Gumbel distribution was dealt with great care by researchers and statisticians. There are traditional methods to estimate two parameters of Gumbel distribution known as Maximum Likelihood, the Method of Moments and recently the method of re-sampling called (Jackknife). However, these methods suffer from some mathematical difficulties in solving them analytically. Accordingly, there are other non-traditional methods, like the principle of the nearest neighbors, used in computer science especially, artificial intelligence algorithms, including the genetic algorithm, the artificial neural network algorithm, and others that may to be classified as meta-heuristic methods. Moreover, this principle of nearest neighbors has useful statistical features. The objective of this paper is thus to propose a new algorithm where it allows getting the estimation of the parameters of Gumbel probability distribution directly. Furthermore, it overcomes the mathematical difficulties in this matter without need to the derivative of the likelihood function. Taking simulation approach under consideration as empirical experiments where a hybrid method performs optimization of these three traditional methods. In this regard, comparisons have been done between the new proposed method and each pair of the traditional methods mentioned above by efficiency criterion Root of Mean Squared Error (RMSE). As a result, (36) experiments of different combinations of initial values of two parameters (λ: shift parameter and θ: scale parameter) in three values that take four different sample sizes for each experiment. To conclude, the proposed algorithm showed its superiority in all simulation combinations associated with all sample sizes for the two parameters (λ and θ). In addition, the method of Moments was the best in estimating the shift parameter (λ) and the method of Maximum Likelihood was in estimating the scale parameter (θ).
Background: The evaluation of the chronological age is a practical method in crime investigation field that assists in identifying individuals to treat them as underage or adult. This study aimed to assess the stages of third molars mineralization in relation to chronological age of Iraqi individuals, determine the gender differences and arches (maxillary/mandibular) differences.
Materials and Methods: A total of 300 orthopantomograms of orthodontic patients were collected according to specific criteria and evaluated visually. The developmental stages of maxillary and mandibular third molars were determined according to Demirjian method. T
... Show MoreThis research will cover different aspects of estimating process of construction work in a desert area. The inherent difficulties which accompany the cost estimating of the construction works in desert environment in a developing country, will stem from the limited information available, resources scarcity, low level of skilled workers, the prevailing severe weather conditions and many others, which definitely don't provide a fair, reliable and accurate estimation. This study tries to present unit price to estimate the cost in preliminary phase of a project. Estimations are supported by developing mathematical equations based on the historical data of maintenance, new construction of managerial and school projects.
... Show MoreIn this paper, a relationship between the liquid limit and the coefficient of consolidation of Iraqi soils are studied. The samples of soil used in study are undisturbed silty clay. These samples are taken from different locations and depths of Middle and South of Iraq by cooperation with Consulting Engineering Bureau- University of Baghdad- College of Engineering. The depth reached about 20 meters. The experimental work is made to calculate the liquid limit and the coefficient of consolidation. From these sites, 280 points are obtained. The relationship between the liquid limit and the coefficient of consolidation is drawn as a curve. This curve is studied and compared with the curve that obtained from other studies. From these curves, it
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Multipoint forming process is an engineering concept which means that the working surface of the punch and die is produced as hemispherical ends of individual active elements (called pins), where each pin can be independently, vertically displaced using a geometrically reconfigurable die. Several different products can be made without changing tools saved precious production time. Also, the manufacturing of very expensive rigid dies is reduced, and a lot of expenses are saved. But the most important aspects of using such types of equipment are the flexibility of the tooling. This paper presents an experimental investigation of the effect of three main parameters which are blank holder, rubber thickness and forming speed th
... Show MoreThe aim of this research is to construct a three-dimensional maritime transport model to transport nonhomogeneous goods (k) and different transport modes (v) from their sources (i) to their destinations (j), while limiting the optimum quantities v ijk x to be transported at the lowest possible cost v ijk c and time v ijk t using the heuristic algorithm, Transport problems have been widely studied in computer science and process research and are one of the main problems of transport problems that are usually used to reduce the cost or times of transport of goods with a number of sources and a number of destinations and by means of transport to meet the conditions of supply and demand. Transport models are a key tool in logistics an
... Show MoreIncremental sheet metal forming is a modern technique of sheet metal forming in which a uniform sheet is locally deformed during the progressive action of a forming tool. The tool movement is governed by a CNC milling machine. The tool locally deforms by this way the sheet with pure deformation stretching. In SPIF process, the research is concentrate on the development of predict models for estimate the product quality. Using simulated annealing algorithm (SAA), Surface quality in SPIF has been modeled. In the development of this predictive model, spindle speed, feed rate and step depth have been considered as model parameters. Maximum peak height (Rz) and Arithmetic mean surface roughness (Ra) are used as response parameter to assess th
... Show MoreBootstrap is one of an important re-sampling technique which has given the attention of researches recently. The presence of outliers in the original data set may cause serious problem to the classical bootstrap when the percentage of outliers are higher than the original one. Many methods are proposed to overcome this problem such Dynamic Robust Bootstrap for LTS (DRBLTS) and Weighted Bootstrap with Probability (WBP). This paper try to show the accuracy of parameters estimation by comparison the results of both methods. The bias , MSE and RMSE are considered. The criterion of the accuracy is based on the RMSE value since the method that provide us RMSE value smaller than other is con
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