Acoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator was used to evaluate communication without networking, and then with networking using the coding or dynamic source routing (DSR) protocols. The results confirmed that a network was essential to ensure effective fleet-wide communication. The flooding protocol provided extremely reliable communication but with low message volumes. The DSR protocol, a popular routing protocol due to its effectiveness in terrestrial radio networks, proved to be a bad choice in an acoustic environment: in most cases, it suffered from both poor reliability and low message volumes. Due to the high acoustic latency, even moderate vehicle speeds caused the network topology to change faster than DSR could adapt. DSR's reliance on shortest-path routing also proved to be a significant disadvantage. Several DSR optimizations were also tested; most proved to be unhelpful or actually harmful in an underwater acoustic network. LASR was developed to address the problems noted in flooding and DSR. LASR was loosely derived from DSR, most significantly retaining source routes and the reply/request route discovery technique. However, LASR added features which proved, in simulation, to be significant advantages -- two of the most effective were a link/route metric and a node tracking system. To replace shortest-path routing, LASR used the expected transmission count (ETX) metric. / This allowed LASR to make more informed routing decisions which greatly increased performance compared to DSR. The node tracking system was the most novel addition: using only implicit communication coupled with the use of time-division multiple access (TDMA), the tracking system provided predicted node locations. These predictions made it possible for LASR to proactively respond to topology changes. In most cases, LASR outperformed flooding and DSR in message delivery reliability and message delivery volume. / by Edward A. Carlson. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Controlling the cooperative behaviors of a fleet of autonomous underwater vehicles in a stochastic, complex environment is a formidable challenge in artificial intelligence. The complexity arises from the challenges of limited navigation and communication capabilities of underwater environment. A time critical cooperative operation by acoustic networks of Multiple Cooperative Vehicles (MCVs) necessitates a robust task allocation mechanism and an efficient path planning model. In this work, we present solutions to investigate two aspects of the cooperative schema for multiple underwater vehicles under realistic underwater acoustic communications: a Location-aided Task Allocation Framework (LAAF) algorithm for multi-target task assignment and a mathematical programming model, the Grid-based Multi-Objective Optimal Programming (GMOOP), for finding an optimal vehicle command decision given a set of objectives and constraints. We demonstrate that, the location-aided auction strategies perform significantly better than the generic auction algorithm in terms of effective task allocation time and information bandwidth requirements. In a typical task assignment scenario, the time needed in the LAAF algorithm is only a fraction compared to the generic auction algorithm. On the other hand; the GMOOP path planning technique provides a unique means for multi-objective tasks by cooperative agents with limited communication capabilities. Under different environmental settings, the GMOOP path planning technique is proved to provide a method with balance of sufficient expressive power and flexibility, and its solution algorithms tractable in terms of mission completion time, with a limited increase of overhead in acoustic communication. Prior to this work, existing multi-objective action selection methods were limited to robust networks where constant communication available. / The dynamic task allocation, together with the GMOOP path planning controller, provides a comprehensive solution to the search-classify tasks for cooperative AUVs. / by Yueyue Deng. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

For people without speech, voice output communication aids are an assistive technology––but can also be restrictive: whilst Text-To-Speech synthesis can say anything, it affords little choice of how this is spoken. An absence of nuanced tone of voice can inhibit social interaction. This research explores this profound but relatively overlooked issue in augmentative and alternative communication through the lens––with the sensibilities and skills––of interaction design. Tone of voice is such an elusive and intangible quality: difficult for even phoneticians to define, let alone AAC users and carers to discuss in the context of their everyday lives. Therefore the activities of design exploration and design practice have been employed to visualise tone of voice, in order to catalyse new conversations, through two original research projects: Six Speaking Chairs, curated with Andrew Cook, is a collection of interactive artefacts that illustrate alternative models of tone of voice developed by academics and practitioners as diverse as sociolinguists and playwrights;Speech Hedge, created with the assistance of Ryan McLeod, is a visualisation of how someone might interact with nuanced tone of voice using a conventional communication aid in combination with an interface on a smart phone. Audience responses to each project have illuminated the perspectives from which laypeople conceive of tone of voice, challenging the conventional emotional model that dominates speech technology in favour of something more complex and heterogeneous. In order to reconcile such complexity with simplicity of use, design principles have been distilled that could inspire future user interfaces but also inform further research. This research has been published and presented within different academic fields, including design research, interaction design and augmentative and alternative communication.

A fully integrated, fast-locking fractional-N frequency synthesizer is proposed and demonstrated in this work. In this design, to eliminate the need for large, inaccurate capacitors and resistors in a loop filter, an analog continuous-time loop filter whose performance is sensitive to process and temperature variations and aging has been replaced with a programmable digital Finite Impulse Response (FIR) filter. In addition, using the adaptive loop gain control proportional to the frequency difference, the frequency-locking time has been reduced. Also, the phase noise and spurs have been reduced by a Multi-stAge noise SHaping (MASH) controlled Fractional Frequency Detector (FFD) that generates a digital output corresponding directly to the frequency difference. The proposed frequency synthesizer provides many benefits in terms of high integration ability, technological robustness, fast locking time, low noise level, and multimode flexibility. To prove performance of the proposed frequency synthesizer, the frequency synthesizers analysis, design, and simulation have been carried out at both the system and the circuit levels. Then, the performance was also verified after fabrication and packaging.

In a MIMO system, a transmitter with perfect knowledge of the underlying channel state information (CSI) can achieve a higher channel capacity compared to transmission without CSI. When reciprocity of the wireless channel does not hold, the identification and utilization of partial CSI at the transmitter are important issues. This thesis is focused on partial CSI acquisition and utilization techniques for MIMO channels. We propose a feedback algorithm for tracking the dominant channel subspaces for MIMO systems in a continuously time-varying environment. We exploit the correlation between channel states of adjacent time instants and quantize the variation of channel states. Specifically, we model a subspace as one point in a Grassmann manifold, treat the variations in principal right singular subspaces of the channel matrices as a piecewise-geodesic process in the Grassmann manifold, and quantize the velocity matrix of the geodesic. We design a complexity-constrained MIMO OFDM system where the transmitter has knowledge of channel correlations. The transmitter is constrained to perform at most one inverse Discrete Fourier Transform per OFDM symbol on the average. We show that in the MISO case, time domain beamforming can be used to do two-dimensional eigen-beamforming. For the MIMO case, we derive design criteria for the transmitter beamforming and receiver combining weighting vectors and show some suboptimal solutions. The feedback channel may have uncertainties such as unexpected delay or error. We consider channel mean feedback with an unknown delay and propose a broadcast approach that is able to adapt to the quality of the feedback. Having considered CSI feedback problems where the receiver tries to convey its attained CSI to the transmitter, we turn to noncoherent coding design for fast fading channels, where the receiver does not have reliable CSI. We propose a data-dependent superimposed training scheme to improve the performance of training based codes. The transmitter is equipped with multiple training sequences and dynamically selects a training sequence for each data sequence to minimize channel estimation error. The set of training sequences are optimized to minimize pairwise error probability between codewords.

We have investigated, in various multiple senses, the “capacity” of several models of erasure networks. The defining characteristic of a memoryless erasure network is that each channel between any two nodes is an independent erasure channel. The models that we explore differ in the absence or presence of interference at either the transmitters, the receivers, or both; and in the availability of feedback at the transmitters. The crux of this work involves the investigation and analysis of several different performance measures for these networks: traditional information capacity (including multicast capacity and feeback capacity), secrecy capacity, and transport capacity. / text

This work deals with design of communication protocol for data transmission between control computer and computing cores implemented on FPGA chips. The purpose of the communication is speeding the performance demanding software algorithms of non-stream data processing by their hardware computation on accelerating system. The work defines a terminology used for protocol design and analyses current solutions of given issue. After that the work designs structure of the accelerating system and communication protocol. In the main part the work describes the implementation of the protocol in VHDL language and the simulation of implemented modules. At the end of the work the aplication of designed solution is presented along with possible extension of this work.

Designprozesse in Unternehmen sind durch immer enger vernetzte Arbeitsweisen und steigende Wissensintensität geprägt. Die Bedeutung der Kommunikation in diesen interdisziplinären Kontexten wächst. Für das Design stellt diese Entwicklung eine besondere Herausforderung dar: sowohl bezüglich der Inhalte die es kommuniziert, der Methoden und Werkzeuge, die dafür eingesetzt werden, wie auch der Entwicklung einer kommunikativen Grundkompetenz als Teil einer umfassenden Designkompetenz. [... aus dem Text]

This study evaluates the perceived credibility of a technical chatbot based on its communication style - the way it interacts with its users embodied through text and emojis. A chatbot’s initial communication style was compared to a humble version. The humble communication style was developed from a design workshop held together with six participants and is presented in this paper as a design style guide. The perceived credibility was divided into six dimensions; Competence, Goodwill, Honesty, Predictability, Reputation, and Trustworthiness. The results from the evaluation of the two chatbot versions showed that the credibility was, in general, perceived higher for the chatbot using a humble communication style. Two exceptions were found; (1) the dimension of Trustworthiness stayed at the same level between the versions, and (2) the dimension of Goodwill was perceived higher for the chatbot not using the humble communication style. The satisfaction with the chatbot was measured and resulted in an NPS of 17 for the chatbot using the humble communication style compared to a negative score of -16 for the chatbot not using it. This study found that a more humble communication style would not harm the perceived credibility of a technical professional chatbot. / Den här studien utvärderar den upplevda trovärdigheten hos en teknisk chatbot baserat på dess kommunikationsstil - hur den interagerar med sina användare genom text och emojis. En chatbots initiala kommunikationsstil jämfördes med en ödmjuk version. Den ödmjuka kommunikationsstilen utvecklades från en designworkshop och presenteras i denna studie som en designguide. Den upplevda trovärdigheten delades upp i 6 dimensioner; Kompetens, Välvilja, Ärlighet, Förutsägbarhet, Rykte, och Pålitlighet. Resultatet av utvärderingen av de två chatbot versionerna visade att trovärdigheten upplevdes generellt högre för den ödmjukare chatboten. Två undantag påvisades dock; (1) Pålitlighet blev oförändrad mellan de två kommunikationsstilarna, och (2) Välvilja resulterade i ett högre värde hos den initiala kommunikationsstilen. Användarnas tillfredsställelse med chatboten utvärderades och resulterade i ett NPS värde på 17 för chatboten som använde den ödmjuka kommunikationsstilen igämförelse med ett negativt värde på -16 för chatboten som använde den initiala kommunikationsstilen. Denna studie visade att en mer ödmjuk kommunikationsstil inte skadar den upplevda trovärdigheten hos en teknisk professionell chatbot.

This thesis examines the problem of providing high data-rate wireless connectivity to users in indoor environments. The goal is to be able to reach Gbps/user rates even when there are multiple users present. The technology that we study is to use the 60 GHz spectrum whose special propagation properties make it ideally suited to this task. The approaches developed include using multiple spatially distributed smart antennas in a room or multiple co-located antennas to provide coverage where needed and when needed. All the antennas are connected to a single access point which allows us to dynamically change spectrum and link allocation among the users (as they move or as their needs change). The innovations in this work include the exploitation of the special properties of 60 GHz and the corresponding design of algorithms for efficient spectrum allocation. We use detailed simulations to demonstrate that very high data rates are indeed achievable.