Group Cognition in Problem Solving Dialogues: Analyzing differences between voice and computer transcripts

This project shadows the work of student groups in Math 110, a quantitative literacy class, engaged in exploratory learning excercises. An instructor monitors these groups by both walking around the room and observing group conversation at another computer. Our goal is to put this exercise online, and as a result leave the entire monitoring process up to the computer, assuming the role that the instructor traditionally assumes. Using annotation techniques to decipher meaning in dialogue of students working in groups for a Math 110, we try to see how students collaborate to solve problems together. “Bits of realization”, conversation, and problem solving tags are sorted out and gathered to identify the main points that are expressed during the problem solving of the two-person game, Poison. Expanding upon previous research done by other students, we are able to add bits of realization that students encounter in their work. Our first effort is to explore the differences between voice recorded dialogue and computer-mediated chat dialogue

Ultra-high temperature ceramic coatings and structures formed by vacuum plasma spray

Group IVB and VB transition metal carbides, nitrides, borides and oxides are attractive for extreme environment applications. While stoichiometric phases tend to exhibit the highest temperature capability, highest hardness and superior chemical inertness, mixtures of binary stoichiometric phases and non-stoichiometric phases have demonstrated tailorable mechanical properties. Ternary systems have also exhibited unique mechanical properties in addition to superior oxidation behavior. Efforts at Plasma Processes, using vacuum plasma spray (VPS) fabrication, have focused on advancing the technology readiness level (TRL) and manufacturing readiness level (MRL) of various ultra-high temperature ceramics in the form of coatings and structural components. Studies have included fabrication and characterization of VPS deposits comprised of the following chemistries: Ta-C, Ta-Hf-C, Hf-N, Hf-Ta-N, Zr-C, Zr-O, Zr‑C-Hf-O. This presentation will provide an overview of select chemistries and discuss the following: Temperature-dependent physical and mechanical properties Processing-microstructure-property relationship Progression from coupon to sub‑scale to full-scale fabrication Approved for Public Release 17-MDA-9213 (24 May 17

Ultra-high temperature ceramic coatings and structures formed by vacuum plasma spray

Group IVB and VB transition metal carbides, nitrides, borides and oxides are attractive for extreme environment applications. While stoichiometric phases tend to exhibit the highest temperature capability, highest hardness and superior chemical inertness, mixtures of binary stoichiometric phases and non-stoichiometric phases have demonstrated tailorable mechanical properties. Ternary systems have also exhibited unique mechanical properties in addition to superior oxidation behavior. Efforts at Plasma Processes, using vacuum plasma spray (VPS) fabrication, have focused on advancing the technology readiness level (TRL) and manufacturing readiness level (MRL) of various ultra-high temperature ceramics in the form of coatings and structural components. Studies have included fabrication and characterization of VPS deposits comprised of the following chemistries: Ta-C, Ta-Hf-C, Hf-N, Hf-Ta-N, Zr-C, Zr-O, Zr‑C-Hf-O. This presentation will provide an overview of select chemistries and discuss the following: Temperature-dependent physical and mechanical properties Processing-microstructure-property relationship Progression from coupon to sub‑scale to full-scale fabrication Approved for Public Release 17-MDA-9213 (24 May 17

Construction of direction selectivity in V1: from simple to complex cells

Despite detailed knowledge about the anatomy and physiology of the primary visual cortex (V1), the immense number of feed-forward and recurrent connections onto a given V1 neuron make it difficult to understand how the physiological details relate to a given neuron’s functional properties. Here, we focus on a well-known functional property of many V1 complex cells: phase-invariant direction selectivity (DS). While the energy model explains its construction at the conceptual level, it remains unclear how the mathematical operations described in this model are implemented by cortical circuits. To understand how DS of complex cells is constructed in cortex, we apply a nonlinear modeling framework to extracellular data from macaque V1. We use a modification of spike-triggered covariance (STC) analysis to identify multiple biologically plausible "spatiotemporal features" that either excite or suppress a cell. We demonstrate that these features represent the true inputs to the neuron more accurately, and the resulting nonlinear model compactly describes how these inputs are combined to result in the functional properties of the cell. In a population of 59 neurons, we find that both simple and complex V1 cells are selective to combinations of excitatory and suppressive motion features. Because the strength of DS and simple/complex classification is well predicted by our models, we can use simulations with inputs matching thalamic and simple cells to assess how individual model components contribute to these measures. Our results unify experimental observations regarding the construction of DS from thalamic feed-forward inputs to V1: based on the differences between excitatory and inhibitory inputs, they suggest a connectivity diagram for simple and complex cells that sheds light on the mechanism underlying the DS of cortical cells. More generally, they illustrate how stage-wise nonlinear combination of multiple features gives rise to the processing of more abstract visual information

Hierarchical Models for Relational Event Sequences

Interaction within small groups can often be represented as a sequence of events, where each event involves a sender and a recipient. Recent methods for modeling network data in continuous time model the rate at which individuals interact conditioned on the previous history of events as well as actor covariates. We present a hierarchical extension for modeling multiple such sequences, facilitating inferences about event-level dynamics and their variation across sequences. The hierarchical approach allows one to share information across sequences in a principled manner---we illustrate the efficacy of such sharing through a set of prediction experiments. After discussing methods for adequacy checking and model selection for this class of models, the method is illustrated with an analysis of high school classroom dynamics

PALEOECOLOGY AND FUNCTIONAL MORPHOLOGY OF THE PERMIAN LYTTONIID BRACHIOPOD PIRGULIA

The lyttoniid brachiopods of the Permian exhibit a unique valve morphology: a branched lobate structure takes the form of the dorsal valve. In one group of lyttoniids, the genus Pirgulia, the ventral valve wraps around to form a cone that fully encloses the lobate structure. This has consequences for the dynamics of water flow and mode of life possible for these heteromorphic brachiopods. Here, we describe the skeletal microstructure and morphology of Pirgulia collected from the Upper Permian Sosio Limestone megablocks of Sicily and housed at the Yale Peabody Museum. We reconstruct the paleoecology of Pirgulia, characterizing it as semi-infaunal in soft sediment. By analogy to Richthofenia, the conical ventral valve and flapping dorsal valve functional morphology could have resisted fouling and assisted feeding in this environment. By comparison with the functional morphology of Pirgulia with other lyttoniids and richthofenids, we propose a revised mode of life for this genus, which involves adaptation to secondary soft-bottom substrates and support by sediment sticking. Despite constraints to the fundamental brachiopod body plan, modification of the valves in Pirgulia to achieve a conical morphology allowed it to inhabit a paleoecological niche distinct from that of other reef-building lyttoniids

Group Cognition in Problem Solving Dialogues: Analyzing differences between voice and computer transcripts

This project shadows the work of student groups in Math 110, a quantitative literacy class, engaged in exploratory learning excercises. An instructor monitors these groups by both walking around the room and observing group conversation at another computer. Our goal is to put this exercise online, and as a result leave the entire monitoring process up to the computer, assuming the role that the instructor traditionally assumes. Using annotation techniques to decipher meaning in dialogue of students working in groups for a Math 110, we try to see how students collaborate to solve problems together. “Bits of realization”, conversation, and problem solving tags are sorted out and gathered to identify the main points that are expressed during the problem solving of the two-person game, Poison. Expanding upon previous research done by other students, we are able to add bits of realization that students encounter in their work. Our first effort is to explore the differences between voice recorded dialogue and computer-mediated chat dialogue