658 research outputs found
Conflict and Uncertainty: A Dynamic Approach
Most of the conflict theory papers have used a one-shot game set-up. This does not correspond to reality and is certainly incapable of modeling real conflict situations. We propose a dynamic model with N-agents in an infinite time frame which allow us to adequately analyze conflicts. The dynamic aspects of the conflict come at least from two sources: first, the preferences on the good in dispute are not static; second, agentsin conflict can influence the future of the conflict by making investment in conflict's technology. We use a simple deterministic rule that defines the evolution of the subjective valuation for the good in dispute according to the results obtained by the agents in the recent past. During each period the realization of stochastic variables of the nature's states induces uncertainty in the game. The model is a theoretical approach that can be applied to evaluate the role of uncertainty and valuations' evolution on the optimal choices of forward-looking economic agents that seek to appropriate a share of a divisible resource.Conflict Theory, Dynamic Economic Model, Uncertainty
Identities For Homogeneous Utility Functions
Using a homogeneous and continuous utility function that represents a household's preferences, this paper proves explicit identities between most of the different objects that arise from the utility maximization and the expenditure minimization problems. The paper also outlines the homogeneity properties of each object. Finally, we show explicit algebraic ways to go from the indirect utility function to the expenditure function and from the Marshallian demand to the Hicksian demand and vice versa, without the need of any other function, thus simplifying the integrability problem avoiding the use of differential equations.Identities, homogeneous utility functions and household theory.
Dark Matter in Draco: new considerations of the expected gamma flux in IACTs
A new revision of the gamma flux that we expect to detect in Imaging
Atmospheric Cherenkov Telescopes (IACTs) from SUSY dark matter annihilation in
the Draco dSph is presented using the dark matter density profiles compatible
with the latest observations. This revision takes also into account the
important effect of the Point Spread Function (PSF) of the Cherenkov telescope.
We show that this effect is crucial in the way we will observe and interpret a
possible signal profile in the telescope. Given these new considerations, some
light can be shed on the recent signal excess reported by the CACTUS
experiment.Comment: 7 pages, 5 figures, to appear in the Proceedings of the workshop "The
dark side of the Universe", Madrid, June 20-24, 200
Organizaciones resilientes, invariancia y cambio en el sistema
Resiliencia es anticipación y adaptación a tendencias profundas y de largo plazo que pueden interferir con la capacidad de producir los resultados esperados, la propuesta de Hamel y Valikangas es cero trauma en la organización, lo que implica la habilidad para reinventar dinámicamente los modelos de negocios y las estrategias al mismo tiempo que las circunstancias y el entorno cambian, sin sorpresas, sin cambios bruscos, sin profundas reingenierías. Este artículo establece una manera de abordar la sencilla receta que platean estos autores a partir de la propuesta de los profesores Etkin y Schvarstein, esto es: identificación de la invariancia, la estructura y los dominios de la organización y de las relaciones que entre ellos existen.Resilience is anticipating and adapting to trends profound and long-term that may interfere with the ability to produce the expected results, the proposed from Hamel and Valikangas is trauma zero in the organization, which includes the ability to dynamically reinvent business models and strategies at the same time as changing circumstances and environment, with no surprises, no sudden changes, without deep reengineering. This article provides a simple way of dealing with the recipe silver these authors from the proposal of the teachers Etkin and Schvarstein, it is: identification of the invariance, the structure and domains of the organization and the relationships that exist between them
Design of hardware-based security solutions for interconnected systems
Among all the different research lines related to hardware security, there is a particular topic
that strikingly attracts attention. That topic is the research regarding the so-called Physical
Unclonable Functions (PUF). The PUFs, as can be seen throughout the Thesis, present the
novel idea of connecting digital values uniquely to a physical entity, just as human biometrics
does, but with electronic devices. This beautiful idea is not free of obstacles, and is the core
of this Thesis. It is studied from different angles in order to better understand, in particular,
SRAM PUFs, and to be able to integrate them into complex systems that expand their
potential.
During Chapter 1, the PUFs, their properties and their main characteristics are defined. In
addition, the different types of PUFs, and their main applications in the field of security are
also summarized.
Once we know what a PUF is, and the types of them we can find, throughout Chapter 2
an exhaustive analysis of the SRAM PUFs is carried out, given the wide availability of
SRAMs today in most electronic circuits (which dramatically reduces the cost of deploying
any solution). An algorithm is proposed to improve the characteristics of SRAM PUFs, both
to generate identifiers and to generate random numbers, simultaneously. The results of this
Chapter demonstrates the feasibility of implementing the algorithm, so in the following
Chapters it is explored its integration in both hardware and software systems.
In Chapter 3 the hardware design and integration of the algorithm introduced in Chapter 2
is described. The design is presented together with some examples of use that demonstrate
the possible practical realizations in VLSI designs.
In an analogous way, in Chapter 4 the software design and integration of the algorithm
introduced in Chapter 2 is described. The design is presented together with some examples
of use that demonstrate the possible practical realizations in low-power IoT devices. The
algorithm is also described as part of a secure firmware update protocol that has been
designed to be resistant to most current attacks, ensuring the integrity and trustworthiness of
the updated firmware.In Chapter 5, following the integration of PUF-based solutions into protocols, PUFs
are used as part of an authentication protocol that uses zero-knowledge proofs. The cryptographic
protocol is a Lattice-based post-quantum protocol that guarantees the integrity and
anonymity of the identity generated by the PUF. This type of architecture prevents any type of
impersonation or virtual copy of the PUF, since this is unknown and never leaves the device.
Specifically, this type of design has been carried out with the aim of having traceability of
identities without ever knowing the identity behind, which is very interesting for blockchain
technologies.
Finally, in Chapter 6 a new type of PUF, named as BPUF (Behavioral and Physical Unclonable
Function), is proposed and analyzed according to the definitions given in Chapter 1.
This new type of PUF significantly changes the metrics and concepts to which we were
used to in previous Chapters. A new multi-modal authentication protocol is presented in this
Chapter, taking advantage of the challenge-response tuples of BPUFs. An example of BPUFs
is illustrated with SRAMs.
A proposal to integrate the BPUFs described in Chapter 6 into the protocol of Chapter 5,
as well as the final remarks of the Thesis, can be found in Chapter 7
A Minimalist Model of Characteristic Earthquakes
In a spirit akin to the sandpile model of self-organized criticality, we
present a simple statistical model of the cellular-automaton type which
produces an avalanche spectrum similar to the characteristic-earthquake
behavior of some seismic faults. This model, that has no parameter, is amenable
to an algebraic description as a Markov Chain. This possibility illuminates
some important results, obtained by Monte Carlo simulations, such as the
earthquake size-frequency relation and the recurrence time of the
characteristic earthquake.Comment: 9 pages, 4 figure
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