Solving heterogeneous-agent models with parameterized cross-sectional distributions

A new algorithm is developed to solve models with heterogeneous agents and aggregate uncertainty that avoids some disadvantages of the prevailing algorithm that strongly relies on simulation techniques and is easier to implement than existing algorithms. A key aspect of the algorithm is a new procedure that parameterizes the cross-sectional distribution, which makes it possible to avoid Monte Carlo integration. The paper also develops a new simulation procedure that not only avoids cross-sectional sampling variation but is also more than ten times faster than the standard procedure of simulating an economy with a large but finite number of agents. This procedure can help to improve the efficiency of the most popular algorithm in which simulation procedures play a key role.incomplete markets ; numerical solutions ; projection methods ; simulations

Review on possible gravitational anomalies

This is an updated introductory review of 2 possible gravitational anomalies that has attracted part of the Scientific community: the Allais effect that occur during solar eclipses, and the Pioneer 10 spacecraft anomaly, experimented also by Pioneer 11 and Ulysses spacecrafts. It seems that, to date, no satisfactory conventional explanation exist to these phenomena, and this suggests that possible new physics will be needed to account for them. The main purpose of this review is to announce 3 other new measurements that will be carried on during the 2005 solar eclipses in Panama and Colombia (Apr. 8) and in Portugal (Oct.15).Comment: Published in 'Journal of Physics: Conferences Series of the American Institute of Physics'. Contribution for the VI Mexican School on Gravitation and Mathematical Physics "Approaches to Quantum Gravity" (Playa del Carmen, Quintana Roo, Mexico, Nov. 21-27, 2004). Updates to this information will be posted in http://www.lsc-group.phys.uwm.edu/~xavier.amador/anomalies.htm

Experimental and numerical characterization of anisotropic damage evolution of forged Al6061-T6 alloy

AbstractAluminum alloy 6061-T6 (Al-Mg-Si) has been selected as the material of the vessel for the construction of Jules-Horowitz material testing reactor. Fracture mechanism of this alloy has been investigated using mechanical testing of smooth and notched tensile specimens loaded in different directions. A strong anisotropic fracture behavior has been observed. Microstructural studies using tomography and image analysis have shown a presence of anisotropic distributed coarse precipitates which is the key microstructural feature affecting the damage evolution. These observations were complemented by investigations on fractured tensile samples. A damage scenario of anisotropic growth and coalescence of voids is proposed to explain the fracture behavior associated with the distribution of precipitates. A GTN (Gurson-Tvergaard-Needleman) damage model is used to simulate this scenario and to predict damage evolution

Feasibility of using a flat bottom electrode for PEA space charge measurement on mini-cables under high temperatures

Pulsed Electro-Acoustic (PEA) apparatus has been developed to measure the space charge distribution inside XLPE based mini-cable insulation. The technique relies on the acoustic contact between the cylindrical cable surface and a flat aluminium plate to couple the acoustic waves to the sensor. This work addresses the feasibility of using this technique over a temperature range of 25°C to 70°C. The results demonstrate that increasing the temperature under constant clamping force causes the cable insulation to soften and distort increasing the contact area and signal from the PEA apparatus. However on subsequent cooling to 25°C the mechanical distortion remains frozen-in with little change to the contact area. For reproducible space charge measurements it is necessary to first condition the cable sample by taking the cable and PEA through a temperature cycle before application of the applied voltage

A system for PEA space charge measurement on HVDC mini-cables under different isothermal temperatures: Influence of cable clamping force on PEA measurements on HVDC mini-cables

A Pulsed Electro-Acoustic (PEA) apparatus has been developed to measure the space charge distribution inside cable insulation. The technique relies on acoustic contact between the cylindrical cable surface and a flat aluminium plate to couple the acoustic waves to the sensor. This work addresses the practical issue of the clamping force required to maintain good contact and how this may alter the measured space charge distribution. Space charge measurements on mini-cables (model cables)were carried out over a wide range of clamping force and additionally a finite-element simulation model has been developed to model mechanical deformation of mini-cables and provide data that cannot be easily obtained from experiments. A clamping force range for reproducible measurements at room temperature has been determined by comparing results from a group test on a mini-cable

Presencia en Cuba de la especie marina invasora Unomia stolonifera (Gohar, 1938) (Octocorallia, Alcyonacea). Acciones para su control y eliminación

Se señala la presencia en Cuba de la especie marina invasora Unomia stolonifera, introducida en Venezuela, de donde debe haber llegado a Cuba y que representa un peligro para los arrecifes coralinos de Cuba y del resto del Mar Caribe. Se describen las acciones realizadas para su erradicación.Los muestreos contaron con el apoyo financiero y logístico brindado por Wildlife Conservation Society (WCS) y de la Fundación Antonio Núñez Jiménez de la Naturaleza y el Hombre (FANJ). Ninguno de los autores de este trabajo ha recibido ningún tipo de financiamiento para realizar la investigación

On the formalization of termination techniques based on multiset orderings

Multiset orderings are a key ingredient in certain termination techniques like the recursive path ordering and a variant of size-change termination. In order to integrate these techniques in a certifier for termination proofs, we have added them to the Isabelle Formalization of Rewriting. To this end, it was required to extend the existing formalization on multiset orderings towards a generalized multiset ordering. Afterwards, the soundness proofs of both techniques have been established, although only after fixing some definitions. Concerning efficiency, it is known that the search for suitable parameters for both techniques is NP-hard. We show that checking the correct application of the techniques-where all parameters are provided-is also NP-hard, since the problem of deciding the generalized multiset ordering is NP-hard. © René Thiemann, Guillaume Allais, and JulianNagele

Flowing Between Fermionic Fixed Points

We study holographic Wilsonian renormalization group flows for bulk spinor fields in AdS. We use this to compute the all-loop beta function for fermionic double trace operators in the dual conformal field theory.Comment: 21 pages. V2: Acknowledgement added; v3: Typo correcte

Strong subadditivity and the covariant holographic entanglement entropy formula

Headrick and Takayanagi showed that the Ryu-Takayanagi holographic entanglement entropy formula generally obeys the strong subadditivity (SSA) inequality, a fundamental property of entropy. However, the Ryu-Takayanagi formula only applies when the bulk spacetime is static. It is not known whether the covariant generalization proposed by Hubeny, Rangamani, and Takayanagi (HRT) also obeys SSA. We investigate this question in three-dimensional AdS-Vaidya spacetimes, finding that SSA is obeyed as long as the bulk spacetime satisfies the null energy condition. This provides strong support for the validity of the HRT formula.Comment: 38 page

A Quantum-Conceptual Explanation of Violations of Expected Utility in Economics

The expected utility hypothesis is one of the building blocks of classical economic theory and founded on Savage's Sure-Thing Principle. It has been put forward, e.g. by situations such as the Allais and Ellsberg paradoxes, that real-life situations can violate Savage's Sure-Thing Principle and hence also expected utility. We analyze how this violation is connected to the presence of the 'disjunction effect' of decision theory and use our earlier study of this effect in concept theory to put forward an explanation of the violation of Savage's Sure-Thing Principle, namely the presence of 'quantum conceptual thought' next to 'classical logical thought' within a double layer structure of human thought during the decision process. Quantum conceptual thought can be modeled mathematically by the quantum mechanical formalism, which we illustrate by modeling the Hawaii problem situation, a well-known example of the disjunction effect, and we show how the dynamics in the Hawaii problem situation is generated by the whole conceptual landscape surrounding the decision situation.Comment: 9 pages, no figure