Volatility modelling and accurate minimun capital risk requirements : a comparison among several approaches

In this paper we estimate, for several investment horizons, minimum capital risk requirements for short and long positions, using the unconditional distribution of three daily indexes futures returns and a set of GARCH-type and stochastic volatility models. We consider the possibility that errors follow a t-Student distribution in order to capture the kurtosis of the returns distributions. The results suggest that an accurate modeling of extreme returns obtained for long and short trading investment positions is possible with a simple autoregressive stochastic volatility model. Moreover, modeling volatility as a fractional integrated process produces, in general, excessive volatility persistence and consequently leads to large minimum capital risk requirement estimates. The performance of models is assessed with the help of out-of-sample tests and p-values of them are reported

An experimental comparison of several approaches to the linear least squares problem

Algorithms and original data matrix approaches compared for linear least squares proble

SEVERAL APPROACHES IN PRESENTING TRIGONOMETRIC INTRODUCTION LEARNING

This research was the result of library study explaining several approaches in presenting trigonometric introduction learning viewed from the chronology of trigonometry inception to be a starting point or an outline in developing a trigonometric learning scenario. Presenting a challenging, joyful, and meaningful trigonometric learning is a challenge to teachers. It is because trigonometry is a complex and applicative material but considered as difficult by students. Considering the findings of some field researches, the students were found memorizing many trigonometric formulas and understanding them separately, and thereby less meaningful. Consequently, the students did not understand trigonometry completely, and even it was only recitation that will be forgettable soon. For that reason, there should be a good preparation on how to present trigonometric learning to make the students understand and master it. Trigonometric mastery cannot be apart from knowledge on background and chronology of trigonometry inception history. The creation of a concept is very important to the students to construction their own conception. Many things became the students’ question and it could not be answered because they did not know background and chronology of the creation of concept being studied. Such the condition forces the students to receive the theory as the way it is by means of memorizing only, so that the learning process becomes less meaningful. Departing from that background, this article raised a theme of the historical chronology of trigonometry inception to explain three approaches: circle unit, right triangle, and function, and to formulate six possible scenarios of trigonometric introduction learning combined from those three approaches. Key words: mathematics, trigonometry, chronology, history

Fair comparison of skin detection approaches on publicly available datasets

Skin detection is the process of discriminating skin and non-skin regions in a digital image and it is widely used in several applications ranging from hand gesture analysis to track body parts and face detection. Skin detection is a challenging problem which has drawn extensive attention from the research community, nevertheless a fair comparison among approaches is very difficult due to the lack of a common benchmark and a unified testing protocol. In this work, we investigate the most recent researches in this field and we propose a fair comparison among approaches using several different datasets. The major contributions of this work are an exhaustive literature review of skin color detection approaches, a framework to evaluate and combine different skin detector approaches, whose source code is made freely available for future research, and an extensive experimental comparison among several recent methods which have also been used to define an ensemble that works well in many different problems. Experiments are carried out in 10 different datasets including more than 10000 labelled images: experimental results confirm that the best method here proposed obtains a very good performance with respect to other stand-alone approaches, without requiring ad hoc parameter tuning. A MATLAB version of the framework for testing and of the methods proposed in this paper will be freely available from https://github.com/LorisNann