Platform Competition as Network Contestability

Recent research in industrial organisation has investigated the essential place that middlemen have in the networks that make up our global economy. In this paper we attempt to understand how such middlemen compete with each other through a game theoretic analysis using novel techniques from decision-making under ambiguity. We model a purposely abstract and reduced model of one middleman who pro- vides a two-sided platform, mediating surplus-creating interactions between two users. The middleman evaluates uncertain outcomes under positional ambiguity, taking into account the possibility of the emergence of an alternative middleman offering intermediary services to the two users. Surprisingly, we find many situations in which the middleman will purposely extract maximal gains from her position. Only if there is relatively low probability of devastating loss of business under competition, the middleman will adopt a more competitive attitude and extract less from her position.Comment: 23 pages, 3 figure

Binary classification by minimizing the mean squared slack

The paper presents a new binary classification method based on the minimization of the slack variables energy called the Mean Squared Slack (MSS). We deliver preliminary mathematical results which support the motivation behind our approach. We show that (a) in the linearly separable case the minimum MSS is attained at a separating vector, while (b) the minimizer in the linearly non-separable case is bounded but not zero. The method is conceptually simple: it solves a linear system at each iteration and it converges, typically, within a few iterations. Its complexity is obviously related to the size of the system which, in the linear case, is equal to the input pattern dimension. The method is extended to the non-linear case using kernels. Simulations demonstrate that the method is competitive with respect to computation time, accuracy, and generalization performance compared to state of the art SVM methods. © 2012 IEEE

Towards minimizing the energy of slack variables for binary classification

This paper presents a binary classification algorithm that is based on the minimization of the energy of slack variables, called the Mean Squared Slack (MSS). A novel kernel extension is proposed which includes the withholding of just a subset of input patterns that are misclassified during training. The later leads to a time and memory efficient system that converges in a few iterations. Two datasets are exploited for performance evaluation, namely the adult and the vertebral column dataset. Experimental results demonstrate the effectiveness of the proposed algorithm with respect to computation time and scalability. Accuracy is also high. In specific, it equals 84.951% for the adult dataset and 91.935%, for the vertebral column dataset, outperforming state-of-the-art methods. © 2012 EURASIP

Pricing in Economies with a Variable Number of Commodities

We present a general equilibrium model that encompasses the endogenous selection of a set of tradeable commodities. At its foundation we introduce the notion of a trade infrastructure as a set of social institutions describing the trade and production technologies available to the agents in the economy. Our model bridges the analyses of economies with a finite number of commodities and those with an infinite number, and it provides a general framework for investigating a very large class of possible applications. We discuss in detail a simple example on the development of a guild economy into a market based economy. We introduce an equilibrium concept that describes the pricing of trade infrastructures, based on the notion of valuation equilibrium for economies with abstract public goods, as in Diamantaras and Gilles (1996, International Economic Review, 37, 851-860). Through this concept we are able to price the tradeability of a commodity by itself. As our main results we obtain the existence as well as the decentralization of Pareto efficient allocations using the concept of valuation equilibrium. JEL classification: D23, D41, D46, D59, D90, H40, O12Trading systems infrastructures welfare theorems general equilibrium Public economics

A note on the decentralization of Pareto optima in economies with public projects and nonessential private goods

Welfare Economics;Public Goods

Efficiency and separability in economies with a trade center

We discuss the endogenous selection of a costly allocation mechanism in a pure exchange economy. The allocation mechanism is modeled as an abstract trade center exhibiting setup costs, access costs and linear transaction costs. Exactly one trade center has to be selected. We define Pareto efficiency in this setting and decentralize decision making concerning consumption as well as the choice of a trade center through the concept of a separable valuation equilibrium. In this equilibrium concept trade centers are assigned individualized nonlinear prices.Efficiency;International Trade;Costs;Allocation;Separability;international economics

Identificação das espécies geradas em reator de plasma de ar atmosférico a baixa pressão por espectroscopia de emissão ótica

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Físicas e Matemáticas. Curso de Química.Neste trabalho, um reator foi construído com objetivo de gerar plasma de descarga glow de ar atmosférico a baixa pressão com propósito de aplicar a técnica de espectroscopia de emissão ótica (OES – optical emission spectroscopy) para estudar a descarga e as espécies geradas. O plasma foi gerado por uma fonte pulsada de corrente alternada com frequência e tensão ajustável. Com o auxílio de um osciloscópio, caracterizou-se a fonte utilizada em termos da tensão e frequência aplicada. Os valores de frequência estudada variaram entre 400 Hz e 3400 Hz, e a tensão variou entre 1300 V e 2493 V. Os espectros obtidos pela técnica de OES mostraram um aumento da intensidade de emissão de espécies reativas com o aumento da tensão e frequência, atingindo valores máximos em frequência e tensão máxima (3400 Hz 2493 V). Os espectros permitiram a identificação do primeiro sistema positivo (FPS), do segundo sistema positivo (SPS) do N2 e primeiro sistema negativo (FNS) do N2+. A análise dos dados permitiu concluir que o sistema de plasma é capaz de promover o estado de energia vibracional com v’’ = 10 do estado eletrônico C3?????????????????? . O estudo espectroscópico permitiu a discussão sobre a existência de espécies derivadas do ar atmosférico no sistema, as quais a formação é promovida pelo plasma, tais como: O?, N?, NO, e O3. A partir de um software de simulação espectral e através da técnica de sobreposição espectral, foi estimada a temperatura vibracional e rotacional do sistema, sendo 2901 K e 522 K, respectivamente. Por fim, baseado em todos os resultados obtidos, discutiu-se aplicações para o sistema na esterilização de materiais termolábeis e funcionalização de superfícies poliméricas