Technology-Supported Storytelling (TSST) Strategy in Virtual World for Multicultural Education

Learning culture through stories is an effective way for multicultural education, since stories are one of the most powerful and personal ways that we learn about the world. Storytelling, the process of telling stories, is a form of communication and a universal expression of culture. With the development of technology, storytelling emerges out of diverse ways. This study explores the storytelling in virtual worlds for multicultural education, and devises a Technology-Supported storytelling (TSST) strategy by examining and considering the characteristics of virtual worlds which could be incorporated into the storytelling, and then uses this strategy to teach Korean culture to students with different culture background. With this innovative TSST strategy in virtual world, this study expects to provide a guide to practice for teaching multicultural in digital era

Interstellar MHD Turbulence and Star Formation

This chapter reviews the nature of turbulence in the Galactic interstellar medium (ISM) and its connections to the star formation (SF) process. The ISM is turbulent, magnetized, self-gravitating, and is subject to heating and cooling processes that control its thermodynamic behavior. The turbulence in the warm and hot ionized components of the ISM appears to be trans- or subsonic, and thus to behave nearly incompressibly. However, the neutral warm and cold components are highly compressible, as a consequence of both thermal instability in the atomic gas and of moderately-to-strongly supersonic motions in the roughly isothermal cold atomic and molecular components. Within this context, we discuss: i) the production and statistical distribution of turbulent density fluctuations in both isothermal and polytropic media; ii) the nature of the clumps produced by thermal instability, noting that, contrary to classical ideas, they in general accrete mass from their environment; iii) the density-magnetic field correlation (or lack thereof) in turbulent density fluctuations, as a consequence of the superposition of the different wave modes in the turbulent flow; iv) the evolution of the mass-to-magnetic flux ratio (MFR) in density fluctuations as they are built up by dynamic compressions; v) the formation of cold, dense clouds aided by thermal instability; vi) the expectation that star-forming molecular clouds are likely to be undergoing global gravitational contraction, rather than being near equilibrium, and vii) the regulation of the star formation rate (SFR) in such gravitationally contracting clouds by stellar feedback which, rather than keeping the clouds from collapsing, evaporates and diperses them while they collapse.Comment: 43 pages. Invited chapter for the book "Magnetic Fields in Diffuse Media", edited by Elisabete de Gouveia dal Pino and Alex Lazarian. Revised as per referee's recommendation

Near Mission Operations: Demonstrated Strengths and Weaknesses of a Faster, Better, Cheaper Program

The Near Earth Asteroid Rendezvous (NEAR) Mission was successfully launched on February 17, 1996 from Cape Canaveral Air Force Base. A small mission operations team of 8 to 12 people have controlled the NEAR spacecraft from the JHU/APL campus in Maryland since then, using Deep Space Network ground stations and NASCOM circuitry, a Commercial Off The Shelf (COTS) ground computer system, and a unique streamlined concept of operations. The primary science data gathering portion of the mission will not begin until rendezvous with the asteroid EROS in January 1999, but 3 exciting bonus science observations have already occurred: visible images of the Earth\u27s Moon were taken on mission day 4, passive momentum dumping was demonstrated using solar pressure and small attitude offsets held for long periods of time, and visible images of the comet Hyakutake were taken from 1 million kilometers range on mission day 37. These bonus science observations were made possible by the less-formal concept of operations coupled with a very experienced senior group of people running operations. In the arena of mission operations, the mantra faster, better, cheaper should be discarded and replaced with faster, cheaper, increased risk . No significant failures have occurred in any flight or ground subsystem, and that is fortunate because short-term operational risk was uncomfortably high in the area of contingency readiness. Contingency readiness was limited in scope due to lack of schedule time ( faster ) and man-hours ( cheaper ). No long-term operational risks are expected, but there was a sobering amount of team cross training and software tool development which remained unfinished 30 days after launch. The NEAR mission three year cruise period provides ample time to complete this work: early mission experience with simultaneous operations and software tool development will be discussed

The Commodity Terms of Trade, Unit Roots, and Nonlinear Alternatives: A Smooth Transition Approach

This article extends the recent literature on the Prebisch-Singer hypothesis of a long-run decline in the relative prices of primary commodities. Our main innovation is testing for and estimating nonlinear alternatives to a secular deterioration. Specifically, we use bootstrap procedures to test the linear unit root model against models belonging to the family of smooth transition autoregressions (STARs) for twenty-four commodities, 1900–2003. In nineteen cases we reject the linear null at usual significance levels. In sixteen cases we are able to successfully fit STAR-type models. Simulation results show there is little support for the Prebisch-Singer hypothesis. Copyright 2009, Oxford University Press.

Adding State and Visibility Control to Traits using Lexical Nesting

Traits are reusable building blocks that can be explicitly composed to share methods across unrelated class hierarchies. In their original form, traits do not contain state and cannot express visibility control for methods. Two extensions, stateful traits and freezable traits, have been proposed to overcome these limitations. However, these extensions introduce complexity and have not yet been combined to add both state and visibility control to traits at the same time. This paper revisits the problem of adding state and visibility control to traits. Rather than extending the original traits model with additional operations, we use a fundamentally different approach by allowing traits to be lexically nested within other modules. This enables traits to express (shared) state and visibility control by hiding variables or methods in their lexical scope. Although the Traits’ “flattening property ” no longer holds when traits can be lexically nested, the combination of traits with lexical nesting results in a simple and more expressive trait model. We formally specify the operational semantics of this combination. Lexically nested traits are fully implemented in AmbientTalk, where they are used among others in the development of a Morphic-like UI framework