Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

High performance continuous-time filters for information transfer systems

Vast attention has been paid to active continuous-time filters over the years. Thus as the cheap, readily available integrated circuit OpAmps replaced their discrete circuit versions, it became feasible to consider active-RC filter circuits using large numbers of OpAmps. Similarly the development of integrated operational transconductance amplifier (OTA) led to new filter configurations. This gave rise to OTA-C filters, using only active devices and capacitors, making it more suitable for integration. The demands on filter circuits have become ever more stringent as the world of electronics and communications has advanced. In addition, the continuing increase in the operating frequencies of modern circuits and systems increases the need for active filters that can perform at these higher frequencies; an area where the LC active filter emerges. What mainly limits the performance of an analog circuit are the non-idealities of the used building blocks and the circuit architecture. This research concentrates on the design issues of high frequency continuous-time integrated filters. Several novel circuit building blocks are introduced. A novel pseudo-differential fully balanced fully symmetric CMOS OTA architecture with inherent common-mode detection is proposed. Through judicious arrangement, the common-mode feedback circuit can be economically implemented. On the level of system architectures, a novel filter low-voltage 4th order RF bandpass filter structure based on emulation of two magnetically coupled resonators is presented. A unique feature of the proposed architecture is using electric coupling to emulate the effect of the coupled-inductors, thus providing bandwidth tuning with small passband ripple. As part of a direct conversion dual-mode 802.11b/Bluetooth receiver, a BiCMOS 5th order low-pass channel selection filter is designed. The filter operated from a single 2.5V supply and achieves a 76dB of out-of-band SFDR. A digital automatic tuning system is also implemented to account for process and temperature variations. As part of a Bluetooth transmitter, a low-power quadrature direct digital frequency synthesizer (DDFS) is presented. Piecewise linear approximation is used to avoid using a ROM look-up table to store the sine values in a conventional DDFS. Significant saving in power consumption, due to the elimination of the ROM, renders the design more suitable for portable wireless communication applications

Study of applications of bio-space technology to patient monitoring systems Final report

Investigation of application of NASA developed technology to cardiovascular and pulmonary patient monitoring to improve availability of data for medical diagnosi

The Listening Shift: Evaluating a Communication-Strategies Training Program for Telepractice Nurses Experiencing Hearing Challenges

Workers who wish to remain employed should be supported in doing so, even if they are experiencing age-related disabilities, such as hearing loss. I aimed to better understand the strategies from which workers with hearing loss might benefit, and how they can be supported in adopting these strategies. To collect rich data, I recruited telepractice nurses who rely on listening to make critical decisions about triaging and health care recommendations. My first research question was: What strategies exist for making telephone speech more intelligible for health care providers and patients with hearing challenges? I performed a scoping review following the Joanna Briggs Institute’s protocol. I identified 11 types of strategies, many of which required cooperation from, and disclosure to, providers’ employers, co-workers, and clients. This led me to consider the public narrative workers associated themselves with when they disclosed. Thus, my second research question was: How do Canadian newspapers portray workers with hearing loss? Through a thematic analysis of newspapers articles on this topic, I found they are predominantly portrayed as striving cheerfully both towards functioning normally and towards differentiating themselves and their hearing loss as unique and positive. To further explore how a subset of adults with hearing loss strive to work with a hearing loss, I developed an online communication-strategies training program tailored to nurses with hearing challenges. I then used a multiple case study to answer the following research question: How do nurses with hearing challenges change in terms of their telephone performance and workplace wellbeing in response to participation in an online communication strategies training program? Results suggested that nurses engaged in a problem-solving process before adopting strategies, and that strategy adoption could positively contribute to their performance. Together, the findings from these studies suggest that strategies exist to enhance the performance of workers with hearing loss, but the process of adopting these strategies can be demanding. Organizations should take steps to proactively support their nurses, health-care providers, and potentially other workers with hearing loss in identifying communication strategies and adapting them to their unique context

A Framework for anonymous background data delivery and feedback

The current state of the industry’s methods of collecting background data reflecting diagnostic and usage information are often opaque and require users to place a lot of trust in the entity receiving the data. For vendors, having a centralized database of potentially sensitive data is a privacy protection headache and a potential liability should a breach of that database occur. Unfortunately, high profile privacy failures are not uncommon, so many individuals and companies are understandably skeptical and choose not to contribute any information. It is a shame, since the data could be used for improving reliability, or getting stronger security, or for valuable academic research into real-world usage patterns. We propose, implement and evaluate a framework for non-realtime anonymous data collection, aggregation for analysis, and feedback. Departing from the usual “trusted core” approach, we aim to maintain reporters’ anonymity even if the centralized part of the system is compromised. We design a peer-to-peer mix network and its protocol that are tuned to the properties of background diagnostic traffic. Our system delivers data to a centralized repository while maintaining (i) source anonymity, (ii) privacy in transit, and (iii) the ability to provide analysis feedback back to the source. By removing the core’s ability to identify the source of data and to track users over time, we drastically reduce its attractiveness as a potential attack target and allow vendors to make concrete and verifiable privacy and anonymity claims

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks