Fast Parallel Randomized Algorithm for Nonnegative Matrix Factorization with KL Divergence for Large Sparse Datasets

Nonnegative Matrix Factorization (NMF) with Kullback-Leibler Divergence (NMF-KL) is one of the most significant NMF problems and equivalent to Probabilistic Latent Semantic Indexing (PLSI), which has been successfully applied in many applications. For sparse count data, a Poisson distribution and KL divergence provide sparse models and sparse representation, which describe the random variation better than a normal distribution and Frobenius norm. Specially, sparse models provide more concise understanding of the appearance of attributes over latent components, while sparse representation provides concise interpretability of the contribution of latent components over instances. However, minimizing NMF with KL divergence is much more difficult than minimizing NMF with Frobenius norm; and sparse models, sparse representation and fast algorithms for large sparse datasets are still challenges for NMF with KL divergence. In this paper, we propose a fast parallel randomized coordinate descent algorithm having fast convergence for large sparse datasets to archive sparse models and sparse representation. The proposed algorithm's experimental results overperform the current studies' ones in this problem

Information Technology and The World Growth Resurgence

This paper analyzes the impact of investment in information technology (IT) on the recent resurgence of world economic growth. We describe the growth of the world economy, seven regions, and fourteen major economies during the period 1989-2004. We allocate the growth of world output between input growth and productivity and find, surprisingly, that input growth greatly predominates! Moreover, differences in per capita output levels are explained by differences in per capita input, rather than variations in productivity. The contributions of IT investment have increased in all regions, but especially in industrialized economies and Developing Asia.growth, investment, productivity, information technology

How strong is the global integration of emerging market regions? An empirical assessment

In recent years, various emerging market regions have actively taken part in the movements of globalization and world market integration. However, the process of financial integration appears to vary over time and differs significantly across emerging market regions. This paper attempts to evaluate the time-varying integration of emerging markets from a regional perspective (Asia, Latin America, Middle East, and Southeast Europe) based on a conditional version of the International Capital Asset Pricing Model (ICAPM) with DCC-GARCH parameters that allows for dynamic changes in the degree of market integration, global market risk premium, regional exchange-rate risk premium, and local market risk premium. Overall, our findings reveal several interesting facts. First, the time-varying degree of integration of four emerging regions, satisfactorily explained by the regional level of trade openness and the term premium of US interest rates, has recently tended to increase, but these markets still remain substantially segmented from the world market. Second, the local market risk premium is found to explain more than 50% of the total risk premium for emerging market returns. Finally, we show that conditional correlations usually underestimate and overstate the measure of time-varying market integration. The empirical results of this study have some important implications for both global investors and policy makers with respect to dedicated portfolio investments in emerging markets and policy adjustments.time-varying integration, emerging markets, ICAPM, risk premium, DCC-GARCH

Testing for Structural Breaks and Dynamic Changes in Emerging Market Volatility

This paper aims to test for structural breaks and dynamic changes in emerging market volatility. We typically relate these issues to stock market liberalization since the latter is often considered as one of the most important forces that promote economic growth and rapid maturation of the emerging markets of the world. Using a bivariate GARCH-M model, stability tests in a linear framework and a pooled time-series cross-section model, we show that structural breaks detected in emerging market volatility series do not happen together with official liberalization dates, but they rather coincide with dates of the first ADR/Country Fund introduction and with dates of large increases in the US capital flows. Consistently, the pooled estimation results indicate that liberalization methods other than liberalization via a formal policy decree are the ones that significantly affect volatility.Stock Market Liberalization, Return Volatility, Emerging Markets, Bivariate GARCH-M models, Structural Breaks, Pooled Time-Series Analysis

Does financing behavior of Tunisian firms follow the predictions of the market timing theory of capital structure?

In this paper, we show how capital structure decisions made by non-financial firms listed in the Tunis Stock Exchange are affected by the predictions of the so-called market timing theory. Using a set of some relevant variables which reflect the market-timing signals, the firm fundamentals, and the performance of local stock market, we mainly find that leverage ratio of Tunisian firms is short-term driven by their current market valuations. In the long run, the market timing effects are not present at all. Rather, Tunisian firms seem to behave according to the tradeoff theory of capital structure by attempting to adjust their leverage levels towards a target ratio.Market timing theory

Does Macroeconomic Transparency Help Governments Be Solvent? Evidence from Recent Data

This paper investigates whether macroeconomic and data transparency standards lead to lower borrowing costs in sovereign bond markets. We essentially show that emerging market countries which subscribed to the Special Data Dissemination Standard (SDDS) experienced a significant decline in borrowing cost proxied by sovereign yield spreads on secondary markets. However, the adherence of these markets to the Code of Good Practices on Transparency in Monetary and Financial Policies caused a significant increase in the yield spreads. There is no impact of the adherence to the Code of Good Practices in Fiscal Transparency on the changes of sovereign spreads. In addition, the results suggest that a debtor country’s internal liquidity factor (measured by the total reserves to total external debt service ratio) and external liquidity conditions (measured by the yield on US longterm bond) are the most important determinants of emerging market spreads.Emerging markets, Transparency, Standards and Codes, International financial architecture, Sovereign debt and yield spreads

Information technology and the world economy

The purpose of this paper is to analyze the impact of investment in information technology (IT) equipment and software on the recent resurgence in world economic growth. The crucial role of IT investment in the growth of the U.S. economy has been thoroughly documented and widely discussed. Jorgenson (2001) has shown that the remarkable behavior of IT prices is the key to understanding the resurgence of American economic growth. This behavior can be traced to developments in semiconductor technology that are widely understood by technologists and economists.

Modeling the volatility of Mediterranean stock markets: a regime-switching approach

In this paper we use the Markov regime-switching model to investigate the volatility behavior of six Mediterranean stock markets (France, Spain, Greece, Egypt, Tunisia, and Turkey) over the turbulent period 1995-2010. Our results show strong evidence of regime shifts in each of these markets. We also find that the Mediterranean developed markets are less affected by international market events such as Asian and Russian financial crisis than emerging markets.Stock return volatility, Markov regime-switching model, Mediterranean stock markets