12,306 research outputs found
Private Data System Enabling Self-Sovereign Storage Managed by Executable Choreographies
With the increased use of Internet, governments and large companies store and
share massive amounts of personal data in such a way that leaves no space for
transparency. When a user needs to achieve a simple task like applying for
college or a driving license, he needs to visit a lot of institutions and
organizations, thus leaving a lot of private data in many places. The same
happens when using the Internet. These privacy issues raised by the centralized
architectures along with the recent developments in the area of serverless
applications demand a decentralized private data layer under user control. We
introduce the Private Data System (PDS), a distributed approach which enables
self-sovereign storage and sharing of private data. The system is composed of
nodes spread across the entire Internet managing local key-value databases. The
communication between nodes is achieved through executable choreographies,
which are capable of preventing information leakage when executing across
different organizations with different regulations in place. The user has full
control over his private data and is able to share and revoke access to
organizations at any time. Even more, the updates are propagated instantly to
all the parties which have access to the data thanks to the system design.
Specifically, the processing organizations may retrieve and process the shared
information, but are not allowed under any circumstances to store it on long
term. PDS offers an alternative to systems that aim to ensure self-sovereignty
of specific types of data through blockchain inspired techniques but face
various problems, such as low performance. Both approaches propose a
distributed database, but with different characteristics. While the
blockchain-based systems are built to solve consensus problems, PDS's purpose
is to solve the self-sovereignty aspects raised by the privacy laws, rules and
principles.Comment: DAIS 201
Singularity Theory in Classical Cosmology
This paper compares recent approaches appearing in the literature on the
singularity problem for space-times with nonvanishing torsion.Comment: 4 pages, plain-tex, published in Nuovo Cimento B, volume 107, pages
849-851, year 199
Novel features of the energy momentum tensor of a Casimir apparatus in a weak gravitational field
The influence of the gravity acceleration on the regularized energy-momentum
tensor of the quantized electromagnetic field between two plane parallel
conducting plates is derived. A perturbative expansion, to first order in the
constant acceleration parameter, of the Green functions involved and of the
energy-momentum tensor is derived by means of the covariant geodesic point
splitting procedure. The energy-momentum tensor is covariantly conserved and
satisfies the expected relation between gauge-breaking and ghost parts.Comment: 8 pages, based on a talk given by Luigi Rosa at the QFEXT07
Conference, Leipzig. Equation (13) and the formulae for rho and energy E
stored in the Casimir device have been amended, jointly with related
discussio
Beta decays with momentum space Majorana spinors
We construct and apply to beta decays a truly neutral local quantum field
that is entirely based upon momentum space Majorana spinors. We make the
observation that theory with momentum space Majorana spinors of real C parities
is equivalent to Dirac's theory. For imaginary C parities, the neutrino mass
can drop from the single beta decay trace and reappear in 0\nu \beta \beta, a
curious and in principle experimentally testable signature for a non-trivial
impact of Majorana framework in experiments with polarized sources.Comment: 7 pages, 1 figure; needs svjour.cls, svepj.cl
New Developments in the Spectral Asymptotics of Quantum Gravity
A vanishing one-loop wave function of the Universe in the limit of small
three-geometry is found, on imposing diffeomorphism-invariant boundary
conditions on the Euclidean 4-ball in the de Donder gauge. This result suggests
a quantum avoidance of the cosmological singularity driven by full
diffeomorphism invariance of the boundary-value problem for one-loop quantum
theory. All of this is made possible by a peculiar spectral cancellation on the
Euclidean 4-ball, here derived and discussed.Comment: 7 pages, latex file. Paper prepared for the Conference "QFEXT05:
Quantum Field Theory Under the Influence of External Conditions", Barcelona,
September 5 - September 9, 2005. In the final version, the presentation has
been further improved, and yet other References have been adde
The Neumann eigenvalue problem for the -Laplacian
The first nontrivial eigenfunction of the Neumann eigenvalue problem for the
-Laplacian, suitable normalized, converges as goes to to a
viscosity solution of an eigenvalue problem for the -Laplacian. We show
among other things that the limit of the eigenvalue, at least for convex sets,
is in fact the first nonzero eigenvalue of the limiting problem. We then derive
a number of consequences, which are nonlinear analogues of well-known
inequalities for the linear (2-)Laplacian.Comment: Corrected few typos. Corollary 5 adde
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