In this paper we propose a mixture of two different distributions such as Exponential-Gamma, Exponential-Weibull and Gamma-Weibull to model heterogeneous survival data. Various properties of the proposed mixture of two different distributions are discussed. Maximum likelihood estimations of the parameters are obtained by using the EM algorithm. Illustrative example based on real data are also g...

The rotated-sigmoid form is a characteristic of old-growth, uneven-aged forest stands caused by past disturbances such as cutting, fire, disease, and insect attacks. The diameter frequency distribution of the rotated-sigmoid form is bimodal with the second rounded peak in the midsized classes, rather than a smooth, steeply descending, monotonic curve. In this study a finite mixture of two Weibu...

In wood engineering, lower quantile estimation is vital to the safety of the construction with wood materials. In this thesis, we will first study the censored Weibull maximum likelihood estimate (MLE) of the lower quantile as in the current industrial standard D5457 (ASTM, 2004a) from a statistical point of view. According to our simulations, the lower quantile estimated by the censored Weibul...

In recent years the processing of blind image separation has been investigated. As a result, a number of feature extraction algorithms for direct application of such image structures have been developed. For example, separation of mixed fingerprints found in any crime scene, in which a mixture of two or more fingerprints may be obtained, for identification, we have to separate them. In this pap...

A statistical mixture model is used to fit time-to-emesis data. The Weibull probability distribution is shown to provide a good fit for those subjects who either become sick or withdraw from the experiment within 2 h. The second part of the mixture accounts for those subjects who neither quit nor vomit within 2 h. The log-normal probability model is shown to give a poorer fit to the data and fi...

background: combination of cyromazine as an insect growth regulator (igr) and nasonia vitripennis (hymenop tera: pteromalidae) a parasitic wasp may be an effective tool for reducing the house-fly populations in poultry houses and livestock farms. this study was conducted to assess the side effects of the igr cyromazine on the level of parasit ism and numbers and the longevity of emerged n. vitr...

The Weibull distribution function is essential for planning and designing wind-farm implementation projects wind-resource assessments. However, the limited those areas with high frequencies of calm winds. One solution to use hybrid distribution. In fact, when wind speed data present heterogeneous structures, it makes sense group them into classes that describe different regimes. single presents...

Bathtub shape is one of the most important behaviors of the hazard rate function that is quite common in lifetime data analysis. Such shapes are actually the combination of three different shapes and, as such, there have been several proposals to model such behavior. One such proposal is to combine at most three different distributions, often the Weibull or some similar model, separately for de...