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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.
1

Reactivity Meter Analysis of Rod-Drop Experiments in Zed-2

Moniz, Manuel 09 1900 (has links)
One of two project reports. The other one is designated PART A: McMASTER (ON-CAMPUS) PROJECT / <p> A reactivity meter code based on point kinetics was developed. Rod-drop experiments performed in the ZED-2 reactor tested the code for various detector and rod-drop positions. A delayed neutron hold-up effect was observed whenever a rod was dropped close to a detector. A better understanding of this effect was obtained through a theoretical analysis of the pertinent experiments. The three-dimensional kinetics code, CERBERUS, was used for the theoretical analysis. </p> / Thesis / Master of Engineering (MEngr)
2

Privacy in Voice-over-IP mitigating the risks at SIP intermediaries

Neumann, Thorsten 02 September 2010 (has links)
Telephony plays a fundamental role in our society. It enables remote parties to interact and express themselves over great distances. The telephone as a means of communicating has become part of every day life. Organisations and industry are now looking at Voice over IP (VoIP) technologies. They want to take advantage of new and previously unavailable voice services. Various interested parties are seeking to leverage the emerging VoIP technology for more flexible and efficient communication between staff, clients and partners. <o>VoIP is a recent innovation enabled by Next Generation Network (NGN). It provides and enables means of communication over a digital network, specifically the Internet. VoIP is gaining wide spread adoption and will ultimately replace traditional telephony. The result of this trend is a ubiquitous, global and digital communication infrastructure. VoIP, however, still faces many challenges. It is not yet as reliable and dependable as the current Public Switched Telephone Network (PSTN). The employed communication protocols are immature with many security flaws and weaknesses. Session Initiation Protocol (SIP), a popular VoIP protocol does not sufficiently protect a users privacy. A user’s information is neither encrypted nor secured when calling a remote party. There is a lack of control over the information included in the SIP messages. Our specific concern is that private and sensitive information is exchanged over the public internet. This dissertation concerns itself with the communication path chosen by SIP when establishing a session with a remote party. In SIP, VoIP calls are established over unknown and untrusted intermediaries to reach the desired party. We analyse the SIP headers to determine the information leakage at each chosen intermediary. Our concerns for possible breach of privacy when using SIP were confirmed by the findings. A user’s privacy can be compromised through the extraction of explicit private details reflected in SIP headers. It is further possible to profile the user and determine communication habits from implicit time, location and device information. Our research proposes enhancements to SIP. Each intermediary must digitally sign over the SIP headers ensuring the communication path was not be altered. These signatures are added sequentially creating a chain of certified intermediaries. Our enhancements to SIP do not seek to encrypt the headers, but to use these intermediary signatures to reduce the risk of information leakage. We created a model of our proposed enhancements for attaching signatures at each intermediary. The model also provides a means of identifying unknown or malicious intermediaries prior to establishing a SIP session. Finally, the model was specified in Z notation. The Z specification language was well suited to accurately and precisely represent our model. This formal notation was adopted to specify the types, states and model behaviour. The specification was validated using the Z type-checker ZTC. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Computer Science / unrestricted
3

Hacka dig själv och upptäck attacker

Fransén, Johan, Sorlija, Adnan January 2019 (has links)
Denna uppsats bygger på idén om att hacka det egna systemet före en utomstående hackare gör det för att upptäcka systemets läckor. Detta görs med ett automatiserat hackingverktyg som utför penetrationstester mot en utvecklad hemsida. Lagringstekniken som används är en eventdatabas med namnet Event Store som lagrar varje händelse som skedde mot hemsidan. Syftet med Event Store är att upptäcka de olika penetrationstesterna och lagra dess händelser för att sedan ge indikationer till administratören att hemsidan var under attack. Uppsatsen riktar sig främst på ifall Event Store är lämpligt att implementera tillsammans med en hemsida som blir attackerad med penetrationstester och vilka för- och nackdelar det finns med att använda Event Store. Resultatet visar att Event Store kan användas för att identifiera anomalier mot en hemsida vid hackingattacker. Med stor sannolikhet kan intrång mot hemsidan bevisas med hjälp utav det utvecklade systemet med Event Store. / This thesis is based on the idea of hacking your own system before an outside hacker does it to find the system vulnerabilities. This is done with an automated hacking tool that performs penetration tests against the created website. The database technology that is used is the event database Event Store that stores every event that take place against the website. The task of Event Store in this case is to discover the different penetration tests and to store the events and to give indications to the administrator that the website was under attack. The study is primarily aimed at finding out whether Event Store is advisable to implement with a website where different penetration testing shall be made, and what the advantages and disadvantages are to using Event Store. Results show that Event Store can be used to identify anomalies against a website during attacks. Intrusions against the website can with great probability be proven with the help of the developed system with Event Store.
4

Modeling and Sensitivity/Uncertainty Analyses of ZED-2 Benchmark Experiments Using DRAGON, DONJON & SUSD3D

Dabiran, Shahab 10 1900 (has links)
<p>Due to the strong interest in thorium fuels in CANDU reactors rooting back to 1970’s and 1980’s, four experiments were done in the ZED-2 critical facility at Chalk River Laboratories to test the properties of (Th,Pu)O­<sub>2</sub> fuel. The fuel was placed in five bundles with a typical CANDU design, stacked vertically in the center of the core (K0 site) and surrounded by natural uranium fuel.</p> <p>The simulation of these experiments using the transport code DRAGON coupled with the diffusion code DONJON is presented. DRAGON is initially used to model two lattices and the full cores in 2D. These models are designed to calculate direct/adjoint flux, k<sub>∞</sub> and k<sub>eff</sub> values using the collision probability method. Furthermore, the models determine a set of homogenized and condensed cross sections in two energy groups. Subsequently, DONJON is used to model the full core facility in three dimensions. Using the homogenized and condensed macroscopic cross section libraries obtained from the DRAGON models, DONJON is able to calculate the flux alongside with the k<sub>eff</sub> values for the specific cases in two energy groups. The results are then compared to those from the experiments and will further validate the accuracy of the simulations.</p> <p>Sensitivity and uncertainty results for the infinite lattices and the 2D full core model using DRAGON and SUSD3D code are discussed. The direct and adjoint flux values determined by DRAGON for the lattices and the full core model are used by SUSD3D to calculate the sensitivity profiles for specific reactions of the isotopes present. The sensitivity profiles are then used alongside with the covariance matrices to calculate the uncertainty contribution of nuclear data to criticality. The sensitivity and uncertainty (S/U) results of the 2D model for full core, using the DRAGON/SUSD3D code coupling are then compared with the S/U results of a 3D model of the full core using the code TSUNAMI within the SCALE6 package in reference. The comparisons will show an excellent degree of consistency between the two methods, while reasons for possible differences in the results are also presented.</p> / Master of Applied Science (MASc)
5

Řízení robotické sekačky trávy / Control of a robotic lawn mower

Škapa, Antonín January 2020 (has links)
This master‘s thesis deals with development and realisation of robotic lawn mower with satelite navigation. It begins with preparation of a platform for outdoor mobile robot navigation and it’s control HW and SW. There are discussed different options of navigation both commercial and experimental. Further on I have chosen the right GNSS receiver based on market research and user experience. The GNSS receiver’s parameters are measured with different antennas. Following with the choice of suitable open-source control unit and it’s software implementation. Furthermore control from a companion computer is described and physical realisation is done. In the end of the thesis activation of the whole mower is performed and described. Lastly there are discussed possible ways of future development.
6

Analýza vlastností stereokamery ZED ve venkovním prostředí / Analysis of ZED stereocamera in outdoor environment

Svoboda, Ondřej January 2019 (has links)
The Master thesis is focused on analyzing stereo camera ZED in the outdoor environment. There is compared ZEDfu visual odometry with commonly used methods like GPS or wheel odometry. Moreover, the thesis includes analyses of SLAM in the changeable outdoor environment, too. The simultaneous mapping and localization in RTAB-Map were processed separately with SIFT and BRISK descriptors. The aim of this master thesis is to analyze the behaviour ZED camera in the outdoor environment for future implementation in mobile robotics.
7

Robot Goalkeeper : A robotic goalkeeper based on machine vision and motor control

Adeboye, Taiyelolu January 2018 (has links)
This report shows a robust and efficient implementation of a speed-optimized algorithm for object recognition, 3D real world location and tracking in real time. It details a design that was focused on detecting and following objects in flight as applied to a football in motion. An overall goal of the design was to develop a system capable of recognizing an object and its present and near future location while also actuating a robotic arm in response to the motion of the ball in flight. The implementation made use of image processing functions in C++, NVIDIA Jetson TX1, Sterolabs’ ZED stereoscopic camera setup in connection to an embedded system controller for the robot arm. The image processing was done with a textured background and the 3D location coordinates were applied to the correction of a Kalman filter model that was used for estimating and predicting the ball location. A capture and processing speed of 59.4 frames per second was obtained with good accuracy in depth detection while the ball was well tracked in the tests carried out.
8

Lepší vymezení herního prostoru pro VR pomocí 3D sensorů / Better Chaperone Bounds Using 3D Sensors

Tinka, Jan January 2018 (has links)
Room-scale tracking encourages users to move more freely and even walk. Even though there has been much research on making the limited physical workspace feel larger in the VR,  these approaches have their limitations and require certain conditions to be met. This thesis proposes an alternative approach to the conventional play-area boundaries of high-end VR products such as the HTC Vive and Oculus Rift which are set by the user in a 2-D fashion as a means of enhance workspace utilization. A 3-D scanner is used to make a 3-D point-cloud model of the play area's surroundings. This model is then used to detect collisions and provide feedback to the user. Evaluation based on user tests showed that this approach can be useful, is well accepted by users and might be worth further research.

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