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Technology-mediated language learning today encompasses multifaceted issues connected with the role of digital technologies in mediating opportunities for language learning. Such opportunities arrive when teachers assign digital learning materials and tasks in a face-to-face classroom, when language programmes develop online courses that include computer-mediated interactions, and when language learners seek opportunities for study, help, and social interactions on their own. Each of these three uses of technology has arisen within a particular milieu of research and practice in applied linguistics. However, today the three intersect in dynamic and complex ways. Moreover, the areas and their intersections converge with aspects of second language studies including instructed second language acquisition, language assessment, learner autonomy and motivation, as well as informal language learning. This chapter examines the practices, issues, findings, and challenges in each of these three interconnected areas, beginning with the classroom, where the study of computer-assisted language learning has its roots in the middle of the twentieth century.
We address the issue of parameter variations in POD approximations of time-dependent
problems, without any specific restriction on the form of parameter dependence.
Considering a parabolic model problem, we propose a POD construction strategy allowing us
to obtain some a priori error estimates controlled by the POD remainder –
in the construction procedure – and some parameter-wise interpolation errors for the model
solutions. We provide a thorough numerical assessment of this strategy with the
FitzHugh − Nagumo 1D model. Finally, we give detailed illustrations of the approach in two
parameter estimation applications, the first in a variational estimation framework with
the FitzHugh − Nagumo model, and the second with a beating heart mechanical model for
which we employ a sequential estimation method to characterize model parameters using real
image data in a clinical case.
With the aim of summarizing years of research comparing pedagogies for second/foreign language teaching supported with computer technology and pedagogy not-supported by computer technology, a meta-analysis was conducted of empirical research investigating language outcomes. Thirty-seven studies yielding 52 effect sizes were included, following a search of literature from 1970 to 2006 and screening of studies based on stated criteria. The differences in research designs required subdivision of studies, but overall results favored the technology-supported pedagogy, with a small, but positive and statistically significant effect size. Second/foreign language instruction supported by computer technology was found to be at least as effective as instruction without technology, and in studies using rigorous research designs the CALL groups outperformed the non-CALL groups. The analyses of instructional conditions, characteristics of participants, and conditions of the research design did not provide reliable results because of the small number of effect sizes representing each group. The meta-analysis results provide an empirically-based response to the questions of whether or not technology-supported pedagogies enhance language learning, and the process of conducting the meta-analysis pointed to areas in research methodology that would benefit from attention in future research.
We propose a numerical analysis of proper orthogonal decomposition (POD) model reductions in which a priori error estimates are expressed in terms of the projection errors that are controlled in the construction of POD bases. These error estimates are derived for generic parabolic evolution PDEs, including with non-linear Lipschitz right-hand sides, and for wave-like equations. A specific projection continuity norm appears in the estimates and – whereas a general uniform continuity bound seems out of reach – we prove that such a bound holds in a variety of Galerkin bases choices. Furthermore, we directly numerically assess this bound – and the effectiveness of the POD approach altogether – for test problems of the type considered in the numerical analysis, and also for more complex equations. Namely, the numerical assessment includes a parabolic equation with super-linear reaction terms, inspired from the FitzHugh-Nagumo electrophysiology model, and a 3D biomechanical heart model. This shows that the effectiveness established for the simpler models is also achieved in the reduced-order simulation of these highly complex systems.
We propose a general reduced-order filtering strategy adapted to Unscented Kalman Filtering for any choice of sampling points distribution. This provides tractable filtering algorithms which can be used with large-dimensional systems when the uncertainty space is of reduced size, and these algorithms only invoke the original dynamical and observation operators, namely, they do not require tangent operator computations, which of course is of considerable benefit when nonlinear operators are considered. The algorithms are derived in discrete time as in the classical UKF formalism – well-adapted to time discretized dynamical equations – and then extended into consistent continuous-time versions. This reduced-order filtering approach can be used in particular for the estimation of parameters in large dynamical systems arising from the discretization of partial differential equations, when state estimation can be handled by an adequate Luenberger observer inspired from feedback control. In this case, we give an analysis of the joint state-parameter estimation procedure based on linearized error, and we illustrate the effectiveness of the approach using a test problem inspired from cardiac biomechanics.
THE PACE OF TECHNOLOGICAL EVOLUTION has accelerated rapidly over time. In the beginning, human beings survived for 300,000 years by fashioning flint into tools used for hunting, preparing food, and building shelters. For another 10,000 years, metal tools primarily served the same purpose. The Industrial Revolution in Germany began more than 200 years ago sometime during the long reign of metal tools, marking in earnest the beginning of the relationship between humans and machines that continues to this day. Most recently, human-computer interaction, a refined version of human and machine interaction, has become the identifying characteristic of the information age — a fledgling and brief era compared with the long run simple hand tools have enjoyed, but also one marked by rapid growth. For example, on June 23, 2008, the world took note of the sale of the one billionth computer. It took more than fifty years to reach that milestone. By contrast, according to a BBC News report, the two billionth computer will be sold in the year 2014. Given that Germany ranks number four on the list of number of in-use computers in the world, Germans are not strangers to the effects of this rapid technological acceleration.
This astonishing growth rate, coupled with the remarkable capabilities of information technology (IT), has allowed denizens of the information age to co-opt the word “technology” in the seemingly exclusive service of the world of computing.
This paper argues that the vertical spread of computer-assisted language learning (CALL), i.e., a spread throughout language materials and curricula, makes it difficult to draw a clear distinction between CALL and other language materials. In view of the emphasis that teachers, researchers, and administrators have placed on evaluating CALL, I argue that some valuable lessons about materials evaluation can be drawn from reflection on issues in CALL evaluation. In particular, I discuss the opportunities for professionals to reconsider assumptions held about comparative research, draw upon research perspectives and methods from applied linguistics in materials evaluation, and include critical perspectives which examine the opportunities that materials offer language learners to engage in language and culture learning.
Les cellules souches mésenchymateuses (CSM) sont présentes dans divers tissus de l’organisme adulte dont la moelle osseuse. In vitro, les CSM peuvent se différencier en de nombreux types cellulaires du mésoderme, de l’endoderme et de l’ectoderme ; in vivo, elles ont la capacité de migrer vers un organe lésé. Il existe cependant peu d’informations sur le devenir et le potentiel thérapeutique lors de l’injection de ces cellules souches dans un organisme ayant subit une irradiation accidentelle ou thérapeutique. Nos travaux ont permis de mettre en évidence la répartition spatiale et le taux de prise de greffe des CSM injectées par voie intraveineuse (IV) dans un organisme en fonction de la configuration pour une irradiation gamma. Les CSM ont été isolées à partir de moelle osseuse humaine (CSMh) et injectées à des souris immunodéficientes 24 heures après irradiation. Nous avons mis au point trois types de configurations, une configuration d’irradiation corps entier (ICE) à une dose sublétale de 3,5 Gy et deux configurations d’irradiations localisées, pour lesquelles les souris reçoivent une dose locale totale de 8 Gy au niveau de l’abdomen ou de 30 Gy au niveau de la patte droite postérieure. Le taux d’implantation des CSMh dans les différents organes de l’organisme 15 jours après irradiation a été quantifié par amplification du gène humain de la bêta-Globine par PCR. Puis leur localisation in situ a été mise en évidence par marquage immuno-histochimique de la bêta-2-microglobuline humaine sur des sections d’organes murins possédant de l’ADN humain. En absence d’irradiation, les CSMh ont été détectées en très faible quantité. En revanche, le taux de CSMh implantées est plus important au niveau des zones irradiées à forte dose, suggérant que la colonisation des CSMh dans les tissus après irradiation est dépendante de la configuration d’irradiation. L’implantation des CSMh dans les organes n’appartenant pas aux zones surexposées évoque un état inflammatoire généralisé radio-induit. Cette observation met en avant l’existence d’un effet à distance (abscopal) des atteintes tissulaires locales radio-induites. L’ensemble de nos résultats suggère que la thérapie cellulaire par les CSM pourrait être utilisée pour la régénération des tissus normaux lésés suite à une irradiation accidentelle ou chez les patients soumis à une radiothérapie.
Computer technology provides learners with new and varied options for language learning through interactive tasks delivered through CD-ROMs, Web pages, and communications software on the Internet. Researchers need to reconsider any approach to second language acquisition (SLA) concerned with explaining how language development is prompted by exposure to the target language in view of the dramatic differences in language experience learners engage in due to computer technology. Virtually all theories are concerned with the role of linguistic input or the environment (VanPatten & Williams, 2007), and therefore technology needs to be considered.
De nombreuses études suggèrent que les cellules souches adultes et plus particulièrement les cellules souches Mésenchymateuses humaines (CSMh) pourraient être utilisées pour réparer de nombreux organes. Nous avons étudié la capacité des CSMh à réduire les lésions cutanées radio induite. Pour induire des lésions sévères de la peau, des souris NOD/SCID ont été irradiées au niveau de la patte droite postérieure (30 Gy, débit 2,7 Gy/mn) en utilisant une source gamma au 60Co. Les CSMh ont été injectées 24 heures après irradiation par voie intraveineuse. La présence de cellules humaines, la sévérité des lésions et les processus de cicatrisation ont été étudiés sur les échantillons de peau prélevés de 3 à 8 semaines après irradiation. Nous avons pu observer que chez les souris greffées avec des CSMh, le niveau d’atteinte cutanée radio induite est significativement plus faible. Les scores cliniques utilisés pour l’étude de l’évolution des lésions cutanées de la peau sont significativement améliorés et une cicatrisation plus rapide est observée en comparaison des souris non injectées. La présence de cellules humaines a pu être détectée par PCR quantitative dans les zones cutanées en cours de cicatrisation. Ces résultats suggèrent premièrement que les CSMh sont capables de coloniser la peau altérée par les rayonnements ionisants et deuxièmement qu’elles accélèrent le processus de réparation de ce tissu limitant ainsi les complications tissulaires radio induites. La greffe de CSMh pourrait être un traitement thérapeutique efficace des phases précoces du syndrome cutané radio induit.
In the previous chapter we argued that teachers, test developers and language-testing researchers need to add to their professional knowledge by learning about how technology is changing the possibilities and realities for language assessment. What are the specific changes implicated by the use of technology in language assessment? We have discussed how technology presents changes that are relevant to the language teacher, language test developer, and language-testing researcher, but in this chapter we will focus specifically on how technology-assisted assessment methods differ from methods available to test developers in the past through paper and pencil, audio/video, and face-to-face oral interviews. We focus on the positive aspects of computer-assisted techniques, and only touch upon some of the problems associated with technology in assessment, a topic we take up more fully in Chapter 3. Our analysis draws on the perspective language-testing researchers have found productive for studying language test methods. From this perspective, it is more informative to consider test methods in terms of specific characteristics that comprise the testing event rather than holistically with terms such as “multiple-choice” or “oral interview” (Bachman, 1990). We begin with a brief discussion of the test method characteristics, and then look at the ways that technology affects each one.
Test method characteristics
Language use is affected by the context in which it takes place. It seems almost too obvious to point out that we use language differently depending upon where we are, whom we are addressing, why we are communicating, what we are communicating about, how we feel about it, and whether we are speaking or writing.
If CALT is different from other forms of testing, should computer-based testing be evaluated against a different set of standards from that used to evaluate other tests? Chapter 3 focused specifically on the potential threats that may limit the validity of inferences and uses of CALT. Such threats have occupied the public's attention, but this chapter takes up the more technical issue of how CALT should be evaluated overall. Surely, an evaluation of the quality of a test should not be centered entirely on the aspects of the test that catch the attention of the informed layperson. This chapter addresses CALT evaluation in view of specific suggestions that have been made by CALT developers. These suggestions in particular and CALT evaluation more generally are discussed from the perspective of the profession's views of how all language tests should be evaluated. It begins with a look at guidelines and advice suggested to promote quality during CALT development and evaluation, and then summarizes research focused on specific aspects of CALT quality. A subsequent section demonstrates the types of findings obtained through the use of Bachman and Palmer's (1996) test usefulness framework. The final part discusses CALT evaluation within more recent perspectives in educational measurement (Kane, 2001) about developing a validity argument through the definition of inferences intended to underlie score interpretation and use. We argue that specific technology-related issues should be placed within a broader framework of test evaluation.
Guidelines and advice
From the time that computer-assisted testing began to be established in the 1970s, the unique set of issues posed by the medium was recognized by educational measurement researchers.