The Stability of the Roommate Problem Revisited

The lack of stability in some matching problems suggests that alternative solution concepts to the core might be applied to find predictable matchings. We propose the absorbing sets as a solution for the class of roommate problems with strict preferences. This solution, which always exists, either gives the matchings in the core or predicts some other matchings when the core is empty. Furthermore, it satisfies an interesting property of outer stability. We also characterize the absorbing sets, determine their number and, in case of multiplicity, we find that they all share a similar structure.

Solutions for New Terrestrial Broadcasting Systems Offering Simultaneously Stationary and Mobile Services

221 p.

Hezur erlaxazioaren eraginaren analisia hortzetako protesi mekanizatu baten euste torlojuen aurre-tenkaketan.

[EU]Hortzetako protesi osoek edentulismo partzial edo osoa jasaten duten pertsonentzat soluzio alternatibo bat suposatzen dute hortz bakarreko inplanteen aurrean, goialdeko edo behealdeko hortz guztiak (edo batzuk) pieza bakarrarekin ordezkatuz [11]. Protesi sistema hauen pieza bakoitzaren fabrikazioak zehaztasun handia eskatzen du eta aztertu beharreko hainbat faktore daude, amaiera produktuaren funtzionamendua egokia izatea nahi bada. Hauetako aspektu asko aurretik gauzatuak izan diren lanetan jorratu dira jadanik, tolerantzia gap-a eta torlojutze sekuentzia bezalako aldagaiei buruz hainbat ikerkuntza eginez [1]. Lan honen bidez, bi faktore hauez gain hezur erlaxazioaren eragina kontuan hartu nahi da, All On Four sistema batean edukiko duen irismena neurtzeko. Horrela, protesiaren fabrikazio edota ezarpenerako baldintza onargarri minimoak ezagutzea espero da, erabiltzailearentzat protesia egokia suerta dadin.

Contributions to High-Throughput Computing Based on the Peer-to-Peer Paradigm

XII, 116 p.

Optimal Minimum Wage in a Competitive Economy: an Alternative Modelling Approach

This paper analyzes whether a minimum wage can be an optimal redistribution policy when distorting taxes and lump-sum transfers are also available in a competitive economy. We build a static general equilibrium model with a Ramsey planner making decisions on taxes, transfers, and minimum wage levels. Workers are assumed to differ only in their productivity. We find that optimal redistribution may imply the use of a minimum wage. The key factor driving our results is the reaction of the demand for low skilled labor to the minimum wage law. Hence, an optimal minimum wage appears to be most likely when low skilled households are scarce, the complementarity between the two types of workers is large or the difference in productivity is small. The main contribution of the paper is a modelling approach that allows us to adopt analysis and solution techniques widely used in recent public finance research. Moreover, this modelling strategy is flexible enough to allow for potential extensions to include dynamics into the model.

An Approach to the stability of international environmental agreements: the absorbing sets solution

We study international environmental negotiations when agreements between countries can not be binding. A problem with this kind of negotiations is that countries have incentives for free-riding from such agreements. We develope a notion of equilibrium based on the assumption that countries can create and dissolve agreements in their seeking of a larger welfare. This approach leads to a larger degree of cooperation compared to models based on the internal-external stability approach.

An empirical comparison of the performance of alternative option pricing models

Published as an article in: Investigaciones Economicas, 2005, vol. 29, issue 3, pages 483-523.

The structure and the dynamics of poly(vinyl methyl ether) PVME and in PVME concentrated water solution : a study by neutron scattering and fully atomistic molecular dynamics simulations

175 p. : il.

The coincidence of the kernel and nucleolus of a convex game: an alternative proof

In 1972, Maschler, Peleg and Shapley proved that in the class of convex the nucleolus and the kernel coincide. The only aim of this note is to provide a shorter, alternative proof of this result.

Optimization of solution-processed oligothiophene:fullerene based organic solar cells by using solvent additives

The optimization of solution-processed organic bulk-heterojunction solar cells with the acceptor-substituted quinquethiophene DCV5T-Bu-4 as donor in conjunction with PC61BM as acceptor is described. Power conversion efficiencies up to 3.0% and external quantum efficiencies up to 40% were obtained through the use of 1-chloronaphthalene as solvent additive in the fabrication of the photovoltaic devices. Furthermore, atomic force microscopy investigations of the photoactive layer gave insight into the distribution of donor and acceptor within the blend. The unique combination of solubility and thermal stability of DCV5T-Bu-4 also allows for fabrication of organic solar cells by vacuum deposition. Thus, we were able to perform a rare comparison of the device characteristics of the solution-processed DCV5T-Bu-4:PC61BM solar cell with its vacuum-processed DCV5T-Bu-4:C-60 counterpart. Interestingly in this case, the efficiencies of the small-molecule organic solar cells prepared by using solution techniques are approaching those fabricated by using vacuum technology. This result is significant as vacuum-processed devices typically display much better performances in photovoltaic cells. Keywords

Wage stickiness and unemployment fluctuations: an alternative approach

28 p.

A new solution for the roommate problem: The Q-stable matchings

The aim of this paper is to propose a new solution for the roommate problem with strict preferences. We introduce the solution of maximum irreversibility and consider almost stable matchings (Abraham et al. [2])and maximum stable matchings (Ta [30] [32]). We find that almost stable matchings are incompatible with the other two solutions. Hence, to solve the roommate problem we propose matchings that lie at the intersection of the maximum irreversible matchings and maximum stable matchings, which are called Q-stable matchings. These matchings are core consistent and we offer an effi cient algorithm for computing one of them. The outcome of the algorithm belongs to an absorbing set.

An Alternative View of the US Price-Dividend Ratio Dynamics

As a necessary condition for the validity of the present value model, the price-dividend ratio must be stationary. However, significant market episodes seem to provide evidence of prices significantly drifting apart from dividends while other episodes show prices anchoring back to dividends. This paper investigates the stationarity of this ratio in the context of a Markov- switching model à la Hamilton (1989) where an asymmetric speed of adjustment towards a unique attractor is introduced. A three-regime model displays the best regime identification and reveals that the first part of the 90’s boom (1985-1995) and the post-war period are characterized by a stationary state featuring a slow reverting process to a relatively high attractor. Interestingly, the latter part of the 90’s boom (1996-2000), characterized by a growing price-dividend ratio, is entirely attributed to a stationary regime featuring a highly reverting process to the attractor. Finally, the post-Lehman Brothers episode of the subprime crisis can be classified into a temporary nonstationary regime.

Evaluation of two alternative carbon capture and storage technologies

4 p.

Alternative trajectories for decarbonizing urban transportation

4 p.