ISSN 2738-0971 | eISSN 2738-1013
Bulletin of Natural Sciences Research
Open access journal | Double-blind peer review

Milena Petrović

Faculty of mathematics and natural sciences, University of Priština, Kosovska Mitrovica

Articles

Open Access Original Scientific Paper

DETERMINATION OF ACCELERATED FACTORS IN GRADIENT DESCENT ITERATIONS BASED ON TAYLOR’S SERIES

by Milena Petrović, Nataša Kontrec, Stefan Panić

In this paper the efficiency of accelerated gradient descent methods regarding the way of determination of accelerated factor is considered. Due to the previous researches we assert that the use of Taylor’s series of posed gradient descent iteration in calculation of accelerated parameter gives better final results than some other choices. We give a comparative analysis of efficiency of several methods with different approaches in obtaining accelerated parameter. According to the achieved results of numerical experiments we make a conclusion about the one of the most optimal way in defining accelerated parameter in accelerated gradient descent schemes.

View Full-Text DOI 10.5937/univtho7-14337 Published: 17 Jul 2017
Open Access Original Scientific Paper

IMPLEMENTATION OF GRADIENT METHODS FOR OPTIMIZATION OF UNDERAGE COSTS IN AVIATION INDUSTRY

by Nataša Kontrec, Milena Petrović

Underage costs are not easily quantifiable in spare parts management. These costs occur when a spare part is required and none are available in inventory. This paper provides another approach to underage cost optimization for subassemblies and assemblies in aviation industry. The quantity of spare parts is determined by using a method for airplane spare parts forecasting based on Rayleigh's model. Based on that, the underage cost per unit is determined by using the Newsvendor model. Then, by implementing a transformed accelerated double-step size gradient method, the underage costs for spare sub-assemblies and assemblies in airline industry are optimized.

View Full-Text DOI 10.5937/univtho6-10134 Published: 29 May 2016
Open Access

COMPARATIVE PERFORMANCE ANALYSIS OF SOME ACCELERATED AND HYBRID ACCELERATED GRADIENT MODELS

by Milena Petrović, Milica Ivanović, Marijana Đorđević

We analyze a performance profile of several accelerated and hybrid accelerated methods. All comparative methods are at least linearly convergent and have satisfied numerical characteristics regarding tested metrics: number of iterations, CPU time and number of function evaluations. Among the chosen set of methods we numerically show which one is the most efficient and the most effective. Therewith, we derived a conclusion about what type of method is more preferable to use considering analyzed metrics.

View Full-Text DOI 10.5937/univtho9-18174