185 research outputs found

    Automating Content Analysis of Video Games

    Get PDF
    Content analysis of video games tends to be an extremely arduous task, involving the collection of a very large quantity of data and statistics detailing the experiences of gameplay. Nevertheless, it is an important process that supports many business, policy, social, and scholarly activities related to the games industry. Consequently, supports are clearly necessary to facilitate content analysis procedures for video games. This paper discusses an innovative approach to automating content analysis for video games through the use of software instrumentation. By properly instrumenting video game software to enable data collection and processing, content analysis procedures can be either partially or fully automated, depending on the game in question. This paper discusses our overall approach to automation, as well as our experiences to date with Epic’s Unreal Engine. Sample results from initial experiments conducted so far are also presented. These results have been quite positive, demonstrating great promise for continued work in this area

    A Digital Alkali Spin Maser

    Full text link
    Self-oscillating atomic magnetometers, in which the precession of atomic spins in a magnetic field is driven by resonant modulation, offer high sensitivity and dynamic range. Phase-coherent feedback from the detected signal to the applied modulation creates a resonant spin maser system, highly responsive to changes in the background magnetic field. Here we show a system in which the phase condition for resonant precession is met by digital signal processing integrated into the maser feedback loop. This system uses a modest chip-scale laser and mass-produced dual-pass caesium vapour cell and operates in a 50 microtesla field, making it a suitable technology for portable measurements of the geophysical magnetic field. We demonstrate a Cramer-Rao lower bound-limited resolution of 50 fT at 1 s sampling cadence, and a sensor bandwidth of 10 kHz. This device also represents an important class of atomic system in which low-latency digital processing forms an integral part of a coherently-driven quantum system.Comment: 12 pages, 5 figure

    Micro-fabricated caesium vapour cell with 5mm optical path length

    Get PDF
    Micro-fabricated vapour cells have applications in a number of emerging quantum technology based devices including miniaturized atomic magnetometers, atomic clocks and frequency references for laser systems. Increasing the cell optical path length (OPL) and smallest cell dimension is normally desirable to increase the signal to noise ratio (SNR) and minimize the de-polarization rate due to collisions between atomic or molecular species and the cell walls. This paper presents a fully wafer-level scalable fabrication process to manufacture vapour cells with dimensions approaching those of glass-blown cells. The fabrication process is described and spectroscopic measurements (optical absorption and magnetic resonance) are reported. A magnetic resonance linewidth of 350 Hz is demonstrated, this is the smallest linewidth reported to date for a micro-fabricated vapour cell

    Free-induction-decay magnetometer with enhanced optical pumping

    Get PDF
    Spin preparation prior to a free-induction-decay (FID) measurement can be adversely affected by transverse bias fields, particularly in the geophysical field range. A strategy that enhances the spin polarization accumulated before readout is demonstrated, by synchronizing optical pumping with a magnetic field pulse that supersedes any transverse fields by over two order of magnitude. The pulsed magnetic field is generated along the optical pumping axis using a compact electromagnetic coil pair encompassing a micro-electromechanical systems (MEMS) vapor cell. The coils also resistively heat the cesium (Cs) vapor to the optimal atomic density without spurious magnetic field contributions as they are rapidly demagnetized to approximately zero field during spin readout. The demagnetization process is analyzed electronically, and directly with a FID measurement, to confirm that the residual magnetic field is minimal during detection. The sensitivity performance of this technique is compared to existing optical pumping modalities across a wide magnetic field range. A noise floor sensitivity of 238fT/Hz238\,\mathrm{fT/\surd{Hz}} was achieved in a field of approximately 50μT\mathrm{50\,\mu{T}}, in close agreement with the Cram\'{e}r-Rao lower bound (CRLB) predicted noise density of 258fT/Hz258\,\mathrm{fT/\surd{Hz}}.Comment: 10 pages, 7 figure

    Prey Records for the Eastern Indigo Snake (Drymarchon couperi)

    Get PDF
    Prey items for the federally protected Eastern Indigo Snake (Drymarchon couperi) were compiled from published and gray literature, field observations, necropsies, dissection of museum specimens, and personal communications from reliable sources. One hundred and eighty-six records were obtained for 48 different prey species. Anurans, Gopher Tortoises, snakes, and rodents comprised ca. 85% of the prey items. Most records (n = 143) that mentioned size were from adult indigos; 17 were from juveniles. Prey records were collected from 1940-2008 and were available for all months of the year. These data confirm that Eastern Indigo Snakes eat a wide assortment of prey of varying sizes. This strategy allows D. couperi to potentially forage successfully in many different types of habitats and under fluctuating environmental conditions, a valuable trait for a top-level predator that requires a large home range

    Pleasure and meaningful discourse: an overview of research issues

    Get PDF
    The concept of pleasure has emerged as a multi-faceted social and cultural phenomenon in studies of media audiences since the 1980s. In these studies different forms of pleasure have been identified as explaining audience activity and commitment. In the diverse studies pleasure has emerged as a multi-faceted social and cultural concept that needs to be contextualized carefully. Genre and genre variations, class, gender, (sub-)cultural identity and generation all seem to be instrumental in determining the kind and variety of pleasures experienced in the act of viewing. This body of research has undoubtedly contributed to a better understanding of the complexity of audience activities, but it is exactly the diversity of the concept that is puzzling and poses a challenge to its further use. If pleasure is maintained as a key concept in audience analysis that holds much explanatory power, it needs a stronger theoretical foundation. The article maps the ways in which the concept of pleasure has been used by cultural theorists, who have paved the way for its application in reception analysis, and it goes on to explore the ways in which the concept has been used in empirical studies. Central to our discussion is the division between the ‘public knowledge’ and the ‘popular culture’ projects in reception analysis which, we argue, have major implications for the way in which pleasure has come to be understood as divorced from politics, power and ideology. Finally, we suggest ways of bridging the gap between these two projects in an effort to link pleasure to the concepts of hegemony and ideology

    Optical pumping enhancement of a free-induction-decay magnetometer

    Get PDF
    Spin preparation prior to a free-induction-decay (FID) measurement can be adversely affected by transverse bias fields, particularly in the geophysical field range. A strategy that enhances the spin polarization accumulated before readout is demonstrated, by synchronizing optical pumping with a magnetic field pulse that supersedes any transverse fields by over two order of magnitude. The pulsed magnetic field is generated along the optical pumping axis using a compact electromagnetic coil pair encompassing a micro-electromechanical systems (MEMS) vapor cell. The coils also resistively heat the cesium (Cs) vapor to the optimal atomic density without spurious magnetic field contributions as they are rapidly demagnetized to approximately zero field during spin readout. The demagnetization process is analyzed electronically, and directly with a FID measurement, to confirm that the residual magnetic field is minimal during detection. The sensitivity performance of this technique is compared to existing optical pumping modalities across a wide magnetic field range. A noise floor sensitivity of 238 fT/√Hz was achieved in a field of approximately 50 μT, in close agreement with the Cramér-Rao lower bound (CRLB) predicted noise density of 258 fT/√Hz

    ChePep Controls Helicobacter pylori Infection of the Gastric Glands and Chemotaxis in the Epsilonproteobacteria

    Get PDF
    Microbes use directed motility to colonize harsh and dynamic environments. We discovered that Helicobacter pylori strains establish bacterial colonies deep in the gastric glands and identified a novel protein, ChePep, necessary to colonize this niche. ChePep is preferentially localized to the flagellar pole. Although mutants lacking ChePep have normal flagellar ultrastructure and are motile, they have a slight defect in swarming ability. By tracking the movement of single bacteria, we found that ∆ChePep mutants cannot control the rotation of their flagella and swim with abnormally frequent reversals. These mutants even sustain bursts of movement backwards with the flagella pulling the bacteria. Genetic analysis of the chemotaxis signaling pathway shows that ChePep regulates flagellar rotation through the chemotaxis system. By examining H. pylori within a microscopic pH gradient, we determined that ChePep is critical for regulating chemotactic behavior. The chePep gene is unique to the Epsilonproteobacteria but is found throughout this diverse group. We expressed ChePep from other members of the Epsilonproteobacteria, including the zoonotic pathogen Campylobacter jejuni and the deep sea hydrothermal vent inhabitant Caminibacter mediatlanticus, in H. pylori and found that ChePep is functionally conserved across this class. ChePep represents a new family of chemotaxis regulators unique to the Epsilonproteobacteria and illustrates the different strategies that microbes have evolved to control motility

    Pushdown automata in statistical machine translation

    Get PDF
    This article describes the use of pushdown automata (PDA) in the context of statistical machine translation and alignment under a synchronous context-free grammar. We use PDAs to compactly represent the space of candidate translations generated by the grammar when applied to an input sentence. General-purpose PDA algorithms for replacement, composition, shortest path, and expansion are presented. We describe HiPDT, a hierarchical phrase-based decoder using the PDA representation and these algorithms. We contrast the complexity of this decoder with a decoder based on a finite state automata representation, showing that PDAs provide a more suitable framework to achieve exact decoding for larger synchronous context-free grammars and smaller language models. We assess this experimentally on a large-scale Chinese-to-English alignment and translation task. In translation, we propose a two-pass decoding strategy involving a weaker language model in the first-pass to address the results of PDA complexity analysis. We study in depth the experimental conditions and tradeoffs in which HiPDT can achieve state-of-the-art performance for large-scale SMT. </jats:p
    corecore