Nuclear Shape Fluctuations in Fermi-Liquid Drop Model

Within the nuclear Fermi-liquid drop model, quantum and thermal fluctuations are considered by use of the Landau-Vlasov-Langevin equation. The spectral correlation function of the nuclear surface fluctuations is evaluated in a simple model of an incompressible and irrotational Fermi liquid. The dependence of the spectral correlation function on the dynamical Fermi-surface distortion is established. The temperature at which the eigenvibrations become overdamped is calculated. It is shown that, for realistic values of the relaxation time parameter and in the high temperature regime, there is a particular eigenmode of the Fermi liquid drop where the restoring force is exclusively due to the dynamical Fermi-surface distortion.Comment: 23 pages, revtex, file and 3 figures, accepted for publication in Nuclear Physics

Small damping approach in Fermi-liquid theory

The validity of small damping approximation (SDA) for the quasi-classical description of the averaged properties of nuclei at high temperatures is studied within the framework of collisional kinetic theory. The isoscalar collective quadrupole vibrations in hot nuclei are considered. We show that the extension of the SDA, by accounting for the damping of the distribution function $\delta f$ in the collision integral reduces the rate of variation with temperature of the Fermi surface distortion effects. The damping of the $\delta f$ in the collision integral increases significantly the collisional width of the giant quadrupole resonance (GQR) for small enough values of the relaxation time. The temperature dependence of the eigenenergy of the GQR becomes much more weaker than in the corresponding SDA case.Comment: 11 pages, 3 figure

Cloud-Magnetic Resonance Imaging System: In the Era of 6G and Artificial Intelligence

Magnetic Resonance Imaging (MRI) plays an important role in medical diagnosis, generating petabytes of image data annually in large hospitals. This voluminous data stream requires a significant amount of network bandwidth and extensive storage infrastructure. Additionally, local data processing demands substantial manpower and hardware investments. Data isolation across different healthcare institutions hinders cross-institutional collaboration in clinics and research. In this work, we anticipate an innovative MRI system and its four generations that integrate emerging distributed cloud computing, 6G bandwidth, edge computing, federated learning, and blockchain technology. This system is called Cloud-MRI, aiming at solving the problems of MRI data storage security, transmission speed, AI algorithm maintenance, hardware upgrading, and collaborative work. The workflow commences with the transformation of k-space raw data into the standardized Imaging Society for Magnetic Resonance in Medicine Raw Data (ISMRMRD) format. Then, the data are uploaded to the cloud or edge nodes for fast image reconstruction, neural network training, and automatic analysis. Then, the outcomes are seamlessly transmitted to clinics or research institutes for diagnosis and other services. The Cloud-MRI system will save the raw imaging data, reduce the risk of data loss, facilitate inter-institutional medical collaboration, and finally improve diagnostic accuracy and work efficiency.Comment: 4pages, 5figures, letter

Data For VM Allocation

The package contains two folders: “initialContractSpecification” contains the Json files for contract specification corresponding to Fig.2 and “policyGenerated” contains three policy generated in the process of VM allocation. Creation of data: 12/2015 Type of data: processed data Software used: Netbeans and motOrBAC Data format: XML and Json Source: experiments Number of samples: 5 Total size per sample: 10 K

Interopérabilité et négociation des politiques de sécurité

Security policy provides a way to define the constraints on behavior of the members belonging to a system, organization or other entities. With the development of IT technology such as Grid Computing and Cloud Computing, more and more applications and platforms exchange their data and services for cooperating. Toward this trend, security becomes an important issue and security policy has to be applied in order to ensure the safety of data and service interaction. In this thesis, we deal with one type of security policy: access control policy. Access control policy protects the privileges of resource's utilization and there exist different policy models for various scenarios. Our goal is to ensure that the service customer well expresses her security requirements and chooses the service providers that fit these requirements.The first part of this dissertation is dedicated to service provider selection. In case that the security policies of the service provider are accessible to the service customer, we provide a method for measuring the similarity between security policies. Another case is that security policies are not accessible to the service customer or not specified explicitly. Our solution is proposing a policy-based framework which enables the derivation from attribute-based security requirements to concrete security policies. The second part of the dissertation focuses on the security policy negotiation. We investigate the process of reaching agreement through bargaining process in which negotiators exchange their offers and counter offers step by step. The positive result of the negotiation generates a policy contract.Suite au développement des technologies de l'information, et en particulier au déploiement d'infrastructures telles que le Cloud Computing, de plus en plus d'applications et plateformes coopèrent en échangeant des données et des services. Cette tendance renforce l'importance de la gestion de la sécurité. Afin d'assurer la sécurité des données et de l'interaction de service une politique de sécurité doit être appliquée. Dans cette thèse, nous nous intéressons aux politiques de contrôle d'accès. Ce type de politique spécifie les privilèges de l'utilisation des ressources et est implémentée par différents modèles selon différents scénarios. Notre objectif ici est d'aider le client du service à bien exprimer ses exigences de sécurité et à choisir les fournisseurs de services qui peuvent la déployer. La première partie de cette thèse est dédiée à la sélection des fournisseurs de service. Dans le cas où les politiques de sécurité du fournisseur sont accessibles au client, nous proposons une méthode pour mesurer la similarité entre les politiques de sécurité. Dans le cas où les politiques de sécurité ne sont pas accessibles au client ou ne sont pas explicitement spécifiées, nous proposons un cadre à base de règles permettant la dérivation à partir des exigences de sécurité aux politiques de sécurité concrètes. La seconde partie de la thèse porte sur la négociation de politiques de sécurité. Nous étudions le processus permettant aux parties en négociation de parvenir à un accord par une série d'échanges d'offres et de contre-offres. Lorsque le résultat de la négociation est positif, un contrat incluant la politique de sécurité acceptée par les parties est généré