Scenario Sampling for Large Supermodular Games

This paper introduces a simulation algorithm for evaluating the log-likelihood function of a large supermodular binary-action game. Covered examples include (certain types of) peer effect, technology adoption, strategic network formation, and multi-market entry games. More generally, the algorithm facilitates simulated maximum likelihood (SML) estimation of games with large numbers of players, $T$, and/or many binary actions per player, $M$ (e.g., games with tens of thousands of strategic actions, $TM=O(10^4)$). In such cases the likelihood of the observed pure strategy combination is typically (i) very small and (ii) a $TM$-fold integral who region of integration has a complicated geometry. Direct numerical integration, as well as accept-reject Monte Carlo integration, are computationally impractical in such settings. In contrast, we introduce a novel importance sampling algorithm which allows for accurate likelihood simulation with modest numbers of simulation draws.Comment: 40 pages, 2 Figures and an 8 page Appendi

Local perspectives on transnational relations of Cameroonian migrants

No Abstrac

On the bivariate Sarmanov distribution and copula. An application on insurance data using truncated marginal distributi

The Sarmanov family of distributions can provide a good model for bivariate random variables and it is used to model dependency in a multivariate setting with given marginals. In this paper, we focus our attention on the bivariate Sarmanov distribution and copula with different truncated extreme value marginal distributions. We compare a global estimation method based on maximizing the full log-likelihood function with the estimation based on maximizing the pseudo-log-likelihood function for copula (or partial estimation). Our aim is to estimate two statistics that can be used to evaluate the risk of the sum exceeding a given value. Numerical results using a real data set from the motor insurance sector are presented

Frauen- und Männerfreundschaften im Kameruner Grasland: ein komparativer Ansatz

'Wie zeitgenössische ethnologische und soziologische Studien gezeigt haben, hat sich das im Westen populäre Modell von Freundschaft als dyadischer, nicht-utilitaristischer, egalitärer und emotionsgeladener Sozialbeziehung als nicht-verallgemeinerbares Ideal erwiesen. Freundschaft bedarf einer kontextbezogenen Analyse, welche historische, regionale, kulturelle, soziale, wirtschaftliche und politische Bedingungen in Betracht zieht. Im vorliegenden Artikel wird Freundschaft im Rahmen interethnischer Beziehungen zwischen Mbororo (agro-pastorale Fulbe), Hausa und Mitgliedern der Kameruner Grasland-Gesellschaften untersucht. Der Fokus liegt dabei auf gender- und altersspezifischen Unterschieden in der Konzeption und der Ausgestaltung von Freundschaftsbeziehungen. Um den polyvalenten und flexiblen Charakter realer Sozialbeziehungen zu erfassen, zieht der Autor einen weit gefassten Freundschaftsbegriff vor, der Überschneidungen und Übergänge zwischen verschiedenen analytischen Kategorien wie Freundschaft, Verwandtschaft, Nachbarschaft, Geschäfts- und Patronagebeziehungen zulässt.' (Autorenreferat)'Contemporary anthropological and sociological friendship studies have revealed that the popular understanding of friendship as a dyadic, non-utilitarian, egalitarian, and emotion-laden relationship is a Western ideal. Subtle and adequate analyses require studying friendship relations embedded in their respective historical, social, cultural, political, and economic contexts. In this contribution friendship is studied within the framework of interethnic relations among Mbororo (agro-pastoral Fulbe), Hausa and Grassfields peoples in North West Cameroon. Focus is laid an the Impact of Bender and age differences an local ideas and practices of friendship. In order to grasp the polyvalent and supple character of actual relations I favor a broad notion of friendship which allows for overlaps with and transitions to other analytical categories like kinship, neighbourhood, Business relations and patron-client relationships.' (author's abstract)

Strategies of Successful Government IT Projects Based on Cost and Time

From 2001 through 2015, some information technology (IT) project managers failed to deliver U.S. Government IT projects on time and within budget. The failure of IT project managers to complete projects on time and within budget provoked the U.S. Government Accountability Office to classify IT projects as high risk. This multiple case study explored strategies government contracted IT project managers use to reduce cost overruns and improve on-time delivery. The participants in this study were government contracted IT project managers from organizations that provide IT project management in the Maryland area. Employing purposeful sampling of the explicit population, 5 selected participants from 5 firms provided data. The conceptual framework for this study was the actor-network theory. Data were collected and triangulated from 5 semistructured interviews and business documentation. Yin\u27s 5-step data analysis process resulted in the emergence of multiple themes. The emergent themes included clearly defined requirements, monitor and control, and demonstrated leadership. As more government organizations realize the benefits of IT project success strategies, funding may become available for leaders to advance additional positive social change projects in various communities. IT project managers may implement the practical strategies found within this study to improve the outcome of their government contracted IT projects

On the bivariate Sarmanov distribution and copula. An application on insurance data using truncated marginal distributions

The Sarmanov family of distributions can provide a good model for bivariate random variables and it is used to model dependency in a multivariate setting with given marginals. In this paper, we focus our attention on the bivariate Sarmanov distribution and copula with different truncated extreme value marginal distributions. We compare a global estimation method based on maximizing the full log-likelihood function with the estimation based on maximizing the pseudolog- likelihood function for copula (or partial estimation). Our aim is to estimate two statistics that can be used to evaluate the risk of the sum exceeding a given value. Numerical results using a real data set from the motor insurance sector are presented