Applied sciences

Bulletin of the Polish Academy of Sciences Technical Sciences

Content

Bulletin of the Polish Academy of Sciences Technical Sciences | 2013 | 61 | No 3

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Abstract

Abstract Nowadays, the growth and complexity of functionalities of current information systems, especially dynamic, distributed and heterogeneous information systems, makes the design and creation of such systems a difficult task and at the same time, strategic for businesses. A very important stage of data protection in an information system is the creation of a high level model, independent of the software, satisfying the needs of system protection and security. The process of role engineering, i.e. the identification of roles and setting up in an organization is a complex task. The paper presents the modeling and design stages in the process of role engineering in the aspect of security schema development for information systems, in particular for dynamic, distributed information systems, based on the role concept and the usage concept. Such a schema is created first of all during the design phase of a system. Two actors should cooperate with each other in this creation process, the application developer and the security administrator, to determine the minimal set of user’s roles in agreement with the security constraints that guarantee the global security coherence of the system.
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Authors and Affiliations

A. Poniszewska-Marańda
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Abstract

Abstract The purpose of this paper is to present a multichannel ultrasonic range finder which was designed for the navigation system for blind people. A substantial number of consultations with blind people in the Blind People Centre in Krakow have shown that the navigation and obstacle detection with a help of a white stick only, is not sufficient enough to assure a high safety level. Electronic aids which are being designed for blind people should be mobile, comfortable and low-powered. That is why the MOBIAN© (a mobile safety system for the blind) project is being carried out by the authors to create a highly reliable safety navigation system for blind people. It could not only improve blind people quality of life but also their safety, especially when they are walking in unknown areas. As a part of this project, the multichannel ultrasonic range finder was designed, produced and tested. The tests have proven the device is capable of detecting objects from different directions in a range over 4 m. The device interface is easy to manage and can be controlled by almost any microcontroller or FPGA chip. The designed range finder is to be implemented in the electronic assistant project for blind people. Other systems, including the industrial ones, for instance, mobile robots or gates that count people entries, could benefit from this multichannel range finder. Usually, some low-cost ultrasonic range finders use two transducers for each channel (a transmitter and a receiver). The designed device employs only one transducer per channel which minimizes the end-device size and cost and at the same time provides with the main functionality. Novelty of this device is its multichannel design and the emplacement of the ultrasonic transducers, which can be used due to the application of the multichannel analog multiplexer. Thus, it is possible to detect obstacles, even the inclined ones, with higher reliability and increase the safety of blind people while walking. Also, this design and the transducers’ placement allow to detect obstacles much quicker, when the blind user suddenly turns.
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Authors and Affiliations

W. Gelmuda
A. Kos

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