Computing the conditional stationary distribution in Markov chains of level-dependent M/G/1-type

This paper considers the computation of the conditional stationary distribution in Markov chains of level-dependent M/G/1-type, given that the level is not greater than a predefined threshold. This problem has been studied recently and a computational algorithm is proposed under the assumption that matrices representing downward jumps are nonsingular. We first show that this assumption can be eliminated in a general setting of Markov chains of level-dependent G/G/1-type. Next we develop a computational algorithm for the conditional stationary distribution in Markov chains of level-dependent M/G/1-type, by modifying the above-mentioned algorithm slightly. In principle, our algorithm is applicable to any Markov chain of level-dependent M/G/1-type, if the Markov chain is irreducible and positive-recurrent. Furthermore, as an input to the algorithm, we can set an error bound for the computed conditional distribution, which is a notable feature of our algorithm. Some numerical examples are also provided.     

A bivariate distribution with Lomax and geometric margins

We develop a stochastic model describing the joint distribution of $(X,N)$, where $N$ has a geometric distribution while $X$ is the sum of $N$ dependent, heavy-tail Pareto components. Models of this form arise in many applications, ranging from hydro-climatology to finance and insurance. We present fundamental properties of this vector, including marginal and conditional distributions, moments, representations, and parameter estimation. We also include an example from finance, illustrating modeling potential of this new bivariate distribution.     

Optimal consumption and portfolio selection with negative wealth constraints,subsistence consumption constraints,and CARA utility

We consider the optimal consumption and portfolio selection problem with constant absolute risk aversion (CARA) utility. The economic agent in this model receives constant labor income, and her economic behavior is restricted on consumption and wealth, which are called the subsistence consumption constraint and the negative wealth constraint. We use the convex duality method to derive the value function and the optimal policies in closed-form solutions. Also we illustrate some numerical examples.     

Parametric inference based on judgment post stratified samples

In this paper, we consider a judgment post stratified (JPS) sample of set size $H$ from a location and scale family of distributions. In a JPS sample, ranks of measured units are random variables. By conditioning on these ranks, we derive the maximum likelihood (MLEs) and best linear unbiased estimators (BLUEs) of the location and scale parameters. Since ranks are random variables, by considering the conditional distributions of ranks given the measured observations we construct Rao-Blackwellized version of MLEs and BLUEs. We show that Rao-Blackwellized estimators always have smaller mean squared errors than MLEs and BLUEs in a JPS sample. In addition, the paper provides empirical evidence for the efficiency of the proposed estimators through a series of Monte Carlo simulations.     

Financial frictions and indebtedness of Balkan firms: A comparison with Mediterranean and Central European countries

Using a large database of financial data for non-financial corporations, we study the process of debt accumulation and its influence on liquidity through the boom-bust-recovery regimes (2006–2010) in the Balkan countries and benchmark this against the Mediterranean and Central European countries. The domestic amplification effects (through the financial accelerator and collateral pricing) of both the capital surge from developed EU countries at the onset of the crisis and the capital reversal afterwards are the focus of the analysis. We show that domestic generators and amplificators of the crisis have much larger effects in the Balkan countries than in the Mediterranean countries, not to mention the countries of Central Europe. In the boom period, the financial accelerator was several times stronger in the Balkan countries than in the Mediterranean and Central European countries. In the bust and recovery periods, however, the direct effects of the financial accelerator declined, but the indirect effects increased considerably due to liquidity squeezes and contagion, especially strong were corresponding intercompany debt effects. In the Balkan countries, these effects in the bust and recovery periods were at least 50% larger than in the Mediterranean and Central European countries. Higher crisis costs in the Balkan countries, relative to the benchmark regions, could be attributed to the late integration of these economies into international financial and trade flows, weak institutions of financial intermediation, and inexperienced regulators; however, the importance of the contribution of misguided EU convergence doctrine cannot be ignored. Lessons for improving macromanagement in EU periphery countries are suggested.     

The impact of social heterogeneity and commodity price shocks on civil conflicts

Do exogenous economic shocks promote civil conflicts directly? Do they affect all the societies alike? The current approach presents a large sample panel data evidence not only on the effect of commodity export price shocks on conflict incidence, rather than onsets, but also on the joint impact of both ethnic and religious polarization and fractionalization on political instability. In this regard, we find out that in ethnically polarized societies, the commodity export price shocks increase violence. Nonetheless, in ethnically and religiously fractionalized societies (as well as religiously polarized), the effect of commodity export price shocks on civil conflicts depends on the type of income shocks and category of commodity. These findings contribute to the existing literature by illuminating the compound effect of both income shocks and social diversity on intrastate conflicts.     

The role of macroeconomic policies in the global crisis

This paper argues that the lack of timely and decisive policy action to correct domestic and external imbalances contributed crucially to the build-up of financial excesses that led to the financial crisis and the Great Recession. We focus on 2002–2007 and perform a number of counterfactual simulations to investigate two central elements of the story, namely: (a) an over-expansionary US monetary policy and the absence of effective macro-prudential supervision, which permitted a prolonged expansion of debt-financed consumer spending and (b) the choice by China and other emerging countries to pursue an export-led growth strategy supported by pegging their currencies to the US dollar, in conjunction with sluggish domestic demand in major advanced economies characterized by low potential output growth. The results of the simulations lend support to the view that if substantial, globally coordinated demand rebalancing had been undertaken early on, the macroeconomic and financial imbalances would not have accumulated to the extent that they did and the financial turmoil might have had less drastic global consequences.     

A generalized Fleming and Harrington's class of tests for interval‐censored data

The class $G^{\rho,\lambda }$ of weighted log‐rank tests proposed by Fleming & Harrington [Fleming & Harrington (1991) Counting Processes and Survival Analysis, Wiley, New York] has been widely used in survival analysis and is nowadays, unquestionably, the established method to compare, nonparametrically, k different survival functions based on right‐censored survival data. This paper extends the $G^{\rho,\lambda }$ class to interval‐censored data. First we introduce a new general class of rank based tests, then we show the analogy to the above proposal of Fleming & Harrington. The asymptotic behaviour of the proposed tests is derived using an observed Fisher information approach and a permutation approach. Aiming to make this family of tests interpretable and useful for practitioners, we explain how to interpret different choices of weights and we apply it to data from a cohort of intravenous drug users at risk for HIV infection. The Canadian Journal of Statistics 40: 501–516; 2012 © 2012 Statistical Society of Canada     

Marketing an imagined Muslim woman: Muslim Girl magazine and the politics of race,gender and representation

This article examines the magazine Muslim Girl (started publication 2007) and explores how the representations on the magazine's pages construct a particular type of identity for Muslim women: an ‘idealized’ Muslim woman who is both North American/Western and Muslim. Such a woman is portrayed as liberal, educated, fashionable, a ‘can-do’ woman, who is also committed to her faith. This ‘ideal’ woman is situated squarely as a neo-liberal subject in an increasingly consumerist world: she is ‘marketable’ (and marketed) as the ‘good Muslim’ (Mamdani, 2004) and is positioned as the ‘familiar stranger’ (Ahmed, 2000) in North America. This so-called ‘modern’ Muslim (read: ‘good Muslim’) is juxtaposed both against the ‘fundamentalist’ Muslim (read: ‘bad Muslim’) and the ‘normalized’ white North American subject. Against the discourse of post 9/11 nationalism and within the context of (gendered) Orientalism, this article argues that such idealized representations present easily recognizable tropes, which serve important political, ideological and cultural purposes within North American society. An analysis of these representations – and the purposes which they serve – provides an important window into the nuances of the structured discourses that seek to control and discipline the gendered Muslim body. On the one hand, the representations in Muslim Girl focus on the so-called ‘integrated North American Muslim’ – a ‘modern’ or ‘good’ Muslim – within the context of the multicultural, neo-liberal and post 9/11 nation-state. On the other hand, these representations also highlight examples of Muslim women, who seemingly remain committed to their faith and community. Such representations of hybridized North American Muslims speak powerfully to the forces – ideological, cultural, political and social – that are at play in the post 9/11 world. In analyzing the representations found in Muslim Girl, this paper provides an insight into some of these forces and their implications.     

Return and volatility interaction between oil prices and stock markets in Saudi Arabia

The paper aims at investigating the links between world oil price and stock sector markets in Saudi Arabia over the weekly period from January 10, 2007 until September 28, 2011. To that effect, we make use of the VAR-GARCH process developed by Ling and McAleer (2003), which has the advantage to address the issue of return and volatility spillovers among the series we consider. Globally, the empirical findings show evidence of return and volatility transmission between oil price and stock sectors. However, the spillover effects are unidirectional from oil to some sectors for returns, but bidirectional for volatility patterns with more apparent links from sectors to oil. The optimal weights and hedge ratios for oil/stock portfolio holdings are sensitive to the sectors considered, and allow a better understanding of the links between sectors and oil for investors who seek for investment opportunities and want to diversify their portfolios. The findings are of great interest and have important implications for investors, market participants and policy makers.