The Banzhaf Value in the Presence of Externalities

[eng] We propose two generalizations of the Banzhaf value for partition function form games. In both cases, our approach is based on probability distributions over the set of possible coalition structures that may arise for any given set of agents. First, we introduce a family of values, one for each collection of the latter probability distributions, defined as the Banzhaf value of an expected coalitional game. Then, we provide two characterization results for this new family of values within the framework of all partition function games. Both results rely on a property of neutrality with respect to amalgamation of players. Second, as this collusion transformation fails to be meaningful for simple games in partition function form, we propose another generalization of the Banzhaf value which also builds on probability distributions of the above type. This latter family is characterized by means of a neutrality property which uses an amalgamation transformation of players for which simple games are closed.

The Banzhaf Value in the Presence of Externalities

[eng] We propose two generalizations of the Banzhaf value for partition function form games. In both cases, our approach is based on probability distributions over the set of possible coalition structures that may arise for any given set of agents. First, we introduce a family of values, one for each collection of the latter probability distributions, defined as the Banzhaf value of an expected coalitional game. Then, we provide two characterization results for this new family of values within the framework of all partition function games. Both results rely on a property of neutrality with respect to amalgamation of players. Second, as this collusion transformation fails to be meaningful for simple games in partition function form, we propose another generalization of the Banzhaf value which also builds on probability distributions of the above type. This latter family is characterized by means of a neutrality property which uses an amalgamation transformation of players for which simple games are closed.

Is the matching function Cobb-Douglas?

[cat] Estudiem les propietats teòriques que una funció d.emparellament ha de satisfer per tal de representar un mercat laboral amb friccions dins d'un model d'equilibri general amb emparellament aleatori. Analitzem el cas Cobb-Douglas, CES i altres formes funcionals per a la funció d.emparellament. Els nostres resultats estableixen restriccions sobre els paràmetres d'aquests formes funcionals per assegurar que l.equilibri és interior. Aquestes restriccions aporten raons teòriques per escollir entre diverses formes funcionals i permeten dissenyar tests d'error d'especificació de model en els treballs empírics.

La réinvention d'Athènes par les écrivains en grec de l'époque impériale

Quan els organitzadors d"aquesta jornada d"homenatge a Nicole Loraux em van oferir l"oportunitat de participar-hi activament em vaig posar molt con- tenta perquè jo, tot i no haver-la freqüentat tant i amb tanta intensitat com to- tes i tots els que m"han precedit en l"ús de la paraula, sentia alhora una gran admiració per la seva intel·ligència i capacitat de treball, i sobretot una gran estimació per la gran persona que era, per la seva simpatia, la seva afabilitat i la seva vitalitat...

Is the matching function Cobb-Douglas?

[cat] Estudiem les propietats teòriques que una funció d.emparellament ha de satisfer per tal de representar un mercat laboral amb friccions dins d'un model d'equilibri general amb emparellament aleatori. Analitzem el cas Cobb-Douglas, CES i altres formes funcionals per a la funció d.emparellament. Els nostres resultats estableixen restriccions sobre els paràmetres d'aquests formes funcionals per assegurar que l.equilibri és interior. Aquestes restriccions aporten raons teòriques per escollir entre diverses formes funcionals i permeten dissenyar tests d'error d'especificació de model en els treballs empírics.

Estudo do jato urinário intravesical com Doppler colorido em pacientes com e sem refluxo vesicoureteral

OBJETIVO: O presente estudo teve como objetivo comparar os achados da uretrocistografia miccional com o ultra-som Doppler duplex colorido, em pacientes com suspeita de refluxo vesicoureteral. MATERIAIS E MÉTODOS: A pesquisa foi realizada através do estudo dos ângulos dos jatos urinários intravesicais, nos planos axial e longitudinal. Foi analisada, também, a distância (em centímetros) entre os meatos ureterais. RESULTADOS: Do total de 32 pacientes estudados (com média de idade de 5 anos e 2 meses), 18 pacientes apresentaram refluxo vesicoureteral (10 com refluxo unilateral, sendo 4 no lado direito e 6 no lado esquerdo, e 8 com refluxo bilateral) e 14 pacientes não apresentaram refluxo. Os valores angulares dos jatos urinários intravesicais e as distâncias entre os meatos ureterais foram obtidos para todos os pacientes e foram calculados a média, o desvio-padrão e o coeficiente de variação. CONCLUSÃO: Os dados evidenciaram tendência de que a lateralização do meato ureteral seja sinal de predisposição ao refluxo vesicoureteral. A análise estatística não-paramétrica de Mann-Whitney não evidenciou diferenças significativas (p > 0,05) entre os grupos (ângulos de inclinação dos jatos urinários intravesicais e distância entre os meatos ureterais).

Determinación de la base imponible en estimación objetiva

Es tracta d'una pràctica fiscal de determinació de la base imponible en estimació objectiva.

Economic and social convergence in Colombia

GDP has usually been used as a proxy for human well-being. Nevertheless, other social aspects should also be considered, such as life expectancy, infant mortality, educational enrolment and crime issues. With this paper we investigate not only economic convergence but also social convergence between regions in a developing country, Colombia, in the period 1975-2005. We consider several techniques in our analysis: sigma convergence, stochastic kernel estimations, and also several empirical models to find out the beta convergence parameter (cross section and panel estimates, with and without spatial dependence). The main results confirm that we can talk about convergence in Colombia in key social variables, although not in the classic economic variable, GDP per capita. We have also found that spatial autocorrelation reinforces convergence processes through deepening market and social factors, while isolation condemns regions to nonconvergence.

A nonparametric method for the measurement of size diversity with emphasis on data standardization

The most suitable method for estimation of size diversity is investigated. Size diversity is computed on the basis of the Shannon diversity expression adapted for continuous variables, such as size. It takes the form of an integral involving the probability density function (pdf) of the size of the individuals. Different approaches for the estimation of pdf are compared: parametric methods, assuming that data come from a determinate family of pdfs, and nonparametric methods, where pdf is estimated using some kind of local evaluation. Exponential, generalized Pareto, normal, and log-normal distributions have been used to generate simulated samples using estimated parameters from real samples. Nonparametric methods include discrete computation of data histograms based on size intervals and continuous kernel estimation of pdf. Kernel approach gives accurate estimation of size diversity, whilst parametric methods are only useful when the reference distribution have similar shape to the real one. Special attention is given for data standardization. The division of data by the sample geometric mean is proposedas the most suitable standardization method, which shows additional advantages: the same size diversity value is obtained when using original size or log-transformed data, and size measurements with different dimensionality (longitudes, areas, volumes or biomasses) may be immediately compared with the simple addition of ln k where kis the dimensionality (1, 2, or 3, respectively). Thus, the kernel estimation, after data standardization by division of sample geometric mean, arises as the most reliable and generalizable method of size diversity evaluation

A Computer program for estimating population size by the removal method

A BASIC computer program (REMOVAL) was developed to compute in a VAXNMS environment all the calculations of the removal method for population size estimation (catch-effort method for closed populations with constant sampling effort). The program follows the maximum likelihood methodology,checks the failure conditions, applies the appropriate formula, and displays the estimates of population size and catchability, with their standard deviations and coefficients of variation, and two goodness-of-fit statistics with their significance levels. Data of removal experiments for the cyprinodontid fish Aphanius iberus in the Alt Emporda wetlands are used to exemplify the use of the program

Cómo aplicar las pruebas paramétricas bivariadas t de Student y ANOVA en SPSS.

Las pruebas paramétricas son un tipo de pruebas de significación estadística que cuantifican la asociación o independencia entre una variable cuantitativa y una categórica. Las pruebas paramétricas exigen ciertos requisitos previos para su aplicación: la distribución Normal de la variable cuantitativa en los grupos que se comparan, la homogeneidad de varianzas en las poblaciones de las que proceden los grupos y una n muestral no inferior a 30. Su incumplimiento conlleva la necesidad de recurrir a pruebas estadísticas no paramétricas. Las pruebas paramétricas se clasifican en dos: prueba t (para una muestra o para dos muestras relacionadas o independientes) y prueba ANOVA (para más de dos muestras independientes).

Programa MicroEconometria. Paquet estadístic i economètric

MicroEconometria és un paquet estadístic i economètric que contempla l’estimació de models uniequacionals: 1- Regressió simple i múltiple: anàlisi de residus, influència i atipicitat, diagnòstics de multicol·linealitat, estimació robusta, predicció, diagnòstics d’estabilitat, bootstrap. 2- Regressió en panell: efectes fixes, efectes aleatoris i efectes combinats. 3- Regressió lògit i probit. 4- Regressió censurada: tobit i model de selecció de Heckman. 5- Regressió multinomial. 6- Regressió poisson: model ‘count data’. 7- Índexs amb variables renda i riquesa i impostos transferències. Genera un informe per a cada una de les possibilitats contemplades que conté la presentació dels resultats de les estimacions, incloent les sortides gràfiques pertinents. L’input del programa és qualsevol base de dades, en la que es pugui identificar la variable endògena i les variables exògenes del model utilitzat, continguda en un llibre d’EXCEL de Microsoft.

Disseny de cel·les digitals paramètriques per a electrònica impresa

L’objectiu d’aquest treball és el disseny i la implementació d’un conjunt de cel·les definides de forma paramètrica, i orientades a l’àmbit tecnològic emergent de l’electrònica impresa. L’ús de cel·les paramètriques en aquest entorn tecnològic poc madur, ha de permetre que els dissenys s’adaptin als canvis de regles de disseny de les tecnologies en aquest cas per estils de disseny PMOS.

Aproximación al reajuste automático de centroides mediante la heurística de Lloyd para resolver el problema de las K-Medias

Peer-reviewed

The permanence of the client under uncertain estimations

Marketing has studied the permanence of a client within an enterprise because it is a key element in the study of the value (economic) of the client (CLV). The research that they have developed is based in deterministic or random models, which allowed estimating the permanence of the client, and the CLV. However, when it is not possible to apply these schemes for not having the panel data that this model requires, the period of time of a client with the enterprise is uncertain data. We consider that the value of the current work is to have an alternative way to estimate the period of time with subjective information proper of the theory of uncertainty.