262,363 research outputs found
Emprisonnement, déchéance et abandon : Fort-de-France vue par Alfred Alexandre = Imprisonment, Degradation and Abandoning : Fort-de-France Seen by Alfred Alexandre
No full textThis article analyses Alfred Alexandre’s novel Bord de Canal (2004), in which the capital of Martinique turnes into a setting for human decay. The description of squalid environments,
populated by human debris, shows the lack of interest by the administration in taking responsibility for the lot of the most deprived inhabitants. They end up confined to working-class areas in inhuman living conditions. Through an analysis of places symbolising this degraded and degrading urban environment, which is transformed into a place of social exclusion and persecution, the study shows the renewal of the literary treatment of the city by Alexandre, an author of the post-creolité.Cet article propose une analyse du roman d’Alfred Alexandre
Bord de Canal (2004) où la capitale de la Martinique se révèle
un théâtre de déchéance humaine : l’évocation de milieux sor-
dides habités par des loques humaines montre le manque d’in-
térêt de la part de l’administration pour s’assumer le sort des
habitants les plus démunis qui se trouvent finalement confi-
nés dans les quartiers populaires dans des conditions de vie
inhumaines. À travers l’analyse de lieux symboles de ce cadre
urbain dégradé et dégradant, qui se transforme en lieu d’ex-
clusion et de persécution sociales, l’étude montre le renouveau
du traitement littéraire de la ville chez Alexandre, auteur de la
post-créolité
Above and Beyond Robotic Surgery and 3D Modelling in Paediatric Cancer Surgery
No full textAlthough the survival rates for children's cancers have more than doubled in the last few decades, the surgical practise has not significantly changed. Among the most recent innovations introduced in the clinic, robotic surgery and augmented reality are two of the most promising, even if they are not widespread. The increased flexibility of the motion, the magnification of the surgical field and the tremor reduction provided by robotic surgery have been beneficial to perform complex oncological procedures in children. Besides, augmented reality has been proven helpful in planning for tumour removal, facilitating early discrimination between cancer and healthy organs. Nowadays, research in the field of surgical oncology is moving fast, and new technologies and innovations wich will help to shape a new way to perform cancer surgery. Paediatric surgeons need to be ready to adopt these novel devices and intraoperative techniques to allow more radical tumour resections with fewer complications. This review aims to present the mechanism of action and indications of several novel technologies such as optical imaging surgery, high definition cameras, and intraoperative loco-regional treatments. We hope this will enhance early adoption and more research on how to employ technology for the benefit of children
Un’analisi critica delle risposte ultrasonore ottenute da difetti artificiali e cricche di fatica
No full textNel campo delle PnD, le relazioni quantitative tra la risposta del metodo adottato e la dimensione del difetto sono tipicamente fornite o ricavate in funzione di una opportuna dimensione lineare (profondità, diametro,...) del difetto stesso. Esempi di tali relazioni sono le curve “Probability of Detection”, le curve ADA per il metodo UT o i limiti di accettabilità del metodo PT applicato alle saldature.
La presente memoria analizza le risposte UT ottenute sperimentalmente da cricche di fatica generate su assili ferroviari e le confronta con quelle ricavate da difetti artificiali di forme significativamente differenti ottenuti mediante lavorazioni tradizionali (fori e fresate) o innovative (difetti concavi o convessi per elettro-erosione). Le misure sono state eseguite sia mediante sonde tradizionali monocristallo, sia mediante un sistema phased array. L’elaborazione dei risultati sperimentali ha permesso di osservare che le curve ottenute dai difetti artificiali, significativamente differenziate se diagrammate in funzione della profondità del difetto, collassano su una singola curva, corrispondente a quella delle cricche di fatica, se diagrammate in termini di area riflettente. Tale risultato permette di ripensare in un’ottica completamente nuova la forma dei difetti artificiali adottabili, ad esempio, in blocchi campione per la taratura dei sistemi UT per l’ispezione di assili ferroviari sia in fase di produzione, sia di manutenzione durante il normale esercizio
Tecnologie per la raccolta, la sanitizzazione, l'elaborazione e il rilascio sicuro di dati
No full textNell'ultima decade si è verificato un grande aumento nell'offerta dei servizi cloud. Il trend è facilitato dai bassi costi, l'alta affidabilità, e dalla riduzione dei rischi associati alla perdita dati. Sebbene caricare dati in cloud comporti dei vantaggi, ci sono anche molte sfide legate alla sicurezza e alla privacy. L'esperienza della comunità di ricerca testimonia che non è sufficiente cambiare la visibilità del dato per ottenere un livello di protezione adeguato. Piuttosto, è necessario organizzare meticolosamente l'intero ciclo di vita del dato, dalla raccolta e sanitizzazione, alla memorizzazione ed elaborazione, e infine il rilascio. Questa tesi analizza ciascuno di questi stadi, proponendo soluzioni Open Source innovative. La prima parte di tesi studia la raccolta dati, in particolare in ambiente mobile. Si tratta di un ambiente importante, in quanto è caratterizzato da dispositivi con limitata memoria, connessi alla rete, e con la possibilità di rilevare informazioni sensibili. Per accedere a queste informazioni, un'app deve ottenere i permessi opportuni. Malgrado ciò, tutti i componenti al suo interno condividono lo stesso ambiente d'esecuzione, quindi hanno la stessa visibilità e restrizioni d'accesso. Si tratta di una limitazione degli attuali OS. Focalizzandoci su Android, che è Open Source, proponiamo una serie di modifiche per compartimentalizzare internamente l'app sfruttando il livello MAC. Con questo approccio, lo sviluppatore può caricare un policy module in app per confinare ogni suo componente, limitando l'accesso alla memoria interna e ai servizi.
In seguito alla raccolta, un utente può sanitizzare i dati prima di caricarli in cloud. La sanitizzazione è un processo che altera irreversibilmente i dati, in modo tale che ciascun soggetto referenziato dai essi non possa essere identificato, entro certi parametri di sicurezza, evitando che i dati siano resi inutilizzabili. Nella seconda parte della tesi viene presentato un approccio basato su k-anonimity e l-diversity per sanitizzare grandi collezioni di dati. L'approccio descritto è parallelizzabile ed è caratterizzato da una limitata perdita d'informazione.
La terza parte di tesi investiga gli stadi di memorizzazione ed elaborazione. In questo scenario, il cloud provider viene considerato honest-but-curious, si assume cioè che esso eseguirà sempre le richieste dell'utente, ma potrebbe abusare dell'accesso alle informazioni. L'obiettivo è consentire l'esecuzione di interrogazioni su dati caricati in cloud, senza che il gestore ne abbia accesso in chiaro. Sfortunatamente, l'uso di cifratura deterministica non offre una protezione adeguata, dato che le informazioni cifrate mantengono la stessa distribuzione di quelle in chiaro. La soluzione proposta si applica a dati relazionali, e consente l'esecuzione di interrogazioni con predicati di uguaglianza e intervallo. Le tuple vengono salvate su server in blocchi di uguali dimensioni. I blocchi vengono gestiti dal server come unità atomiche inintelliggibili, e sono acceduti per mezzo di un indice cifrato multidimensionale, anch'esso caricato sul server. Mappe locali vengono invece salvate dal client per eseguire ricerche nell'indice in modo efficiente. L'approccio proposto garantisce perfetta indistinguibilità ad un attaccante con accesso alla memoria. Ciò si ottiene applicando crittografia non deterministica e distruggendo le frequenze dell'indice. L'indice è costruito con un'evoluzione della tecnica presentata nella seconda parte della tesi.
L'ultima parte della tesi si occupa della fase di rilascio dei dati. L'assunzione di onestà è confutata, in quanto in un ambiente decentralizzato le parti non si fidano reciprocamente. Le parti sono invece modellate come razionali. Sotto questa assunzione, viene proposta una soluzione utilizzabile per schedulare il rilascio dati senza la necessità di una parte fidata.The last decade has seen a significant increase in usage of cloud services. This trend is facilitated by the low cost, the high reliability, and the reduced risks linked to data loss.
Albeit there are advantages in uploading data to the cloud, there are also several security and privacy challenges. The experience gained by the Research community attest that it is not enough to just change data visibility to ensure an adequate level of protection. Rather, it is required to pay attention to the whole data lifecycle, from data collection and sanitization, to storage and processing, and finally the release. This thesis analyzes each of these stages, proposing Open Source solutions pushing forward the current state of the art.
The first part of the thesis deals with the collection of data, in particular in the mobile scenario. The mobile environment is especially relevant as smartphones are devices with limited storage, that are connected to the network, and with the ability to log confidential data. To access this information, an app must be granted the proper permission. Yet, all the components running inside it share the same execution environment, thus have the same visibility and access constraints. This is a limitation of the current OS. Focusing on the Android, which is Open Source, we propose a set of modifications to achieve internal app compartmentalization leveraging the MAC layer. With this approach, the developer can add a policy module to the app to confine each component, effectively restricting access to the internal storage and to services.
After the data are collected, a user may apply to it sanitization before being uploaded to the cloud. Sanitization is a process by which data are irreversibly altered so that a subject (referenced within the data) cannot be identified, given a certain security parameter, while the data remain practically useful. The second part of the thesis presents an approach based on k-anonymity and l-diversity to apply sanitization over large collections of data. The approach described can be applied in a distributed environment and is characterized by a limited information loss.
The third part of the thesis investigates the storage and processing stages. In this scenario, the cloud provider is considered honest-but-curious, which assumes that it complies with the requests issued by the user, but may abuse the access to the information provided. Hence, the goal is to support the execution of queries over outsourced data with a guarantee that the cloud provider does not have access to the data content. Unfortunately, the use of deterministic encryption does not offer protection, as the encrypted data maintain the same distribution of the original data. The approach we present is applicable to relational data, and enables the execution of queries involving equality and range conditions. Data is saved encrypted to the server into equally large blocks of tuples. The blocks are managed by the server as atomic units, and accessed through an encrypted multidimensional index also stored by the server. The cloud provider is then unable to identify the single items stored within each block. Local maps are saved by the client to search the index efficiently. The approach provides perfect indistinguishability to an attacker with access to the stored data. This is achieved applying non-deterministic encryption, and by destroying the frequencies of the index. The index is built as an evolution of the technique presented in part two of the thesis.
The last part of the thesis addresses the data release stage. As we move to a decentralized environment in which the parties are mutually distrusting, the honesty assumption is refuted. The parties are instead modeled as rational. In this setting, we propose a solution that can be used to schedule the release of data without the need for a Trusted Party. The approach is based on economic incentives and penalties, enforced by a smart contract
Policy and Security Conguration Management in Distributed Systems
No full textThe evolution of information system sees a continuously increasing need of flexible and sophisticated approaches for the management of security requirements. On one hand, systems are increasingly more integrated (e.g., Bring Your Own Device) and present interfaces for the invocation of services accessible through network connections. On the other hand, system administrators have the responsibility to guarantee that this integration and the consequent exposure of internal resources does not introduce vulnerabilities. The need to prove that the system correctly manages the security requirements is not only motivated by the increased exposure, but also by the need to show compliance with respect to the many regulations promulgated by governments and commercial bodies.
In modern information systems a particular area of security requirement is access control management, with security policies that describe how resources and services should be protected. These policies offer a classification of the actions on the system that distinguishes them into authorized and forbidden, depending on a variety of parameters. Given the critical role of security and their large size and complexity, concerns arise about the correctness of the policy. It is not possible anymore to rely on the security designer to have a guarantee that the policy correctly represents how the system should protect the access to resources.
The research documented in this thesis investigates new approaches for the development of a collection of both methodologies and tools, which are flexible enough to help the system administrators, or generally users, in the correct management of security requirements. Due to the complexity of this topic, the research was focused on (i) enterprise and (ii) mobile scenario
Surgical Approaches to Neuroblastoma: Review of the Operative Techniques
No full textNeuroblastoma (NB) is the most commonly occurring soft-tissue malignancy of childhood. Surgery plays an important role in multidisciplinary treatment and its principal aim is a local control of the disease, respecting the integrity of the surrounding structures. There is no unanimous consensus on the best surgical technique, and the operative approach largely depends on the anatomical location and the extension of the mass. To have a complete overview of the different type of treatment, we made a review of the literature from the last twenty years of all the surgical approaches applied for NBs resection, accordingly to the anatomical site
Evaluating the Development Status of Fluorescence-Guided Surgery (FGS) in Pediatric Surgery Using the Idea, Development, Exploration, Assessment, and Long-Term Study (IDEAL) Framework
No full textFluorescence-guided surgery (FGS) is used in many pediatric subspecialties but there are currently no standard guidelines or outcome data. We aimed to assess the current status of FGS in pediatrics using the Idea, Development, Exploration, Assessment, and Long-term study (IDEAL) framework. Clinical papers on FGS in children published from January 2000 to December 2022 were systematically reviewed. The stage of research development was measured considering seven fields of application: biliary tree imaging, vascular perfusion for gastrointestinal procedures, lymphatic flow imaging, tumor resection, urogenital surgery, plastic surgery, and miscellaneous procedures. Fifty-nine articles were selected. For each field of application, the overall IDEAL stage was determined to be 2a for biliary tree imaging (10 publications, 102 cases), 1 for vascular perfusion for gastrointestinal procedures (8 publications, 28 cases), 1 for lymphatic flow imaging (12 publications, 33 cases), 2a for tumor resection (20 publications, 238 cases), 2a for urogenital surgery (9 publications, 197 cases), and 1-2a for plastic surgery (4 publications, 26 cases). One report did not belong to any categories. FGS in children is still in an early phase of adoption and development. We recommend using the IDEAL framework as a guide and suggest developing multicenter studies to define the standard guidelines, effectiveness, and outcomes
Fluorescence‐Guided Surgery (FGS) during a laparoscopic Redo Nissen Fundoplication: The First Case in Children
No full textWe present the first case of fluorescence‐guided surgery (FGS) using indocyanine green (ICG) in a pediatric redo‐Nissen fundoplication. The patient is a 17‐year‐old male with recurrent gastroesophageal symptoms who underwent primary antireflux surgery at 10 months of age. During the redo fundoplication, ICG was intravenously administered to help the visualization during the adhesiolysis between liver, stomach and right crus of the diaphragm and to spare small oesoph-ageal vessels and the left gastric artery. In this case, FGS made the surgery easier than usual and likely reduced the risk of intra‐operative complications. Therefore, we believe that this new tech-nology should be regularly used in these types of complex intra‐abdominal redo operations
Thoracophrenolaparotomic approach for complete resection of thoracoabdominal neuroblastomas in children
No full textComplete and safe resection of thoracoabdominal neuroblastomas still represent a surgical challenge. The Authors propose a new surgical approach that has proved a safe and well accepted approach. Wide tumor exposure facilitates tumor resectio
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