Analysis of speed accuracy using video analysis software

Determining an athlete’s speed from broadcast video is a common practice in sport. Many software packages that perform data extraction from video files are expensive; however, open source software is also available, but lacks published validation for speed measurements. The purpose of this research was to examine the error of speed measurements extracted from video during an ice hockey skating exercise using open source software. The subject completed four exercises, at two speeds recorded by broadcast cameras set at five angles. The speeds from the broadcast cameras were compared to speeds calculated from a high-speed camera placed orthogonally to the exercise. Speeds from the broadcast cameras correlated well with the high-speed video for motion more than 12 m away from the broadcast camera. When comparing all the measured speeds, no significant difference was found between the speeds calculated by the high-speed camera (slow: 4.46 m/s ± 0.2; fast: 7.2 m/s ± 0.7) and the speed calculated from the broadcast cameras (slow: 4.50 m/s ± 0.4; fast: 7.34 m/s ± 0.6) (p > 0.05). The open source method was found to be less accurate when the athlete was close to (within 12 m of camera position) or moving directly toward the broadcast cameras.     

A note on the effect of schooling,experience and aging on wage growth

Our analysis of the National Longitudinal Survey of Young Men data suggests that changes in job experience and schooling play a large part in explaining wage growth, leaving a negative effect of chronological aging per se.     

Collaborative multimodal composing: tracing the unique partnerships of three pairs of adolescents composing across three digital projects

Although a large body of research emphasises the collaborative nature of adolescents' multimodal composing processes in and out of school, little is known about how or why collaborative partnerships might differ across composers or digital tools. Integrating sociocultural and social semiotics theoretical frameworks, this study examined how three pairs of culturally and linguistically diverse Grade 12 students collaboratively composed across three multimodal projects – a website, hypertext literary analysis and podcast – when responding to and analysing literature. Data sources included screen capture and video observations, student design interviews and written reflections. Qualitative data analysis revealed three different types of collaborative partnerships: (1) designer and assistant collaboration, (2) balanced division collaboration and (3) alternating lead collaboration. The division of labor between students was based on the convergence of mediating factors, with students negotiating multiple modes and tools, along with their partner's and their own technical skills, content knowledge and design preferences. These findings demonstrate how collaborative multimodal composing processes were multilayered and offered students flexibility for tailoring unique collaborative partnerships. Implications are discussed for understanding and supporting adolescents' collaborative multimodal composing processes in the classroom.     

Intake assessments for alternative teacher education: moving from legitimation towards predictive validity

There is little empirical evidence concerning the predictive validity of indicators used in intake assessments for alternative teacher education programs. However, pinpointing potentially successful candidates requires predictors of teacher competence, which may be used to assess candidates’ dispositions, knowledge and skills. Available evidence regarding six possible predictors of teacher competence is examined and their limitations and possibilities are pointed out. Recommendations and methodological guidelines are given for developing and using these indicators in valid and reliable ways. Directions are explored for instrument development and assessment practice.     

Distance education via the Internet: the student experience

This is the second in a series of papers that describes the use of the Internet on a distance-taught undergraduate Computer Science course (Thomas et al ., 1998). This paper examines students' experience of a large-scale trial in which students were taught using electronic communication exclusively. The paper compares the constitution and experiences of a group of Internet students to those of conventional distance learning students on the same course. Learning styles, background questionnaires, and learning outcomes were used in the comparison of the two groups. The study reveals comparable learning outcomes with no discrimination in grade as the result of using different communication media. The student experience is reported, highlighting the main gains and issues of using the Internet as a communication medium in distance education. This paper also shows that using the Internet in this context can provide students with a worthwhile experience.     

Event-specific impact test protocol for ice hockey goaltender masks

ABSTRACT

Goaltenders in the sport of ice hockey are at high risk for concussions from falls to the ice, player collisions and puck impacts. However, current methods used to certify helmets only consider head accelerations for drop tests which may not describe all common injury mechanisms relating to concussion. The purpose of this study was to describe the characteristics of 3 events associated with concussions for ice hockey goaltenders. A helmeted medium National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform was impacted under conditions representing 3 injury events. Three impact locations’ velocities were selected for each event based on video analysis of real-world concussive events. Peak resultant linear acceleration, rotational acceleration and rotational velocity of the headform were measured. The University College Dublin Brain Trauma Model (UCDBTM) was used to calculate maximum principal strain (MPS) and von Mises stress in the cerebrum. Each impact event produced a unique dynamic response and brain stress and strain values. This demonstrates that a single impact event (i.e. falls) cannot adequately describe all impact events. As a result, impact protocols which assess multiple impact events such as the protocol described in this study should be used to evaluate ice hockey goaltender masks.     

Science identity development: how multimodal composition mediates student role-taking as scientist in a media-rich learning environment

Educational technology research and development - Science identity has been widely discussed in recent years; however, research on its development in multimodal composing environments, especially...     

Composing across modes: a comparative analysis of adolescents’ multimodal composing processes

Although the shift from page to screen has dramatically redefined conceptions of writing, very little is known about how youth compose with multiple modes in digital environments. Integrating multimodality and multiliteracies theoretical frameworks, this comparative case study examined how urban twelfth-grade students collaboratively composed across three multimodal projects when responding to and analyzing literature. Data sources included screen capture and video observations, student design interviews, written reflections, and multimodal products. Findings revealed that multimodal composing was a complex, dynamic, and varied process mediated by the interaction of multiple factors. Students exhibited modal preferences when working with open and flexible digital tools – spending a majority of time working with that particular mode and relying on it to carry the communicative weight of their compositions. The development of multimodal composing timescapes for this study provided new insights into students’ rapid and frequent cross-modal traversals as they worked on their digital projects.