Fundamenta Informaticae - Volume 119, issue 3-4

Authors: Redziejowski, Roman R.

Article Type: Research Article

Abstract: In an earlier paper, the author used derivatives to construct a deterministic automaton recognizing the language defined by an ω-regular expression. The construction was related to a determinization method invented by Safra. This paper describes a new construction, inspired by Piterman's improvement to Safra's method. It produces an automaton with fewer states. In addition, the presentation and proofs are simplified by going via a nondeterministic automaton having derivatives as states.

DOI: 10.3233/FI-2012-744

Citation: Fundamenta Informaticae, vol. 119, no. 3-4, pp. 393-406, 2012

Authors: Rzeszótko, Jarosław | Nguyen, Sinh Hoa

Article Type: Research Article

Abstract: Recently, GPS car navigation became popular enough for a significant number of drivers in any large city to be able to potentially send their current GPS positions and velocities to a central traffic-managing server in real time. This data could be used to reconstruct a map of current traffic in the whole city and make predictions for the future, which would be valuable for traffic control, congestion analysis and prevention. The difficulty lying in the traffic reconstruction problem is that the number of cars equipped with a GPS transmitter is a small in comparison with the total number of cars …in the road network. Information obtained from GPS transmitters is therefore rare and incomplete, raising the problem of approximating travel velocities from sparse information. In this context, the paper proposes approaches to solving two problems: (1) of reconstruction of routes of the individual cars in a street graph from a temporal stream of its coordinates and (2) of approximating the average velocity on a given street from irregular time series of instantaneous velocities of cars passing through that street. Determining the car's position in the road network is quite expensive computationally when done in a naive way, so we propose a method to speed up the car's localization based on the R-tree data structure [10]. Additionally, a resilient propagation neural network [13] is applied to approximate the average velocity on any edge of a street graph. Our methods were applied to one of the problems announced in the competition organized in June 2010 by Tom-Tom - a company producing automotive navigation systems [15]. The results of experiments show the capacity of our approach to make useful predictions. Show more

Keywords: machine learning, data mining, spatio-temporal data mining, GPS, R-Tree, GIS, neural networks

DOI: 10.3233/FI-2012-745

Citation: Fundamenta Informaticae, vol. 119, no. 3-4, pp. 407-420, 2012

Authors: Skowron, Andrzej | Stepaniuk, Jarosław | Jankowski, Andrzej | Bazan, Jan G. | Swiniarski, Roman

Article Type: Research Article

Abstract: We consider several issues related to reasoning about changes in systems interacting with the environment by sensors. In particular, we discuss challenging problems of reasoning about changes in hierarchical modeling and approximation of transition functions or trajectories. This paper can also be treated as a step toward developing rough calculus.

Keywords: rough sets, reasoning about changes, hierarchical modeling, granular computing, approximation space, relation (function) approximation, rough calculus, intelligent systems, computational finance, forex, algorithmic trading

DOI: 10.3233/FI-2012-746

Citation: Fundamenta Informaticae, vol. 119, no. 3-4, pp. 421-437, 2012

Article Type: Other

Citation: Fundamenta Informaticae, vol. 119, no. 3-4, pp. 439-440, 2012