizzano o sono in grado di accedere ai dati dei propri amici offline, rendendoli disponibili a tutti i propri vicini che hanno diritto ad accedervi. È stata inoltre realizzata un’implementazione del nostro modello in PeerSim, un simulatore scalabile per reti P2P. I risultati raccolti con le nostre simulazioni testimoniano la bontà dell’approccio proposto. Distributed Online Social Networks (DOSNs) are a subset of OSNs that ensure a high level of autonomy and privacy. This thesis proposes a dynamic and fully distributed approach to the problem of data persistence in DOSNs. Our model is based on node availability and on trust between users and ensures a high level of data availability in the network. Data persistence in the system is achieved through the election of a set of points of storage, called social caches, for users’ data. Social caches, which are chosen according to their centrality and their availability in the system, store or are able to access to their offline friends’ data, making them available to all their neighbours who have the right to access them. We also show an implementation of our model in PeerSim, a scalable P2P simulator. The results obtained with our simulations show the validity of our approach

Probabilistic assessment of Net Transfer Capacity considering forecast uncertainties

In transmission system planning, researchers propose methods to assess the effect of uncertainties of power system operating condition due to forecasting errors of intermittent generation and loads. In particular probabilistic power flow methods are used to calculate the probability distributions of the voltages and the branch currents, starting from the distributions of power injections/absorptions. These uncertainties play a key role in the operational planning of power systems, as certain configurations of load and intermittent generation can cause security problems. This paper aims to propose a probabilistic methodology to assess Net Transfer Capacity (NTC) among network areas, which quantifies forecast error uncertainties by applying the Point Estimate Method (PEM) combined with Third Order Polynomial Normal (TPN) Transformation. This approach is compared with a conventional NTC assessment technique and has been tested on an IEEE test system

ODINet - Online Data Integration Network

Along with the expansion of Open Data and according to the latest EU directives for open access, the attention of public administration, research bodies and business is on web publishing of data in open format. However, a specialized search engine on the datasets, with similar role to that of Google for web pages, is not yet widespread. This article presents the Online Data Integration Network (ODINet) project, which aims to define a new technological framework for access to and online dissemination of structured and heterogeneous data through innovative methods of cataloging, searching and display of data on the web. In this article, we focus on the semantic component of our platform, emphasizing how we built and used ontologies. We further describe the Social Network Analysis (SNA) techniques we exploited to analyze it and to retrieve the required information. The testing phase of the project, that is still in progress, has already demonstrated the validity of the ODINet approach

MicroRNA 19a replacement partially rescues fin and cardiac defects in zebrafish model of Holt Oram syndrome

Holt-Oram Syndrome (HOS) is an autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene, a transcription factor capable of regulating hundreds of cardiac-specific genes through complex transcriptional networks. Here we show that, in zebrafish, modulation of a single miRNA is sufficient to rescue the morphogenetic defects generated by HOS. The analysis of miRNA-seq profiling revealed a decreased expression of miR-19a in Tbx5-depleted zebrafish embryos compared to the wild type. We revealed that the transcription of the miR-17-92 cluster, which harbors miR-19a, is induced by Tbx5 and that a defined dosage of miR-19a is essential for the correct development of the heart. Importantly, we highlighted that miR-19a replacement is able to rescue cardiac and pectoral fin defects and to increase the viability of HOS zebrafish embryos. We further observed that miR-19a replacement shifts the global gene expression profile of HOS-like zebrafish embryos towards the wild type condition, confirming the ability of miR-19a to rescue the Tbx5 phenotype. In conclusion our data demonstrate the importance of Tbx5/miR-19a regulatory circuit in heart development and provide a proof of principle that morphogenetic defects associated with HOS can be rescued by transient miRNA modulation

ODINet un framework innovativo per l\u27accesso e la diffusione on-line di dati strutturati ed eterogenei

ODINet is a research and development project, approved as part of the Regional Operational Programme through the European Regional Development Fund 2007-2013. The project involves the construction of a semantic search engine prototype able to catalog the data in a ontological graph, to extract the most relevant information depending on user requests and return them in a highly usable way. The application domain concerns the social, economic and health, in order to cover most of the data held by public bodies in the national context. The focus of this report is in the first place the description of the semantic components of the platform, emphasizing how the ontologies have been used to build an index in the form of graph. We also present a description of our semantic searches and finally an analysis of the results obtained in the final stage of the ODINEt prototype testing

Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up

Background Congenital hip dysplasia may lead to severe acetabular and femoral abnormalities that can make total hip arthroplasty a challenging procedure. We assessed a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using cementless tapered stem and here we report the outcomes at long-term follow-up. Materials and methods Twenty-eight patients (24 women and 4 men) aged between 44 and 50 years (mean 47 years) were observed. Clinical evaluation was rated with the Harris Hip Score. Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe’s classification, 16 hips presented dysplasia grade 1, 14 grade 2, and 4 grade 3. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis). Six patients were operated bilaterally, with a totally of 34 hips operated. After surgery, the patients were clinically and radiographically checked at 3, 6, and 12 months and yearly thereafter until an average follow-up of 12 years (range 10–14 years). Results Average Harris Hip Score was 56 ± 9 (range 45–69) preoperatively, 90 ± 9 (range 81–100) 12 months after surgery, and 91 ± 8 (range 83–100) at last follow-up. Radiographic evaluation demonstrated excellent osteointegration of the implants. Signs of bone resorption were present in 6 hips, nevertheless no evidence of loosening was observed and none of the implants has been revised. Conclusions Even in dysplasic femur, the tapered stem allowed adequate stability and orientation of the implant. We consider tapered stem a suitable option for total hip arthroplasty in developmental hip dysplasia, also in case of young patients, thanks to the favourable long-term results

Dynamic models for Distributed Energy Resources in a Microgrid environment

Security assessment issues on modern power systems become more and more important also because of the growing penetration of DG (Distributed Generation) sources on the electric power systems. Today their penetration is still marginal with respect to the overall system load, but in the future they can cover a significant part of the consumptions, which means that research on power system security assessment has to investigate the possible impacts of such a phenomenon on security issues. Moreover, these models are essential for Microgrid studies and evaluation of their performances. In order to assess the actual impacts of DG sources on operational security it is necessary to have adequate dynamic models of the sources themselves. This paper presents the dynamic models of several renewable and fossil fuel based Distributed Energy Resources (DER) implemented in a well-known time domain simulator for power systems. Some simulation results are discussed

Trusted Dynamic Storage for Dunbar-Based P2P Online Social Networks

Online Social Networks (OSNs) are becoming more and more popular in today’s Internet. 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. The main challenge of DOSNs comes from guaranteeing availability of the data when the data owner is offline. In this paper we propose a new P2P dynamic approach to the problem of data persistence in DOSNs. By following Dunbar’s approach, our system stores the data of a user only on a restricted number of friends which have regular contacts with him/her. Users in this set are chosen by considering several criteria targeting different goals. Differently from other approaches, nodes chosen to keep data replicas are not statically defined but dynamically change according to users’ churn. Our dynamic friend selection achieves availability higher than 90% with a maximum of 2 online profile replicas at a time for users with at least 40 friends. By using real Facebook data traces we prove that our approach offers high availability even when the online time of users is low

Controllo dei carichi termostatici per la sicurezza del sistema elettrico

Il potenziale contributo dei carichi termostatici alla regolazione primaria di frequenza \ue8 analizzato rispetto alla disponibilit\ue0 della risorsa nel tempo e all\u2019efficacia dell\u2019intervento, considerando anche le condizioni alle quali questo servizio potrebbe essere applicato