Vojnotehnicki glasnik / Military Technical Courier

5-14

Authors: Kozić Mirko S.

In the first part of the paper, the results of the research are presented, giving the increment of the power obtained with two contra-rotating hydro turbines, compared to one turbine, placed in a Venturi tube and rotating at 50 rpm. Since a small increment of power is obtained, research was carried out in order to give an answer to the question whether a larger increment of power could be obtained by increasing a number of revolutions per minute. In the second part of the paper, the results are shown for one and two contra-rotating turbines at the highest revolution at which no cavitation appears on the blades. The results are obtained with numerical simulations using software for solving Navier-Stokes equations.

26-52

Authors: Jeftović Milojko V., Pavlović Boban Z.

Security of communications over broadband ATM networks is analyzed in this paper. Attacks on ATM networks (faber tapping, SONET (Synchronous Optical network) drop/add multiplexor attacks, eavesdropping, spoofing, virtual channel stealing, service denial, traffic analysis, protocol weaknesses, ILMI (Integrated Local Management Interface) attacks, PNNI (Private Network to Network Interface) attacks), model of ATM and ATM security framework are described. Some problems occurring within security and protection realization in the communication over ATM networks are also specified.

73-80

Authors: Anđelković-Lukić Mirjana N.

The characteristics of three-component RDX/PS/Al mixtures have been described s well as the method for their preparation. Polystirene as a binder is a thermostable polymer with satisfactory characteristics for bonding explosives. The constant content of 5% m/m PS was applied for different contents of hexogen and aluminium. The content of Al in the mixtures was 10, 15, and 20% m/m. The composition of the bonded explosives was examined as well as the detonation velocity of these mixtures.

108-131

Authors: Radojević Slobodan M., Ćurčić Jovica T.

The development and the present concept of the Global Positioning System (GPS) are presented clearly. There is also a short description of the basic operation principle and of the main GPS characteristics given, as well as its accuracy. The present accuracy of the system is mostly appropriate for orientation, nautical navigation, land navigation and aero navigation; however, for many other activities better accuracy is required. The article analyses methods to improve the characteristics of the satellite positioning system so as to comply with more stringent safety demands. The paper gives a clear overview of the development of a GPS modernization program up to the year 2030.