Syntactic Topic Models

The syntactic topic model (STM) is a Bayesian nonparametric model of language that discovers latent distributions of words (topics) that are both semantically and syntactically coherent. The STM models dependency parsed corpora where sentences are grouped into documents. It assumes that each word is drawn from a latent topic chosen by combining document-level features and the local syntactic context. Each document has a distribution over latent topics, as in topic models, which provides the semantic consistency. Each element in the dependency parse tree also has a distribution over the topics of its children, as in latent-state syntax models, which provides the syntactic consistency. These distributions are convolved so that the topic of each word is likely under both its document and syntactic context. We derive a fast posterior inference algorithm based on variational methods. We report qualitative and quantitative studies on both synthetic data and hand-parsed documents. We show that the STM is a more predictive model of language than current models based only on syntax or only on topics

From Fault Tree to Credit Risk Assessment: A Case Study

Reliability has been largely applied to industrial systems in order to study the various possibilities of systems’ failure. The goal is to establish the chain of events leading to any system’s failure, namely the top event. Looking for the minimal paths leading to any system’s fault allows for a better control of systems’ safety. To this end, reliability is composed of a static approach (see Ngom et al. [1999] for example) as well as a dynamic approach (see Reory & Andrews [2003] for example). In this paper, we extend the framework stated by Gatfaoui (2003) allowing for the application of fault tree theory to credit risk assessment. The author explains that fault tree is one alternative approach of reliability, which matches default risk analysis in a simple framework. Our extension includes other distributions of probability to model the lifetimes of French firms while studying the related empirical default probabilities. We use mainly, but not exclusively, continuous distributions for which the exponential law used by Gatfaoui (2003) constitutes a particular case. Our results exhibit both the exponential nature of French .rms. lifetimes as well as strong convex and fast decreasing time varying failure rates. Such a feature has some non- negligible impact insofar as it characterizes corresponding credit spreads’ Term structure.credit risk, default probability, failure rate, fault tree, reliability, survival probability

Post-communist Welfare Capitalisms: Bringing Institutions and Political Agency Back In

This article explores the post-communist worlds of welfare capitalism in Central, Eastern and South Eastern Europe, including the successor states of the former Soviet Union. It discusses recent developments, whilst offering some additional theoretical reflections on the key factors that have shaped welfare state change over time. The text explores key institutional features characterising these worlds of welfare capitalism in transition. In order to highlight the actions of political elites in the market, we discuss the notions of “state-enabled”, “state-influenced” and “state-interfered” market economies. In this article, we introduce the term “captured welfare systems” to refer to the ways in which some states and political elites interfere in the market in order to capture resources. In the conclusion, we move beyond classical approaches to institutional change based on path-dependency and lock-in arguments, drawing attention to the importance of bringing institutions and political agency back into the analysis of welfare and its transformations.political economy of welfare capitalism, captured welfare system, Central and Eastern Europe, South Eastern Europe, former Soviet Union

Causes of Efficiency Change in Transition: Theory and Cross-Country Survey Evidence from Agriculture

Studies on efficiency changes in transition agriculture yield mixed results. This paper develops both a theoretical model and an empirical analysis of how distribution of efficiency scores changes with the various stages of transition. We use a unique set of representative farm survey data to calculate farm level efficiency scores, compare the efficiency distributions of different transition countries and correlate these with various indicators of particular reforms. Our study indicates that, in particular, general institutional reforms and reforms focused on market institutions and on reducing market imperfections in input and output markets have an important positive impact on farm efficiency.Farm Management, Productivity Analysis,