<p>Software Defined Radios (SDRs) are redefining the current landscape of wireless communications in both military and commercial sectors. The rapidly evolving capabilities of digital electronics are making it possible to execute significant amounts of signal processing on general purpose processors ratherthan using special-purpose hardware.</p><p>As a consequence of the availability of SDR, applications can be used to implement flexible communication systems in an operating prototype within a very short time. However, the initial lack of standards and design rules leads to incompatibility problems when using products from different manufacturers. This problem is critical for the military and public safety sectors, for this reason the US Army was interested in SDR and carried out research into the specification of a common software infrastructure for SDR. This initiative started in the mid-1990s and evolved into the Software Communications Architecture (SCA).</p><p>SCA is a non-proprietary, open architecture framework that allows a designer to design interoperable and platform independent SDR applications. At the same time the SCA framework, by abstracting the radio communication system, speeds up waveform development because developers no longer have to worry about hardware details.</p><p>This thesis project uses OSSIE, an open source SCA implementation, to illustrate the process of developing a waveform. Today companies are exploiting open source solutions and investing money to evaluate and improve available technologies rather than developing their own solutions: OSSIE provides a working SCA framework without any license cost. OSSIE also provides some tools to develop SCA waveforms. Of course open source software comes with some limitations that a designer must take into account. Some of these limitations will be described for OSSIE (specifically the limited documentation and lack of libraries), along with some suggestions for how to reduce their impact.</p><p>This thesis project shows in detail the development process for SCA waveforms in OSSIE. These details are examined in the course of successfully implementing a target waveform to enable the reader to understand the advantagies and disadvantages of this technology and to facilitate more people using OSSIE to develop waveforms. Although a waveform was successfully implemented there were unexpected issues with regard to the actual behavior of the waveform when implemented on the hardware used for testing.</p> / QC 20100831

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<p> Given the pervasion of multi-touch tablet, pen-based applications have rapidly moved onto this new platform. Users draw both with bare fingers and using capacitive pens as they would do on paper in the past. Unlike paper, these tablets cannot distinguish legitimate finger/pen input from accidental touches by other parts of the user's hand. In this thesis, we refer it to as errant touch rejection problem since users may unintentionally touch the screen with other parts of their hand. </p><p> In this thesis, I design, implement and evaluate new approaches, bezel-focus rejection, of preventing errant touches on multi-touch tablets. I began the research by conducting a formal study to collect and characterize errant touches. I analyzed the data collected from the study and the results are guiding me to design rejection techniques. I will conclude this research by developing bezel-focus rejection and evaluate its performance. The results show that bezel-focus rejection yields high rejection rate of errant touches and make users more inclined to rest hands on tablet than comparison techniques. </p><p> This research has two major contributions to Human Computer Interaction (HCI) community. First, my proposed errant touch rejection approaches can be applied the other pen-based note-taking applications. Second, my experimental results can serve as a guide to other developing similar techniques.</p>