Search results for " Competition"
showing 10 items of 819 documents
Changes in Transport and Non Transport Costs: Local vs. Global Impacts in a Spatial Network
2007
We develop a multi-country Dixit-Stiglitz trade model and analyze how industry location and welfare respond to changes in: (i) transport frictions (e.g., infrastructure, transportation technology); and (ii) non-transport frictions (e.g., tariffs, standards and regulations). We show that changes in non-transport frictions, which are usually origin-destination specific, do not allow for any clear prediction as to changes in industry location and welfare; whereas changes in transport frictions, which are usually not origin-destination specific, may allow for such predictions. In particular, we show that reductions in transport frictions occurring at links around which the spatial network is lo…
Strategic behavior and partial cost sharing
2003
Abstract The main objects here are games in which players mainly compete but nonetheless collaborate on some subsidiary activities. Play assumes a two-stage nature in that first-stage moves presume coordination of some subsequent tasks. Specifically, we consider instances where second-stage coordination amounts to partial cost sharing, anticipated and sustained as a core solution. Examples include regional Cournot oligopolies with joint transportation. We define and characterize equilibria, and inquire about their existence.
Does complexity explain the structure of trade?
2013
This paper analyzes whether complexity, measured by the number of skilled tasks that are performed in production, explains countries commodity trade structure. We modify the Romalis ( ) model to incorporate advantage differences in complexity across commodities together with differences in the number of mistakes made by workers in the production process in developed and developing countries as a source of comparative advantage. Our model predicts that the share of developed countries in world trade increases with products complexity. Empirical tests confirm this prediction. Moreover, we find that complexity complements the explanation provided by skillintensity on countries commodity trade …
Mixture and Distribution of Different Water Qualities: An Experiment on Alternative Scenarios Concerning Vertical Structure in a Complex Market
2001
We set up a model of water management, which is inspired by the possibility of mixing water of different qualities. Water is supplied to two types of consumers with different preferences for water quality and quantity. A distributional knot may exist which optimally distributes the supplied water in the downstream market. Different scenarios compare experimentally the advantages of a centralized versus a decentralized resource management. We conducted experiments with 14 markets in three different settings, labelled as "upstream monopoly", "upstream duopoly" and "duopoly-monopsony". We find that a two-product monopoly performs better than the duopoly regarding social welfare and volatility …
Fingerprint image enhancement using directional morphological filter
2005
Fingerprint images quality enhancement is a topic phase to ensure good performance in an automatic fingerprint identification system (AFIS) based on minutiae matching. In this paper a new fingerprint enhancement algorithm based on morphological filter is introduced. The algorithm is based on three steps: directional decomposition, morphological filter and composition. The performance of the proposed approach has been evaluated on two sets of images: the first one is DB3 database from Fingerprint Verification Competition (FVC) and the second one is self collected using an optical scanner
An Advanced Technique for User Identification Using Partial Fingerprint
2013
User identification is a very interesting and complex task. Invasive biometrics is based on traits uniqueness and immutability over time. In forensic field, fingerprints have always been considered an essential element for personal recognition. The traditional issue is focused on full fingerprint images matching. In this paper an advanced technique for personal recognition based on partial fingerprint is proposed. This system is based on fingerprint local analysis and micro-features, endpoints and bifurcations, extraction. The proposed approach starts from minutiae extraction from a partial fingerprint image and ends with the final matching score between fingerprint pairs. The computation o…
Signals of demographic expansion in Drosophila virilis
2008
Background. The pattern of genetic variation within and among populations of a species is strongly affected by its phylogeographic history. Analyses based on putatively neutral markers provide data from which past events, such as population expansions and colonizations, can be inferred. Drosophila virilis is a cosmopolitan species belonging to the virilis group, where divergence times between different phylads go back to the early Miocene. We analysed mitochondrial DNA sequence variation among 35 Drosophila virilis strains covering the species' range in order to detect demographic events that could be used to understand the present characteristics of the species, as well as its differences …
Stable isotope analysis reveals trophic segregation between the invasive zebra mussel Dreissena polymorpha and the native duck mussel Anodonta anatin…
2022
AbstractNon-indigenous freshwater bivalves negatively affect invaded ecosystems through different mechanisms, including inter-specific competition for trophic resources. Here, we investigated in Lake Trasimeno (Central Italy) the diet of the invasive Dreissena polymorpha and the native Anodonta anatina. δ15N and δ13C stable isotopes were measured in winter and summer in bivalves, phytoplankton, and sedimentary organic matter (SOM); the relative dietary contributions of the two resources were determined using Bayesian mixing models. To elucidate the different carbon and nitrogen pools characterizing the study site, isotopic analyses were extended to zooplankton and to representatives of the …
General Equilibrium Models of Monopolistic Competition: CRRA Versus CARA
2005
We analyze a class of "large group" Chamberlinian monopolistic competition models using multiplicatively quasi-separable (MQS) and additively quasi-separable (AQS) functions. We first prove that the MQS and AQS functions are equivalent to the "constant relative risk aversion" (CRRA) and "constant absolute risk aversion" (CARA) classes of functions, respectively. Whereas both approaches allow for closed-form solutions, only the AQS functions yield profit-maximizing prices that decrease in the mass of competing firms. We then characterize the equilibrium in both cases and discuss some possible applications of the AQS framework to trade, growth, and development.
Transformacja Polskiego Związku Łowieckiego w świetle ewolucji modelu łowiectwa w Polsce
2020
The Polish Hunting Association is a nationwide organization of Polish hunters and hunting clubs, whose traditions date back to the interwar period. This study presents the genesis and evolution of the Polish Hunting Association, which, in the wake of social and political changes in the country, has been transformed from a voluntary association into a monopolistic and compulsory-membership organization, which is to carry out tasks commissioned by public authorities. Additionally, as a result of further amendments, the Association has been transformed into a governmental agency, organizationally subordinated to the minister of the environment also in the scope of appointing its high-rank staf…