The abstraction transition taxonomy: developing desired learning outcomes through the lens of situated cognition

We report on a post-hoc analysis of introductory programming lecture materials. The purpose of this analysis is to identify what knowledge and skills we are asking students to acquire, as situated in the activity, tools, and culture of what programmers do and how they think. The specific materials analyzed are the 133 Peer Instruction questions used in lecture to support cognitive apprenticeship -- honoring the situated nature of knowledge. We propose an Abstraction Transition Taxonomy for classifying the kinds of knowing and practices we engage students in as we seek to apprentice them into the programming world. We find students are asked to answer questions expressed using three levels of abstraction: English, CS Speak, and Code. Moreover, many questions involve asking students to transition between levels of abstraction within the context of a computational problem. Finally, by applying our taxonomy in classifying a range of introductory programming exams, we find that summative assessments (including our own) tend to emphasize a small range of the skills fostered in students during the formative/apprenticeship phase

An Evaluation of Appearance Models for Cloth Rendering

Cloth is a common material which exhibits complex, anisotropic reflection behavior. Because cloth is such an important material class in human-centric environments, many models have attempted to describe its appearance. This thesis aims to clarify the state of the art of cloth rendering by comparing two recent models, by Irawan et al. and by Sadeghi et al., which both describe cloth as woven microcylinders. We fit each of these models to a set of measured fabrics and link the resulting differences to theoretical elements of the models. Through this comparison, we find that Sadeghi's model is able to more closely match the appearance of complex fabrics.Additionally, we present measurements of 8 fabric samples, which exhibit several different structural characteristics. These samples include woven, knitted, nap and pile fabrics. Sadeghi's model is used to reproduce the appearance of the samples. This both allows us to further evaluate this model, and expands the library of cloth types which Sadeghi's model has been used to describe. We find the model to be largely successful in matching the samples, although we also discover a key limitation inherent to woven cloth models. To address this, we suggest an extension, called the thread direction curve which would further generalize the model.The measurements in this thesis have been included in a supplementary archive

An Evaluation of Appearance Models for Cloth Rendering

Cloth is a common material which exhibits complex, anisotropic reflection behavior. Because cloth is such an important material class in human-centric environments, many models have attempted to describe its appearance. This thesis aims to clarify the state of the art of cloth rendering by comparing two recent models, by Irawan et al. and by Sadeghi et al., which both describe cloth as woven microcylinders. We fit each of these models to a set of measured fabrics and link the resulting differences to theoretical elements of the models. Through this comparison, we find that Sadeghi's model is able to more closely match the appearance of complex fabrics.Additionally, we present measurements of 8 fabric samples, which exhibit several different structural characteristics. These samples include woven, knitted, nap and pile fabrics. Sadeghi's model is used to reproduce the appearance of the samples. This both allows us to further evaluate this model, and expands the library of cloth types which Sadeghi's model has been used to describe. We find the model to be largely successful in matching the samples, although we also discover a key limitation inherent to woven cloth models. To address this, we suggest an extension, called the thread direction curve which would further generalize the model.The measurements in this thesis have been included in a supplementary archive