Summative Stage Research Articles

Efficient computation of correlation coefficient using negative reference in template matching applications

Design and implementation of a new early termination algorithm for efficient calculation of correlation coefficient for template matching is presented. The proposed algorithm correlates the candidates against `negative` (bit-inverted) version of reference instead of the original to implement a low cost early termination criterion. Around 10% computational savings have been demonstrated while using the proposed algorithm to compute normalised correlation as error metric for motion estimation in software implementation of H.264 video encoder. The algorithm lends itself to efficient hardware implementation because of its simple cost function. Further hardware savings have been realised by noting that the multiplication products generated by the proposed negative reference correlation algorithm tend to have low magnitudes with significantly less variance than those generated by other schemes. This allows a low-precision summation stage to accumulate majority of the multiplication products without losing the precision of results. Results of the hardware implementation on Xilinx Virtex-5 FPGA have been provided. The overall design is shown to consume around 85% less logic resources and operate at 140% higher speed than existing architectures.

Additivity of nonsimultaneous masking for short Gaussian-shaped sinusoids

The additivity of nonsimultaneous masking was studied using Gaussian-shaped tone pulses (referred to as Gaussians) as masker and target stimuli. Combinations of up to four temporally separated Gaussian maskers with an equivalent rectangular bandwidth of 600 Hz and an equivalent rectangular duration of 1.7 ms were tested. Each masker was level-adjusted to produce approximately 8 dB of masking. Excess masking (exceeding linear additivity) was generally stronger than reported in the literature for longer maskers and comparable target levels. A model incorporating a compressive input/output function, followed by a linear summation stage, underestimated excess masking when using an input/output function derived from literature data for longer maskers and comparable target levels. The data could be predicted with a more compressive input/output function. Stronger compression may be explained by assuming that the Gaussian stimuli were too short to evoke the medial olivocochlear reflex (MOCR), whereas for longer maskers tested previously the MOCR caused reduced compression. Overall, the interpretation of the data suggests strong basilar membrane compression for very short stimuli.

Triadic Assessment

This article describes the findings of, and the conclusions drawn from, a research project sponsored by the University of Plymouth Student Centred Learning Initiative (SCLI) with the intention of gaining an indepth view of self, peer and tutor (triadic) assessment. The research employed an essentially qualitative methodology incorporating the use of questionnaire and semi-structured interview techniques. The research cohort was drawn from groups of students studying at different stages of the BA(Hons) Education and Training programme within the Faculty of Arts & Education at the University of Plymouth. The research project was designed to examine triadic assessment within the context of the formative and summative stages of the assessment process of the programme. Of significance to the research was the fact that triadic assessment was seen to form an integral part of the formative and summative stages of the programme assessment procedures. This involved all students in a collaborative process of setting their own assessment criteria; a process supported through directed study activities and ongoing monitoring and review. While the researchers all subscribed to the view that this process is a key part of triadic assessment, the discourse evaluation that the research also involved ensured that the assessment practices examined were closely and critically evaluated. The ongoing process of interrogation and re-conceptualisation of the epistemological foundations of the research practice were sustained throughout the research process. Questions of power and knowledge were closely examined, alongside a close critical analysis of the way in which the professional identity and assessment practice style of those involved in the research were influenced by the way in which they were situated within a variety of different practice contexts. This article proposes a problematising of triadic assessment and concludes that it is clearly not a transparent activity that reveals easily generalisable and universalisable features and characteristics. Depending upon chosen perspectives, triadic assessment will, therefore, possess strengths and weaknesses. Evidence from the research suggests that notions of self- and peer assessment are contested and negotiated within the context of situated and active discursive construction.

An evaluation plan to assess the process and outcomes of a learner-centered training program for clinical research

In 1994, the National Center for Research Resources' Committee on Addressing Career Paths for Clinical Research reported that insufficient training in research methods, inadequate mentoring, and inappropriate timing of training presented major barriers to the development of clinical researchers. The National Institutes of Health responded to the need for additional training programs by supporting 57 institutions through the Clinical Research Curriculum Award (K30) Program. The ability to assess the success of these programs depends on the nature and extent of their evaluation plans. Evaluation plans for clinical research training programs should include means of assessing both process and outcomes of a program's implementation in its formative and summative stages. This article describes the University of Wisconsin-Madison's Clinical Investigator Preparatory Program and an evaluation plan that incorporates process and outcome assessments based on a theoretical framework of adult and professional education.

Assessment of Gifted Student Learning in the Language Arts

This paper discusses important principles for assessing language arts instruction for gifted learners in classrooms. It stresses the importance of multiple measures and approaches being employed at formative and summative stages of the instructional process. Examples of rubrics, portfolios, and performance-based models are provided. The article concludes with ideas for constructing an assessment model that incorporates all of these features.

Nonlinearities in the coding of intensity within the context of a temporal summation model

A model of temporal summation and intensity coding relates the subject's internal percept y(t) to the stimulus input x(t) by the equation y(t) = g(St - oof[x(tau)] h [t, tau, x (tau)]d tau). In words, some transformation f[x (t)] of the stimulus intensity is weighted by a function h and integrated; the result is transformed into the internal percept by a function g. This system postulates a linear integral operator preceded and followed by transformations which may be nonlinear. Based on forward masking of clicks by white noise, we (1) show that the above characterization of the model is appropriate (which involves showing that there is a linear temporal summation stage), and (2) derive certain characteristics of the system's nonlinearities. In particular, the integral of h times f is shown to be a nonlinear function of the input intensity exhibiting more compression than a power function. It is also shown that h must depend upon the intensity of the stimulus.