27,115 research outputs found

    Facing the Mirror: Dilemmas and Issues Encountered on a TESOL programme in an International University Environment

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    Abstract: This paper investigates the experiences of three postgraduate students studying on an MA TESOL and Applied Linguistics course in a British university context. It demonstrates how subtle discourses of „ownership‟ of English (Holliday, 2014; Pennycook, 1994, 2001; Kumaravadevelu, 2003) persist in such training contexts, despite the general shift towards internationalizing higher education environments in the UK. The paper will discuss how the participants negotiated the teaching practice components of the course, and the issues they faced through being „non-native‟ speakers of English. It further examines the impact this had on their professional development and self-perceptions of „legitimacy‟ as teachers of English. The different constructs of a TESOL teacher are discussed and the need for a heightened awareness of training needs for teachers across diverse contexts

    Potential shaping and the method of controlled Lagrangians

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    We extend the method of controlled Lagrangians to include potential shaping for complete state-space stabilization of mechanical systems. The method of controlled Lagrangians deals with mechanical systems with symmetry and provides symmetry-preserving kinetic shaping and feedback-controlled dissipation for state-space stabilization in all but the symmetry variables. Potential shaping complements the kinetic shaping by breaking symmetry and stabilizing the remaining state variables. The approach also extends the method of controlled Lagrangians to include a class of mechanical systems without symmetry such as the inverted pendulum on a cart that travels along an incline

    Quantum algorithms for hidden nonlinear structures

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    Attempts to find new quantum algorithms that outperform classical computation have focused primarily on the nonabelian hidden subgroup problem, which generalizes the central problem solved by Shor's factoring algorithm. We suggest an alternative generalization, namely to problems of finding hidden nonlinear structures over finite fields. We give examples of two such problems that can be solved efficiently by a quantum computer, but not by a classical computer. We also give some positive results on the quantum query complexity of finding hidden nonlinear structures.Comment: 13 page

    Use of cohesive elements in fatigue analysis

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    Cohesive laws describe the resistance to incipient separation of material surfaces. A cohesive finite element is formulated on the basis of a particular cohesive law. Cohesive elements are placed at the boundary between adjacent standard volume finite elements to model fatigue damage that leads to fracture at the separation of the element boundaries per the cohesive law. In this work, a cohesive model for fatigue crack initiation is taken to be the irreversible loadingunloading hysteresis that represents fatigue damage occuring due to cyclic loads leading to the initiation of small cracks. Various cohesive laws are reviewed and one is selected that incorporates a hysteretic cyclic loading that accounts for energetic dissipative mechanisms. A mathematical representation is developed based on an exponential effective load-separation cohesive relationship. A three-dimensional cohesive element is defined using this compliance relationship integrated at four points on the mid-surface of the area element. Implementation into finite element software is discussed and particular attention is applied to numerical convergence issues as the inflection point between loading and 'unloading in the cohesive law is encountered. A simple example of a displacementcontrolled fatigue test is presented in a finite element simulation. Comments are made on applications of the method to prediction of fatigue life for engineering structures such as pressure vessels and piping

    Accessing Patient Records in Virtual Healthcare Organisations

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    The ARTEMIS project is developing a semantic web service based P2P interoperability infrastructure for healthcare information systems that will allow healthcare providers to securely share patient records within virtual healthcare organisations. Authorisation decisions to access patient records across organisation boundaries can be very dynamic and must occur within a strict legislative framework. In ARTEMIS we are developing a dynamic authorisation mechanism called PBAC that provides a means of contextual and process oriented access control to enforce healthcare business processes. PBAC demonstrates how healthcare providers can dynamically share patient records for care pathways across organisation boundaries

    High discharge rate characteristics of nickel-cadmium batteries for pulse load filtering

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    Several tests of specially fabricated nickel-cadmium batteries having circular disk type electrodes were considered. These batteries were evaluated as filter elements between a constant current power supply and a five hertz pulsed load demanding approximately twice the power supply current during the load on portion of the cycle. Short tests lasting 10,000 cycles were conducted at up to a 21 C rate and an equivalent energy density of over 40 Joules per pound. In addition, two batteries were subjected to 10 to the 7 charge/discharge cycles, one at a 6.5 C rate and the other at a 13 C rate. Assuming an electrode to battery weight ratio of 0.5, these tests represent an energy density of about 7 and 14 Joules per pound respectively. Energy density, efficiency, capacitance, average voltage, and available capacity were tracked during these tests. After 10 to the 7 cycles, capacity degradation was negligible for one battery and about 20% for the other. Cadmium electrode failure may be the factor limiting lifetime at extremely low depth of discharge cycling. The output was examined and a simple equivalent circuit was proposed

    Measurement of exciton correlations using electrostatic lattices

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    We present a method for determining correlations in a gas of indirect excitons in a semiconductor quantum well structure. The method involves subjecting the excitons to a periodic electrostatic potential that causes modulations of the exciton density and photoluminescence (PL). Experimentally measured amplitudes of energy and intensity modulations of exciton PL serve as an input to a theoretical estimate of the exciton correlation parameter and temperature. We also present a proof-of-principle demonstration of the method for determining the correlation parameter and discuss how its accuracy can be improved.Comment: 10 pages, 11 figure

    Interannual variability of Mars South Polar cap

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    Telescopic data on the twentieth century regressions of Mars' south polar cap were reexamined for evidence of interannual variability. Several regressions, particularly that of 1956, are found to differ significantly from the mean. The possibility of correlations with major dust storms is explored

    A model for a socially-aware mobile tourist recommendation system

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    People, whether for business or pleasure, often travel or visit locations they are unfamiliar with. To overcome this, a mobile tourist recommendation system can be used. This system is able to generate tourist attraction recommendations for a person, based on a number of criteria such as time and location. One criterion often overlooked though, is a person's social environment. This is an important consideration as touring is often done with more than one person. By not considering the other people within a person's social environment, recommendations will only be limited to the preferences of a single person. The purpose of this paper is to propose a model for a mobile tourist guide recommendation system that considers a persons social environment when generating tourist attraction recommendations. This is done by studying other tourist recommendation systems, eliciting key requirements for a socially aware tourist guide system from them, and using these requirements as input for a mobile tourist recommendation system model that can harness a person's social environment when recommending tourist attractions

    Dissipation and Controlled Euler-Poincaré Systems

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    The method of controlled Lagrangians is a technique for stabilizing underactuated mechanical systems which involves modifying a system’s energy and dynamic structure through feedback. These modifications can obscure the effect of physical dissipation in the closed-loop. For example, generic damping can destabilize an equilibrium which is closed-loop stable for a conservative system model. In this paper, we consider the effect of damping on Euler-Poincaré (special reduced Lagrangian) systems which have been stabilized about an equilibrium using the method of controlled Lagrangians. We describe a choice of feed-back dissipation which asymptotically stabilizes a sub-class of controlled Euler-Poincaré systems subject to physical damping. As an example, we consider intermediate axis rotation of a damped rigid body with a single internal rotor
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