Design of a flexible and low-power ionospheric sounder

Thesis (M.S.) University of Alaska Fairbanks, 2014Characterizing the structure of the ionosphere has practical applications for telecommunications and scientific applications for studies of the near-earth space environment. Among several methods for measuring parameters of the ionosphere is ionospheric sounding, a radar technique that determines the electron content of the ionosphere as a function of height. Various research, military, and commercial institutions operate hundreds of ground-based ionosondes throughout the globe, and new ionosondes continue to be deployed in increasingly remote and distant locations. This thesis presents the design of an ionospheric sounder that reduces the power, size, and cost compared to existing systems. Key improvements include the use of an open-source software-defined radio platform and channel-aware dynamic sounding scheduling.Chapter 1. Introduction -- 1.1. A brief historical background -- 1.2. The ionosphere -- 1.3. Instruments for studying the ionosphere -- 1.4. Thesis organization -- Chapter 2. Radio waves and the ionosphere -- 2.1. Dispersion relation of electromagnetic waves in the ionosphere -- 2.2. Power reflected from the ionosphere -- 2.3 Noise in the HF spectrum -- 2.4. Ionograms -- Chapter 3. Radar principles -- 3.1. Target detection -- 3.2. Range and doppler elocity -- 3.3. Range-doppler ambiguity -- 3.4. Resolution and precision --3.5. Multi-pulse integration -- 3.6. Pulse compression -- 3.7. Practical limits of performance -- Chapter 4. Survey of current systems -- 4.1. Coherent transmission/reception and digital systems -- 4.2. Phase-coded pulses -- 4.3. Coherent integration of multiple pulses -- 4.4. Phased antenna arrays -- 4.5. O- and X-mode discrimination -- Chapter 5. System description -- 5.1. Design approach -- 5.2. Overview of the Ettus Research USRP -- 5.3. Using the USRP as a radar -- 5.4. Waveform Generation -- 5.5. Processing the received signal -- 5.6. Scheduling -- 5.7. Completing the system -- Chapter 6. Sounding results -- 6.1. Single frequency soundings -- 6.2. Swept frequency soundings -- Chapter 7. Conclusion -- 7.1. Evaluation of performance -- 7.2. Costs -- 7.3. Future improvements -- 7.4. Deploying a terrestrial ionosonde -- 7.5. Deploying a space-borne ionosonde -- References

User involvement in a Cochrane systematic review:using structured methods to enhance the clinical relevance, usefulness and usability of a systematic review update

Background: This paper describes the structured methods used to involve patients, carers and health professionals in an update of a Cochrane systematic review relating to physiotherapy after stroke and explores the perceived impact of involvement.Methods: We sought funding and ethical approval for our user involvement. We recruited a stakeholder group comprising stroke survivors, carers, physiotherapists and educators and held three pre-planned meetings during the course of updating a Cochrane systematic review. Within these meetings, we used formal group consensus methods, based on nominal group techniques, to reach consensus decisions on key issues relating to the structure and methods of the review.Results: The stakeholder group comprised 13 people, including stroke survivors, carers and physiotherapists with a range of different experience, and either 12 or 13 participated in each meeting. At meeting 1, there was consensus that methods of categorising interventions that were used in the original Cochrane review were no longer appropriate or clinically relevant (11/13 participants disagreed or strongly disagreed with previous categories) and that international trials (which had not fitted into the original method of categorisation) ought to be included within the review (12/12 participants agreed or strongly agreed these should be included). At meeting 2, the group members reached consensus over 27 clearly defined treatment components, which were to be used to categorise interventions within the review (12/12 agreed or strongly agreed), and at meeting 3, they agreed on the key messages emerging from the completed review. All participants strongly agreed that the views of the group impacted on the review update, that the review benefited from the involvement of the stakeholder group, and that they believed other Cochrane reviews would benefit from the involvement of similar stakeholder groups.Conclusions: We involved a stakeholder group in the update of a Cochrane systematic review, using clearly described structured methods to reach consensus decisions. The involvement of stakeholders impacted substantially on the review, with the inclusion of international studies, and changes to classification of treatments, comparisons and subgroup comparisons explored within the meta-analysis. We argue that the structured approach which we adopted has implications for other systematic reviews.</p

Strange Places

Strange Places is a collection of short stories and short shorts written during my time at The University of Southern Mississippi. Set primarily in Akron, Ohio, the stories in this collection explore a range of themes, such as trauma, death, alienation, social class, and the struggle to connect to others. This collection is preceded by a critical introduction

Simultaneous bilaternal training for improving arm function after stroke

Background Simultaneous bilateral training, the completion of identical activities with both arms simultaneously, is one intervention to improve arm function and reduce impairment. Objectives To determine the effects of simultaneous bilateral training for improving arm function after stroke. Search strategy We searched the Cochrane Stroke Trials Register (last searched August 2009) and 10 electronic bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2009), MEDLINE, EMBASE, CINAHL and AMED (August 2009). We also searched reference lists and trials registers. Selection criteria Randomised trials in adults after stroke, where the intervention was simultaneous bilateral training compared to placebo or no intervention, usual care or other upper limb (arm) interventions. Primary outcomes were performance in activities of daily living (ADL) and functional movement of the upper limb. Secondary outcomes were performance in extended activities of daily living and motor impairment of the arm. Data collection and analysis Two authors independently screened abstracts, extracted data and appraised trials. Assessment of methodological quality was undertaken for allocation concealment, blinding of outcome assessor, intention-to-treat, baseline similarity and loss to follow up. Main results We included 18 studies involving 549 relevant participants, of which 14 (421 participants) were included in the analysis (one within both comparisons). Four of the 14 studies compared the effects of bilateral training with usual care. Primary outcomes: results were not statistically significant for performance in ADL (standardised mean difference (SMD) 0.25, 95% confidence interval (CI) -0.14 to 0.63); functional movement of the arm (SMD -0.07, 95% CI -0.42 to 0.28) or hand (SMD -0.04, 95% CI -0.50 to 0.42). Secondary outcomes: no statistically significant results. Eleven of the 14 studies compared the effects of bilateral training with other specific upper limb (arm) interventions. Primary outcomes: no statistically significant results for performance of ADL (SMD -0.25, 95% CI -0.57 to 0.08); functional movement of the arm (SMD -0.20, 95% CI -0.49 to 0.09) or hand (SMD -0.21, 95% CI -0.51 to 0.09). Secondary outcomes: one study reported a statistically significant result in favour of another upper limb intervention for performance in extended ADL. No statistically significant differences were found for motor impairment outcomes. Authors' conclusions There is insufficient good quality evidence to make recommendations about the relative effect of simultaneous bilateral training compared to placebo, no intervention or usual care. We identified evidence that suggests that bilateral training may be no more (or less) effective than usual care or other upper limb interventions for performance in ADL, functional movement of the upper limb or motor impairment outcome

A review of occupational regulation and its impact

This Evidence Report develops a deeper understanding of the nature and impact of occupational regulation in the UK. The term, occupational regulation, is a broad heading for various mechanisms (including licence to practice and voluntary forms) through which minimum skill standards are applied within occupations. As such, occupational regulation is one of a range of levers, or best market solutions, which are designed to encourage employers to train on a collective basis. The use of occupational regulation as a mechanism for increasing the demand for, and supply of, skills was considered alongside other measures, as part of the UK Commission for Employment and Skills’ Review of Employer Collective Measures. However, that Review acknowledged the general topic of occupational regulation was under researched in the UK. This research, conducted by the National Institute of Economic and Social Research, helps to address this and deepens our knowledge of the area by: providing a discussion on the existing theory on occupational regulation by examining existing economic literature; providing a detailed review of the existing evidence on occupational regulation in the UK, America, Canada and Europe (Germany, France and Italy), again via existing literature; providing a comprehensive map of occupational regulation in the UK, through the mapping of managerial, professional and non-professional occupations at the Unit Group level of the Standard Occupational Classification (2000); producing estimates of the labour market impact of occupational regulation in the UK. Its prevalence is estimated by comparing the mapping output with Unit Group data obtained from the Quarterly Labour Force Survey (QLFS). Further analysis, via cross-sectional analysis, produces estimates on levels of qualifications, wages and rates of job-related training between workers in regulated and unregulated occupations. This uses QLFS 2010 data. And a Difference-in-Differences analysis is employed to evaluate the impact of switches in regulation status on skill levels, job-related education and training, wages and employment. This uses QLFS data between 2001 and 2010

Generic Programming with Extensible Data Types; Or, Making Ad Hoc Extensible Data Types Less Ad Hoc

We present a novel approach to generic programming over extensible data types. Row types capture the structure of records and variants, and can be used to express record and variant subtyping, record extension, and modular composition of case branches. We extend row typing to capture generic programming over rows themselves, capturing patterns including lifting operations to records and variations from their component types, and the duality between cases blocks over variants and records of labeled functions, without placing specific requirements on the fields or constructors present in the records and variants. We formalize our approach in System R{\omega}, an extension of F{\omega} with row types, and give a denotational semantics for (stratified) R{\omega} in Agda.Comment: To appear at: International Conference on Functional Programming 2023 Corrected citations from previous versio

O(N) models within the local potential approximation

Using Wegner-Houghton equation, within the Local Potential Approximation, we study critical properties of O(N) vector models. Fixed Points, together with their critical exponents and eigenoperators, are obtained for a large set of values of N, including N=0 and N\to\infty. Polchinski equation is also treated. The peculiarities of the large N limit, where a line of Fixed Points at d=2+2/n is present, are studied in detail. A derivation of the equation is presented together with its projection to zero modes.Comment: 27 pages, LaTeX with psfig, 7 PostScript figures. One reference corrected and one added with respect to the journal versio