Terahertz (THz)-band communication is envisioned as a critical technology that could satisfy the need for much higher data rates in sixth generation wireless communi- cation (6G) systems and beyond. Although THz signal propagation suffers from huge spreading and molecular absorption losses that limit the achievable commu- nication ranges, ultra-massive multiple-input multiple-output (UM-MIMO) antenna arrays can introduce the required beamforming gains to compensate for these losses. The reconfigurable UM-MIMO systems of small footprints motivate the use of spatial modulation techniques. Furthermore, the ultra-wideband fragmented THz spectrum motivates the use of index modulation techniques over multicarrier channels. In this thesis, we consider the problem of efficient index mapping and data detection in THz- band index modulation paradigms. We first propose an accurate frequency-domain statistical UM-MIMO channel model for wideband multicarrier THz-band commu- nications by considering THz-specific features. We then propose several THz-band generalized index modulation schemes that provide various performance and complex- ity tradeoffs. We propose efficient algorithms for mapping information bits to antenna and frequency indices at the transmitter side to enhance the achievable data rates in THz channel uses. We further propose complementary low-complexity parameter estimation and data detection techniques at the receiver side that can scale efficiently with very high rates. We derive theoretical bounds on the achievable performance gains of the proposed solutions and generate extensive numerical results promoting the corresponding future 6G use cases.

This thesis investigates the use of Maximum Likelihood Sequence Estimation (MLSE) in the presence of unknown channel parameters. MLSE is a fundamental problem that is closely related to many modern research areas like Space-Time Coding, Overloaded Array Processing and Multi-User Detection. Per-Survivor Processing (PSP) is a technique for approximating MLSE for unknown channels by embedding channel estimation into the structure of the Viterbi Algorithm (VA). In the case of successful acquisition, the convergence rate of PSP is comparable to that of the pilot-aided RLS algorithm. However, the performance of PSP degrades when certain sequences are transmitted. In this thesis, the blind acquisition characteristics of PSP are discussed. The problematic sequences for any joint ML data and channel estimator are discussed from an analytic perspective. Based on the theory of indistinguishable sequences, modifications to conventional PSP are suggested that improve its acquisition performance significantly. The effect of tree search and list-based algorithms on PSP is also discussed. Proposed improvement techniques are compared for different channels. For higher order channels, complexity issues dominate the choice of algorithms, so PSP with state reduction techniques is considered. Typical misacquisition conditions, transients, and initialization issues are reported. / Master of Science

Bilder und grafische Darstellungen gehören heutzutage zu den gängigen Kommunikationsmitteln und Möglichkeiten des Informationsaustauschs sowie der Wissensvermittlung. Das bildliche Medium kann allerdings, wenn es rein visuell präsentiert wird, ganze Nutzergruppen ausschließen. Blinde Menschen benötigen beispielsweise Alternativtexte oder taktile Darstellungen, um Zugang zu grafischen Informationen erhalten zu können. Diese müssen jedoch an die speziellen Bedürfnisse von blinden und hochgradig sehbehinderten Menschen angepasst sein. Eine Übertragung von visuellen Grafiken in eine taktile Darstellung erfolgt meist durch sehende Grafikautoren und -autorinnen, die teilweise nur wenig Erfahrung auf dem Gebiet der taktilen Grafiktranskription haben. Die alleinige Anwendung von Kriterienkatalogen und Richtlinien über die Umsetzung guter taktiler Grafiken scheint dabei nicht ausreichend zu sein, um qualitativ hochwertige und gut verständliche grafisch-taktile Materialien bereitzustellen. Die direkte Einbeziehung einer sehbehinderten Person in den Transkriptionsprozess soll diese Problematik angehen, um Verständnis- und Qualitätsproblemen vorzubeugen. Großflächige dynamisch taktile Displays können einen nicht-visuellen Zugang zu Grafiken ermöglichen. Es lassen sich so auch dynamische Veränderungen an Grafiken vermitteln. Im Rahmen der vorliegenden Arbeit wurde ein kollaborativer Zeichenarbeitsplatz für taktile Grafiken entwickelt, welcher es unter Einsatz eines taktilen Flächendisplays und auditiver Ausgaben ermöglicht, eine blinde Person aktiv als Lektorin bzw. Lektor in den Entstehungsprozess einer Grafik einzubinden. Eine durchgeführte Evaluation zeigt, dass insbesondere unerfahrene sehende Personen von den Erfahrungen sehbehinderter Menschen im Umgang mit taktilen Medien profitieren können. Im Gegenzug lassen sich mit dem kollaborativen Arbeitsplatz ebenso unerfahrene sehbehinderte Personen im Umgang mit taktilen Darstellungen schulen. Neben Möglichkeiten zum Betrachten und kollaborativen Bearbeiten werden durch den zugänglichen Zeichenarbeitsplatz auch vier verschiedene Modalitäten zur Erzeugung von Formen angeboten: Formenpaletten als Text-Menüs, Gesteneingaben, Freihandzeichnen mittels drahtlosem Digitalisierungsstift und das kamerabasierte Scannen von Objektkonturen. In einer Evaluation konnte gezeigt werden, dass es mit diesen Methoden auch unerfahrenen blinden Menschen möglich ist, selbständig Zeichnungen in guter Qualität zu erstellen. Dabei präferieren sie jedoch robuste und verlässliche Eingabemethoden, wie Text-Menüs, gegenüber Modalitäten, die ein gewisses Maß an Können und Übung voraussetzen oder einen zusätzlichen technisch aufwendigen Aufbau benötigen. / Pictures and graphical data are common communication media for conveying information and know\-ledge. However, these media might exclude large user groups, for instance visually impaired people, if they are offered in visual form only. Textual descriptions as well as tactile graphics may offer access to graphical information but have to be adapted to the special needs of visually impaired and blind readers. The translation from visual into tactile graphics is usually implemented by sighted graphic authors, some of whom have little experience in creating proper tactile graphics. Applying only recommendations and best practices for preparing tactile graphics does not seem sufficient to provide intelligible, high-quality tactile materials. Including a visually impaired person in the process of creating a tactile graphic should prevent such quality and intelligibility issues. Large dynamic tactile displays offer non-visual access to graphics; even dynamic changes can be conveyed. As part of this thesis, a collaborative drawing workstation was developed. This workstation utilizes a tactile display as well as auditory output to actively involve a blind person as a lector in the drawing process. The evaluation demonstrates that inexperienced sighted graphic authors, in particular, can be\-ne\-fit from the knowledge of a blind person who is accustomed to handling tactile media. Furthermore, inexperienced visually impaired people may be trained in reading tactile graphics with the help of the collaborative drawing workstation. In addition to exploring and manipulating existing graphics, the accessible drawing workstation offers four different modalities to create tactile shapes: text-based shape-palette-menus, gestural drawing, freehand drawings using a wireless stylus and scanning object silhouettes by a ToF-camera. The evaluation confirms that even untrained blind users can create drawings in good quality by using the accessible drawing workstation. However, users seem to prefer robust, reliable modalities for drawing, such as text menus, over modalities which require a certain level of skill or additional technical effort.

Le contexte de cette thèse est celui de la géolocalisation d'émetteurs (estimation de la position dans l’espace) de radiocommunication à partir de plusieurs stations multi-capteur qui sont spatialement éloignées. Les méthodes conventionnelles de géolocalisation telles que la triangulation sont en 2 étapes (la première étape estime des paramètres intermédiaires et la seconde étape "fusionne" ces mesures effectuées sur plusieurs stations afin de fournir la position des émetteurs). Les méthodes en 1 étape quant à elles utilisent les observations issues de toutes les antennes pour estimer directement et de manière optimale la position des sources. Le fait de traiter les signaux directement sur l'antenne globale (composée de toutes les stations d'antenne locales) entraîne un effet large bande sur les signaux entre stations. La thèse propose d'étudier l'effet large bande résiduel présent sur l'antenne globale des méthodes en 1 étape. Elle propose ensuite des améliorations sur des méthodes de géolocalisation en 1 étape, notamment grâce à l'apport de la théorie de matrice aléatoire à grande dimension et à l'introduction d'une nouvelle méthode nommée LOST-FIND. Finalement, une nouvelle approche visant à aborder différemment le problème large bande a été introduite donnant l'algorithme TARGET. / The context of the thesis is the transmitters geolocalization (position estimation in the space) of radiocommunication from several widely spaced multi-sensor stations. The conventional geolocalization methods as the tirnagulation are in 2 staps (the first step estimates intermediate parameters and the second step "merges" these mesures from the stations in order to obtain the transmitters positions). The 1 stap methods use the observertions from all the stations to directly and optimally estimate the sources positions. Directly handling the signals on the global array (composed of all the local stations) leads to a broadband effect on the signals between the stations.The thesis proposes to study the residual broadband effect on the global array of the 1 step methods. Then we propose improvements on some 1 step geolocalization methods, especially based on the random matrix theory in large dimension and on the introduction of a new method named LOST-FIND. Finally, a new approach differently tackling the braodband problem has been introduced and leads to TARGET algorithm.

There is a lack of knowledge in the area of training needs for Deaf/Blind vocational rehabilitation and/or independent living service providers in Florida. This quantitative study utilized self-report surveys of Deaf/Blind providers in Florida to determine what needs to be done related to professional development. The researcher attempted to determine what service providers identify as areas of strength, and what areas they perceive to be those which require additional professional development training. The study participants were 31 professionals who worked at state agencies, non-profits, for-profits, private, or federal agencies that provide services to the Deaf/Blind population in Florida in the areas of vocational rehabilitation and/or independent living. The survey was developed by the researcher based on previous research in the areas of best practice in vocational rehabilitation and independent living. The areas that the survey addressed are interagency collaboration/relationship building, self-determination, parent involvement/parent support, and additional training areas. There were 18 questions on the survey that took participants no longer than 15 minutes to complete. Quantitative data were collected using a commercial platform to keep respondents’ information confidential and analyzed using descriptive statistics which include percentages and other data. Key areas were identified in which providers to the Deaf/Blind may need additional training in the areas of vocational rehabilitation and independent living. The results suggested that the background training of Deaf/Blind providers is varied. Even though Deaf/Blind providers’ training is varied, perceived strengths and weaknesses were suggested.

The improvement of static properties of combined rivet and adhesive bonded joints have been proven by several authors [1, 2]. On the other side, dynamic properties of joints (for example fatigue and corrosion) significantly affect final function of structures during their service life. In this thesis, the combine joints created by blind rivets and hyper elastic sealant are solved. Complex description of dynamic properties of this particular combined joining technology has not been publicised, yet. Description of sealant layer influence on stress concentration in rivet hole regions is one of the main goal of this work. The next stage of the thesis is focused on the influence of above mentioned sealant layer on fatigue properties of combined blind rivet and solid countersunk rivet joints. Stress strain analysis of rivet and combined joints done by FE analysis and by experimental optical measurement of strain field proved that hyper elastic sealant layer has a positive effect on decreasing of stress peaks in rivet hole regions. This findings are in direct compliance with fatigue measurement of combined joint (AAPL). The influence of applied sealant in this combined joints improved fatigue properties by twenty percentage increasing of stress to failure in comparison with rivet joints.

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By 2010, forty-six years after the Civil Rights Act of 1964 and two years after the election of the nation's first Black president, Barack Obama, the U.S. had seemingly become a post-racial society. However, in 2010, Arizona’s Senate Bill 1070 was under fire and challenged as racially discriminatory. While the bill was popular among white Arizonians, critics charged that SB1070 could facilitate the racial profiling of all Latinos in state law enforcement officers' efforts to check the legal status of those they suspect are undocumented. Analyzing 70 recordings from the Arizona house floor, press conferences, and television interviews during 2009-2012, I investigate how elected and public officials discuss their support for this contested legislation. Proponents of the bill largely used color-blind maneuvers in response to questions concerning racial profiling and Latinos, but simultaneously constructed racialized undocumented immigrants as criminals and economic burdens. Consequently, political supporters of SB 1070 engaged in a racial discourse evoking an implicit white injury ideology that positioned whites as injured by the presence of racialized immigrants, while all Latinos were discursively constructed as immigrants irrespective of their citizenship status, and therefore constructed as outside the (white injured) citizenry.