Validation of a videogrammetry technique for analysing American football helmet kinematics     

Ann Bailey  James Funk  David Lessley  Chris Sherwood  Jeff Crandall  William Neale 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(5):678-700

ABSTRACT

Professional American football games are recorded in digital video with multiple cameras, often at high resolution and high frame rates. The purpose of this study was to evaluate the accuracy of a videogrammetry technique to calculate translational and rotational helmet velocity before, during and after a helmet impact. In total, 10 football impacts were staged in a National Football League (NFL) stadium by propelling helmeted 50th percentile male crash test dummies into each other or the ground at speeds and orientations representative of concussive impacts for NFL players. The tests were recorded by experienced sports film crews to obtain video coverage and quality typically available for NFL games. A videogrammetry procedure was used to track the position and rotation of the helmet throughout the relevant time interval of the head impact. Compared with rigidly mounted retroreflective marker three dimensional (3-D) motion tracking that was concurrently collected in the experiments, videogrammetry accurately calculated changes in translational and rotational velocity of the helmet using high frame rate (two cameras at 240 Hz) video (7% and 15% error, respectively). Low frame rate (2 cameras at 60 Hz) video was adequate for calculating pre-impact translational velocity but not for calculating the translational or rotational velocity change of the helmet during impact.  相似文献   

Supporting the information gathering practices of academically advanced college-bound students     

Melanie S. Meyer  Jeff Cranmore 《Psychology in the schools》2020,57(7):1057-1076

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Transferring technology to the small manufacturing firm: A study of technology transfer in three countries     

Thomas J. Allen  Diane B. Hyman  David L. Pinckney 《Research Policy》1983,12(4):199-211

Case histories were compiled of 100 instances of technological change in 102 manufacturing companies in eight industries in Ireland, Spain and Mexico. The cases are analyzed for the source of initial ideas and for sources of technology employed in resolving major problems.Technology is found to flow principally through informal channels within industries. Very little information was obtained from the formal mechanisms or institutions normally considered central to the technology transfer process.Foreign subsidiaries obtain the greatest proportion of their technology from their parent firms. Surprisingly, they are found to have several channels of technology blocked to them, which are more readily available to domestic firms. Domestic firms, in many ways have easier access to foreign technology than do the subsidiaries of multinational firms.Product and process innovations originate in somewhat different quarters. Process innovations are slightly more likely to be based on foreign technology; product innovations are more likely to be based on domestic technology.The results reported in the present paper are very similar in many ways to results reported previously in Brazil and Australia.  相似文献   

Can creative destruction be destroyed? Military IR&D and destruction along the value-added chain     

Allen Kaufman  Mark Brumer 《Research Policy》2003,32(9):1537-1554

We elaborate a supply chain innovation matrix that can be applied to both commercial and military supply chains. By shifting the analysis from a focal firm to industry structure, we argue that the market structure of the entire supply chain functions as a major moderating variable in determining both the timing and adoption of innovations, both for commercial and military markets. We extend work on supply chain resource dependency by drawing a distinction between market-structure-induced resource dependency and supplier over-reliance on a customer in a competitive market. This has policy implications for the organization of military industrial research and development (IR&D). Joint service research and development (Jointness) will certainly bring about innovation, but it will be incremental, reinforcing established military hierarchies. Policy makers may need to add this probable consequence when comparing Jointness and inter-service rivalry. The cost savings inherent in Jointness may unwittingly sustain a military force unready for fighting the next war.  相似文献   

The UK National Arts Education Archive: Ideas and Imaginings          下载免费PDF全文

Jeff Adams  Rowan Bailey  Neil Walton 《The International Journal of Art & Design Education》2017,36(2):176-187

The National Arts Education Archive (NAEA) is housed and maintained by the Yorkshire Sculpture Park (YSP), and managed by YSP coordinators and educators with a well‐established volunteer programme. This year, 2017, as part of the celebrations of the YSP's 40th anniversary, the Archive will hold its own exhibition entitled Treasures Revealed: a collection of items selected by people who have been involved in the Archive, whether as donors, volunteers, researchers, artists, trustees or steering group members. In parallel with the exhibition, this article aims to give voice to a selection of individuals and groups associated with the Archive, discussing their interests and experiences of it, and their thoughts on its value and importance as a repository of arts education materials, ideals and practices. Our primary motivations were to consider these different voices in relation to the purpose, direction and relevance of the NAEA today. These exchanges raise fundamental questions and debates about what art education is and what it might become, and how these historical collections, and creative engagements with it, might help to shape our contemporary thinking.  相似文献   

Intervention fidelity in participatory research: a framework     

Edison Trickett  Stacy M. Rasmus  James Allen 《Educational Action Research》2020,28(1):128-141

ABSTRACT

In community interventions more generally, the concept of fidelity refers to the degree to which a program is delivered as intended. The present paper discusses ways in which fundamental aspects of participatory research challenge the concept of fidelity and differ from more traditional science-dominated approaches. We begin with a discussion of the fidelity concept and some of its strengths and limitations. We then discuss both social problems and proposed solutions as representing complex problems defying simple or permanent solutions. We suggest that three prominent aspects of participatory research highlight this complexity and pose challenges in assessing fidelity. First, in participatory research, the goal is not only scientific but also social action on a local issue as well. Second, the participatory process among varied partners is itself part of the intervention itself to be understood as affecting both processes and outcomes. Third, the goals of participatory research include community-level as well as individual-level changes. These issues are illustrated in a discussion of how culture is conceptualized and acknowledged in fidelity assessment. We conclude with some recommendations for approaching fidelty in participatory research in a way that appreciates its differences from more traditional paradigms underlying community interventions.  相似文献   

Ways to say thank you!     

Patsy Allen 《Early Childhood Education Journal》1992,20(1):44-44

Patsy Allen has taught in and directed preschool, secondary, and college early childhood education programs. Currently, she is writing, consulting, and practicing her parenting skills with her three children in Friona, TX.  相似文献   

Interactivity Defuses the Impact of Mathematics Anxiety in Primary School Children     

Michael Allen  Frédéric Vallée-Tourangeau 《International Journal of Science and Mathematics Education》2016,14(8):1553-1566

Math anxiety impedes performance in simple arithmetic tasks. Anxiety constrains working memory capacity and particularly the attentional functions of the central executive. The experiment reported here explored how interactivity mitigated the impact of math anxiety on the performance of elementary school students with simple additions. It manipulated two independent variables. The first was the length of the additions—involving either 7 or 11 number tokens (the value of the tokens ranged from 1 to 20). The other was the level of interactivity: in the low interactivity condition participants could not touch or point to the number tokens that configured the sums, and in a high interactivity condition participants could manipulate the tokens as they saw fit in deriving their answer. The length of the addition had an impact on accuracy, with longer sums leading to poorer performance. However, overall, performance in the high interactivity condition was superior, in terms of accuracy, absolute calculation error and efficiency, than performance in the low interactivity condition. Mathematics anxiety significantly predicted performance in the low interactivity condition, but not in the high interactivity condition. These results suggest that working memory resources are augmented through interactivity with the physical problem presentation, defusing the impact of anxiety on performance.  相似文献   

Reception Studies in the Rhetoric of Science     

Randy Allen Harris 《Technical Communication Quarterly》2005,14(3):249-255

This article encourages the increased attention to issues of reception in rhetoric of science, according with the sentiment but not the argument of Paul, Charney, and Kendall's “Moving beyond the Moment.” In particular, it offers two works as exemplary of the disciplinary maturity that has occasioned this focus on reception, Ceccarelli's monograph, Shaping Science with Rhetoric, and Harris's collection, Rhetoric and Incommensurability.  相似文献   

Learning set-ups     

Doris Allen  Angela Collins 《Early Childhood Education Journal》1976,4(2):35-36

A child reaching toddler stage is ready to learn about the basic shapes that comprise much of his/her world. With an accent on fun, here are some simple activities designed to teach children how to identify and distinguish between the shapes ... of things to come! Doris Allen is a career teacher in early childhood education. She has been a member of the Board of Directors of the Oswego Community Day Care center, and has co-authored an article on handwriting in the current edition of theBook of Knowledge. Angela Collins is currently a kindergarten teacher in an Open Education program based on the British Primary System model, and during the summers directs remedial reading programs.  相似文献