Informatica

To offer high quality services, when users are increasingly demanding and competition more and more hard, is now a major problem that transportation companies are faced with. So, ensuring a regular traffic needs to identify the randomly occurring disturbances that affect the transportation system and to eliminate or reduce their impacts on the traffic.

Recently, e-commerce becomes widespread; hence electronic department stores come into being. As a result, Chan and Chang proposed a scheme for digital gift certificates in 2002. Because it is hard to estimate the number of the clients of the electronic department stores, reducing the computation complexity of the electronic department stores becomes an important issue. Due to the need, we propose two schemes for digital gift certificates. Our proposed schemes are very practical since the computation load is light. So the schemes can be applied to the terminals with low computation power.

The paper analyses the problem of aggregation of internal quality characteristics of an information system specification language. It surveys main categories of aggregation operators, their mathematical and behavioural properties and proposes how to aggregate quality characteristics taking into account measurements of all lowest-level characteristics in a proper way. The paper shows that four different kinds of dependencies can occur among characteristics of internal quality and discusses in detail what aggregation techniques are reasonable for each case. It also describes a heuristic for minimisation of possible deviations of measurement results obtained after using a number of different metrics or because of the inaccuracy of used measurement techniques.

This paper presents a new approach for human cataract automatical detection based on ultrasound signal processing. Two signal decomposition techniques, empirical mode decomposition and discrete wavelet transform are used in the presented method. Performance comparison of these two decomposition methods when applied to this specific ultrasound signal is given. Described method includes ultrasonic signal decomposition to enhance signal specific features and increase signal to noise ratio with the following decision rules based on adaptive thresholding. The resulting detection performance of the proposed method using empirical mode decomposition was better to compare to discrete wavelet transform and resulted in 70% correctly identified “healthy subject” cases and 82%, 97% and 100% correctly identified “cataract cases” in the incipience, immature and mature cataract subject groups, respectively. Discussion is given on the reasons of different results and the differences between the two used signal decomposition techniques.

The Star Plot approach to high-dimensional data visualization is applied to multi-attribute dichotomies. It is observed that the areas of the plot for the two parts of a dichotomy may be used as an aggregate measure of their relative dominance. An optimization model is developed to determine a topology (or weighted configuration of the attributes) that maximizes the resolution of this measure with respect to a given set of reference dichotomies.

Due to high nonlinearities and time-varying dynamics of today's control systems fuzzy learning controllers find appliance in practice. The present paper proposes a method for the synthesis of the learning fuzzy controllers where an expert knowledge about a process is applied to form a learning mechanism that is used to acquire information for the knowledge base of the main fuzzy controller. According to the proposed method an expert knowledge is used to describe how the controller should learn to control rather than to control the process. The results of experiments on heating system and level/pressure system prove the practical relevance of the design strategy of a learning fuzzy controller.

T wave features suitable for automatic T wave alternans detection in low signal-to-noise ratio electrocardiograms are explored using a correlation-to-template-based algorithm for detecting T waves of variable duration. Amplitude and area features of T waves are found to be notably less sensitive to template selection than are duration features. T wave alternans features and measures which can be determined more stably provide better classification accuracy of patients with and without coronary artery lesions.

Vector Product Format (VPF) based databases store geographical data in a relational framework, where individual VPF files are arranged hierarchically in a directory tree structure. Access and update of the VPF data can become difficult due to fragmentation of data among multiple tables. This paper presents an object-oriented model for the management of a VPF database, which provides easy access and automatic update for the VPF data, and is compatible with ESRI ArcView. This model has been successfully implemented in Java, for Digital Nautical Charts (DNC).