An additional study and implementation of tone calibrated technique of modulation

The Tone Calibrated Technique (TCT) was shown to be theoretically free from an error floor, and is only limited, in practice, by implementation constraints. The concept of the TCT transmission scheme along with a baseband implementation of a suitable demodulator is introduced. Two techniques for the generation of the TCT signal are considered: a Manchester source encoding scheme (MTCT) and a subcarrier based technique (STCT). The results are summarized for the TCT link computer simulation. The hardware implementation of the MTCT system is addressed and the digital signal processing design considerations involved in satisfying the modulator/demodulator requirements are outlined. The program findings are discussed and future direction are suggested based on conclusions made regarding the suitability of the TCT system for the transmission channel presently under consideration

A satellite-based personal communication system for the 21st century

Interest in personal communications (PCOMM) has been stimulated by recent developments in satellite and terrestrial mobile communications. A personal access satellite system (PASS) concept was developed at the Jet Propulsion Laboratory (JPL) which has many attractive user features, including service diversity and a handheld terminal. Significant technical challenges addressed in formulating the PASS space and ground segments are discussed. PASS system concept and basic design features, high risk enabling technologies, an optimized multiple access scheme, alternative antenna coverage concepts, the use of non-geostationary orbits, user terminal radiation constraints, and user terminal frequency reference are covered

Combined trellis coding and feedforward processing for MSS applications

The idea of using a multiple (more than two) symbol observation interval to improve error probability performance is applied to differential detection of trellis coded MPSK over a mobile satellite (fading) channel. Results are obtained via computer simulation. It is shown that only a slight increase (e.g., one symbol) in the length of the observation interval will provide a significant improvement in bit error probability performance both in AWGN and fading environments

Fossil fuel-fired peak heating for geothermal greenhouses

This report examines the capital and operating costs for fossil fuel-fired peak heating systems in geothermally (direct use) heated greenhouses. Issues covered include equipment capital costs, fuel requirements, maintenance and operating costs, system control and integration into conventional hot water greenhouse heating systems. Annual costs per square foot of greenhouse floor area are developed for three climates: Helena, MT; Klamath Falls, OR and San Bernardino, CA, for both boiler and individual unit heater peaking systems. In most applications, peaking systems sized for 60% of the peak load are able to satisfy over 95% of the annual heating requirements and cost less than $0.15 per square foot per year to operate. The propane-fired boiler system has the least cost of operation in all but Helena, MT climate

A Powerful AGN Outburst in RBS 797

Utilizing $\sim 50$ ks of Chandra X-ray Observatory imaging, we present an analysis of the intracluster medium (ICM) and cavity system in the galaxy cluster RBS 797. In addition to the two previously known cavities in the cluster core, the new and deeper X-ray image has revealed additional structure associated with the active galactic nucleus (AGN). The surface brightness decrements of the two cavities are unusually large, and are consistent with elongated cavities lying close to our line-of-sight. We estimate a total AGN outburst energy and mean jet power of $\approx 3 - 6 \times 10^{60}$ erg and $\approx 3 - 6 \times 10^{45}$ erg s$^{-1}$, respectively, depending on the assumed geometrical configuration of the cavities. Thus, RBS 797 is apparently among the the most powerful AGN outbursts known in a cluster. The average mass accretion rate needed to power the AGN by accretion alone is $\sim 1 M_{\odot}$ yr$^{-1}$. We show that accretion of cold gas onto the AGN at this level is plausible, but that Bondi accretion of the hot atmosphere is probably not. The BCG harbors an unresolved, non-thermal nuclear X-ray source with a bolometric luminosity of $\approx 2 \times 10^{44}$ erg s$^{-1}$. The nuclear emission is probably associated with a rapidly-accreting, radiatively inefficient accretion flow. We present tentative evidence that star formation in the BCG is being triggered by the radio jets and suggest that the cavities may be driving weak shocks ($M \sim 1.5$) into the ICM, similar to the process in the galaxy cluster MS 0735.6+7421.Comment: Accepted to ApJ; 20 pages, 11 low-resolution figure

UVM Tobacco Use and Attitudes After Implementation of a Tobacco-Free Policy

Introduction: Widespread public health initiatives have led to falling smoking rates. Currently, 1,620 U.S. colleges have adopted smoke-free policies. In August 2015, the University of Vermont (UVM) adopted a tobacco-free policy that bans all forms of tobacco use on university property. The purpose of this study was to compare tobacco use and attitudes before and after policy implementation.https://scholarworks.uvm.edu/comphp_gallery/1230/thumbnail.jp

A technique to record the sedentary to walk movement during free living mobility : a comparison of healthy and stroke populations

Background Hesitation between moving from a sedentary posture (lying/sitting) to walking is a characteristic of mobility impaired individuals, as identified from laboratory studies. Knowing the extent to which this hesitation occurs during everyday life would benefit rehabilitation research. This study aimed to quantify this transition hesitation through a novel approach to analysing data from a physical activity monitor based on a tri-axial accelerometer and compare results from two populations; stroke patients and age-matched unimpaired controls. Methods Stroke patients living at home with early supported discharge (n=34, 68.9YO ± 11.8) and age matched controls (n=30, 66.8YO ± 10.5) wore a physical activity monitor for 48hrs. The outputs from the monitor were then used to determine the transitions from sedentary to walking. The time delay between a sedentary posture ending and the start of walking classified four transition types: 1) fluent (<=2s), 2) hesitant (>2s<=10s), 3) separated (>10s) and 4) a change from sedentary with no registered walking to a return to sedentary. Results Control participants initiated walking after a sedentary posture on 92% of occasions. Most commonly (43%) this was a fluent transition. In contrast stroke patients walked after changing from a sedentary posture on 68% of occasions with only 9% of transitions classed as fluent, (p<0.05). Discussion/Conclusion A new data analysis technique reports the frequency of walking following a change in sedentary position in stroke patients and healthy controls and characterises this transition according to the time delay before walking. This technique creates opportunities to explore everyday mobility in greater depth

Innovative behaviour: how much transformational leadership do you need?

Studies on the effects of transformational leadership on employee innovative behaviour have yielded mixed results. The authors argue that one possible explanation for these mixed findings is that researchers have assumed a linear relationship between these constructs. In contrast, they suggest that the relationship between transformational leadership and innovative behaviour is non-linear. Specifically, the authors argue that the positive effects of transformational leadership on innovative behaviour will be stronger at low and high levels of transformational leadership. Moreover, they examine whether the relationship between transformational leadership and innovative behaviour is mediated by knowledge sharing within and between teams. The authors undertake a constructive replication by testing these hypothesized relationships in two studies: (1) a multi-actor team-level study conducted in the USA, and (2) a longitudinal employee-level study of teachers in the Netherlands. Results of both studies reveal that knowledge sharing mediates the relationship between transformational leadership and innovative behaviour, and that the indirect relationship is curvilinear. The authors link these findings to leader substitution theory, proposing that employees turn to their peers and other parties when there is an absence of effective leadership

Snapshot of Research Issues in Service Robots

A service (social) robot is defined as the Internet of Things (IoT) consisting of a physical robot body that connects to one or more Cloud services to facilitate human-machine interaction activities to enhance the functionality of a traditional robot. Many studies found that anthropomorphic designs in robots resulted in greater user engagement. Humanoid service robots usually behave like natural social interaction partners for human users, with emotional features such as speech, gestures, and eye-gaze, referring to the users’ cultural and social background. During the COVID-19 pandemic, service robots play a much more critical role in helping to safeguard people in many countries nowadays. This paper gives an overview of the research issues from technical and social-technical perspectives, especially in Human-Robot Interaction (HRI), emotional expression, and cybersecurity issues, with a case study of gamification and service robots