The relationship between risk and return has been one of the most important and extensively investigated issues in the financial economics literature. The theoretical results predict a positive relation between the two. Nevertheless, the empirical findings so far have been contradictory. Evidence presented in this paper show that these contradictions are the result of negative skewness in the d...

We present a variational Expectation-Maximization algorithm to learn probabilistic mixture models. The algorithm is similar to Kohonen’s Self-Organizing Map algorithm and not limited to Gaussian mixtures. We maximize the variational free-energy that sums data loglikelihood and Kullback-Leibler divergence between a normalized neighborhood function and the posterior distribution on the components...

This paper applies a new clustering approach for identifying and segmenting motion in image sequences. We estimate a matrix whose entries represent similarity probabilities between local motion estimates. We adopt a two step iterative algorithm which consists of a variant of the expectationmaximization algorithm for segmenting regions with similar motion. The proposed algorithm updates cluster ...

We present a method for simultaneous dimension reduction and metastability analysis of high dimensional time series. The approach is based on the combination of hidden Markov models (HMMs) and principal component analysis. We derive optimal estimators for the loglikelihood functional and employ the Expectation Maximization algorithm for its numerical optimization. We demonstrate the performance...

The programming environment provided by Matlab makes it easy to write code for the interactive analysis of data from ring-recovery and recapture studies. In particular, it is simple to write down a loglikelihood for any given model, to maximise this loglikelihood to estimate the parameters of the model and calculate their standard errors, to perform likelihood ratio and score test comparisons o...

Nonlinear mixed effects models have received a great deal of attention in the statistical literature in recent years because of the flexibility they offer in handling unbalanced repeated measures data that arise in different areas of investigation, such as pharmacokinetics and economics. Several different methods for estimating the parameters in nonlinear mixed effects model have been proposed....

Twitter has become the foremost standard of social media in today’s world. Over 335 million users are online monthly, and near about 80% accessing it through their mobiles. Further, is now supporting 35+ which enhance its usage too much. It facilitates people having different languages. Near 21% total from US 79% outside US. A tweet restricted to a hundred forty characters; hence contains such ...

relative to a hereditary torsion theory $tau$ we introduce a dimension for a module $m$, called {em $tau$-rank of} $m$, which coincides with the reduced rank of $m$ whenever $tau$ is the goldie torsion theory. it is shown that the $tau$-rank of $m$ is measured by the length of certain decompositions of the $tau$-injective hull of $m$. moreover, some relations between the $tau$-rank of $m$ and c...