510,934 research outputs found

    Nucleon Polarizabilities

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    The subject of nucleon polarizabilities in real, virtual, and doubly virtual Compton scattering is discussed with respect to what is known and how such quantities can be extracted from data.Comment: 13 page Latex file; Talk given at Chiral Dynamics 2000 Workshop, Jefferson Lab, July 200

    +SPACES: Serious Games for Role-Playing Government Policies

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    The paper explores how role-play simulations can be used to support policy discussion and refinement in virtual worlds. Although the work described is set primarily within the context of policy formulation for government, the lessons learnt are applicable to online learning and collaboration within virtual environments. The paper describes how the +Spaces project is using both 2D and 3D virtual spaces to engage with citizens to explore issues relevant to new government policies. It also focuses on the most challenging part of the project, which is to provide environments that can simulate some of the complexities of real life. Some examples of different approaches to simulation in virtual spaces are provided and the issues associated with them are further examined. We conclude that the use of role-play simulations seem to offer the most benefits in terms of providing a generalizable framework for citizens to engage with real issues arising from future policy decisions. Role-plays have also been shown to be a useful tool for engaging learners in the complexities of real-world issues, often generating insights which would not be possible using more conventional techniques

    Agent Street: An Environment for Exploring Agent-Based Models in Second Life

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    Urban models can be seen on a continuum between iconic and symbolic. Generally speaking, iconic models are physical versions of the real world at some scaled down representation, while symbolic models represent the system in terms of the way they function replacing the physical or material system by some logical and/or mathematical formulae. Traditionally iconic and symbolic models were distinct classes of model but due to the rise of digital computing the distinction between the two is becoming blurred, with symbolic models being embedded into iconic models. However, such models tend to be single user. This paper demonstrates how 3D symbolic models in the form of agent-based simulations can be embedded into iconic models using the multi-user virtual world of Second Life. Furthermore, the paper demonstrates Second Life\'s potential for social science simulation. To demonstrate this, we first introduce Second Life and provide two exemplar models; Conway\'s Game of Life, and Schelling\'s Segregation Model which highlight how symbolic models can be viewed in an iconic environment. We then present a simple pedestrian evacuation model which merges the iconic and symbolic together and extends the model to directly incorporate avatars and agents in the same environment illustrating how \'real\' participants can influence simulation outcomes. Such examples demonstrate the potential for creating highly visual, immersive, interactive agent-based models for social scientists in multi-user real time virtual worlds. The paper concludes with some final comments on problems with representing models in current virtual worlds and future avenues of research.Agent-Based Modelling, Pedestrian Evacuation, Segregation, Virtual Worlds, Second Life

    How to upload a physical state to the correlation space

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    In the framework of the computational tensor network [D. Gross and J. Eisert, Phys. Rev. Lett. {\bf98}, 220503 (2007)], the quantum computation is performed in a virtual linear space which is called the correlation space. It was recently shown [J. M. Cai, W, D\"ur, M. Van den Nest, A. Miyake, and H. J. Briegel, Phys. Rev. Lett. {\bf103}, 050503 (2009)] that a state in the correlation space can be downloaded to the real physical space. In this letter, conversely, we study how to upload a state from a real physical space to the correlation space being motivated by the virtual-real hybrid quantum information processing. After showing the impossibility of the cloning of a state between the real physical space and the correlation space, we propose a simple teleportation-like method of the upload. Applications of this method also enable the Gottesman-Chuang gate teleportation trick and the entanglement swapping in the virtual-real hybrid setting. Furthermore, compared with the inverse of the downloading method by Cai, et. al., which also works as the upload, our uploading method has several advantages.Comment: 8 pages, 4 figure

    Social movements in world of warcraft

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    Virtual worlds provide new forms of social interaction. They offer alternative spaces where social functions can be carried out in online three-dimensional virtual environments. In this paper we explore how collective action on a global scale is enabled by these virtual worlds. We used qualitative research to examine the organization of one social movement in World of Warcraft (WoW), the most widely used massively multiplayer online role playing game in the world. Using New Social Movement Theory, our paper suggests that there are a number of differences between real world and virtual world social movements, namely in their (a) locality, (b) issues, (c) periods of activity, (d) hierarchies, and (e) membership

    The photon: A virtual reality

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    It has been observed that every photon is, in a sense, virtual - being emitted and then sooner or later absorbed. As the motif of a quantum radiation state, the photon shares these characteristics of any virtual state: that it is not directly observable; and that it can signify only one of a number of indeterminable intermediates, between matter states that are directly measurable. Nonetheless, other traits of real and virtual behavior are usually quite clearly differentiable. How 'real', then, is the photon? To address this and related questions it is helpful to look in detail at the quantum description of light emission and absorption. A straightforward analysis of the dynamic electric field, based on quantum electrodynamics, reveals not only the entanglement of energy transfer mechanisms usually regarded as 'radiative' and 'radiation less'; it also gives significant physical insights into several other electromagnetic topics. These include: the propagating and non-propagating character in electromagnetic fields; near-zone and wave-zone effects; transverse and longitudinal character; the effects of retardation, manifestations of quantum uncertainty and issues of photon spin. As a result it is possible to gain a clearer perspective on when, or whether, the terms 'real' and 'virtual' are helpful descriptors of the photon

    The effects of viewpoint on the virtual space of pictures

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    Pictorial displays whose primary purpose is to convey accurate information about the 3-D spatial layout of an environment are discussed. How and how well, pictures can convey such information is discussed. It is suggested that picture perception is not best approached as a unitary, indivisible process. Rather, it is a complex process depending on multiple, partially redundant, interacting sources of visual information for both the real surface of the picture and the virtual space beyond. Each picture must be assessed for the particular information that it makes available. This will determine how accurately the virtual space represented by the picture is seen, as well as how it is distorted when seen from the wrong viewpoint
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