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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Aeronautical Channel Modeling for Packet Network Simulators

Khanal, Sandarva 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The introduction of network elements into telemetry systems brings a level of complexity that makes performance analysis difficult, if not impossible. Packet simulation is a well understood tool that enables performance prediction for network designs or for operational forecasting. Packet simulators must however be customized to incorporate aeronautical radio channels and other effects unique to the telemetry application. This paper presents a method for developing a Markov Model simulation for aeronautical channels for use in packet network simulators such as OPNET modeler. It shows how the Hidden Markov Model (HMM) and the Markov Model (MM) can be used together to first extract the channel behavior of an OFDM transmission for an aeronautical channel, and then effortlessly replicate the statistical behavior during simulations in OPENT Modeler. Results demonstrate how a simple Markov Model can capture the behavior of very complex combinations of channel and modulation conditions.
12

Empirické porovnání komerčních systémů dobývání znalostí z databází / An Empirical Comparison of Commercial Data Mining Tools

Faruzel, Petr January 2009 (has links)
The presented work "An Empirical Comparison of Commercial Data Mining Tools" deals with data mining tools from world's leading software providers of statistical solutions. The aim of this work is to compare commercial packages IBM SPSS Modeler and SAS Enterprise Miner in terms of their specification and utility considering a chosen set of evaluation criteria. I would like to achieve the appointed goal by a detailed analysis of selected features of the surveyed software packages as well as by their application on real data. The comparison is founded on 29 component criteria which reflect user's requirements regarding functionality, usability and flexibility of the system. The pivotal part of the comparative process is based on an application of the surveyed data mining tools on data concerning meningoencephalitis. Results predestinate evaluation of their performance while analyzing small and large data. Quality of developed data models and duration of their derivation are stated in reference to the use of six comparable data mining techniques for classification. Small data more likely comply with IBM SPSS Modeler. Although it produces slightly less accurate models, their development times are much shorter. Increasing the amount of data changes the situation in favor of competition. SAS Enterprise Miner manages better results while analyzing large data. Considerably more accurate models are accompanied by slightly shorter times of their development. Functionality of the surveyed data mining tools is comparable, whereas their usability and flexibility differentiate. IBM SPSS Modeler offers apparently better usability and learnability. Users of SAS Enterprise Miner have a slightly more flexible data mining tool at hand.
13

Simulační model IPTV služby s protokolem RTP / IPTV multicast model with RTP protocol

Ležák, Aleš January 2008 (has links)
This diploma thesis contains questions of simulation data transfer by ASM multicast. In simulation tool Opnet Modeler is proceed design of service IPTV. IPTV means television which is transfered in network by IP protocol. Data of IPTV service are sending by multicast transfer. Multicast is a technology which uses a group transfer. It is actually communication of a one source of data with many users. These users are receiving the same data. A main target of this technology is to decrement loading of source node and transference system in distribution of data towards group of users. Most often is multicast used in distribution of audiovisual data. Relation RTP/RTCP is simulated with a different numbers of users. Observed is interval of transmission of control RTCP packets. This will be reached by two methods which will be confront in the end. One is a theoretic calculation by course of a equation and second is a practical simulation in Opnet Modeler.
14

Modelování řízeného využití síťových zdrojů v sítích UMTS / Modelling of UMTS network resource control

Bednárik, Ján January 2009 (has links)
The main aim of my master thesis was to get acquainted with the implementation of quality-of-service support methods in UMTS 3G mobile network and the evaluation of these methods in a simulation environment with main interest in the characteristic features of the traffic classes. The impact of the QoS methods available on different service types were verified in the OPNET Modeler simulation environment. I examined mainly the potentials of the model to support the required quality parameters for the connections. The models of typical network applications, available in real UMTS networks, together with two examples of mobile networks, operating voice and video services in combination with standard data services, were defined in this simulation environment. My work also contains the detailed description of configuration parameters fundamental for correct behavior of the simulation models. The simulation also shows the case, when the transport service is rejected due to the lack of network resources. The key parameters of the model are also described and their effect on the service quality with and without QoS control are compared in separate scenarios. Finally, I investigated the effect of mobility of the end stations on the communication process, especially on the duration of a file transmission.
15

Generování datových jednotek v prostředí OPNET Modeler / Generation of data units in OPNET Modeler environment

Mikulica, Vladimír January 2010 (has links)
This dissertation deals with the generating of data units at different levels of TCP/IP network model in OPNET Modeler environment. A part of the dissertation is a brief introduction to the simulation environment OPNET Modeler where important components of this comprehensive simulation software are elucidated. The structure of my dissertation reflects individual layers of the model TCP/IP, whereas the function of the process model OPNET Modeler and the data unit used at corresponding levels of TCP/IP is always described. Particular parts of communication models that were created in the simulation environment OPNET Modeler at selected layers of the network model TCP/IP are closely documented in each chapter. Relevant scenarios are described in such a way that they can be later re-arranged by eventual customers.
16

Řízení pohybu stanice v simulačním prostředí OPNET Modeler podle mapového podkladu / Map-based Movement Control of Mobile Station in OPNET Modeler Simulation Environment

Jakúbek, Peter January 2011 (has links)
Diploma thesis focuses on a motion control of a mobile station in the simulation environment OPNET Modeler (OM). The thesis is summarized and described the possibilities of controlling the motion of a wireless mobile station. A significant part concentrates on the motion controlling of the station via an external file containing the path of movement. In this type of governance is a continuous movement of the station. The movement is driven by a simulation engine OM. External files designed for a motion control of the station can be created manually or used to write a data directly from OM to store the random generated routes for later use. For the manual creation of the trajectory is chosen the MATLAB tool that handles pre-created maps in the form of the input image into a form that the output of the tool can be used for motion control station in OM. To automate the process of creation and the subsequent trajectory motion control station is used by her library MATLAB Engine. It allows to call MATLAB functions from the language C/C ++ on which is based OM. For automated process of the movement control of the station is used a direct manipulation with the station position which is an alternative of the motion control station according to a set of the trajectory. The direct manipulation station position provides discrete movement of the station. The user’s created process which uses the discrete trajectory values manage the control.
17

Směrovací protokol OLSR pro MANET sítě v simulačním prostředí OPNET Modeler / OLSR routing protocol for MANET networks in OPNET Modeler simulation environment

Hošek, Petr January 2011 (has links)
The first part focuses on general routing of computer networks. It describes the importance of routing, basic elements, algorithms and protocols. It also describes the so-called MANET networks, where there are discussed routing protocols in these networks. The next chapter deals with the analysis of routing protocols OSPF version 3 and OLSR protocol. For both protocols basic algorithms, their use and structure are described. In OSPF protocol there is also described historical development and differences between versions 2 and 3. The OLSR protocol properly describes the principle of MPR nodes, which is one of the most important parts of the protocol which differs it from the others. Next there is a brief introduction of a powerful simulation tool OPNET Modeler which allows simulating the operation and behavior of almost any computer network with a very extensive possibility of options for the functioning of the entire network, as well as nodes it selves. The practical part is divided into five parts. The first section describes the structure of process models, the basic elements, variables, and block editors OSLR routing protocol in OPNET Modeler program. The second part is devoted to the ICI data structure, which is used for inter-process communication and verify the creation and reception of messages using this function. The third part deals with the process model of OLSR routing model. There is a description of various blocks and functions involved in its function of protocol and significance. The fourth chapter shows an extension of data unit protocol OLSR HELLO messages to other fields, which is able to transmit a numeric value between neighboring stations, and these values print it in the console. The last block of the practical part is dedicated to creating its own message which is broadcast between stations like part of the OLSR packet messages. This message includes the parameter of actual data traffic rate of each communicating stations. These values are for each station exported to an external file for later processing.
18

Ovládání generátoru sítového provozu z prostředí OPNET Modeler / Control of network operation generator from OPNET Modeler environment

Bartl, Milan January 2011 (has links)
In this work an interface between network simulator OPNET Modeler and network operations generator IxChariot is described. The goal is to control the generator by data from an OPNET modeler simulation. More accurately the generator is supposed to produce a data flow with desired settings of DSCP field, which is used to support quality of service mechanism. The goal can be achieved by two possible approaches: using IxChariot TCL API or IxChariot C API. Both of these approaches are described and conclusions are made at the end.
19

Zvýšení efektivity handoveru v reálném síťovém prostředí / Increasing the efficiency of the handover in real network environment

Michalec, Richard January 2011 (has links)
The aim of this work is to study methods of handover used in WiMAX and WLAN networks, next suggest the posibility of simulation methods for WLAN handover in the simulation environment OPNET Modeler. This work is focused primarily on obtaining the information about neighboring AP and subsequent selection of a new AP using such information. The work describes in detail each processes solutions that are used to implement newscanning methods
20

Pokročilé metody řízení trajektorie modelu stanice v prostředí OPNET Modeler / Advanced trajectory management techniques for model station in the OPNET Modeler environmen

Ludvíček, Pavel January 2011 (has links)
The aim of this work is to study and theoretically process existing movement options of station in OPNET Modeler environment. These options are described in first part. Furthermore to design and implement function to display path obtained from real-world conditions and done to station following this route during simulation. Coordinates used to move station are obtained by GPX format, which is used to store clearly the GPS coordinates. Second part is devoted to describing creation of this function, first using PHP script, then direct implementation into OPNET Modeler environment using C++.

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