POKORNÝ MARTIN, ZACH PETR: Design, implementation and security of a typical educational laboratory computer network. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 4, pp. 1077-1087 Computer network used for laboratory training and for diff erent types of network and security experiments represents a special environment where hazardous activities take place, which may not aff ect any production system or network. It is common that students need to have administrator privileges in this case which makes the overall security and maintenance of such a network a diffi cult task. We present our solution which has proved its usability for more than three years. First of all, four user requirements on the laboratory network are defi ned (access to educational network devices, to laboratory services, to the Internet, and administrator privileges of the end hosts), and four essential security rules are stipulated (enforceable end host security, controlled network access, level of network access according to the user privilege level, and rules for hazardous experiments), which protect the rest of the laboratory infrastructure as well as the outer university network and the Internet. The main part of the paper is dedicated to a design and implementation of these usability and security rules. We present a physical diagram of a typical laboratory network based on multiple circuits connecting end hosts to diff erent networks, and a layout of rack devices. A er that, a topological diagram of the network is described which is based on diff erent VLANs and port-based access control using the IEEE 802.1x/EAP-TLS/RADIUS authentication to achieve defi ned level of network access. In the second part of the paper, the latest innovation of our network is presented that covers a transition to the system virtualization at the end host devices -inspiration came from a similar solution deployed at the Department of Telecommunications at Brno University of Technology. This improvement enables a greater fl exibility in the end hosts maintenance and a simultaneous network access to the educational devices as well as to the Internet. In the end, a vision of a system of virtual machines preparation and automated deployment tailored for our needs is briefl y outlined. computer networks, network security, education, laboratory network, operating system virtualization Laboratory of computer networking at the Department of Informatics (Faculty of Business and Economics, Mendel University in Brno) was founded in 2009 in order to support courses specialized in computer networking, network security and operating systems taught for bachelor and master degrees, and to provide an experimental environment for fi nal thesis and for networking or security tests. The equipment of the laboratory covers basic areas in routing and switching, network security, wireless networking, VoIP, and server virtualization.User requirements, design, implementation and maintenance of an educational network dedicated to laborat...
KOLMAN PAVEL, ZACH PETR, HOLOUBEK JOSEF:The development of e-learning applications solving problems from graph theory. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 7, pp. 2311-2316 Authors are in long term developing e-learning supports for some parts of Operation Research course. The original purpose was to prepare e-learning supports for students of FBE Mendelu, mainly for part-time form students, who have subscribed Economic mathematical methods course (EMM). Considering decreasing number of lessons on part-time form of study (16 hours in a semester, in comparison to 56 hours in full-time form of study), was for part-time form students even more diffi cult to fulfi ll exam requirements. As a help for students there was stage by stage prepared several of programs, they allow self-contained practicing of some linear programming methods. Programs did allow to users step-by-step verify their solution, i.e. whether their calculation are in accordance with algorithm described in lectures. Advantage for the students consists in fact, that each mistake (numerical or algorithmic) they were able to uncover, what contributes to increase of self-study eff ectiveness and from that resulting higher study motivation. Resulting from existing experience, authors decided to request for a new FRVŠ grant for academic year 2012, focused on e-learning support of selected graph theory problems. Within this project there was developed a tool allowing to make and according to the user needs interactively modify created graphs. On this graph it is possible individually, step by step (in compliance with on lectures presented algorithm) to practice solving of selected graph theory and network analysis problems (e.g. minimal spanning tree, shortest path in a graph, testing for cycles in a graph, critical path method etc.). Project is realized as modular and was realized in Delphi developing tool. Described algorithms are saved in dynamic linked libraries. There for it is very easy to add here new (newly programmed) algorithms. Project results (i.e. project experience obtained from e-learning supports) will be available for all FBE Mendelu members interested in this problematic. graph theory, optimization, operations research, Delphi Growing content of EMM course and decreasing time allowance, mainly in part-time form of study, led to request to off er students supporting study materials. This materials should students allow and ease their individual home preparation and raise their study motivation. Increased usage of information technologies off ers new ways in accessing study matherials to students. Several e-learning courses and educational so ware (e.g. Pokorný, Stávková, 2007) are implemented to improve study effi ciency. Foltýnek (2006) and Tomanová (2010) deal with methodology and effi ciency of e-learning matherials.Authors of this paper have in last few years prepared and released for students of FBE lot of programs, which allowed students to acquire linear programming methods ...
FEJFAR JIŘÍ ŠŤASTNÝ JIŘÍ, POKORNÝ MARTIN, BALEJ JIŘÍ, ZACH PETR: Analysis of sound data streamed over the network. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 7, pp. 2105-2110
Nowadays, WiFi is mostly operating in 2.4 GHz band, which allows only 3 non-overlapping channels. For deployment in building it could be a problem to repeat only three channels. In this paper we compare standard three channel scheme (channels 1, 6 and 11) with four channel schemes. The most promising scheme is with channels 1, 5, 9 and 13, which involves overlapping channels, but the overlap is minimal and in certain distances (power levels) is possible to use this scheme. The problem could be in some countries which do not allow usage of 13 channels. We also compare other schemes, with overlapping channels, but they have a much lower throughput than scheme with channels 1, 5, 9 and 13.
A management of computer classroom is undoubtedly a diffi cult task for the administrator which has to prepare virtual operating systems for education. It is quite common that lectors need to edit the particular machine during the semester, and that is the case where the main problems can appear. The process of changes deployment is not just very time-consuming but during it a virtual machine inconsistency can appear. The main part of this paper focuses on system process diagrams and its pseudocode. At fi rst, the machine is created on the remote server by lector or administrator. A er a proper approval, the machine is able to be deployed. The lector then specifi es the details about date, time and destinations of the virtual machine deployment. Once these details are approved, the virtual machine will be automatically deployed at the specifi ed time. The automatic deployment includes also an initial confi guration of the virtual machine at remote desktop and its post-install confi guration (hostname, MAC address, etc.). Once all steps are completed, the process will be marked as succeed. We present an automatized solution which provides a possibility how to easily manage computer classroom with virtual operating systems. The proposed solution should deliver a greater fl exibility, more reliability and faster deployment in comparison with the current solution used in our computer classroom. The proposal is also able to manipulate with already deployed machines for easy changes (e.g. so ware updates). The main advantage is the improvement of classroom management process automation.
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