39 research outputs found
Scripting human animations in a virtual environment
The current deficiencies of virtual environment (VE) are well known: annoying lag time in drawing the current view, drastically simplified environments to reduce that time lag, low resolution and narrow field of view. Animation scripting is an application of VE technology which can be carried out successfully despite these deficiencies. The final product is a smoothly moving high resolution animation displaying detailed models. In this system, the user is represented by a human computer model with the same body proportions. Using magnetic tracking, the motions of the model's upper torso, head and arms are controlled by the user's movements (18 degrees of freedom). The model's lower torso and global position and orientation are controlled by a spaceball and keypad (12 degrees of freedom). Using this system human motion scripts can be extracted from the user's movements while immersed in a simplified virtual environment. Recorded data is used to define key frames; motion is interpolated between them and post processing adds a more detailed environment. The result is a considerable savings in time and a much more natural-looking movement of a human figure in a smooth and seamless animation
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Integrating software architectures for distributed simulations and simulation analysis communities.
The one-year Software Architecture LDRD (No.79819) was a cross-site effort between Sandia California and Sandia New Mexico. The purpose of this research was to further develop and demonstrate integrating software architecture frameworks for distributed simulation and distributed collaboration in the homeland security domain. The integrated frameworks were initially developed through the Weapons of Mass Destruction Decision Analysis Center (WMD-DAC), sited at SNL/CA, and the National Infrastructure Simulation & Analysis Center (NISAC), sited at SNL/NM. The primary deliverable was a demonstration of both a federation of distributed simulations and a federation of distributed collaborative simulation analysis communities in the context of the same integrated scenario, which was the release of smallpox in San Diego, California. To our knowledge this was the first time such a combination of federations under a single scenario has ever been demonstrated. A secondary deliverable was the creation of the standalone GroupMeld{trademark} collaboration client, which uses the GroupMeld{trademark} synchronous collaboration framework. In addition, a small pilot experiment that used both integrating frameworks allowed a greater range of crisis management options to be performed and evaluated than would have been possible without the use of the frameworks
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Parallel computing in enterprise modeling.
This report presents the results of our efforts to apply high-performance computing to entity-based simulations with a multi-use plugin for parallel computing. We use the term 'Entity-based simulation' to describe a class of simulation which includes both discrete event simulation and agent based simulation. What simulations of this class share, and what differs from more traditional models, is that the result sought is emergent from a large number of contributing entities. Logistic, economic and social simulations are members of this class where things or people are organized or self-organize to produce a solution. Entity-based problems never have an a priori ergodic principle that will greatly simplify calculations. Because the results of entity-based simulations can only be realized at scale, scalable computing is de rigueur for large problems. Having said that, the absence of a spatial organizing principal makes the decomposition of the problem onto processors problematic. In addition, practitioners in this domain commonly use the Java programming language which presents its own problems in a high-performance setting. The plugin we have developed, called the Parallel Particle Data Model, overcomes both of these obstacles and is now being used by two Sandia frameworks: the Decision Analysis Center, and the Seldon social simulation facility. While the ability to engage U.S.-sized problems is now available to the Decision Analysis Center, this plugin is central to the success of Seldon. Because Seldon relies on computationally intensive cognitive sub-models, this work is necessary to achieve the scale necessary for realistic results. With the recent upheavals in the financial markets, and the inscrutability of terrorist activity, this simulation domain will likely need a capability with ever greater fidelity. High-performance computing will play an important part in enabling that greater fidelity
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Mathematical approaches for complexity/predictivity trade-offs in complex system models : LDRD final report.
The goal of this research was to examine foundational methods, both computational and theoretical, that can improve the veracity of entity-based complex system models and increase confidence in their predictions for emergent behavior. The strategy was to seek insight and guidance from simplified yet realistic models, such as cellular automata and Boolean networks, whose properties can be generalized to production entity-based simulations. We have explored the usefulness of renormalization-group methods for finding reduced models of such idealized complex systems. We have prototyped representative models that are both tractable and relevant to Sandia mission applications, and quantified the effect of computational renormalization on the predictive accuracy of these models, finding good predictivity from renormalized versions of cellular automata and Boolean networks. Furthermore, we have theoretically analyzed the robustness properties of certain Boolean networks, relevant for characterizing organic behavior, and obtained precise mathematical constraints on systems that are robust to failures. In combination, our results provide important guidance for more rigorous construction of entity-based models, which currently are often devised in an ad-hoc manner. Our results can also help in designing complex systems with the goal of predictable behavior, e.g., for cybersecurity
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Robust message routing for mobile (wireless) ad hoc networks.
This report describes the results of research targeting improvements in the robustness of message transport in wireless ad hoc networks. The first section of the report provides an analysis of throughput and latency in the wireless medium access control (MAC) layer and relates the analysis to the commonly used 802.11 protocol. The second section describes enhancements made to several existing models of wireless MAC and ad hoc routing protocols; the models were used in support of the work described in the following section. The third section of the report presents a lightweight transport layer protocol that is superior to TCP for use in wireless networks. In addition, it introduces techniques that improve the performance of any ad hoc source routing protocol. The fourth section presents a novel, highly scalable ad hoc routing protocol that is based on geographic principles but requires no localization hardware
Effect of Dam Emplacement and Water Level Changes on Sublacustrine Geomorphology and Recent Sedimentation in Jackson Lake, Grand Teton National Park (Wyoming, United States)
Dam installation on a deep hydrologically open lake provides the experimental framework necessary to study the influence of outlet engineering and changing base levels on limnogeological processes. Here, high-resolution seismic reflection profiles, sediment cores, and historical water level elevation datasets were employed to assess the recent depositional history of Jackson Lake, a dammed glacial lake located adjacent to the Teton fault in western Wyoming (USA). Prograding clinoforms imaged in the shallow stratigraphy indicate a recent lake-wide episode of delta abandonment. Submerged âź11â12Â m below the lake surface, these Gilbert-type paleo-deltas represent extensive submerged coarse-grained deposits along the axial and lateral margins of Jackson Lake that resulted from shoreline transgression following dam construction in the early 20th century. Other paleo-lake margin environments, including delta plain, shoreline, and glacial (drumlins, moraines) landforms were likewise inundated following dam installation, and now form prominent features on the lake floor. In deepwater, a detailed chronology was established using 137Cs, 210Pb, and reservoir-corrected 14C for a sediment core that spans âź1654â2019 Common Era (CE). Dam emplacement (1908â1916 CE) correlates with a nearly five-fold acceleration in accumulation rates and a depositional shift towards carbonaceous sediments. Interbedded organic-rich black diatomaceous oozes and tan silts track changes in reservoir water level elevation, which oscillated in response to regional climate and downstream water needs between 1908 and 2019 CE. Chemostratigraphic patterns of carbon, phosphorus, and sulfur are consistent with a change in nutrient status and productivity, controlled initially by transgression-driven flooding of supralittoral soils and vegetation, and subsequently with water level changes. A thin gravity flow deposit punctuates the deepwater strata and provides a benchmark for turbidite characterization driven by hydroclimate change. Because the Teton fault is a major seismic hazard, end-member characterization of turbidites is a critical first step for accurate discrimination of mass transport deposits controlled by earthquakes in more ancient Jackson Lake strata. Results from this study illustrate the influence of dam installation on sublacustrine geomorphology and sedimentation, which has implications for lake management and ecosystem services. Further, this study demonstrates that Jackson Lake contains an expanded, untapped sedimentary archive recording environmental changes in the American West
Characterization of MHC-I in the blue tit (Cyanistes caeruleus) reveals low levels of genetic diversity and trans-population evolution across European populations
The major histcompatibility complex (MHC) is a vital component of the adaptive immune system in all vertebrates. This study is the first to characterize MHC class I (MHC-I) in blue tits (Cyanistes caeruleus), and we use MHC-I exon 3 sequence data from individuals originating from three locations across Europe: Spain, the Netherlands to Sweden. Our phylogeny of the 17 blue tit MHC-I alleles contains one allele cluster with low nucleotide diversity compared to the remaining more diverse alleles. We found a significant evidence for balancing selection in the peptide-binding region in the diverse allele group only. No separation according to geographic location was found in the phylogeny of alleles. Although the number of MHC-I loci of the blue tit is comparable to that of other passerine species, the nucleotide diversity of MHC-I appears to be much lower than that of other passerine species, including the closely related great tit (Parus major) and the severely inbred Seychelles warbler (Acrocephalus sechellensis). We believe that this initial MHC-I characterization in blue tits provides an important step towards understanding the mechanisms shaping MHC-I diversity in natural populations
Toward a real-time computational analysis middleware for scientific observation that employ sensor & mobile networks
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Toward a real-time computational analysis middleware for scientific observation that employ sensor & mobile networks
EThOS - Electronic Theses Online ServiceGBUnited Kingdo