18,815 research outputs found
Literacy Practices and Schooling: A Case Study from Mozambique
A novel approach to the assessment of literacy is used to tackle the issue of effectiveness of years of schooling. The dichotomy inherent in the literacy rate is rejected in favor of a " practice-based" approach, which considers literacy as a multifaceted phenomenon as advocated in anthropological and economic research. Primary data collected in the poorest region in Mozambique suggest that years of schooling have a differentiated impact on acquired literacy practices of adults. Results that are robust to different specifications are reported. © 2011 Elsevier Ltd
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
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Modelling the fair value of annuities contracts: the impact of interest rate risk and mortality risk
The purpose of this paper is to analyze the problem of the fair valuation of annuities contracts. The market consistent valuation of these products requires a pricing framework which includes the two main sources of risk affecting the value of the annuity, i.e. interest rate risk and mortality risk. As the IASB has not set any specific guidelines as to which models are the most appropriate for these risks, in this note we consider a range of different models calibrated with historical data. We calculate the fair value of the annuity as a portfolio of zero coupon bonds, each with maturity set equal to the date of the annuity payments; the weights in the portfolio are given by the survival probabilities. Moreover, we focus on the additional information provided by stochastic simulations in order to define a suitable risk margin. The nature of the risk margin is one of the main key issues concerning the IASB and Solvency project
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
Quantum thermodynamics of the resonant-level model with driven system-bath coupling
We study nonequilibrium thermodynamics in a fermionic resonant level model
with arbitrary coupling strength to a fermionic bath, taking the wide-band
limit. In contrast to previous theories, we consider a system where both the
level energy and the coupling strength depend explicitly on time. We find that,
even in this generalized model, consistent thermodynamic laws can be obtained,
up to the second order in the drive speed, by splitting the coupling energy
symmetrically between system and bath. We define observables for the system
energy, work, heat, and entropy, and calculate them using nonequilibrium
Green's functions. We find that the observables fulfill the laws of
thermodynamics, and connect smoothly to the known equilibrium results.Comment: 9 pages, 5 figure
Binary Fluids with Long Range Segregating Interaction I: Derivation of Kinetic and Hydrodynamic Equations
We study the evolution of a two component fluid consisting of ``blue'' and
``red'' particles which interact via strong short range (hard core) and weak
long range pair potentials. At low temperatures the equilibrium state of the
system is one in which there are two coexisting phases. Under suitable choices
of space-time scalings and system parameters we first obtain (formally) a
mesoscopic kinetic Vlasov-Boltzmann equation for the one particle position and
velocity distribution functions, appropriate for a description of the phase
segregation kinetics in this system. Further scalings then yield Vlasov-Euler
and incompressible Vlasov-Navier-Stokes equations. We also obtain, via the
usual truncation of the Chapman-Enskog expansion, compressible
Vlasov-Navier-Stokes equations.Comment: TeX, 50 page
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