Eric Jeffrey Peterson

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We present Newton's Pen, a statics tutor implemented on a "pentop computer", a writing instrument with an integrated digitizer and embedded processor. The tutor, intended for undergraduate education, scaffolds students in the construction of free body diagrams and equilibrium equations. This project entailed the development of sketch understanding(More)
Mechanical design tools would be considerably more useful if we could interact with them in the way that human designers communicate design ideas to one another, i.e., using crude sketches and informal speech. Those crude sketches frequently contain pen strokes of two different sorts, one type portraying device structure, the other denoting gestures , such(More)
Generating, grouping, and labeling free-sketch data is a difficult and time-consuming task for both user study participants and researchers. To simplify this process for both parties, we would like to have users draw isolated shapes instead of complete sketches that must be hand-labeled and grouped, and then use this data to train our free-sketch symbol(More)
Objects in freely-drawn sketches often have no spatial or temporal separation, making object recognition difficult. We present a two-step stroke-grouping algorithm that first classifies individual strokes according to the type of object to which they belong, then groups strokes with like classifications into clusters representing individual objects. The(More)
Kirchhoff's Pen is a pen-based tutoring system that teaches students to apply Kirchhoff's voltage law (KVL) and current law (KCL). To use the system, the student sketches a circuit schematic and annotates it to indicate component labels, mesh currents, and nodal voltages. The student then selects either mesh (KVL) or nodal (KCL) analysis, and writes the(More)
Human pegivirus (HPgV)-formerly known as GB virus C and hepatitis G virus-is a poorly characterized RNA virus that infects about one-sixth of the global human population and is transmitted frequently in the blood supply. We create an animal model of HPgV infection by infecting macaque monkeys with a new simian pegivirus (SPgV) discovered in wild baboons.(More)
Simian immunodeficiency virus (SIV) infection of nonhuman primates is the predominant model for preclinical evaluation of human immunodeficiency virus (HIV) vaccines. These studies frequently utilize high-doses of SIV that ensure infection after a single challenge but do not recapitulate critical facets of sexual HIV transmission. Investigators are(More)
Catalysts based on single atoms of scarce precious metals can lead to more efficient use through enhanced reactivity and selectivity. However, single atoms on catalyst supports can be mobile and aggregate into nanoparticles when heated at elevated temperatures. High temperatures are detrimental to catalyst performance unless these mobile atoms can be(More)