Asymmetry in Cournot Duopoly

We analyze the sources of persistent asymmetry between firms and between markets in a given industry. We focus on the case where some exogenous ex ante cost asymmetry can be magnified ex post in terms of cost (capabilities), market shares, prices and profit. Our model - a two-product Cournot duopoly - emphasizes the respective role of market conditions (demand elasticities) and organizational characteristics (organizational inertia). We find that both factors act as substitutes in creating asymmetries in cost; however, organizational factors seem to play a greater role than market ones in explaining asymmetries in market shares and profit. We also show that, from a benevolent social planner's viewpoint, the equilibrium asymmetry in cost that results in the duopoly is not enough : each firm should specialize further in the market where it has an ex ante cost advantage. Nous analysons les cause d'asymétrie entre les firmes et entre les marchés d'une même industrie. Nous nous interrogeons sur le cas où une légère asymétrie technologique présente ex ante se répercute ex post, de manière amplifiée, sur les coûts, les parts de marché, les prix et les profits. Notre modèle, un duopole de Cournot avec deux marchés, met en lumière les rôles respectifs des conditions du marché, en l'occurence celui de l'élasticité de la demande, et des caractéristiques des organisations, plus précisément le rôle de l'inertie organisationnelle. Il est démontré que ces deux types de facteurs ont un impact similaire, voire sont substituts, en ce qui concerne l'asymétrie dans les coûts. L'inertie organisationnelle semble cependant jouer un rôle plus important que les conditions du marché pour l'asymétrie dans les parts de marché et les profits. Enfin, nous montrons que l'asymétrie dans les coûts qui survient à l'équilibre du duopole n'est pas socialement optimale : les firmes devraient se spécialiser davantage là où elles ont un avantage technologique ex ante.Multi Product Duopoly, Organizational Inertia, Capabilities, Duopole multi-produits, Inertie organisationnelle, Capabilités

Mode stability on the real axis

A generalization of the mode stability result of Whiting (1989) for the Teukolsky equation is proved for the case of real frequencies. The main result of the paper states that a separated solution of the Teukolsky equation governing massless test fields on the Kerr spacetime, which is purely outgoing at infinity, and purely ingoing at the horizon, must vanish. This has the consequence, that for real frequencies, there are linearly independent fundamental solutions of the radial Teukolsky equation which are purely ingoing at the horizon, and purely outgoing at infinity, respectively. This fact yields a representation formula for solutions of the inhomogenous Teukolsky equation.Comment: 20 pages, 4 figures. Reference added, revtex4-1 forma

Usability Patterns for Geoportals

Ponencias, comunicaciones y pósters presentados en el 17th AGILE Conference on Geographic Information Science "Connecting a Digital Europe through Location and Place", celebrado en la Universitat Jaume I del 3 al 6 de junio de 2014.Current geoportals and metadata catalogues, as user interfaces for discovery and exploration for geodata do still suffer from lacking usability, regardless whether experts or non-expert users are considered. Design patterns are well established in software development to tackle frequently occurring problems. Usability patterns are a specialization of such design patterns to specifically address user interface issues and related software solutions. However, existing usability patterns are not sufficient to cope with GI-usability issues as for instance related to discovery of geodata. This poster submission introduces an adapted GI-usability pattern concept

Linking crowdsourced observations with INSPIRE

Ponencias, comunicaciones y pósters presentados en el 17th AGILE Conference on Geographic Information Science "Connecting a Digital Europe through Location and Place", celebrado en la Universitat Jaume I del 3 al 6 de junio de 2014.The combination of spatial data from the variety of sources on the web, being either legislative, commercially or voluntarily driven, is a major requirement for the establishment of a fully integrated geospatial web. Therefore, spatial data fusion techniques need to be linked to current web-developments, in particular on Spatial Data Infrastructures and the Semantic Web, to allow for standardized and effective use of combined spatial data for information retrieval. In this paper, crowdsourced environmental observations, representing the rapidly increasing amount of voluntarily collected data on the web, and INSPIRE, acting as the legal framework for spatial environmental information in Europe, are chosen to design and develop capabilities for spatial data fusion on the web. Possible use cases show mutual benefits for both volunteers and INSPIRE data providers, and might thus facilitate further collaboration. A prototypical implementation based on common SDI and Linked Data standards demonstrates the feasibility of the proposed approach and offers a starting point for further exploration

Analysing spatiotemporal patterns of antibiotics prescriptions

Ponencias, comunicaciones y pósters presentados en el 17th AGILE Conference on Geographic Information Science "Connecting a Digital Europe through Location and Place", celebrado en la Universitat Jaume I del 3 al 6 de junio de 2014.The emergence of antibiotic resistances due to antibiotic residues in urban sewage systems is becoming an increasingly important issue. This paper presents a model for the spatiotemporal analysis of antibiotic inputs to derive spatiotemporal distribution patterns which are the basis for later predictions of future antibiotic inputs into the sewer system. To identify spatiotemporal distribution patterns of antibiotic prescriptions data statistical and GIS methods like time series and spatial cluster analysis are used. In order to find possible interrelationships the prescription data is combined with other influencing parameters (e.g. cases of respiratory infections) and tested for statistical correlations. Results show a pronounced seasonal course for three antibiotics of the macrolide group which also show high correlations with cases of respiratory infections in the study area. Further, results show that weekly data of respiratory infections by Google Flu Trends may be used as predictor variable to derive forecasts of future antibiotic inputs into the sewer system

Receiver Architectures for MIMO-OFDM Based on a Combined VMP-SP Algorithm

Iterative information processing, either based on heuristics or analytical frameworks, has been shown to be a very powerful tool for the design of efficient, yet feasible, wireless receiver architectures. Within this context, algorithms performing message-passing on a probabilistic graph, such as the sum-product (SP) and variational message passing (VMP) algorithms, have become increasingly popular. In this contribution, we apply a combined VMP-SP message-passing technique to the design of receivers for MIMO-ODFM systems. The message-passing equations of the combined scheme can be obtained from the equations of the stationary points of a constrained region-based free energy approximation. When applied to a MIMO-OFDM probabilistic model, we obtain a generic receiver architecture performing iterative channel weight and noise precision estimation, equalization and data decoding. We show that this generic scheme can be particularized to a variety of different receiver structures, ranging from high-performance iterative structures to low complexity receivers. This allows for a flexible design of the signal processing specially tailored for the requirements of each specific application. The numerical assessment of our solutions, based on Monte Carlo simulations, corroborates the high performance of the proposed algorithms and their superiority to heuristic approaches

Compatibility Complex for Black Hole Spacetimes

The set of local gauge invariant quantities for linearized gravity on the Kerr spacetime presented by two of the authors (Aksteiner and B\ue4ckdahl in Phys Rev Lett 121:051104, 2018) is shown to be complete. In particular, any gauge invariant quantity for linearized gravity on Kerr that is local and of finite order in derivatives can be expressed in terms of these gauge invariants and derivatives thereof. The proof is carried out by constructing a complete compatibility complex for the Killing operator, and demonstrating the equivalence of the gauge invariants from Aksteiner and B\ue4ckdahl (Phys Rev Lett 121:051104, 2018) with the first compatibility operator from that complex