Adaptive Transmission Techniques for Mobile Satellite Links

Adapting the transmission rate in an LMS channel is a challenging task because of the relatively fast time variations, of the long delays involved, and of the difficulty in mapping the parameters of a time-varying channel into communication performance. In this paper, we propose two strategies for dealing with these impairments, namely, multi-layer coding (MLC) in the forward link, and open-loop adaptation in the return link. Both strategies rely on physical-layer abstraction tools for predicting the link performance. We will show that, in both cases, it is possible to increase the average spectral efficiency while at the same time keeping the outage probability under a given threshold. To do so, the forward link strategy will rely on introducing some latency in the data stream by using retransmissions. The return link, on the other hand, will rely on a statistical characterization of a physical-layer abstraction measure.Comment: Presented at the 30th AIAA International Communications Satellite Systems Conference (ICSSC), Ottawa, Canada, 2012. Best Professional Paper Awar

Developing a Framework to Understand Student Engagement, Team Dynamics, and Learning Outcomes Using ERPsim

The value of enterprise resource planning (ERP) systems to business organizations has long been recognized with their use being integrated into educational business curricula and training. ERPsim games incorporate live business simulations that enable students to learn about ERP concepts firsthand by working in teams and managing their own companies using SAP ERP software. Prior research has examined the use of ERPsim and learning outcomes, yet to date, there is little if any research that has explored the association of learning outcomes with student engagement and team dynamics, two areas that have continued to grow in importance in many business school programs. This research develops and tests a model to examine these relationships. Validated constructs and a validated survey instrument are created and verified. Study results indicate a positive association between student engagement, team dynamics, and learning outcomes. Results and implications are discussed, and recommendations for further research are presented

Assessment of the learning curve in health technologies: a systematic review

Objective: We reviewed and appraised the methods by which the issue of the learning curve has been addressed during health technology assessment in the past. Method: We performed a systematic review of papers in clinical databases (BIOSIS, CINAHL, Cochrane Library, EMBASE, HealthSTAR, MEDLINE, Science Citation Index, and Social Science Citation Index) using the search term "learning curve:" Results: The clinical search retrieved 4,571 abstracts for assessment, of which 559 (12%) published articles were eligible for review. Of these, 272 were judged to have formally assessed a learning curve. The procedures assessed were minimal access (51%), other surgical (41%), and diagnostic (8%). The majority of the studies were case series (95%). Some 47% of studies addressed only individual operator performance and 52% addressed institutional performance. The data were collected prospectively in 40%, retrospectively in 26%, and the method was unclear for 31%. The statistical methods used were simple graphs (44%), splitting the data chronologically and performing a t test or chi-squared test (60%), curve fitting (12%), and other model fitting (5%). Conclusions: Learning curves are rarely considered formally in health technology assessment. Where they are, the reporting of the studies and the statistical methods used are weak. As a minimum, reporting of learning should include the number and experience of the operators and a detailed description of data collection. Improved statistical methods would enhance the assessment of health technologies that require learning

Assessing the learning curve effect in health technologies: Lessons from the non-clinical literature

Introduction: Many health technologies exhibit some form of learning effect, and this represents a barrier to rigorous assessment. It has been shown that the statistical methods used are relatively crude. Methods to describe learning curves in fields outside medicine, for example, psychology and engineering, may be better. Methods: To systematically search non–health technology assessment literature (for example, PsycLit and Econlit databases) to identify novel statistical techniques applied to learning curves. Results: The search retrieved 9,431 abstracts for assessment, of which 18 used a statistical technique for analyzing learning effects that had not previously been identified in the clinical literature. The newly identified methods were combined with those previously used in health technology assessment, and categorized into four groups of increasing complexity: a) exploratory data analysis; b) simple data analysis; c) complex data analysis; and d) generic methods. All the complex structured data techniques for analyzing learning effects were identified in the nonclinical literature, and these emphasized the importance of estimating intra- and interindividual learning effects. Conclusion: A good dividend of more sophisticated methods was obtained by searching in nonclinical fields. These methods now require formal testing on health technology data sets

An Examination of Canadian Civil Society Organizations’ Role and Contribution to the Effort of Global Citizenship Education in Canada

In an era of increased globalization it is difficult to ignore the growing divide between the rich and the poor. This thesis examines the ways public engagement and education about international development issues take place in the public sphere, in Canada. The thesis reviews the role of the Canadian International Development Agency (CIDA), the International Development Research Centre (IDRC) and four Canadian Civil Society Organizations (CCSOs): CARE, Cuso, the McLeod Group as well as the role of the umbrella organization regrouping 92 CCSOs, the Canadian Coalition for International Cooperation (CCIC), in engaging the public about issues surrounding international development. The research relies on information gleaned from the relevant websites, a range of publications and interviews with the four CCSOs. It identifies that the role for public engagement primarily falls on the shoulders of CCSOs, who deem public engagement to be an important part of what they do. It recounts the different ways the CCSOs interviewed are involved in public engagement as well as some of the key methods and strategies they employ. It concludes that CCSOs value public engagement however they are severely restricted in what they can do because of budget restraints and reduced government funding. The thesis also suggests further avenues for research into the way education about issues of international development takes place in other formal, non-formal and informal learning contexts in Canada

The ins and outs of participation in a weather information system

In this paper our aim is to show even though access to technology, information or data holds the potential for improved participation, participation is wired into a larger network of actors, artefacts and information practices. We draw on a case study of a weather information system developed and implemented by a non-profit organisation to both describe the configuration of participation, but also critically assess inclusion and exclusion. We present a set of four questions - a basic, practical toolkit - by which we together with the organisation made sense of and evaluated participation in the system

Training to Be an Early Childhood Professional: Teacher Candidates’ Perceptions about Their Education and Training

Professionalism in the context of early care and education has received considerable attention in recent years (Caulfield, 1997; Harte, 2011; Tigistu, 2013). According to the 2010 National Association for the Education of Young Children (NAEYC) Standards for Initial & Advanced Early Childhood Professional Preparation Programs, teacher candidates prepared in early childhood degree programs should identify and conduct themselves as members of the profession, know and use ethical guidelines and utilize other professional standards related to early childhood practice (NAEYC, 2012). In their final journal entry for a student teaching practicum course, teacher candidates in an accredited early childhood program reflected on what it means to be an early childhood professional. In alignment with the 2010 NAEYC Standards, teacher candidates appeared to recognize that being an early childhood professional means having an understanding of the specialized knowledge required to be effective in early childhood education. They also appeared to be aware that providing responsive, supportive curricula, which acknowledges and respects the whole child and family and their cultural backgrounds, is an integral aspect of the early childhood profession. Implications from this inquiry suggest that the early childhood program should ensure the fidelity to the NAEYC Standards by aligning assignments that incorporate the language and expectations of the Standards

A role for tetraspanin proteins in regulating fusion induced by Burkholderia thailandensis

Burkholderia pseudomallei is the causative agent of melioidosis, a disease with high morbidity that is endemic in South East Asia and northern Australia. An unusual feature of the bacterium is its ability to induce multinucleated giant cell formation (MNGC), which appears to be related to bacterial pathogenicity. The mechanism of MNGC formation is not fully understood, but host cell factors as well as known bacterial virulence determinants are likely to contribute. Since members of the tetraspanin family of membrane proteins are involved in various types of cell:cell fusion, their role in MNGC formation induced by Burkholderia thailandensis, a mildly pathogenic species closely related to B. pseudomallei, was investigated. The effect of antibodies to tetraspanins CD9, CD81, and CD63 in MNGC formation induced by B. thailandensis in infected mouse J774.2 and RAW macrophage cell lines was assessed along with that of recombinant proteins corresponding to the large extracellular domain (EC2) of the tetraspanins. B. thailandensis-induced fusion was also examined in macrophages derived from CD9 null and corresponding WT mice, and in J774.2 macrophages over-expressing CD9. Antibodies to CD9 and CD81 promoted MNGC formation induced by B. thailandensis, whereas EC2 proteins of CD9, CD81, and CD63 inhibited MNGC formation. Enhanced MNGC formation was observed in CD9 null macrophages, whereas a decrease in MNGC formation was associated with overexpression of CD9. Overall our findings show that tetraspanins are involved in MNGC formation induced by B. thailandensis and by implication, B. pseudomallei, with CD9 and CD81 acting as negative regulators of this process

Schubert calculus of Richardson varieties stable under spherical Levi subgroups

We observe that the expansion in the basis of Schubert cycles for $H^*(G/B)$ of the class of a Richardson variety stable under a spherical Levi subgroup is described by a theorem of Brion. Using this observation, along with a combinatorial model of the poset of certain symmetric subgroup orbit closures, we give positive combinatorial descriptions of certain Schubert structure constants on the full flag variety in type $A$. Namely, we describe $c_{u,v}^w$ when $u$ and $v$ are inverse to Grassmannian permutations with unique descents at $p$ and $q$, respectively. We offer some conjectures for similar rules in types $B$ and $D$, associated to Richardson varieties stable under spherical Levi subgroups of SO(2n+1,\C) and SO(2n,\C), respectively.Comment: Section 4 significantly shortened, and other minor changes made as suggested by referees. Final version, to appear in Journal of Algebraic Combinatoric