Informatica

One of the components of the text-to-speech synthesis system is the database of sounds. Two Lithuanian diphone databases in the MBROLA format are presented in this paper. The list of phonemes and the list of diphones necessary for Lithuanian text-to-speech synthesis are described. The problem of phoneme combinations that are not used in the Lithuanian language is dealt with in the work. Also, the article is concerned with transcribing a Lithuanian text.

The paper deals with Knowledge-based Information Systems (IS) engineering. The Enterprise management functions, processes and their interactions are considered as the major components of the domain knowledge. This is the peculiarity of this approach to Enterprise modelling for IS engineering. The resulting framework for Enterprise modelling and Knowledge-based IS engineering – Enterprise meta-model (EMM) – is developed and presented in this paper. The architecture of the advanced CASE system is also discussed in this paper.

The more realistic neural soma and synaptic nonlinear relations and an alternative mean field theory (MFT) approach relevant for strongly interconnected systems as a cortical matter are considered. The general procedure of averaging the quenched random states in the fully-connected networks for MFT, as usually, is based on the Boltzmann Machine learning. But this approach requires an unrealistically large number of samples to provide a reliable performance. We suppose an alternative MFT with deterministic features instead of stochastic nature of searching a solution a set of large number equations. Of course, this alternative theory will not be strictly valid for infinite number of elements. Another property of generalization is an inclusion of the additional member in the effective Hamiltonian allowing to improve the stochastic hill-climbing search of the solution not dropping into local minima of the energy function. Especially, we pay attention to increasing of neural networks retrieval capability transforming the replica-symmetry model by including of different nonlinear elements. Some results of numerical modeling as well as the wide discussion of neural systems storage capacity are presented.

In this paper public available C and C++ packages for interval arithmetic are investigated and experimentally compared. The results of comparison give suggestions which packages and when are preferable.

The aim of the given paper is the development of an approach for parametric identification of Wiener systems with piecewise linear nonlinearities, i.e., when the linear part with unknown parameters is followed by a saturation-like function with unknown slopes. It is shown here that by a simple data reordering and by a following data partition the problem of identification of a nonlinear Wiener system could be reduced to a linear parametric estimation problem. Afterwards, estimates of the unknown parameters of linear regression models are calculated by processing respective particles of input-output data. A technique based on ordinary least squares (LS) is proposed here for the estimation of parameters of linear and nonlinear parts of the Wiener system, including the unknown threshold of piecewise nonlinearity, too. The results of numerical simulation and identification obtained by processing observations of input-output signals of a discrete-time Wiener system with a piecewise nonlinearity by computer are given.

Verifiable encryption is a primitive that can be used to build extremely efficient fair exchange protocols where the items exchanged represent digital signatures. Such protocols may be used to digitally sign contracts on the Internet. This paper presents an efficient protocol for verifiable encryption of digital signatures that improves the security and efficiency of the verifiable encryption scheme of Ateniese. Our protocol can be applied to group signatures, key escrow and publicly verifiable secret and signature sharing to prove the fairness.

When handling engineering problems associated with optimal alternative selection a researcher often deals with not sufficiently accurate data. The alternatives are usually assessed by applying several different criteria. A method takes advantage of the relationship between fuzzy sets and matrix game theories can be offered for multicriteria decision-making. Practical investigations have already been discussed for selecting the variants water supply systems.

Portfolio optimization is to find the stock portfolio minimizing the risk for a required return or maximizing the return for a given risk level. The seminal work in this field is the m ean-variance model formulated as a quadratic programming problem. Since it is not computationally practical to solve the original model directly, a number of alternative models have been proposed.

The evolution of Wireless Sensor Networks has led to the development of protocols that must comply with their new restrictions while being efficient in terms of energy consumption and time. We focus on a collision resolution protocol, the so-called Two Cell Sorted (2CS-WSN). We propose three different ways to improve its performance by minimizing the collision resolution time or the energy consumption. After evaluating these proposals and carrying out the comparison with the original protocol, we recommend an improvement to the protocol which reduces the elapsed time by early $8\% $ and the number of retries and conflicts more than $40\% $.

The paper describes methods for generating image watermark for asymmetric key based watermark embedding and detection scheme in wavelet domain. The proposed method combines DWT-based watermarking and the ability to verify watermark using reliable methods of asymmetric coding. The watermark scheme is developed to be directly incorporated into JPEG2000 image coding standard, while it can be used in existing image coding standards. In presented watermarking method the application of public key infrastructure is emphasized. We use PGP (Pretty Good Privacy) public key management scheme as the element for verification of sender’s identity and also place of storing and retrieval of watermark detection keys. The most public key watermarking schemes use new, independent and cryptologically unverified keys. The reuse existing key verification and exchange infrastructure provides us cryptologically strong and verified keys.