An ensemble Kalman filter (EnKF) based on the Weather Research and Forecasting (WRF) model is used to generate ensemble analyses and forecasts for the extratropical transition (ET) events associated with Typhoons Tokage (2004) and Nabi (2005). Ensemble sensitivity analysis is then used to evaluate the relationship between forecast errors and initial condition errors at the onset of transition, ...

The use of discrete-time stochastic parameterization to account for model error due to unresolved scales in ensembleKalman filters is investigated by numerical experiments. The parameterization quantifies themodel error and produces an improved non-Markovian forecast model, which generates high quality forecast ensembles and improves filter performance. Results are compared with themethods of d...

Predicting the future has been an aspiration of humans since the beginning of time. Today, predicting both macroand micro-economic events is an important activity enabling better policy and the potential for profits. In this work, we present a novel method for automatically extracting forward looking-statement from a specific type of formal corporate documents called earning call transcripts. O...

Title of dissertation: INFORMATION SYNTHESIS ACROSS SCALES IN ATMOSPHERIC STATE ESTIMATION: THEORY AND NUMERICAL EXPERIMENTS Matthew Kretschmer, Doctor of Philosophy, 2015 Dissertation directed by: Professor Edward Ott Department of Physics This thesis studies the benefits of simultaneously considering system information from di↵erent sources when performing ensemble data assimilation. In parti...

This paper assesses the performance of a number of long-term interest rate forecast approaches, namely time series models, structural economic models, expert forecasts and combinations thereof. The predictive performance of these approaches is compared using out of sample forecast errors, where a random walk forecast acts as benchmark. It is found that for five major OECD countries, namely Unit...

In applied forecasting, there is a trade-off between in-sample fit and out-ofsample forecast accuracy. Parsimonious model specifications typically outperform richer model specifications. Consequently, there is often predictable information in forecast errors that is difficult to exploit. However, we show how this predictable information can be exploited in forecast combinations. In this case, o...

In this work, we address the problem of spelling correction in the Arabic language utilizing the new corpus provided by QALB (Qatar Arabic Language Bank) project which is an annotated corpus of sentences with errors and their corrections. The corpus contains edit, add before, split, merge, add after, move and other error types. We are concerned with the first four error types as they contribute...

An objective method of determining and correcting phase or position errors in numerical weather prediction is described and tested in a radar data observing system simulation experiment (OSSE) addressing the forecasting of ongoing thunderstorms. Such phase or position errors are common in numerical forecasts at grid resolutions of 2–20 km (meso-g scale). It is proposed that the process of corre...

One of the basic assumptions of management accounting illustrate that costschanges has a significance Relationship with increasing and decreasing in the levelof activity, recently after being raised of sticky costs issue by Anderson and hiscolleagues this assumption was discussed. It means Increases in costs by increasingthe more activity level of reduction in costs is exchange for the reductio...