On the Frequency of Words Used in Answers to Explain in Plain English Questions by Novice Programmers

© 2019 Association for Computing Machinery. Most previous research studies using Explain in Plain English questions have focussed on categorising the answers of novice programmers according to the SOLO taxonomy, and/or the relationship between explaining code and writing code. In this paper, we study the words used in the explanations of novice programmers. Our data is from twelve Explain in plain English questions presented to over three hundred students in an exam at the end of the students' first semester of programming. For each question, we compare the frequency of certain words used in correct answers, between students who scored a perfect twelve on all the Explain in plain English questions and students with lower scores. We report a number of statistically significant differences in word frequency between the students who answered all questions correctly and students who did not. The students who answered all twelve questions correctly tended to be more precise, more comprehensive, and more likely to choose words not explicitly in the code, but instead words that are an abstraction beyond the code

An architecture for systematic tracking of skills and competence level progression in computer science

A typical Computer Science degree is three to five years long, consists of four to six subjects per semester, and two semesters per year. A student enrolled in such a degree is expected to learn both discipline-specific skills and transferable generic skills. These skills are to be taught in a progressive sequence through the duration of the degree. As the student progresses through the subjects and semesters of a degree, his skill portfolio and competence level for each skill is expected to grow. Effectively modeling these curriculum skills, mapping them to assessment tasks across subjects of a degree, and measuring the progression in learner competence level is, largely, still an unsolved problem. Previous work at this scale is limited. This systematic tracking of skills and competence is crucial for effective quality control and optimization of degree structures. Our main contribution is an architecture for a curriculum information management system to facilitate this systematic tracking of skill and competence level progression in a Computer Science context

Faraday rotation in the MOJAVE blazars: 3C 273 a case study

Radio polarimetric observations of Active Galactic Nuclei can reveal the magnetic field structure in the parsec-scale jets of these sources. We have observed the gamma-ray blazar 3C 273 as part of our multi-frequency survey with the Very Long Baseline Array to study Faraday rotation in a large sample of jets. Our observations re-confirm the transverse rotation measure gradient in 3C 273. For the first time the gradient is seen to cross zero which is further indication for a helical magnetic field and spine-sheath structure in the jet. We believe the difference to previous epochs is due to a different part of the jet being illuminated in our observations.Comment: 6 pages, 3 figures. To appear in the proceedings of "Beamed and Unbeamed Gamma-rays from Galaxies", held in Muonio, Finland, April 11-15, 2011. Journal of Physics: Conference Serie

Coupled Magnetic Excitations in Single Crystal PrBa2Cu3O6.2

The dispersion of the low-energy magnetic excitations of the Pr sublattice in PrBa2Cu3O6.2 is determined by inelastic neutron scattering measurements on a single crystal. The dispersion, which shows the effect of interactions with the Cu spin-waves, is well described by a model of the coupled Cu-Pr magnetic system. This enables values for the principal exchange constants to be determined, which suggest that both Pr-Pr and Cu-Pr interactions are important in producing the anomalously high ordering temperature of the Pr sublattice. Measurements of the Cu optic spin wave mode show that the inter-layer Cu-Cu exchange is significantly lower than in YBa2Cu3O6.2.Comment: To be published Phys. Rev. Let

Transit Photometry with the LCOGT Network

Within a single year, we deployed and commissioned a total of seven 1m telescopes to three sites (McDonald Observatory, CTIO and SAAO). These are complemented by two existing 2m telescopes, located in the northern (Haleakala) and southern (Siding Spring Observatory) hemispheres. Before the end of 2013, one additional 1m telescope will be deployed at McDonald Observatory, and two at Siding Spring Observatory, which will complete the southern ring and enable continuous LCOGT dark time in the southern hemisphere. We present transit observations acquired at each site with currently-deployed 1m telescopes. These data demonstrate some of the network's unique capabilities, such as simultaneous transit observations from multiple sites and construction of full transits by combining partial transit light curves from two sites. Such exercises pave the path toward searching for and characterizing transits of long period exoplanets, simultaneous multi-color transit observations, as well as studying spot distributions and rotation periods of exoplanet host stars using the LCOGT network

Phonon Dispersion Relations in PrBa2Cu3O6+x (x ~ 0.2)

We report measurements of the phonon dispersion relations in non-superconducting, oxygen-deficient PrBa2Cu3O6+x (x ~ 0.2) by inelastic neutron scattering. The data are compared with a model of the lattice dynamics based on a common interaction potential. Good agreement is achieved for all but two phonon branches, which are significantly softer than predicted. These modes are found to arise predominantly from motion of the oxygen ions in the CuO2 planes. Analogous modes in YBa2Cu3O6 are well described by the common interaction potential model.Comment: 4 pages, 3 figures. Minor changes following referees' comment