2,342 research outputs found
Scaffolding School Pupils’ Scientific Argumentation with Evidence-Based Dialogue Maps
This chapter reports pilot work investigating the potential of Evidence-based Dialogue Mapping to scaffold young teenagers’ scientific argumentation. Our research objective is to better understand pupils’ usage of dialogue maps created in Compendium to write scientific ex-planations. The participants were 20 pupils, 12-13 years old, in a summer science course for “gifted and talented” children in the UK. Through qualitative analysis of three case studies, we investigate the value of dialogue mapping as a mediating tool in the scientific reasoning process during a set of learning activities. These activities were published in an online learning envi-ronment to foster collaborative learning. Pupils mapped their discussions in pairs, shared maps via the online forum and in plenary discussions, and wrote essays based on their dialogue maps. This study draws on these multiple data sources: pupils’ maps in Compendium, writings in science and reflective comments about the uses of mapping for writing. Our analysis highlights the diversity of ways, both successful and unsuccessful, in which dialogue mapping was used by these young teenagers
Regression games
The solution of a TU cooperative game can be a distribution of the value of the grand coalition, i.e. it can be a distribution of the payo (utility) all the players together achieve. In a regression model, the evaluation of the explanatory variables can be a distribution of the overall t, i.e. the t of the model every regressor variable is involved. Furthermore, we can take regression models as TU cooperative games where the explanatory (regressor) variables are the players. In this paper we introduce the class of regression games, characterize it and apply the Shapley value to evaluating the explanatory variables in regression models. In order to support our approach we consider Young (1985)'s axiomatization of the Shapley value, and conclude that the Shapley value is a reasonable tool to evaluate the explanatory variables of regression models
Geometric analysis of satellite laser ranging data
The analysis of simultaneous laser data is investigated using the method of trilateration. Analysis of data from 1987 to 1992 is presented with selected baseline rates and station positions. The use of simultaneous Etalon data is simulated to demonstrate the additional global coverage these satellites provide. Trilateration has a great potential for regional deformation studies with monthly LAGEOS American solutions between 3-12 millimeters
The Composition of M-type asteroids II: Synthesis of spectroscopic and radar observations
This work updates and expands on results of our long-term radar-driven
observational campaign of main-belt asteroids (MBAs) focused on Bus-DeMeo Xc-
and Xk-type objects (Tholen X and M class asteroids) using the Arecibo radar
and NASA Infrared Telescope Facilities (Ockert-Bell et al. 2008; 2010; Shepard
et al. 2008; 2010). Eighteen of our targets were near-simultaneously observed
with radar and those observations are described in Shepard et al. (2010). We
combine our near-infrared data with available visible wavelength data for a
more complete compositional analysis of our targets. Compositional evidence is
derived from our target asteroid spectra using two different methods, a \c{hi}2
search for spectral matches in the RELAB database and parametric comparisons
with meteorites. We present four new methods of parametric comparison,
including discriminant analysis. Discriminant analysis identifies meteorite
type with 85% accuracy. This paper synthesizes the results of these two analog
search algorithms and reconciles those results with analogs suggested from
radar data (Shepard et al. 2010). We have observed 29 asteroids, 18 in
conjunction with radar observations. For eighteen out of twenty-nine objects
observed (62%) our compositional predictions are consistent over two or more
methods applied. We find that for our Xc and Xk targets the best fit is an iron
meteorite for 34% of the samples. Enstatite Chondrites were best fits for 6 of
our targets (21%). Stony-iron meteorites were best fits for 2 of our targets
(7%). A discriminant analysis suggests that asteroids with no absorption band
can be compared to iron meteorites and asteroids with both a 0.9 and 1.9 {\mu}m
absorption band can be compared to stony-iron meteorites.Comment: 30 pages, 5 figures, 10 table
Elemental energy spectra of cosmic rays measured by CREAM-II
We present new measurements of the energy spectra of cosmic-ray (CR) nuclei
from the second flight of the balloon-borne experiment CREAM (Cosmic Ray
Energetics And Mass). The instrument (CREAM-II) was comprised of detectors
based on different techniques (Cherenkov light, specific ionization in
scintillators and silicon sensors) to provide a redundant charge identification
and a thin ionization calorimeter capable of measuring the energy of cosmic
rays up to several hundreds of TeV. The data analysis is described and the
individual energy spectra of C, O, Ne, Mg, Si and Fe are reported up to ~ 10^14
eV. The spectral shape looks nearly the same for all the primary elements and
can be expressed as a power law in energy E^{-2.66+/-0.04}. The nitrogen
absolute intensity in the energy range 100-800 GeV/n is also measured.Comment: 4 pages, 3 figures, presented at ICRC 2009, Lodz, Polan
Proton and Helium Spectra from the CREAM-III Flight
Primary cosmic-ray elemental spectra have been measured with the
balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment since 2004. The
third CREAM payload (CREAM-III) flew for 29 days during the 2007-2008 Antarctic
season. Energies of incident particles above 1 TeV are measured with a
calorimeter. Individual elements are clearly separated with a charge resolution
of ~0.12 e (in charge units) and ~0.14 e for protons and helium nuclei,
respectively, using two layers of silicon charge detectors. The measured proton
and helium energy spectra at the top of the atmosphere are harder than other
existing measurements at a few tens of GeV. The relative abundance of protons
to helium nuclei is 9.53+-0.03 for the range of 1 TeV/n to 63 TeV/n. The ratio
is considerably smaller than other measurements at a few tens of GeV/n. The
spectra become softer above ~20 TeV. However, our statistical uncertainties are
large at these energies and more data are needed
Measurements of cosmic-ray energy spectra with the 2nd CREAM flight
During its second Antarctic flight, the CREAM (Cosmic Ray Energetics And
Mass) balloon experiment collected data for 28 days, measuring the charge and
the energy of cosmic rays (CR) with a redundant system of particle
identification and an imaging thin ionization calorimeter. Preliminary direct
measurements of the absolute intensities of individual CR nuclei are reported
in the elemental range from carbon to iron at very high energy.Comment: 4 pages, 3 figures, presented at XV International Symposium on Very
High Energy Cosmic Ray Interactions (ISVHECRI 2008
On the Security of a Popular Web Submission and Review Software (WSaR) for Cryptology Conferences
Most, if not all, conferences use an online system to handle paper submissions and reviews. Introduction of these systems has significantly facilitated the administration, submission and review process compared to traditional paper-based ones. However, it is crucial that these systems have strong resistance against Web attacks as they involve confidential data and privacy. Some submissions could be leading edge breakthroughs that authors do not wish to leak out and be subtly plagiarized. Also, security of the employed system will attract more submissions to conferences that use it and gives confidence of the quality that the conferences uphold. In this paper, we analyze the security of the Web-Submission-and-Review (WSaR) software - latest version 0.53 beta at the time of writing; developed by Shai Halevi from IBM Research. WSaR is currently in use by top cryptology conferences including Eurocrypt 2007 & 2008, Crypto 2007, and Asiacrypt 2007, annually sponsored by the International Association for Cryptologic Research (IACR). We present detailed analysis on WSaR's security features. In particular, we first discuss the desirable security features that are designed into WSaR and what attacks these features defend against. Then, we discuss how some untreated security issues may lead to problems, and we show how to enhance WSaR security features to take these issues into consideration. Our results are the first known careful analysis of WSaR, or any type of online submission system for that matter
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