This thesis presents studies of the single top t-channel in the electron plus jets mode. In order to understand this channel, an account of the present theoretical models is given. This work relies on collisions data from the ATLAS detector and its components are presented here. A summary of the work involving the SCT, part of the tracking system in ATLAS, is also explained here. Studies were performed to optimize the measurement of the Lorentz Angle of the holes in the Silicon for the initial data taking period. The data studied was acquired by ATLAS during 2011, with a total integrated luminosity of 4.7 pb−1 at a √s = 7 TeV. Monte Carlo simulation of signal and background events was also used throughout. Background studies were performed to correctly determine the expected amount of QCD via the Jet Electron data-driven method and of light or heavy flavour jets produced in association with a W boson, which is one of the dominant backgrounds for the t-channel. A cut based analysis was then applied to the data and simulation in order to better discriminate the t-channel signal. A binned likelihood fit to the invariant mass of the reconstructed top quark was performed and the cross section value for the t-channel process was calculated: σt−channel = 62.2±8.0(stat)+8.6 −8.8(syst) pb which is in good agreement with the theoretically predicted value. Finally, the response (preco T /ptrue T ) of light quark or gluon initiated jets is evaluated for both the t-channel and the Wt associated production, in order to determine the flavour composition uncertainty, as part of the framework that provides the jet energy scale uncertainties in a multiple jets environment. Other sources of system- atics are also reviewed.

This thesis focuses on analysis, classification, simulation and assessment of the signal fading in the scope of terrestrial digital television reception. This is a phenomenon associated with signal multipath propagation caused by the reflection, dispersion and diffraction of electromagnetic waves in interaction with relief and artificial obstacles. Wave propagation issues in a specific landscape are not the central theme of this project. Signal transmission between the transmitter and receiver is defined by channel profile models. Attention is directed not only to static reception but also to portable and mobile reception. Simulation of this phenomenon takes place in the software environment of MATLAB. In the framework of this project program fundament was created which allows simulate the signal processing across the entire communication chain of television broadcasting, including its transmitting and receiving parts.

This thesis deals with Matlab application developed for simulation of the DVB-T channel coder and decoder. The first part of this thesis includes description of terrestrial digital video broadcasting system and comparison with analogue television. Channel coding and OFDM modulation, used in the DVB-T standard, is described in detail. Application developed in the Matlab environment is described in the second part. The application simulates data transfer of the DVB-T system. Results of the simulated transmission, using developed application are presented in the last part. Namely dependence of the BER on the S/N ratio, using various coder settings, was examined. Maximal possible data rate was determined for these various setting. All obtained values are graphically represented.

Diese Studie stellt die Messung des Wirkungsquerschnitts der elektroschwachen Einzel-Top-Quark-Produktion im t-Kanal vor, bei der das Top-Quark semileptonisch zerfällt. Die Studie basiert auf 4.7 fb^{-1} an Daten aus Proton-Proton-Kollisionen, die vom ATLAS-Detektor am Large Hadron Collider im Jahr 2011 aufgezeichnet wurden. Die ausgewählten Ereignisse beinhalten zwei hochenergetische Jets, von denen einer als von einem b-Quark stammend identifiziert wurde, sowie ein hochenergetisches Elektron oder Myon und fehlende Transversalenergie. Der Fall von drei und vier Jets wird ebenfalls betrachtet, aber schließlich verworfen, da ihre Miteinbeziehung die Präzision des Ergebnisses herabsetzt. Die Ereignisrekonstruktion erfolgt durch einen Chi-Quadrat-basierten kinematischen Fit mit W-Boson- und Top-Quark-Massenzwangsbedingungen. Der Wert des Chi-Quadrat in jedem Ereignis dient dazu, das Ereignis als signal- oder untergrundähnlich zu klassifizieren. Der Wirkungsquerschnitt wird mittels eines template-basierten Maximum-Likelihood-Fits an die Verteilung, die die beste Trennschärfe besitzt, extrahiert: Die Verteilung is derart gewählt, dass die Formunterschiede zwischen Signal und Untergrund bezüglich der Kinematik des typischen leichten Vorwärtsjets des t-Kanals ausgenutzt werden. Eine Beobachtung des Single-Top-t-Kanal-Prozesses mit einer Signifikanz von 5.7 Sigma wird erreicht, und der Wirkungsquerschnitt wird zu 111^{+29}_{-28} pb gemessen. Unter der Annahme |Vtb|^{2} >> |Vtd|^{2} + |Vts|^{2} sowie einer (V-A)-, CP-erhaltenden Wechselwirkung, und unter Berücksichtigung von möglichen anomalen Kopplungen am W-t-b-Vertex, wird der Wert des entsprechenden CKM-Matrixelements mal einem anomalen Formfaktor zu |Vtb*f^{L}_{1}| = 1.30^{+0.13}_{-0.16} bestimmt. Dies führt zu einer unteren Grenze im Standardmodell-Szenario 0 / This study presents the cross-section measurement of electroweak single-top quark production in the t-channel with a semi-leptonically decaying top quark. The study is based on 4.7 fb^{-1} of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider in the year 2011. Selected events contain two highly energetic jets, one of which is identified as originating from a beauty quark, as well as a highly energetic electron or muon and transverse missing energy. The case of three and four jets is also considered but eventually discarded since their inclusion degrades the precision of the result. The event reconstruction is done with a chi-square-based kinematic fit using W boson and top quark mass constraints. The chi-square value in each event serves to classify the event as a signal-like or background-like process. The cross-section is extracted by performing a template-based maximum likelihood fit to the distribution that displays the best discriminatory power: This distribution is chosen such that the shape differences between signal and background with respect to the typical forward light jet kinematics of the t-channel are exploited. An observation of the single-top t-channel process with a significance of 5.7 Sigma is obtained, and the cross-section is measured to be 111^{+29}_{-28} pb. Assuming |Vtb|^{2} >> |Vtd|^{2} + |Vts|^{2} as well as a (V-A), CP-conserving interaction, and allowing for the presence of anomalous couplings at the W-t-b vertex, the associated value of the CKM matrix element times an anomalous form factor is determined as |Vtb*f^{L}_{1}| = 1.30^{+0.13}_{-0.16}. The corresponding lower limit in the standard model scenario 0