In many credit risk and pricing applications, credit transition matrix is modeled by a constant transition probability or generator matrix for Markov processes. Based on empirical evidence, we model rating transition processes as piecewise homogeneous Markov chains with unobserved structural breaks. The proposed model provides explicit formulas for the posterior distribution of the time-varying...

his paper tests for evidence in support of the purchasing power parity (PPP) in the bilateral real exchange rate series of the South African rand against the US dollar. The importance of considering structural breaks in the PPP test is illustrated. Using standard unit root tests without considering structural breaks, the study is unable to reject the null hypothesis of a unit root in the exchan...

While a host of economic variables have been identified in the literature with the apparent in-sample ability to predict the equity premium, Goyal and Welch (2007) find that these variables fail to deliver consistent out-of-sample forecast gains relative to the historical average. In this paper, we demonstrate that despite the failure of individual predictive regression model forecasts to outpe...

Although the DNA double-strand break (DSB) is defined as a rupture in the double-stranded DNA molecule that can occur without chemical modification in any of the constituent building blocks, it is recognized that this form is restricted to enzyme-induced DSBs. DSBs generated by physical or chemical agents can include at the break site a spectrum of base alterations (lesions). The nature and num...

A hierarchical framework is proposed to address the issues of modeling different type of words in keyword spotting (KWS). Keyword models are built at various levels according to the availability of training set resources for each individual word. The proposed approach improves the performance of KWS even when no training speech is available for the keywords. It also suggests an easier way to co...

boolean byte class double else extends final finally float if implements int interface long native new private public return short static super synchronized this throw throws transient try void volatile while ( ) [ ] { } ; , . = Figure 1: Java keywords.