Informatica

Electronic commerce (e-commerce) is a relatively new, emerging and constantly changing area of business management and information technology. One of the technological innovations in banking, finance and e-commerce is the electronic cash (e-cash) transfer system. E-cash transfer systems refers to the technological breakthrough that enables us to perform financial transactions electronically. In this paper we propose a secure e-cash transfer system based on the elliptic curve cryptography. In order to protect the honest participants of the e-cash system we use an elliptic curve blind signature scheme and also we need a trusted third party to trace the criminals.

In this paper we have proposed a novel method for image denoising using local polynomial approximation (LPA) combined with the relative intersection of confidence intervals (RICI) rule. The algorithm performs separable column-wise and row-wise image denoising (i.e., independently by rows and by columns), combining the obtained results into the final image estimate. The newly developed method performs competitively among recently published state-of-the-art denoising methods in terms of the peak signal-to-noise ratio (PSNR), even outperforming them for small to medium noise variances for images that are piecewise constant along their rows and columns.

In the usual statistical approach of spatial classification, it is assumed that the feature observations are independent conditionally on class labels (conditional independence). Discarding this popular assumption, we consider the problem of statistical classification by using multivariate stationary Gaussian Random Field (GRF) for modeling the conditional distribution given class labels of feature observations. The classes are specified by multivariate regression model for means and by common factorized covariance function. In the two-class case and for the class labels modeled by Random Field (RF) based on 0–1 divergence, the formula of the Expected Bayes Error Rate (EBER) is derived. The effect of training sample size on the EBER and the influence of statistical parameters to the values of EBER are numerically evaluated in the case when the spatial framework of data is the subset of the 2-dimensional rectangular lattice with unit spacing.

This paper discusses the disease-free and endemic equilibrium points of a SVEIRS propagation disease model which potentially involves a regular constant vaccination. The positivity of such a model is also discussed as well as the boundedness of the total and partial populations. The model takes also into consideration the natural population growing and the mortality associate to the disease as well as the lost of immunity of newborns. It is assumed that there are two finite delays affecting to the susceptible, recovered, exposed and infected population dynamics.

The aim of the current research is to measure objective congruence (incongruence) of the results obtained in a process of multiple criteria analysis when applying different MCDM methods. The methodology for evaluation of ranking results is developed on the ground of a case study of the redevelopment of derelict buildings as well as on composed experimental tasks. Fuzzified COPRAS, TOPSIS and VIKOR methods are applied for ranking the alternatives. Calculation results are evaluated by applying mathematical statistics methods. A methodology for measuring the congruence (incongruence) of the relative significances of alternatives is proposed.

The aim of the paper is to investigate applicability of object-oriented software design patterns in the context of aspect-oriented design. The paper analyses which of the GoF 23 patterns have a meaning in this context and how they are affected by it. The main assumption is that there exist design patterns that solve software engineering paradigm independent design problems and that such patterns, in the contrast to the patterns solving paradigm-specific design problems, can be expressed in terms of any software engineering paradigm. However, the paper deals only with two paradigms: aspect-oriented (AO) paradigm and object-oriented (OO) paradigm. It proposes a classification of design problems based on this assumption and a technique for redesigning object-oriented patterns into pure aspect-oriented ones. It presents a number of examples how to apply this technique and discusses the results obtained. The results show that 20 of the GoF 23 design patterns solve such design problems that are common at least for both mentioned paradigms and demonstrate in which way these patterns can be adapted for the needs of aspect-oriented design.

In this paper we consider random sequences in the background of which specific short-time random elements can emerge. The theory and constructive methods for recognition of short-time specific random elements that may emerge in the background of random sequences are expounded. The results of experimental investigations are presented. The prospects for a wider application of the results obtained are discussed as well.

We consider that the outer hair cells of the inner ear together with the local structures of the basilar membrane, reticular lamina and tectorial membrane form the primary filters (PF) of the second order. Taking into account a delay in transmission of the excitation signal in the cochlea and the influence of the Reissner membrane, we design a signal filtering system consisting of the PF with the common PF of the neighboring channels. We assess the distribution of the central frequencies of the channels along the cochlea, optimal number of the PF constituting a channel, natural frequencies of the channels, damping factors and summation weights of the outputs of the PF. As an example, we present a filter bank comprising 20 Gaussian-type channels each consisting of five PF. The proposed filtering system can be useful for designing cochlear implants based on biological principles of signal processing in the cochlea.

The current increment in energy consumption has renewed the interest in the development of alternatives to fossil fuels. In this regard, the interest in solving the different control problems existing in nuclear fusion reactors like Tokamaks has been intensified. The aim of this manuscript is to show how the ASTRA code, which is used to simulate the performance of Tokamaks, can be integrated into the Matlab-Simulink tool in order to make easier the development of suitable controllers for Tokamaks. As a demonstrative case study to show the feasibility and the goodness of the proposed integration, a modified anti-windup PID-based controller coupled with an optimization algorithm for the loop voltage has been implemented. This integration represents an original and innovative work in the Tokamak control area and it provides new possibilities for the development and application of advanced control schemes to the standardized ASTRA code.

This paper presents a hand-shape biometric system based on a novel feature extraction methodology using the morphological pattern spectrum or pecstrum. Identification experiments were carried out using the obtained feature vectors as an input to some recognition systems using neural networks and support vector machine (SVM) techniques, obtaining in average an identification of 98.5%. The verification case was analyzed through an Euclidean distance classifier, obtaining the acceptance rate (FAR) and false rejection rate (FRR) of the system for some K-fold cross validation experiments. In average, an Equal Error Rate of 2.85% was obtained. The invariance to rotation and position properties of the pecstrum allow the system to avoid a fixed hand position using pegs, as is the case in other reported systems. The results indicate that the pattern spectrum represents a good alternative of feature extraction for biometric applications.