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  • Simulating conversations for the prediction of speech quality

    The measurement and prediction of speech quality are crucial planning tools for \acf{VoIP} communication providers. Current instrumental models that predict the quality of speech in a conversation scenario mainly rely on parameters of the transmission system for their prediction. However, for some degradations, it has been shown that the impact on the conversation, and thus the perceived quality, cannot be modeled by the parameters of the transmission alone. The effect of transmission delay on a telephone conversation depends on conversational interactivity, as the delayed speech signal slows down the turn-taking of the conversation partners. The impact of packet loss, while being audible in a listening situation, is also dependent on the part of transmitted information that is lost and, thus, whether the conversation partner needs to resolve a misunderstanding with additional repairing dialogue. In conversations where these impairments co-occur, interactivity effects may arise, as the meta-communication due to lost packets is, in turn, affected by transmission delay. As current instrumental quality prediction models do not consider these factors and their interaction, they cannot account for them. This thesis introduces conversation simulation as a new approach to the instrumental prediction of conversational quality. A simulation architecture is described based on incremental spoken dialogue processing that can model standardized conversation scenarios on the concept, turn-taking, and speech signal level. Especially the changes in turn-taking during delayed transmission and the retransmission of information due to packet loss are modeled and evaluated based on empirical conversations. The resulting simulated conversations are assessed with methods from the field of spoken dialogue systems and speech quality, resulting in parameters that represent the changes in conversations due to delay and packet loss. The fullband E-model, a standardized parametric model, is extended for conversational interactivity and bursty packet loss to utilize the parameters extracted from the conversations. Finally, the conversational quality is predicted based on the extended E-model and the parameters from the simulated conversations.
  • Design and realization of widely tunable sampled grating distributed bragg reflector lasers for communication and terahertz applications

    This thesis proposes novel sampled grating distributed Bragg reflector (SG DBR) lasers for communication and terahertz (THz) applications. The lasers are designed to provide a wide tuning range for increasing optical bandwidth and narrow optical linewidth for coherent applications. For the first time, SG DBR lasers are realized based on an InP generic foundry platform. The foundry platform supports integrated optoelectronic components for customers to manufacture photonic integrated circuits (PICs). Due to the difficulty of optimizing tuning sections, it is challenging to optimize widely tunable lasers without the performance degradation of other components. The SG DBR lasers compatible with the foundry process are demonstrated to cover C band. From this work, the SG DBR is a part of a process design kit (PDK) in the foundry platform. SG DBR lasers with an integrated ring resonator (SG DBR RR) are investigated to realize predetermined wavelength channels and improve optical linewidth. It comprises the four section SG DBR laser and the integrated ring resonator (RR), extending the cavity length to reduce the optical linewidth. Moreover, the RR provides predetermined wavelength channels, which can be used for DWDM applications. The lasers are designed with a broadband gain structure and low loss waveguides. Optimized SG DBR lasers are realized to cover a 98 nm tuning range based on the same wafer. A novel fully integrated PIC for continuous wave (CW) THz generation is proposed, consisting of two SG DBR lasers and passive components fabricated by the foundry platform. The two SG DBR lasers offer different tuning ranges with slight overlap, the highest bandwidth obtained with any integrated tunable laser source based on InP platform. The PIC can be an important component of the CW THz system with a small footprint and volume production at a low cost.
  • Tempohomes – Untersuchung sozial-räumlicher Aneignungspraktiken von Geflüchteten in ausgewählten Berliner Gemeinschaftsunterkünften

    Der vorliegende Report, ein Kooperationsprojekt zwischen TU und LAF Berlin, dokumentiert den Alltag und das Leben in Containerdörfern und Tempohomes im Jahr 2018 und präsentiert die Wahrnehmung und Perspektive der Bewohnerinnen und Bewohner, deren Alltag und ihre Proaktivität im Umgang mit den alltäglichen Herausforderungen. Durch architekturethnografische Dokumentationen und Interviews wurden sechs ausgewählte Standorte von Studierenden der TU Berlin untersucht. Die so gewonnenen Einsichten werden in kurzen thematischen Essays zusammengefasst. Die Einführung des LAF ordnet die Arbeit der Studierenden in die turbulenten politischen und planungsrechtlichen Herausforderungen bei der Entwicklung und dem Bau der Standorte zeitgeschichtlich ein. Abschließend wird deren Bedeutung für aktuelle und zukünftige Unterbringungsstrategien aus der Perspektive des LAF reflektiert.
  • Benefits and pitfalls of better lifetime data – the case of batteries in mobile electronic equipment

    Batteries are continuously gaining prominence in an ever-increasingly connected and mobile world. Battery lifetime is a topic of extensive research and discussions. Smart batteries are able to quantify, track, and report their own health status during their use phase, however, the availability of such data to consumers, repair, reuse, and recycling actors is often restricted. This paper establishes how batteries in mobile electronic devices track and report their own health status and to which extent this feature is implemented in today’s smartphone and notebook batteries. The paper further illustrates potential benefits and drawbacks of full battery health data transparency with respect to the lifetime of products and the Circular Economy at large.
  • Understanding consumer disposal behaviour with food to go packaging in a move to circular, zero waste packaging solutions

    It is clear that a shift from the current make-use-dispose mentality of product consumption is required to move to the ideal of a Circular Economy (CE), where the world’s resources are kept in use for as long as possible and their value retained. The idea of waste as a resource within a CE is not new, but the pressure to apply it to the Fast-Moving Consumer Goods (FMCG) packaging industry has been growing in momentum since 2016. Many research studies have focussed on recycling behaviours in the home, but few have looked at consumers behaviour with food to go (FTG) packaging disposed out of the home. This research set out to assess the habit strengths of millennial consumers disposing of FTG packaging out of the home within the UK. The outcome of this research showed that millennial consumers have strong habits (upper quartile) in relation to their FTG packaging disposal routine. However, a significant percentage of participants were placing FTG packaging into incorrect recycling bins, showing there is still confusion amongst consumers about how to dispose of waste out of the home. Understanding of habit strengths at the packaging disposal stage could be one element to help in the design of interventions within packaging or waste system design, developing the responsible consumer behaviours required for a circular, zero waste society to exist.