Informatica

Recently, Sun proposed a private-key encryption scheme based on the product codes with the capability of correcting a special type of structured errors. In this paper, we present a novel method to improve the information rate of Sun's scheme. This method uses the added error vector to carry additional information. Some information bits are mapped into an error vector with the special structure to be added to a codeword. Once the error vector can be identified, the additional information can be recovered.

The problem of recursive estimation of a state of dynamic systems in the presence of time-varying outliers in observations to be processed has been considered. A learning phase used in the state estimation is investigated, assuming that the observations of a noisy output signal and that of a training one are given. A technique based on robust filtering by means of a bank of parallel Kalman filters and on the procedure of optimization of the state estimation itself is used, choosing, at each time moment, a current estimate, that ensures a minimal absolute deviation from the current value of the teaching signal. An approach, based on the relation between the mean squared deviation of state estimates from the true state and innovation sequence variance as well as on the fact that both variables achieve their minimum for the same filter from the respective Kalman filter bank, is proposed here for a working phase, where a training signal will be absent. The recursive technique based on an adaptive state estimation with optimization procedure is worked out. The results of numerical simulation of the linear discrete-time invariant (LTI) system (56) by computer using a bank, consisting of Kalman filters are given (Figs. 1–5).

Two examples of open-loop differential games are considered in the paper. Starting with simplified dynamic Duel, further it was developed to differential economic Duel modelling problem.

In this paper, we present our Form-driven approach for reverse engineering of relationa databases. This methodology uses the information extracted from both form structure and instances as a database reverse engineering input using an interaction with a user. Through a combination of forms structures and data instances analysis, forms relational sub-schemas and their constraints are derived. These relational sub-schemas are mapped to object sub-schemas, which will be merging into global object-oriented schema that presents the whole underlying databases. The resulting global object-oriented schema must be validated as a rich and correct representation of the application domain.

The isolated word speech recognition system based on dynamic time warping (DTW) has been developed. Speaker adaptation is performed using speaker recognition techniques. Vector quantization is used to create reference templates for speaker recognition. Linear predictive coding (LPC) parameters are used as features for recognition. Performance is evaluated using 12 words of Lithuanian language pronounced ten times by ten speakers.

It is shown that nonlinear Volterra, polynomial autoregressive, and bilinear filters have the same layered implementation procedure. Using the layered structure, the order of nonlinearity can be increased by adding more layers to the structure. The structure is modular and consists of the simple moving average (MA) or autoregressive (AR) filters which can be added to the structure to achieve a desired degree of complexity. In addition, the modular layered structures admit very large scale integration (VLSI) implementation of the polynomial nonlinear filters.

Installation dynamics, optimal thruster propulsion, and specific impulse thrust for reignitable fuel motors to regulate pointing error is obtained for geosynchronous (e.g., the Indian National Satellite, INSAT–1B), and sunsynchronous (e.g., the Indian Earth Resource Satellite, IRS–1) satellites parked in transfer orbits. Filter dynamics for slow and fast terrestrial system are obtained. Design for inter satellite link server to maximize drop outlets is given. Technique for extension of commutative rings for coordinated control and communication systems with predetermined target signature in global and protected environment is given. Visibility model of flexible structure terrestrial exploration space monitoring station with associated space coordinate system is given. Technique proposed is applied for information acquisition and synchronization of inertial targets. Design of long range navigation in projective space and robust hybrid controller for AAFM auto pilot system is given. AAFM system reliability is analyzed.

So far rather weak tendencies towards an infrastructure for external ratings by independent agencies have been observed in Europe in recent decades. Especially for small and medium-sized enterprises (SMEs), thus far there has been no possibility of obtaining an objective rating. The reason is that information is very asymmetric between investors and capital demands on small and medium-sized companies. But due to the new capital accord by the Basel Committee on Banking Supervision the situation will change. Our paper shows that having Basel II in mind there is need for rating also medium-sized companies. We will also give an overview of characteristics that have to be incorporated in such ratings and further describe models, products and companies in this sector. Especially so-called soft computing methods like Fuzzy Logic or Neural Networks are very promising approaches in the field of rating SMEs.

Method of simulation of technological processes of civil engineering companies allows evaluate quality of the organizational variants by multicriterial estimation methods (Zavadskas et al., 1995). Simulation methods allow to design a rational work programme according to the financial, technological and organizational parameters.

The problem of comparison of different companies is facing, when looking for possible candidates for the investment portfolio. Screening of the companies, using “well-known” trading strategy parameters, is one of the ways to solve this problem. Actually, using this procedure much more companies appear on the list, than the trader is willing to buy. To define the best companies or group of the best companies self-organizing (Kohonen's) map (SOM) could be used. Using fundamental financial parameters as inputs, the output of SOM forms the different groups of companies located into a number of disjoint clusters.