Entity

Time filter

Source Type


Nikolova N.D.,Nikola Vaptsarov Naval Academy | Armenski I.S.,Technical University of Gabrovo | Tchikova K.T.,Bulgarian Port Infrastructure Company | Tenekedjiev K.I.,Nikola Vaptsarov Naval Academy
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2012

The Port of Varna East is one of the main port facilities on the West Black sea coast. A major issue in its future development is the question of whether to keep the port at its present location within the city limits or move it to another location and develop a recreational center on its place. In this practically-oriented study, four alternatives for the future development of the Port of Varna east area are outlined, and a detailed expert-based analysis is conducted. An original procedure, called REPOMP (Randomized Expert Panel Opinion Marginalizing Procedure) is employed for the selection. A hierarchical structure of criteria is elaborated, and experts have provided their opinion regarding those criteria for each alternative. Simulation procedures are used to define the best point estimate and the standard deviation of the total marginal criterion. Hypothesis testing procedure is also employed to define indifference classes of the alternatives. © 2012 IFAC.


Nikolova N.,Nikola Vaptsarov Naval Academy | Nikolova N.,University of Tasmania | Chai S.,University of Tasmania | Ivanova S.D.,Nikola Vaptsarov Naval Academy | And 3 more authors.
International Journal of Computational Intelligence Systems | Year: 2015

This paper aims to statistically test the null hypothesis H0 for identity of the probability distribution of one-dimensional (1D) continuous parameters in two different populations, presented by fuzzy samples of i.i.d. observations. A degree of membership to the corresponding population is assigned to any of the observations in the fuzzy sample. The test statistic is the Kuiper's statistic, which measures the identity between the two sample cumulative distribution functions (CDF) of the parameter. A Bootstrap algorithm is developed for simulation-based approximation for the CDF of the Kuiper statistic, provided that H0 is true. The pvalue of the statistical test is derived using the constructed conditional distribution of the test statistic. The main idea of the proposed Bootstrap test is that, if H0 is true, then the two available fuzzy samples can be merged into a unified fuzzy sample. The latter is summarized into a conditional sample distribution of the 1D continuous parameter used for generation of synthetic pairs of fuzzy samples in different pseudo realities. The proposed algorithm has four modifications, which differ by the method to generate the synthetic fuzzy sample and by the type of the conditional sample distribution derived from the unified fuzzy sample used in the generation process. Initial numerical experiments are presented which tend to claim that the four modifications produce similar results. © 2015 the authors.


Nikolova N.D.,Nikola Vaptsarov Naval Academy | Ivanova S.,Nikola Vaptsarov Naval Academy | Tenekedjiev K.,Nikola Vaptsarov Naval Academy
Studies in Computational Intelligence | Year: 2014

In the process of quantitative decision making, the bounded rationality of real individuals leads to elicitation of interval estimates of probabilities and utilities. This fact is in contrast to some of the axioms of rational choice, hence the decision analysis under bounded rationality is called fuzzy-rational decision analysis. Fuzzy-rationality in probabilities leads to the construction of x-ribbon and p-ribbon distribution functions. This interpretation of uncertainty prohibits the application of expected utility unless ribbon functions were approximated by classical ones. This task is handled using decision criteria Q under strict uncertainty - Wald, maximax, Hurwicz α, Laplace - which are based on the pessimism-optimism attitude of the decision maker. This chapter discusses the case when the ribbon functions are linearly interpolated on the elicited interval nodes. Then the approximation of those functions using a Q criterion is put into algorithms. It is demonstrated how the approximation is linked to the rationale of each Q criterion, which in three of the cases is linked to the utilities of the prizes. The numerical example demonstrates the ideas of each Q criterion in the approximation of ribbon functions and in calculating the Q-expected utility of the lottery. © 2014 Springer-Verlag Berlin Heidelberg.


Djagarov N.,Nikola Vaptsarov Naval Academy | Bonev M.,Nikola Vaptsarov Naval Academy | Grozdev Z.,Nikola Vaptsarov Naval Academy
2013 13th International Conference on Environment and Electrical Engineering, EEEIC 2013 - Conference Proceedings | Year: 2013

In this article, mathematical model of autonomous power system is suggested including induction drive with part winding starting. With the help of the created model the process of starting is studied, and the results are compared with those of direct starting. The results of the simulations show the effectiveness of the part winding starting that improves all parameters of starting process. © 2013 IEEE.

Discover hidden collaborations