Tracking in Object Action Space
DEFF Research Database (Denmark)
Krüger, Volker; Herzog, Dennis
2013-01-01
In this paper we focus on the joint problem of tracking humans and recognizing human action in scenarios such as a kitchen scenario or a scenario where a robot cooperates with a human, e.g., for a manufacturing task. In these scenarios, the human directly interacts with objects physically by using...... space of the object affordances, i.e., the space of possible actions that are applied on a given object. This way, 3D body tracking reduces to action tracking in the object (and context) primed parameter space of the object affordances. This reduces the high-dimensional joint-space to a low...
Gauged WZW models for space-time groups and gravitational actions
Mora, Pablo; Pais, Pablo(Centro de Estudios Científicos (CECS), Av. Arturo Prat 514, Valdivia, Chile); Willison, Steven
2011-01-01
In this paper we investigate gauged Wess-Zumino-Witten models for space-time groups as gravitational theories, following the trend of recent work by Anabalon, Willison and Zanelli. We discuss the field equations in any dimension and study in detail the simplest case of two space-time dimensions and gauge group SO(2,1). For this model we study black hole solutions and we calculate their mass and entropy which resulted in a null value for both.
Learning Actions Models: Qualitative Approach
DEFF Research Database (Denmark)
Bolander, Thomas; Gierasimczuk, Nina
2015-01-01
identifiability (conclusively inferring the appropriate action model in finite time) and identifiability in the limit (inconclusive convergence to the right action model). We show that deterministic actions are finitely identifiable, while non-deterministic actions require more learning power......—they are identifiable in the limit.We then move on to a particular learning method, which proceeds via restriction of a space of events within a learning-specific action model. This way of learning closely resembles the well-known update method from dynamic epistemic logic. We introduce several different learning...
Space Science in Action: Space Exploration [Videotape].
1999
In this videotape recording, students learn about the human quest to discover what is out in space. Students see the challenges and benefits of space exploration including the development of rocket science, a look back at the space race, and a history of manned space travel. A special section on the Saturn V rocket gives students insight into the…
Using Continuous Action Spaces to Solve Discrete Problems
van Hasselt, Hado; Wiering, Marco
2009-01-01
Real-world control problems are often modeled as Markov Decision Processes (MDPs) with discrete action spaces to facilitate the use of the many reinforcement learning algorithms that exist to find solutions for such MDPs. For many of these problems an underlying continuous action space can be assume
Action-specific remapping of peripersonal space.
Brozzoli, C; Cardinali, L; Pavani, F; Farnè, A
2010-02-01
Peripersonal space processing in monkeys' brain relies on visuo-tactile neurons activated by objects near, not touching, the animal's skin. Multisensory interplay in peripersonal space is now well documented also in humans, in brain damaged patients presenting cross-modal extinction as well as in healthy subjects and typically takes the form of stronger visuo-tactile interactions in peripersonal than far space. We recently showed in healthy humans the existence of a functional link between voluntary object-oriented actions (Grasping) and the multisensory coding of the space around us (as indexed by visual-tactile interaction). Here, we investigated whether performing different actions towards the same object implies differential modulations of peripersonal space. Healthy subjects were asked to either grasp or point towards a target object. In addition, they discriminated whether tactile stimuli were delivered on their right index finger (up), or thumb (down), while ignoring visual distractors. Visuo-tactile interaction was probed in baseline Static conditions (before the movement) and in dynamic conditions (action onset and execution). Results showed that, compared to the Static baseline both actions similarly strengthened visuo-tactile interaction at the action onset, when Grasping and Pointing were kinematically indistinguishable. Crucially, Grasping induced further enhancement than Pointing in the execution phase, i.e., when the two actions kinematically diverged. These findings reveal that performing actions induce a continuous remapping of the multisensory peripersonal space as a function of on-line sensory-motor requirements, thus supporting the hypothesis of a role for peripersonal space in the motor control of voluntary actions. PMID:19837102
Binding space and time through action.
Binetti, N; Hagura, N; Fadipe, C; Tomassini, A; Walsh, V; Bestmann, S
2015-04-22
Space and time are intimately coupled dimensions in the human brain. Several lines of evidence suggest that space and time are processed by a shared analogue magnitude system. It has been proposed that actions are instrumental in establishing this shared magnitude system. Here we provide evidence in support of this hypothesis, by showing that the interaction between space and time is enhanced when magnitude information is acquired through action. Participants observed increases or decreases in the height of a visual bar (spatial magnitude) while judging whether a simultaneously presented sequence of acoustic tones had accelerated or decelerated (temporal magnitude). In one condition (Action), participants directly controlled the changes in bar height with a hand grip device, whereas in the other (No Action), changes in bar height were externally controlled but matched the spatial/temporal profile of the Action condition. The sign of changes in bar height biased the perceived rate of the tone sequences, where increases in bar height produced apparent increases in tone rate. This effect was amplified when the visual bar was actively controlled in the Action condition, and the strength of the interaction was scaled by the magnitude of the action. Subsequent experiments ruled out that this was simply explained by attentional factors, and additionally showed that a monotonic mapping is also required between grip force and bar height in order to bias the perception of the tones. These data provide support for an instrumental role of action in interfacing spatial and temporal quantities in the brain.
Reinforcement Learning in Continuous Action Spaces
Hasselt, H. van; Wiering, M.A.
2007-01-01
Quite some research has been done on Reinforcement Learning in continuous environments, but the research on problems where the actions can also be chosen from a continuous space is much more limited. We present a new class of algorithms named Continuous Actor Critic Learning Automaton (CACLA) that c
Action recognition by motion detection in posture space.
Theusner, Stefanie; de Lussanet, Marc; Lappe, Markus
2014-01-15
The visual recognition of action can be obtained from the change of body posture over time. Even for point-light stimuli in which the body posture is conveyed by only a few light points, biological motion can be perceived from posture sequence analysis. We present and analyze a formal model of how action recognition may be computed and represented in the brain. This model assumes that motion energy detectors similar to those well-established for the luminance-based motion of objects in space are applied to a cortical representation of body posture. Similar to the spatio-temporal receptive fields of regular motion detectors, these body motion detectors attain receptive fields in a posture-time space. We describe the properties of these receptive fields and compare them with properties of body-sensitive neurons found in the superior temporal sulcus of macaque monkeys. We consider tuning properties for 3D views of static and moving bodies. Our simulations show that key properties of action representation in the STS can directly be explained from the properties of natural action stimuli. Our model also suggests an explanation for the phenomenon of implied motion, the perceptual appearance, and neural activation of motion from static images. PMID:24431449
National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes presentation materials and outputs from operational space environment models produced by the NOAA Space Weather Prediction Center (SWPC) and...
Active Affordance Learning in Continuous State and Action Spaces
Wang, C.; Hindriks, K.V.; Babuska, R.
2014-01-01
Learning object affordances and manipulation skills is essential for developing cognitive service robots. We propose an active affordance learning approach in continuous state and action spaces without manual discretization of states or exploratory motor primitives. During exploration in the action
On quantum semigroup actions on finite quantum spaces
Soltan, Piotr M.
2008-01-01
We show that a continuous action of a quantum semigroup $\\mathcal{S}$ on a finite quantum space (finite dimensional $\\mathrm{C}^*$-algebra) preserving a faithful state comes from a continuous action of the quantum Bohr compactification $\\mathfrak{b}\\mathcal{S}$ of $\\mathcal{S}$. Using the classification of continuous compact quantum group actions on $M_2$ we give a complete description of all continuous quantum semigroup actions on this quantum space preserving a faithful state.
Reinforcement learning in continuous state and action spaces
Hasselt, H. van; Wiering, M.A.; Otterlo, M. van
2012-01-01
Many traditional reinforcement-learning algorithms have been designed for problems with small finite state and action spaces. Learning in such discrete problems can been difficult, due to noise and delayed reinforcements. However, many real-world problems have continuous state or action spaces, whic
Creating Space: Engaging Deliberation about Climate Action
Phear, Nicolette
In the United States public discourse, climate change is often framed as a polarized and intractable issue. The purpose of this dissertation was to explore deliberation about climate action, and to evaluate whether effective responses to climate change can be facilitated through new structures and processes that enable and encourage dialogue on the subject of how to reduce greenhouse gas emissions. Working with sustainability leaders at the University of Montana and in the community of Missoula, Montana, the author convened three public deliberations, in which a variety of solutions to climate change were discussed. Three questions guided this study: 1) what motivated individuals to engage in deliberation about climate action; 2) how did individual engagement vary and affect the quality of the deliberation; and 3) how effective were the deliberations in building a sense of individual agency and generating collaborative action strategies to address climate change. Based on a rigorous statistical analysis of survey responses combined with qualitative data, this action research study offers a holistic exploration of the three deliberative events convened. The deliberative processes generated collaborative action strategies and increased participants' sense of agency to take action on climate change; the findings also revealed differences in the ways individuals engaged and affected the quality of the overall group deliberation. This dissertation contributes to the literature on collaborative responses and collective action on climate change, broadens understanding of deliberative processes, and provides new insight into opportunities for leading deliberation about climate action.
Space for action: How practitioners influence environmental assessment
Energy Technology Data Exchange (ETDEWEB)
Kågström, Mari, E-mail: mari.kagstrom@slu.se [Department of Urban and Rural Development, Swedish University of Agricultural Sciences (Sweden); Richardson, Tim, E-mail: tim.richardson@nmbu.no [Department of Landscape Architecture and Spatial Planning, Norwegian University of Life Sciences, Frederik A Dahls vei 15, KA-bygningen, Ås (Norway)
2015-09-15
Highlights: • The concept of ‘space for action’ offers an important new lens on EA practice. • Focuses on the relation between practitioner's understanding and their actions • Environmental assessment practice is decisively shaped by practitioners. • Practitioners may underestimate their potential to make a difference. • Contributes to understanding change in the environmental assessment field. This article contributes to understanding of how change occurs in the field of environmental assessment (EA). It argues that the integration of new issues in EA, such as human health, is significantly influenced by how practitioners' understandings shape their actions, and by what happens when those, possibly different, interpretations of appropriate action are acted out. The concept of space for action is developed as a means of investigating this relation between understanding and action. Frame theory is also used, to develop a sharper focus on how ‘potential spaces for action’ are created, what these imply for (individuals') preferred choices and actions in certain situations, and what happens in practice when these are acted out and ‘actual spaces for action’ are created. This novel approach is then applied in a Swedish case study of transport planning. The analysis reveals the important work done by practitioners, revealing just how EA practice is decisively shaped by practitioners. Analysis of practice using the lens of spaces for action offers an important new perspective in understanding how the field adapts to new challenges.
Iglesias Turrión, Pablo
2004-01-01
This paper is about the new social movements against the Globalisation. In particular, I will speak about the period between the demonstrations of Seattle (November/December 99) and the demonstrations of Genoa (June 2001) and the sector of movement that have practiced strategies of civil disobedience and conflict with the police forces. In this period, it has been developed a particular new form of collective action that I've called model anti-summit. The relationship with mass media and the ...
Collective action and rationality models
Directory of Open Access Journals (Sweden)
Luis Miguel Miller Moya
2004-01-01
Full Text Available The Olsonian theory of collective action (Olson, 1965 assumes a model of economic rationality, based on a simple calculus between costs and benefits, that can be hardly hold at present, given the models of rationality proposed recently by several fields of research. In relation to these fields, I will concentrate in two specific proposals, namely: evolutionary game theory and, over all, the theory of bounded rationality. Both alternatives are specially fruitful in order to propose models that do not need a maximizing rationality, or environments of complete and perfect information. Their approaches, based on the possibility of individual learning over the time, have contributed to the analysis of the emergence of social norms, which is something really necessary to the resolution of problems related to cooperation. Thus, this article asserts that these two new theoretical contributions make feasible a fundamental advance in the study of collective action.
Action-space coding in social contexts.
Ciardo, Francesca; Lugli, Luisa; Nicoletti, Roberto; Rubichi, Sandro; Iani, Cristina
2016-01-01
In two behavioural experiments we tested whether performing a spatial task along with another agent changes space representation by rendering some reference frames more/less salient than others. To this end, we used a Simon task in which stimuli were presented in four horizontal locations thus allowing for spatial coding according to multiple frames of reference. In Experiment 1 participants performed a go/no-go Simon task along another agent, each being in charge of one response. In Experiment 2 they performed a two-choice Simon task along another agent, each being in charge of two responses. Results showed that when participants were in charge of only one response, stimulus position was coded only with reference to the centre of the screen hence suggesting that the co-actor's response, or the position of the co-actor, was represented and used as a reference for spatial coding. Differently, when participants were in charge of two responses, no effect of the social context emerged and spatial coding relied on multiple frames of reference, similarly to when the Simon task is performed individually. These findings provide insights on the influence played by the interaction between the social context (i.e. the presence of others) and task features on individual performance. PMID:26940396
Unsupervised action classification using space-time link analysis
DEFF Research Database (Denmark)
Liu, Haowei; Feris, Rogerio; Krüger, Volker;
2010-01-01
In this paper we address the problem of unsupervised discovery of action classes in video data. Different from all existing methods thus far proposed for this task, we present a space-time link analysis approach which matches the performance of traditional unsupervised action categorization methods...... in a standard dataset. Our method is inspired by the recent success of link analysis techniques in the image domain. By applying these techniques in the space-time domain, we are able to naturally take into account the spatio-temporal relationships between the video features, while leveraging the power of graph...
On algebraic spaces with an action of G_m
Drinfeld, Vladimir
2013-01-01
Let Z be an algebraic space of finite type over a field, equipped with an action of the multiplicative group $G_m$. In this situation we define and study a certain algebraic space equipped with an unramified morphism to $A^1\\times Z\\times Z$, where $A^1$ is the affine line. (If Z is affine and smooth this is just the closure of the graph of the action map $G_m\\times Z\\to Z$.) In articles joint with D.Gaitsgory we use this set-up to prove a new result in the geometric theory of automorphic for...
Pro-Torus Actions on Poincaré Duality Spaces
Indian Academy of Sciences (India)
Ali Özkurt; Doğan Dönmez
2006-08-01
In this paper, it is shown that some of the results of torus actions on Poincaré duality spaces, Borel’s dimension formula and topological splitting principle to local weights, hold if `torus’ is replaced by `pro-torus’.
Evolution in games with a continuous action space
Veelen, van, C.M.; Spreij, P.
2009-01-01
Allowing for games with a continuous action space, we investigate how evolutionary stability, the existence of a uniform invasion barrier, local superiority and asymptotic stability relate to each other. This is done without restricting the populations of which we want to investigate the stability to monomorphic population states or to strategies with finite support.
Evolution in games with a continuous action space
M. van Veelen; P. Spreij
2009-01-01
Allowing for games with a continuous action space, we investigate how evolutionary stability, the existence of a uniform invasion barrier, local superiority and asymptotic stability relate to each other. This is done without restricting the populations of which we want to investigate the stability t
Schild Action and Space-Time Uncertainty Principle in String Theory
Yoneya, T
1997-01-01
We show that the path-integral quantization of relativistic strings with the Schild action is essentially equivalent to the usual Polyakov quantization at critical space-time dimensions. We then present an interpretation of the Schild action which points towards a derivation of superstring theory as a theory of quantized space-time where the squared string scale, $\\ell_s^2 \\sim \\alpha'$, plays the role of the minimum quantum for space-time areas. A tentative approach towards such a goal is proposed, based on a microcanonical formulation of large N supersymmetric matrix model.
Directory of Open Access Journals (Sweden)
Radivoyevitch Tomas
2009-12-01
Full Text Available Abstract Background Ribonucleotide reductase is the main control point of dNTP production. It has two subunits, R1, and R2 or p53R2. R1 has 5 possible catalytic site states (empty or filled with 1 of 4 NDPs, 5 possible s-site states (empty or filled with ATP, dATP, dTTP or dGTP, 3 possible a-site states (empty or filled with ATP or dATP, perhaps two possible h-site states (empty or filled with ATP, and all of this is folded into an R1 monomer-dimer-tetramer-hexamer equilibrium where R1 j-mers can be bound by variable numbers of R2 or p53R2 dimers. Trillions of RNR complexes are possible as a result. The problem is to determine which are needed in models to explain available data. This problem is intractable for 10 reactants, but it can be solved for 2 and is here for R1 and ATP. Results Thousands of ATP-induced R1 hexamerization models with up to three (s, a and h ATP binding sites per R1 subunit were automatically generated via hypotheses that complete dissociation constants are infinite and/or that binary dissociation constants are equal. To limit the model space size, it was assumed that s-sites are always filled in oligomers and never filled in monomers, and to interpret model terms it was assumed that a-sites fill before h-sites. The models were fitted to published dynamic light scattering data. As the lowest Akaike Information Criterion (AIC of the 3-parameter models was greater than the lowest of the 2-parameter models, only models with up to 3 parameters were fitted. Models with sums of squared errors less than twice the minimum were then partitioned into two groups: those that contained no occupied h-site terms (508 models and those that contained at least one (1580 models. Normalized AIC densities of these two groups of models differed significantly in favor of models that did not include an h-site term (Kolmogorov-Smirnov p -15; consistent with this, 28 of the top 30 models (ranked by AICs did not include an h-site term and 28
Introduction. Modelling natural action selection
Tony J Prescott; Bryson, Joanna J; Seth, Anil K.
2007-01-01
Action selection is the task of resolving conflicts between competing behavioural alternatives. This theme issue is dedicated to advancing our understanding of the behavioural patterns and neural substrates supporting action selection in animals, including humans. The scope of problems investigated includes: (i) whether biological action selection is optimal (and, if so, what is optimized), (ii) the neural substrates for action selection in the vertebrate brain, (iii) the role of perceptual s...
A Note on the Derivation of Wave Action Balance Equation in Frequency Space
Institute of Scientific and Technical Information of China (English)
Tai-Wen HSU; Jian-Ming LIAU; Shin-Jye LIANG; Shan-Hwei OU; Yi-Ting LI
2011-01-01
In this paper the wave action balance equation in terms of frequency-direction spectrum is derived.A theoretical formulation is presented to generate an invariant frequency space to replace the varying wavenumber space through a Jacobian transformation in the wave action balance equation.The physical properties of the Jacobian incorporating the effects of water depths are discussed.The results provide a theoretical basis of wave action balance equations and ensure that the wave balance equations used in the SWAN or other numerical models are correct.It should be noted that the Jacobian is omitted in the wave action balance equations which are identical to a conventional action balance equation.
Vangeneugden, Joris; Pollick, Frank; Vogels, Rufin
2009-03-01
Neurons in the rostral superior temporal sulcus (STS) are responsive to displays of body movements. We employed a parametric action space to determine how similarities among actions are represented by visual temporal neurons and how form and motion information contributes to their responses. The stimulus space consisted of a stick-plus-point-light figure performing arm actions and their blends. Multidimensional scaling showed that the responses of temporal neurons represented the ordinal similarity between these actions. Further tests distinguished neurons responding equally strongly to static presentations and to actions ("snapshot" neurons), from those responding much less strongly to static presentations, but responding well when motion was present ("motion" neurons). The "motion" neurons were predominantly found in the upper bank/fundus of the STS, and "snapshot" neurons in the lower bank of the STS and inferior temporal convexity. Most "motion" neurons showed strong response modulation during the course of an action, thus responding to action kinematics. "Motion" neurons displayed a greater average selectivity for these simple arm actions than did "snapshot" neurons. We suggest that the "motion" neurons code for visual kinematics, whereas the "snapshot" neurons code for form/posture, and that both can contribute to action recognition, in agreement with computation models of action recognition.
Conformal Higher Spin Theory and Twistor Space Actions
Haehnel, Philipp
2016-01-01
We consider the twistor description of conformal higher spin theories and give twistor space actions for the self-dual sector of theories with spin greater than two that produce the correct flat space-time spectrum. We identify a ghost-free subsector, analogous to the embedding of Einstein gravity with cosmological constant in Weyl gravity, which generates the unique spin-s three-point anti-MHV amplitude consistent with Poincare invariance and helicity constraints. By including interactions between the infinite tower of higher-spin fields we give a geometric interpretation to the twistor equations of motion as the integrability condition for a holomorphic structure on an infinite jet bundle. Finally, we introduce anti-self-dual interaction terms to define a twistor action for the full conformal higher spin theory.
Affine and degenerate affine BMW algebras: Actions on tensor space
Daugherty, Zajj; Virk, Rahbar
2012-01-01
The affine and degenerate affine Birman-Murakami-Wenzl (BMW) algebras arise naturally in the context of Schur-Weyl duality for orthogonal and symplectic quantum groups and Lie algebras, respectively. Cyclotomic BMW algebras, affine and cyclotomic Hecke algebras, and their degenerate versions are quotients. In this paper we explain how the affine and degenerate affine BMW algebras are tantalizers (tensor power centralizer algebras) by defining actions of the affine braid group and the degenerate affine braid algebra on tensor space and showing that, in important cases, these actions induce actions of the affine and degenerate affine BMW algebras. We then exploit the connection to quantum groups and Lie algebras to determine universal parameters for the affine and degenerate affine BMW algebras. Finally, we show that the universal parameters are central elements--the higher Casimir elements for orthogonal and symplectic enveloping algebras and quantum groups.
Evolution in Games with a Continuous Action Space
Van Veelen, Matthijs
2001-01-01
This discussion paper resulted in a publication in 'Economic Theory' , 2009, 39(3), 355-376. Allowing for games with a continuous action space, we deal with the question whether and when static conceptslike evolutionary stability can shed any light on what happens in the dynamical context of a population playingthese games. The continuous equivalents of theorems for the finite case are either harder to prove or simplyuntrue. In some cases that fall within the latter category, sensible additio...
Autocratic strategies for iterated games with arbitrary action spaces.
McAvoy, Alex; Hauert, Christoph
2016-03-29
The recent discovery of zero-determinant strategies for the iterated prisoner's dilemma sparked a surge of interest in the surprising fact that a player can exert unilateral control over iterated interactions. These remarkable strategies, however, are known to exist only in games in which players choose between two alternative actions such as "cooperate" and "defect." Here we introduce a broader class of autocratic strategies by extending zero-determinant strategies to iterated games with more general action spaces. We use the continuous donation game as an example, which represents an instance of the prisoner's dilemma that intuitively extends to a continuous range of cooperation levels. Surprisingly, despite the fact that the opponent has infinitely many donation levels from which to choose, a player can devise an autocratic strategy to enforce a linear relationship between his or her payoff and that of the opponent even when restricting his or her actions to merely two discrete levels of cooperation. In particular, a player can use such a strategy to extort an unfair share of the payoffs from the opponent. Therefore, although the action space of the continuous donation game dwarfs that of the classic prisoner's dilemma, players can still devise relatively simple autocratic and, in particular, extortionate strategies. PMID:26976578
Space market model space industry input-output model
Hodgin, Robert F.; Marchesini, Roberto
1987-01-01
The goal of the Space Market Model (SMM) is to develop an information resource for the space industry. The SMM is intended to contain information appropriate for decision making in the space industry. The objectives of the SMM are to: (1) assemble information related to the development of the space business; (2) construct an adequate description of the emerging space market; (3) disseminate the information on the space market to forecasts and planners in government agencies and private corporations; and (4) provide timely analyses and forecasts of critical elements of the space market. An Input-Output model of market activity is proposed which are capable of transforming raw data into useful information for decision makers and policy makers dealing with the space sector.
Autonomous mental development in high dimensional context and action spaces.
Joshi, Ameet; Weng, Juyang
2003-01-01
Autonomous Mental Development (AMD) of robots opened a new paradigm for developing machine intelligence, using neural network type of techniques and it fundamentally changed the way an intelligent machine is developed from manual to autonomous. The work presented here is a part of SAIL (Self-Organizing Autonomous Incremental Learner) project which deals with autonomous development of humanoid robot with vision, audition, manipulation and locomotion. The major issue addressed here is the challenge of high dimensional action space (5-10) in addition to the high dimensional context space (hundreds to thousands and beyond), typically required by an AMD machine. This is the first work that studies a high dimensional (numeric) action space in conjunction with a high dimensional perception (context state) space, under the AMD mode. Two new learning algorithms, Direct Update on Direction Cosines (DUDC) and High-Dimensional Conjugate Gradient Search (HCGS), are developed, implemented and tested. The convergence properties of both the algorithms and their targeted applications are discussed. Autonomous learning of speech production under reinforcement learning is studied as an example. PMID:12850025
Autonomous mental development in high dimensional context and action spaces.
Joshi, Ameet; Weng, Juyang
2003-01-01
Autonomous Mental Development (AMD) of robots opened a new paradigm for developing machine intelligence, using neural network type of techniques and it fundamentally changed the way an intelligent machine is developed from manual to autonomous. The work presented here is a part of SAIL (Self-Organizing Autonomous Incremental Learner) project which deals with autonomous development of humanoid robot with vision, audition, manipulation and locomotion. The major issue addressed here is the challenge of high dimensional action space (5-10) in addition to the high dimensional context space (hundreds to thousands and beyond), typically required by an AMD machine. This is the first work that studies a high dimensional (numeric) action space in conjunction with a high dimensional perception (context state) space, under the AMD mode. Two new learning algorithms, Direct Update on Direction Cosines (DUDC) and High-Dimensional Conjugate Gradient Search (HCGS), are developed, implemented and tested. The convergence properties of both the algorithms and their targeted applications are discussed. Autonomous learning of speech production under reinforcement learning is studied as an example.
Action-angle variables for complex projective space and semiclassical exactness
Oh, P; Phillial Oh; Myung-Ho Kim
1994-01-01
We construct the action-angle variables of a classical integrable model defined on complex projective phase space and calculate the quantum mechanical propagator in the coherent state path integral representation using the stationary phase approximation. We show that the resulting expression for the propagator coincides with the exact propagator which was obtained by solving the time-dependent Schr\\"odinger equation.
The What, Who, and How of Ecological Action Space
Directory of Open Access Journals (Sweden)
Karin Skill
2011-12-01
Full Text Available This text presents an analytical concept which is aimed at analysis of the construction of environmental responsibility—ecological action space. The concept makes it possible to analyze what environmental activities householders perform, who takes on the environmental responsibility, and how they motivate and justify everyday practices in relation to other actors. The concept builds on structuration theory, and is useful in studies of sustainable development in everyday life, and in investigations about how actors perceive their role in creating and solving environmental problems, and what actions they take in light of this. The concept should be used for empirical rather than normative studies. Relevant questions for a study about ecological action space are: What activities are considered environmentally friendly? How do the actors conceive of their opportunities to act in environmentally friendly ways and what constraints do they express? These questions are relevant not just for outspoken activists. When promoting increased participation, it is valuable to discuss when, where and how people are expected to get involved.
Public space and free action: Foucault vs. Lefebvre
Directory of Open Access Journals (Sweden)
Prodanović Srđan
2012-01-01
Full Text Available In this paper we will try to offer a systematic insight into the relation of everyday practices and public space. By examining the work of two of the most influential authors in this field, Foucault and Lefebvre, we will try to provide a theoretical explanation of intuition that (public space represents one of the key constitutive elements of free action. In the first part of the paper, we will consider Foucault’s notion of heterotopia in the interest of pointing towards a “spatially intermediated” self-reflection which, to a great degree, resembles the philosophical askesis form his so called letter work. Afterwards, we will consider in which sense Lefebvre’s position that public space represents a Hegelian concrete abstraction - which entails dialectical analysis and tracking of complex historical contradictions - complements and deepens perspective that Foucault puts before us in his heterotopias. In that vein, it will be shown that both authors, despite the difference in their theoretical starting points, defend the idea of such a public space in which all signifiers are removed in the interest of „opening space” for the free agent. [Projekat Ministarstva nauke Republike Srbije, br. 41004 i br. 43007
Developing a Model for Continuous Professional Development by Action Research
Herbert, Susan; Rainford, Marcia
2014-01-01
This paper presents a case study of the work of two teacher educators with an in-service science teacher. This case study forms one cycle of a larger action research study that will eventually lead to a model of how the third-space concept for teacher professional development can be realized in natural school settings. The case study took place in…
Embedding a State Space Model Into a Markov Decision Process
DEFF Research Database (Denmark)
Nielsen, Lars Relund; Jørgensen, Erik; Højsgaard, Søren
2011-01-01
In agriculture Markov decision processes (MDPs) with finite state and action space are often used to model sequential decision making over time. For instance, states in the process represent possible levels of traits of the animal and transition probabilities are based on biological models...... estimated from data collected from the animal or herd. State space models (SSMs) are a general tool for modeling repeated measurements over time where the model parameters can evolve dynamically. In this paper we consider methods for embedding an SSM into an MDP with finite state and action space. Different...
Abstract Action Potential Models for Toxin Recognition
Peterson, James; Khan, Taufiquar
2005-01-01
In this paper, we present a robust methodology using mathematical pattern recognition schemes to detect and classify events in action potentials for recognizing toxins in biological cells. We focus on event detection in action potential via abstraction of information content into a low dimensional feature vector within the constrained computational environment of a biosensor. We use generated families of action potentials from a classic Hodgkin–Huxley model to verify our methodology and build...
Sorokina, Svetlana; Zaichkina, Svetlana; Rozanova, Olga; Aptikaeva, Gella; Romanchenko, Sergei; Smirnova, Helene; Dyukina, Alsu; Peleshko, Vladimir
At present time little is known concerning the biological effects of low-dose-rate high-LET radiation exposure in space. The currently available experimental data on the biological effect of low doses of chronic radiation with high-LET values, which occur under the conditions of aircraft and space flights, have been primarily obtained in the examinations of pilots and astronauts after flights. Another way of obtaining this kind of evidence is the simulation of irradiation conditions during aircraft and space flights on high-energy accelerators and the conduction of large-scale experiments on animals under these conditions on Earth. In the present work, we investigated the cytogenetic effects of low-dose-rate high-LET radiation in the dose ranges of 0.2-30 cGy (1 cGy/day) and 0.5-16 cGy (0.43 cGy/day) in the radiation field behind the concrete shield of the Serpukhov accelerator of 70 GeV protons that simulates the spectral and component composition of radiation fields formed in the conditions of high-altitude flights on SHK mice in vivo. The dose dependence, adaptive response (AR) and the growth of solid tumor were examined. For induction of AR, two groups of mice were exposed to adapting doses of 0.2-30 cGy and the doses of 0.5-16 cGy of high-LET radiation. For comparison, third group of mice from unirradiated males was chronically irradiated with X-rays at adapting doses of 10 cGy (1 cGy/day). After a day, the mice of all groups were exposed to a challenging dose of 1.5 Gy of X-rays (1 Gy/min). After 28 h, the animals of all groups were killed by the method of cervical dislocation. Bone marrow specimens for calculating micronuclei (MN) in polychromatic erythrocytes (PCE) were prepared by a conventional method with minor modifications. The influence of adapting dose of 16 cGy on the growth of solid tumor of Ehrlich ascite carcinoma was estimated by measuring the size of the tumor at different times after the inoculation of ascitic cells s.c. into the femur. It was
Space Flight Cable Model Development
Spak, Kaitlin
2013-01-01
This work concentrates the modeling efforts presented in last year's VSGC conference paper, "Model Development for Cable-Harnessed Beams." The focus is narrowed to modeling of space-flight cables only, as a reliable damped cable model is not yet readily available and is necessary to continue modeling cable-harnessed space structures. New experimental data is presented, eliminating the low-frequency noise that plagued the first year's efforts. The distributed transfer function method is applied to a single section of space flight cable for Euler-Bernoulli and shear beams. The work presented here will be developed into a damped cable model that can be incorporated into an interconnected beam-cable system. The overall goal of this work is to accurately predict natural frequencies and modal damping ratios for cabled space structures.
Awareness, Solidarity, and Action: An Educational Model
Reichenbach, Michael R.
2016-01-01
How Extension fosters social change and innovation can be improved through the use of theory-based educational models. Educational models can serve as foundations for the conceptual designs of educational interventions. I describe, using examples from my own work, one such model: the awareness, solidarity, and action model. This three-part model…
A learning oriented subjective action space as an indicator of giftedness
Directory of Open Access Journals (Sweden)
ALBERT ZIEGLER
2008-06-01
Full Text Available Traditionally, in giftedness research, the intelligence quotient has been presumed to be the best predictor of high achievement levels. From the perspective of the Actiotope Model of Giftedness, however, it is merely one indicator among several on the effectiveness of the academic action repertoire. In this model, learning is considered to be more important than personal traits for attaining high levels of achievement. This is confirmed with three studies conducted with pupils in grades 8 through 11. In Study 1 it was shown that high achieving pupils in the subject of mathematics can be differentiated from other pupils according to the learning orientation of their subjective action space. High achievement can be better predicted over a temporal distance of six months through the learning orientation of the subjective action space than through intelligence. This finding was replicated in Study 2 for the scholastic subject of biology. In Study 3, an investigation was undertaken to determine whether the performance enhancing effect of a learning oriented subjective action space is also beneficial in coming to terms with experiences of failure. This premise could also be confirmed.
Large space shell model calculations with small space results
Zamick, Larry; Yu, Xiafei
2015-01-01
We note that in large space shell model calculaiotns and experiment one sometimes get results, the form of which also appear in smaller space calculations. On the other hand there are some results which demand the large space approach.
Action of space charge on aging and breakdown of polymers
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The study on how space charges affect aging and breakdown of polymers becomes one of the most important domains. Most of the models are based on the injected charges increasing the local field to induce the breakdown of polymers and breaking the large molecule chains. These models ignore the effects of space charge on the microstruc-ture of dielectric materials. In this review, with the calcula-tion of the electromagnetic energy and the electromechanical energy around a trapped charge and with some new experi-mental results, it is proved that aging and breakdown in polymers are caused during the detrapping of the trapped charges. Aging and breakdown of the polymers are related to the release of the electromechanical energy around trapped charges.
Huth, Alexander G; Nishimoto, Shinji; Vu, An T; Gallant, Jack L
2012-12-20
Humans can see and name thousands of distinct object and action categories, so it is unlikely that each category is represented in a distinct brain area. A more efficient scheme would be to represent categories as locations in a continuous semantic space mapped smoothly across the cortical surface. To search for such a space, we used fMRI to measure human brain activity evoked by natural movies. We then used voxelwise models to examine the cortical representation of 1,705 object and action categories. The first few dimensions of the underlying semantic space were recovered from the fit models by principal components analysis. Projection of the recovered semantic space onto cortical flat maps shows that semantic selectivity is organized into smooth gradients that cover much of visual and nonvisual cortex. Furthermore, both the recovered semantic space and the cortical organization of the space are shared across different individuals.
Huth, Alexander G; Nishimoto, Shinji; Vu, An T; Gallant, Jack L
2012-12-20
Humans can see and name thousands of distinct object and action categories, so it is unlikely that each category is represented in a distinct brain area. A more efficient scheme would be to represent categories as locations in a continuous semantic space mapped smoothly across the cortical surface. To search for such a space, we used fMRI to measure human brain activity evoked by natural movies. We then used voxelwise models to examine the cortical representation of 1,705 object and action categories. The first few dimensions of the underlying semantic space were recovered from the fit models by principal components analysis. Projection of the recovered semantic space onto cortical flat maps shows that semantic selectivity is organized into smooth gradients that cover much of visual and nonvisual cortex. Furthermore, both the recovered semantic space and the cortical organization of the space are shared across different individuals. PMID:23259955
Belehaki Anna; Messerotti Mauro; Candidi Maurizio
2014-01-01
COST Action ES0803 “Developing Space Weather products and services in Europe” primarily aimed at forming an interdisciplinary network among European scientists dealing with different issues relevant to Geospace as well as warning system developers and operators in order to assess existing Space Weather products and recommend new ones. The work that has been implemented from 2008 to 2012 resulted in advances in modeling and predicting Space Weather, in recommendations for the validation of Spa...
Action Research to Improve the Learning Space for Diagnostic Techniques
Directory of Open Access Journals (Sweden)
Ellen Ariel
2015-08-01
Full Text Available The module described and evaluated here was created in response to perceived learning difficulties in diagnostic test design and interpretation for students in third-year Clinical Microbiology. Previously, the activities in lectures and laboratory classes in the module fell into the lower cognitive operations of “knowledge” and “understanding.” The new approach was to exchange part of the traditional activities with elements of interactive learning, where students had the opportunity to engage in deep learning using a variety of learning styles. The effectiveness of the new curriculum was assessed by means of on-course student assessment throughout the module, a final exam, an anonymous questionnaire on student evaluation of the different activities and a focus group of volunteers. Although the new curriculum enabled a major part of the student cohort to achieve higher pass grades (p < 0.001, it did not meet the requirements of the weaker students, and the proportion of the students failing the module remained at 34%. The action research applied here provided a number of valuable suggestions from students on how to improve future curricula from their perspective. Most importantly, an interactive online program that facilitated flexibility in the learning space for the different reagents and their interaction in diagnostic tests was proposed. The methods applied to improve and assess a curriculum refresh by involving students as partners in the process, as well as the outcomes, are discussed.
Developing Learner Centered Action Learning Model
Directory of Open Access Journals (Sweden)
Chalard Chantarasombat
2011-01-01
Full Text Available Problem statement: This study aimed to examine the effects of using Learner Centered Action Learning Model. The research was research and development by applying Participatory Action Research method. Instruments used were an achievement test, a questionnaire on students satisfaction and focused group discussion. Approach: The statistic included the Mean, Standard Deviation, effectiveness index and Dependent Sample t-test. The results revealed that the learning model had 2 Key factors: PAR with 6 stages and using the model with 21 sub activity together with learning activity organization showing efficiency in cognitive domain, psychomotor domain, affective domain, effectiveness index and learning retention. Result: The students showed their satisfaction at the highest Level. The factors of success included: Participation in actions of the participants and researcher, responsibility and learning climate. Conclusion: The factor of success in knowledge management outcome on Learner Centered Action Learning with the product after using Participatory Action Research aligned with learning activity implementation, consisted of Key aspects as: (1 the participation in performance practice, (2 the awareness, feeling, thinking, good attitude, responsibility in the course they were studying both of individual performance and group performance, (3 the persistence in acting for achieving common agreement, (4 the learning climate, the instructor was a facilitator encouraging for learning in program, including textbook of he course, media and instrument to search for, AAR and case study from the senor cohorts for comparing the quality of their performances, (5 the evaluation and conclusion of implementation in outcome Learner Centered Action Learning Model regarding to knowledge, feeling and skill of practice in field performance, (6 sharing among the students, instructors and learning network.
Public Health Action Model for Cancer Survivorship.
Moore, Angela R; Buchanan, Natasha D; Fairley, Temeika L; Lee Smith, Judith
2015-12-01
Long-term objectives associated with cancer survivors have been suggested by Healthy People 2020, including increasing the proportion of survivors living beyond 5 years after diagnosis and improving survivors' mental and physical health-related quality of life. Prior to reaching these objectives, several intermediate steps must be taken to improve the physical, social, emotional, and financial well-being of cancer survivors. Public health has a role in developing strategic, actionable, and measurable approaches to facilitate change at multiple levels to improve the lives of survivors and their families. The social ecological model has been used by the public health community as the foundation of multilevel intervention design and implementation, encouraging researchers and practitioners to explore methods that promote internal and external changes at the individual, interpersonal, organizational, community, and policy levels. The survivorship community, including public health professionals, providers, policymakers, survivors, advocates, and caregivers, must work collaboratively to identify, develop, and implement interventions that benefit cancer survivors. The National Action Plan for Cancer Survivorship highlights public health domains and associated strategies that can be the impetus for collaboration between and among the levels in the social ecological model and are integral to improving survivor outcomes. This paper describes the Public Health Action Model for Cancer Survivorship, an integrative framework that combines the National Action Plan for Cancer Survivorship with the social ecological model to demonstrate how interaction among the various levels may promote better outcomes for survivors. PMID:26590641
Ribstein, Bruno; Achatz, Ulrich; Senf, Fabian
2014-05-01
abstract Gravity waves (GWs) and solar tides (STs) are main constituents of the dynamical coupling between troposphere and mesosphere-lower-thermosphere (MLT). Via momentum deposition, GWs control to a large extent the mesospheric mean circulation. STs are large scale waves, mostly due to tropospheric and stratospheric diurnal heating processes, that modulate all dynamical fields in the mesosphere. GWs ant STs also interact strongly with each other. Conventional GW parameterizations used to describe this interaction (e.g. [1]) neglect the time-dependence and horizontal gradients of the background flow, with fatal effects (e.g. [2]). We study here the propagation of GWs in a time-dependent middle-atmosphere background flow, using a new (caustics free) WKB GW model (ray tracer). The background flow is composed by a climatological mean and tidal fields extracted from a general circulation model (HAMMONIA, see [3]). In order to avoid caustics, inevitable in classic ray-tracer implementations, we implemented a new wave-action phase-space density conservation scheme [4, 5]. The scheme attaches to each ray a finite volume in the location & wavenumber phase-space. The location-wavenumber volume is conserved during the propagation, responding in shape to the local stretching and squeezing in wave-number space. From the propagation of GWs we evaluate the deposition of momentum and buoyancy. Rayleigh-friction and temperature-relaxation coefficients are also evaluated. In this extension of the study by [2] it is shown, with an amplitude scheme more stable against numerical instabilities, due to the avoidance of caustics, that STs (and so the time dependence of the background flow) modulate the propagation of GWs. Via Rayleigh-friction and temperature-relaxation coefficients, we also quantify how the pseudo-momentum-, momentum-, and enthalpy-deposition of GWs can influence the amplitude and the phase structure of STs. Finally, we compare momentum and buoyancy fluxes from the
Directory of Open Access Journals (Sweden)
Belehaki Anna
2014-01-01
Full Text Available COST Action ES0803 “Developing Space Weather products and services in Europe” primarily aimed at forming an interdisciplinary network among European scientists dealing with different issues relevant to Geospace as well as warning system developers and operators in order to assess existing Space Weather products and recommend new ones. The work that has been implemented from 2008 to 2012 resulted in advances in modeling and predicting Space Weather, in recommendations for the validation of Space Weather models, in proposals for new Space Weather products and services, and in dissemination, training, and outreach activities. This preface summarizes the most important achievements of this European activity that are detailed in this special issue by the key scientists who participated in COST Action ES0803.
Johnson, Nicholas L.
2001-01-01
Since the Second European Conference on Space Debris in 1997, the Orbital Debris Program Office at the NASA Johnson Space Center has undertaken a major effort to update and improve the principal software tools employed to model the space debris environment and to evaluate mission risks. NASA's orbital debris engineering model, ORDEM, represents the current and near-term Earth orbital debris population from the largest spacecraft to the smallest debris in a manner which permits spacecraft engineers and experimenters to estimate the frequency and velocity with which a satellite may be struck by debris of different sizes. Using expanded databases and a new program design, ORDEM2000 provides a more accurate environment definition combined with a much broader array of output products in comparison with its predecessor, ORDEM96. Studies of the potential long-term space debris environment are now conducted with EVOLVE 4.0, which incorporates significant advances in debris characterization and breakup modeling. An adjunct to EVOLVE 4.0, GEO EVOLVE has been created to examine debris issues near the geosynchronous orbital regime. In support of NASA Safety Standard 1740.14, which establishes debris mitigation guidelines for all NASA space programs, a set of evaluation tools called the Debris Assessment Software (DAS) is specifically designed for program offices to determine whether they are in compliance with NASA debris mitigation guidelines. DAS 1.5 has recently been released with improved WINDOWS compatibility and graphics functions. DAS 2.0 will incorporate guideline changes in a forthcoming revision to NASA Safety Standard 1740.14. Whereas DAS contains a simplified model to calculate possible risks associated with satellite reentries, NASA's higher fidelity Object Reentry Survival Analysis Tool (ORSAT) has been upgraded to Version 5.0. With the growing awareness of the potential risks posed by uncontrolled satellite reentries to people and property on Earth, the
Free space in the processes of action research
DEFF Research Database (Denmark)
Bladt, Mette; Nielsen, Kurt Aagaard
2013-01-01
In Scandinavia there exists an action research tradition called critical utopian action research (CUAR). Within CUAR, criticism and utopia is a core activity in the methods used and in the research as such. The utopian concept in this tradition should be understood as a productive concept, and thus...
Sculpting the space of actions: explaining human action by integrating intentions and mechanisms
Keestra, M.
2014-01-01
How can we explain the intentional nature of an expert’s actions, performed without immediate and conscious control, relying instead on automatic cognitive processes? How can we account for the differences and similarities with a novice’s performance of the same actions? Can a naturalist explanation of intentional expert action be in line with a philosophical concept of intentional action? Answering these and related questions in a positive sense, this dissertation develops a three-step argum...
Hubble Space Telescope Scale Model
1983-01-01
This is a photograph of a 1/15 scale model of the Hubble Space Telescope (HST). The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is 42.5-feet (13- meters) long and weighs about 25,000 pounds (11,600 kilograms). The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.
SpaceNet: Modeling and Simulating Space Logistics
Lee, Gene; Jordan, Elizabeth; Shishko, Robert; de Weck, Olivier; Armar, Nii; Siddiqi, Afreen
2008-01-01
This paper summarizes the current state of the art in interplanetary supply chain modeling and discusses SpaceNet as one particular method and tool to address space logistics modeling and simulation challenges. Fundamental upgrades to the interplanetary supply chain framework such as process groups, nested elements, and cargo sharing, enabled SpaceNet to model an integrated set of missions as a campaign. The capabilities and uses of SpaceNet are demonstrated by a step-by-step modeling and simulation of a lunar campaign.
Fitted Q-iteration in continuous action-space MDPs
Antos, Andras; Munos, Rémi; Szepesvari, Csaba
2007-01-01
International audience We consider continuous state, continuous action batch reinforcement learning where the goal is to learn a good policy from a sufﬁciently rich trajectory generated by some policy. We study a variant of ﬁtted Q-iteration, where the greedy action selection is replaced by searching for a policy in a restricted set of candidate policies by maximizing the average action values. We provide a rigorous analysis of this algorithm, proving what we believe is the ﬁrst ﬁnite-time...
Klein, Annette M; Hauf, Petra; Aschersleben, Gisa
2006-12-01
The present study investigated differences in infant imitation after watching a televised model and a live model and addressed the issue of whether action effects influence infants' action control in both cases. In a 2x2 design, 12-month-old infants observed a live or a televised model performing a three-step action sequence, in which either the 2nd or the 3rd action step was combined with an acoustical action effect. We assumed that infants would use the observed action-effect relations for their own action control in the test phase afterwards. Even though results exhibited differences in the absolute amount of imitation between the two demonstration groups, both groups showed similar result patterns regarding the action effect manipulation: infants imitated the action step that was followed by a salient action effect more often and mostly as the first target action, emphasizing the important role of action effects in infants' action control. PMID:17138306
Cohomology Complex Projective Space with Actions of G5
Institute of Scientific and Technical Information of China (English)
孙淑英; 刘宗泽
2000-01-01
Let M2n be a cohomology CPn and p a prime. Set Dp(M2n) = |d >0| M2n admits a smooth Gp action such that the fixed point set of the action Gontains a codimension-2 submanifold of degree d|, DEp(M2n) = |(d; m1, m2, …, mμ)|M2n admits a Gp action of Type Ⅱ0,having multiplicities m1, m2, …, mμ at the isolated fixed points, and m1 + m2+…+ mμ = n, d is the degree of the fixed codimension-2 submanifold| In this paper, we prove that for n = 5 or 7, if D5(M2n)≠Ф, then D5(M2n) = |1|; if DE5( M2n)≠Ф, then DE5(M2n) = |(1; n, 0) |.
Fractional Order Modelling Using State Space Theory
Directory of Open Access Journals (Sweden)
Pritesh Shah
2013-06-01
Full Text Available There are various fractional order systems existing. This paper deals with the modelling of fractional order systems using an old and unique model structure i.e. state space model. The fractional order process system can be mathematically modelled by state space model. Simulation results validated that the fractional order model using state space is better as compared to other models such as first order with delay.
Effective action for a quantum scalar field in warped spaces
Energy Technology Data Exchange (ETDEWEB)
Hoff da Silva, J.M.; Mendonca, E.L.; Scatena, E. [Universidade Estadual Paulista ' ' Julio de Mesquita Filho' ' -UNESP, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil)
2015-11-15
We investigate the one-loop corrections, at zero as well as finite temperature, of a scalar field taking place in a braneworld motivated warped background. After to reach a well-defined problem, we calculate the effective action with the corresponding quantum corrections to each case. (orig.)
Critical Action Learning--Rituals and Reflective Spaces
Heneberry, Pamela; Turner, Arthur
2016-01-01
This paper is written to outline our ideas on rituals and reflective places and how this thinking has emerged through our writing, facilitation and reflections around critical action learning and critical leadership. We attempt to show the conceptual framework that underpins our vision of Critical Leadership and how out of this work we have begun…
Type II chiral affine Lie algebras and string actions in doubled space
Hatsuda, Machiko; Siegel, Warren
2015-01-01
We present affine Lie algebras generated by the supercovariant derivatives and the supersymmetry generators for the left and right moving modes in the doubled space. Chirality is manifest in our doubled space as well as the T-duality symmetry. We present gauge invariant bosonic and superstring actions preserving the two-dimensional diffeomorphism invariance and the kappa-symmetry where doubled spacetime coordinates are chiral fields. The doubled space becomes the usual space by dimensional reduction constraints.
Effective action in general chiral superfield model
Petrov, A. Yu.
2000-01-01
The effective action in general chiral superfield model with arbitrary k\\"{a}hlerian potential $K(\\bar{\\Phi},\\Phi)$ and chiral (holomorphic) potential $W(\\Phi)$ is considered. The one-loop and two-loop contributions to k\\"{a}hlerian effective potential and two-loop (first non-zero) contribution to chiral effective potential are found for arbitrary form of functions $K(\\bar{\\Phi},\\Phi)$ and $W(\\Phi)$. It is found that despite the theory is non-renormalizable in general case two-loop contributi...
Developing an Action Learning Design Model
Bong, Hyeon-Cheol; Cho, Yonjoo; Kim, Hyung-Sook
2014-01-01
As the number of organizations implementing action learning increases, both successful and failed cases also increase in action learning practice in South Korea. Existing studies on action learning have listed key success factors of action learning at the program level or at the team level but have not paid sufficient attention to the program…
Action potential initiation in the hodgkin-huxley model.
Directory of Open Access Journals (Sweden)
Lucy J Colwell
2009-01-01
Full Text Available A recent paper of B. Naundorf et al. described an intriguing negative correlation between variability of the onset potential at which an action potential occurs (the onset span and the rapidity of action potential initiation (the onset rapidity. This correlation was demonstrated in numerical simulations of the Hodgkin-Huxley model. Due to this antagonism, it is argued that Hodgkin-Huxley-type models are unable to explain action potential initiation observed in cortical neurons in vivo or in vitro. Here we apply a method from theoretical physics to derive an analytical characterization of this problem. We analytically compute the probability distribution of onset potentials and analytically derive the inverse relationship between onset span and onset rapidity. We find that the relationship between onset span and onset rapidity depends on the level of synaptic background activity. Hence we are able to elucidate the regions of parameter space for which the Hodgkin-Huxley model is able to accurately describe the behavior of this system.
Lagrangian formulation of symmetric space sine-Gordon models
Bakas, Ioannis; Shin, H J; Park, Q Han
1996-01-01
The symmetric space sine-Gordon models arise by conformal reduction of ordinary 2-dim \\sigma-models, and they are integrable exhibiting a black-hole type metric in target space. We provide a Lagrangian formulation of these systems by considering a triplet of Lie groups F \\supset G \\supset H. We show that for every symmetric space F/G, the generalized sine-Gordon models can be derived from the G/H WZW action, plus a potential term that is algebraically specified. Thus, the symmetric space sine-Gordon models describe certain integrable perturbations of coset conformal field theories at the classical level. We also briefly discuss their vacuum structure, Backlund transformations, and soliton solutions.
Path-integral action of a particle in the noncommutative phase-space
Gangopadhyay, Sunandan
2016-01-01
In this paper we construct a path integral formulation of quantum mechanics on noncommutative phase-space. We first map the system to an equivalent system on the noncommutative plane. Then by applying the formalism of representing a quantum system in the space of Hilbert-Schmidt operators acting on noncommutative configuration space, the path integral action of a particle is derived. It is observed that the action has a similar form to that of a particle in a magnetic field in the noncommutative plane. From this action the energy spectrum is obtained for the free particle and the harmonic oscillator potential. We also show that the nonlocal nature (in time) of the action yields a second class constrained system from which the noncommutative Heisenberg algebra can be recovered.
Simplicial models for trace spaces
DEFF Research Database (Denmark)
Raussen, Martin
Directed Algebraic Topology studies topological spaces in which certain directed paths (d-paths) - in general irreversible - are singled out. The main interest concerns the spaces of directed paths between given end points - and how those vary under variation of the end points. The original...
Simplicial models of trace spaces
DEFF Research Database (Denmark)
Raussen, Martin
2010-01-01
Directed algebraic topology studies topological spaces in which certain directed paths (d-paths) are singled out; in most cases of interest, the reverse path of a d-path is no longer a d-path. We are mainly concerned with spaces of directed paths between given end points, and how those vary under...
Public space patterns: Modelling the language of urban space
Montenegro, N.; Beirao, J.N.; Duarte, J.P.
2011-01-01
This paper describes the “Public Space Patterns” ontology including its related rule-based model, used as a basic structure of a “City Information Modelling” (CIM). This model was developed within a larger research project aimed at developing a tool for urban planning and design. The main purpose is
Action Research to Improve the Learning Space for Diagnostic Techniques.
Ariel, Ellen; Owens, Leigh
2015-12-01
The module described and evaluated here was created in response to perceived learning difficulties in diagnostic test design and interpretation for students in third-year Clinical Microbiology. Previously, the activities in lectures and laboratory classes in the module fell into the lower cognitive operations of "knowledge" and "understanding." The new approach was to exchange part of the traditional activities with elements of interactive learning, where students had the opportunity to engage in deep learning using a variety of learning styles. The effectiveness of the new curriculum was assessed by means of on-course student assessment throughout the module, a final exam, an anonymous questionnaire on student evaluation of the different activities and a focus group of volunteers. Although the new curriculum enabled a major part of the student cohort to achieve higher pass grades (p learning space for the different reagents and their interaction in diagnostic tests was proposed. The methods applied to improve and assess a curriculum refresh by involving students as partners in the process, as well as the outcomes, are discussed. Journal of Microbiology & Biology Education. PMID:26753024
Directory of Open Access Journals (Sweden)
Giovanni ePezzulo
2013-11-01
Full Text Available The article explores the possibilities of formalizing and explaining the mechanisms that support spatial and social perspective alignment sustained over the duration of a social interaction. The basic proposed principle is that in social contexts the mechanisms for sensorimotor transformations and multisensory integration (learn to incorporate information relative to the other actor(s, similar to the "re-calibration" of visual receptive fields in response to repeated tool use. This process aligns or merges the co-actors' spatial representations and creates a "Shared Action Space" supporting key computations of social interactions and joint actions; for example, the remapping between the coordinate systems and frames of reference of the co-actors, including perspective taking, the sensorimotor transformations required for lifting jointly an object, and the predictions of the sensory effects of such joint action. The social re-calibration is proposed to be based on common basis function maps and could constitute an optimal solution to sensorimotor transformation and multisensory integration in joint action or more in general social interaction contexts. However, certain situations such as discrepant postural and viewpoint alignment and associated differences in perspectives between the co-actors could constrain the process quite differently. We discuss how alignment is achieved in the first place, and how it is maintained over time, providing a taxonomy of various forms and mechanisms of space alignment and overlap based, for instance, on automaticity vs. control of the transformations between the two agents. Finally, we discuss the link between low-level mechanisms for the sharing of space and high-level mechanisms for the sharing of cognitive representations.
Bonini, Luca; Maranesi, Monica; Livi, Alessandro; Fogassi, Leonardo; Rizzolatti, Giacomo
2014-03-12
The macaque ventral premotor area F5 hosts two types of visuomotor grasping neurons: "canonical" neurons, which respond to visually presented objects and underlie visuomotor transformation for grasping, and "mirror" neurons, which respond during the observation of others' action, likely playing a role in action understanding. Some previous evidence suggested that canonical and mirror neurons could be anatomically segregated in different sectors of area F5. Here we investigated the functional properties of single neurons in the hand field of area F5 using various tasks similar to those originally designed to investigate visual responses to objects and actions. By using linear multielectrode probes, we were able to simultaneously record different types of neurons and to precisely localize their cortical depth. We recorded 464 neurons, of which 243 showed visuomotor properties. Canonical and mirror neurons were often present in the same cortical sites; and, most interestingly, a set of neurons showed both canonical and mirror properties, discharging to object presentation as well as during the observation of experimenter's goal-directed acts (canonical-mirror neurons). Typically, visual responses to objects were constrained to the monkey peripersonal space, whereas action observation responses were less space-selective. Control experiments showed that space-constrained coding of objects mostly relies on an operational (action possibility) rather than metric (absolute distance) reference frame. Interestingly, canonical-mirror neurons appear to code object as target for both one's own and other's action, suggesting that they could play a role in predictive representation of others' impending actions.
An Evolution Model of Space Debris Environment
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Various types of models including engineering models andevolution models have been developed to understand space debris environment since 1960s. Evolution model, consisting of a set of supporting models such as Launch Model, Breakup Model and Atmosphere Model, can reliably predicts the evolution of space debris environment. Of these supporting models, Breakup Model is employed to describe the distribution of debris and debris cloud during a explosion or collision case which is one of the main factors affecting the amount of total space debris. An analytical orbit debris environment model referred to as the “Particles-In-Boxes" model has been introduced. By regarding the orbit debris as the freedom particles running in the huge volume, the sources and sinks mechanism is established. Then the PIB model is expanded to the case of multiple-species in multiple-tier system. Combined with breakup model, the evolution of orbit debris environment is predicted.
Cosmological models in the generalized Einstein action
International Nuclear Information System (INIS)
We have studied the evolution of the Universe in the generalized Einstein action of the form R + β R2, where R is the scalar curvature and β = const. We have found exact cosmological solutions that predict the present cosmic acceleration. These models predict an inflationary de-Sitter era occurring in the early Universe. The cosmological constant (Λ) is found to decay with the Hubble constant (H) as, Λ ∝ H4. In this scenario the cosmological constant varies quadratically with the energy density (ρ), i.e., Λ ∝ ρ2. Such a variation is found to describe a two-component cosmic fluid in the Universe. One of the components accelerated the Universe in the early era, and the other in the present era. The scale factor of the Universe varies as a ∼ tn = 1/2 in the radiation era. The cosmological constant vanishes when n = 4/3 and n =1/2. We have found that the inclusion of the term R2 mimics a cosmic matter that could substitute the ordinary matter. (author)
Spatial and frequency domain ring source models for the single muscle fiber action potential
DEFF Research Database (Denmark)
Henneberg, Kaj-åge; R., Plonsey
1994-01-01
In the paper, single-fibre models for the extracellular action potential are developed that will allow the potential to the evaluated at an arbitrary field point in the extracellular space. Fourier-domain models are restricted in that they evaluate potentials at equidistant points along a line...
Action-angle variables for geodesic motions in Sasaki-Einstein spaces $Y^{p,q}$
Visinescu, Mihai
2016-01-01
We use the action-angle variables to describe the geodesic motions in the $5$-dimensional Sasaki-Einstein spaces $Y^{p,q}$. This formulation allows us to study thoroughly the complete integrability of the system. We find that the Hamiltonian involves a reduced number of action variables. Therefore one of the fundamental frequency is zero indicating a chaotic behavior when the system is perturbed.
Model-theoretical foundation of action and progression
Institute of Scientific and Technical Information of China (English)
田启家; 史忠植
1997-01-01
Action is one of the most important concepts in computer science, and situation calculus is the standard formalism for representing and reasoning about actions and their effects. Situation calculus essentially could be presented in a logic framework. Based on the framework LR, such a logic framework is given. Minimal action theory is proposed and studied from the point of view of model theory. By theorems of mathematical logic, some results about the definability about the progression in minimal action theory are obtained.
Inversion Copulas from Nonlinear State Space Models
Smith, Michael Stanley; Maneesoonthorn, Worapree
2016-01-01
While copulas constructed from inverting latent elliptical, or skew-elliptical, distributions are popular, they can be inadequate models of serial dependence in time series. As an alternative, we propose an approach to construct copulas from the inversion of latent nonlinear state space models. This allows for new time series copula models that have the same serial dependence structure as a state space model, yet have an arbitrary marginal distribution - something that is difficult to achieve...
Directory of Open Access Journals (Sweden)
L. R. Cander
2004-06-01
Full Text Available The COST 271 Action («Effects of the Upper Atmosphere on Terrestrial and Earth-space Communications » within the European ionospheric community has the objectives, embodied in the Memorandum of Understanding (MoU: to study the influence of upper atmospheric conditions on terrestrial and Earth-space communications, to develop methods and techniques to improve ionospheric models over Europe for telecommunication and navigation applications and to transfer the results to the appropriate Radiocommunication Study Groups of the International Telecommunication Union (ITU-R and other national and international organizations dealing with the modern communication systems. This introductory paper summarises briefly the background and historical context of COST 271 and outlines the main objectives, working methods and structure. It also lists the participating countries and institutions, the Management Committee (MC Meetings, Workshops and Short-term Scientific Missions. In addition, the paper discusses the dissemination of the results and the collaboration among the participating institutions and researchers, before outlining the content of the Final Report.
On the existence of star products on quotient spaces of linear Hamiltonian torus actions
DEFF Research Database (Denmark)
Herbig, Hans-Christian; Iyengar, Srikanth B.; Pflaum, Markus J.
2009-01-01
We discuss BFV deformation quantization (Bordemann et al. in A homological approach to singular reduction in deformation quantization, singularity theory, pp. 443–461. World Scientific, Hackensack, 2007) in the special case of a linear Hamiltonian torus action. In particular, we show that the Kos......We discuss BFV deformation quantization (Bordemann et al. in A homological approach to singular reduction in deformation quantization, singularity theory, pp. 443–461. World Scientific, Hackensack, 2007) in the special case of a linear Hamiltonian torus action. In particular, we show...... that the Koszul complex on the moment map of an effective linear Hamiltonian torus action is acyclic. We rephrase the nonpositivity condition of Arms and Gotay (Adv Math 79(1):43–103, 1990) for linear Hamiltonian torus actions. It follows that reduced spaces of such actions admit continuous star products....
Measurement Models for Reasoned Action Theory
Hennessy, Michael; Bleakley, Amy; Fishbein, Martin
2012-01-01
Quantitative researchers distinguish between causal and effect indicators. What are the analytic problems when both types of measures are present in a quantitative reasoned action analysis? To answer this question, we use data from a longitudinal study to estimate the association between two constructs central to reasoned action theory: behavioral beliefs and attitudes toward the behavior. The belief items are causal indicators that define a latent variable index while the attitude items are ...
On the Cohomology of Orbit Space of Free $\\mathbb{Z}_p$-Actions on Lens Spaces
Indian Academy of Sciences (India)
Hemant Kumar Singh; Tej Bahadur Singh
2007-08-01
Let $G=\\mathbb{Z}_p, p$ an odd prime, act freely on a finite-dimensional -complex with $\\mathrm{mod} p$ cohomology isomorphic to that of a lens space $L^{2m-1}(p;q_1,\\ldots,q_m)$. In this paper, we determine the $\\mathrm{mod} p$ cohomology ring of the orbit space $X/G$, when $p^2\
Action potential initiation in the hodgkin-huxley model.
Colwell, Lucy J; Brenner, Michael P.
2009-01-01
A recent paper of B. Naundorf et al. described an intriguing negative correlation between variability of the onset potential at which an action potential occurs (the onset span) and the rapidity of action potential initiation (the onset rapidity). This correlation was demonstrated in numerical simulations of the Hodgkin-Huxley model. Due to this antagonism, it is argued that Hodgkin-Huxley-type models are unable to explain action potential initiation observed in cortical neurons in vivo or in...
Measurement Models for Reasoned Action Theory.
Hennessy, Michael; Bleakley, Amy; Fishbein, Martin
2012-03-01
Quantitative researchers distinguish between causal and effect indicators. What are the analytic problems when both types of measures are present in a quantitative reasoned action analysis? To answer this question, we use data from a longitudinal study to estimate the association between two constructs central to reasoned action theory: behavioral beliefs and attitudes toward the behavior. The belief items are causal indicators that define a latent variable index while the attitude items are effect indicators that reflect the operation of a latent variable scale. We identify the issues when effect and causal indicators are present in a single analysis and conclude that both types of indicators can be incorporated in the analysis of data based on the reasoned action approach.
Space Vehicle Reliability Modeling in DIORAMA
Energy Technology Data Exchange (ETDEWEB)
Tornga, Shawn Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-07-12
When modeling system performance of space based detection systems it is important to consider spacecraft reliability. As space vehicles age the components become prone to failure for a variety of reasons such as radiation damage. Additionally, some vehicles may lose the ability to maneuver once they exhaust fuel supplies. Typically failure is divided into two categories: engineering mistakes and technology surprise. This document will report on a method of simulating space vehicle reliability in the DIORAMA framework.
Action Control of Autonomous Agents in Continuous Valued Space Using RFCN
Shirakawa, Shinichi; Nagao, Tomoharu
Researches on action control of autonomous agents and multiple agents have attracted increasing attentions in recent years. The general method using action control of agents are neural network, genetic programming and reinforcement learning. In this study, we use neural network for action control of autonomous agents. Our method determines the structure and parameter of neural network in evolution. We proposed Flexibly Connected Neural Network (FCN) previously as a method of constructing arbitrary neural networks with optimized structures and parameters to solve unknown problems. FCN was applied to action control of an autonomous agent and showed experimentally that it is effective for perceptual aliasing problems. All of the experiments of FCN, however, are in only grid space. In this paper, we propose a new method based on FCN which can decide correct action in real and continuous valued space. The proposed method which called Real valued FCN (RFCN) optimizes input-output functions of each units, parameters of the input-output functions and speed of each units. In order to examine the effectiveness, we applied the proposed method to action control of an autonomous agent to solve continuous valued maze problems.
Multimedia Mapping using Continuous State Space Models
DEFF Research Database (Denmark)
Lehn-Schiøler, Tue
2004-01-01
In this paper a system that transforms speech waveforms to animated faces are proposed. The system relies on continuous state space models to perform the mapping, this makes it possible to ensure video with no sudden jumps and allows continuous control of the parameters in 'face space'. Simulatio...
Models for multimegawatt space power systems
Energy Technology Data Exchange (ETDEWEB)
Edenburn, M.W.
1990-06-01
This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor -- turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor therminonic system. The models estimate performance and mass for the components in each of these systems. 17 refs., 8 figs., 15 tabs.
The Cohomology of Orbit Spaces of Certain Free Circle Group Actions
Indian Academy of Sciences (India)
Hemant Kumar Singh; Tej Bahadur Singh
2012-02-01
Suppose that $G=\\mathbb{S}^1$ acts freely on a finitistic space whose (mod ) cohomology ring is isomorphic to that of a lens space $L^{2m-1}(p;q_1,\\ldots,q_m)$ or $\\mathbb{S}^1×\\mathbb{C}P^{m-1}$. The mod index of the action is defined to be the largest integer such that $^n≠ 0$, where $\\in H^2(X/G;\\mathbb{Z}_p)$ is the nonzero characteristic class of the $\\mathbb{S}^1$-bundle $\\mathbb{S}^1\\hookrightarrow X→ X/G$. We show that the mod index of a free action of on $\\mathbb{S}^1×\\mathbb{C}P^{m-1}$ is -1, when it is defined. Using this, we obtain a Borsuk–Ulam type theorem for a free -action on $\\mathbb{S}^1×\\mathbb{C}P^{m-1}$. It is note worthy that the mod index for free -actions on the cohomology lens space is not defined.
Parametric Cost Models for Space Telescopes
Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtney
2010-01-01
Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.
Transforming community access to space science models
MacNeice, Peter; Hesse, Michael; Kuznetsova, Maria; Maddox, Marlo; Rastaetter, Lutz; Berrios, David; Pulkkinen, Antti
2012-04-01
Researching and forecasting the ever changing space environment (often referred to as space weather) and its influence on humans and their activities are model-intensive disciplines. This is true because the physical processes involved are complex, but, in contrast to terrestrial weather, the supporting observations are typically sparse. Models play a vital role in establishing a physically meaningful context for interpreting limited observations, testing theory, and producing both nowcasts and forecasts. For example, with accurate forecasting of hazardous space weather conditions, spacecraft operators can place sensitive systems in safe modes, and power utilities can protect critical network components from damage caused by large currents induced in transmission lines by geomagnetic storms.
Scaling test of fermion actions in the Schwinger model
International Nuclear Information System (INIS)
We discuss the scaling behaviour of different fermion actions in dynamical simulations of the 2-dimensional massive Schwinger model. We have chosen Wilson, hypercube, twisted mass and overlap fermion actions. As physical observables, the pion mass and the scalar condensate are computed for the above mentioned actions at a number of coupling values and fermion masses. We also discuss possibilities to simulate overlap fermions dynamically avoiding problems with low-lying eigenvalues of the overlap kernel
Scaling test of fermion actions in the Schwinger model
International Nuclear Information System (INIS)
We discuss the scaling behaviour of different fermion actions in dynamical simulations of the 2-dimensional massive Schwinger model. We have chosen Wilson, hypercube, twisted mass and overlap fermion actions. As physical observables, the pion mass and the scalar condensate are computed for the above mentioned actions at a number of coupling values and fermion masses. We also discuss possibilities to simulate overlap fermions dynamically avoiding problems with low-lying eigenvalues of the overlap kernel. (orig.)
Modeling the value of strategic actions in the superior colliculus
Directory of Open Access Journals (Sweden)
Dhushan Thevarajah
2010-02-01
Full Text Available In learning models of strategic game play, an agent constructs a valuation (action value over possible future choices as a function of past actions and rewards. Choices are then stochastic functions of these action values. Our goal is to uncover a neural signal that correlates with the action value posited by behavioral learning models. We measured activity from neurons in the superior colliculus (SC, a midbrain region involved in planning saccadic eye movements, in monkeys while they performed two saccade tasks. In the strategic task, monkeys competed against a computer in a saccade version of the mixed-strategy game “matching-pennies”. In the instructed task, stochastic saccades were elicited through explicit instruction rather than free choices. In both tasks, neuronal activity and behavior were shaped by past actions and rewards with more recent events exerting a larger influence. Further, SC activity predicted upcoming choices during the strategic task and upcoming reaction times during the instructed task. Finally, we found that neuronal activity in both tasks correlated with an established learning model, the Experience Weighted Attraction model of action valuation (Ho, Camerer, and Chong, 2007. Collectively, our results provide evidence that action values hypothesized by learning models are represented in the motor planning regions of the brain in a manner that could be used to select strategic actions.
Evstatiev, E G
2014-01-01
We formulate a finite-size particle numerical model of strongly magnetized plasmas in the drift-kinetic approximation. We use the phase space action as an alternative to previous variational formulations based on Low's Lagrangian or on a Hamiltonian with a non-canonical Poisson bracket. The useful property of this variational principle is that it allows independent transformations of particle coordinates and velocities, i.e., transformations in particle phase space. With such transformations, a finite degree-of-freedom drift-kinetic action is obtained through time-averaging of the finite degree-of-freedom fully-kinetic action. Variation of the drift-kinetic Lagrangian density leads to a self-consistent, macro-particles and fields numerical model. Since the computational particles utilize only guiding center coordinates and velocities, there is a large computational advantage in the time integration part of the algorithm. Numerical comparison between the time-averaged fully-kinetic and drift-kinetic charge and...
A continuous-time neural model for sequential action
Kachergis, George; Wyatte, Dean; O'Reilly, Randall C.; de Kleijn, Roy; Hommel, Bernhard
2014-01-01
Action selection, planning and execution are continuous processes that evolve over time, responding to perceptual feedback as well as evolving top-down constraints. Existing models of routine sequential action (e.g. coffee- or pancake-making) generally fall into one of two classes: hierarchical models that include hand-built task representations, or heterarchical models that must learn to represent hierarchy via temporal context, but thus far lack goal-orientedness. We present a biologically ...
An introduction to Space Weather Integrated Modeling
Zhong, D.; Feng, X.
2012-12-01
The need for a software toolkit that integrates space weather models and data is one of many challenges we are facing with when applying the models to space weather forecasting. To meet this challenge, we have developed Space Weather Integrated Modeling (SWIM) that is capable of analysis and visualizations of the results from a diverse set of space weather models. SWIM has a modular design and is written in Python, by using NumPy, matplotlib, and the Visualization ToolKit (VTK). SWIM provides data management module to read a variety of spacecraft data products and a specific data format of Solar-Interplanetary Conservation Element/Solution Element MHD model (SIP-CESE MHD model) for the study of solar-terrestrial phenomena. Data analysis, visualization and graphic user interface modules are also presented in a user-friendly way to run the integrated models and visualize the 2-D and 3-D data sets interactively. With these tools we can locally or remotely analysis the model result rapidly, such as extraction of data on specific location in time-sequence data sets, plotting interplanetary magnetic field lines, multi-slicing of solar wind speed, volume rendering of solar wind density, animation of time-sequence data sets, comparing between model result and observational data. To speed-up the analysis, an in-situ visualization interface is used to support visualizing the data 'on-the-fly'. We also modified some critical time-consuming analysis and visualization methods with the aid of GPU and multi-core CPU. We have used this tool to visualize the data of SIP-CESE MHD model in real time, and integrated the Database Model of shock arrival, Shock Propagation Model, Dst forecasting model and SIP-CESE MHD model developed by SIGMA Weather Group at State Key Laboratory of Space Weather/CAS.
The STAMP Software for State Space Models
Directory of Open Access Journals (Sweden)
Roy Mendelssohn
2011-05-01
Full Text Available This paper reviews the use of STAMP (Structural Time Series Analyser, Modeler and Predictor for modeling time series data using state-space methods with unobserved components. STAMP is a commercial, GUI-based program that runs on Windows, Linux and Macintosh computers as part of the larger OxMetrics System. STAMP can estimate a wide-variety of both univariate and multivariate state-space models, provides a wide array of diagnostics, and has a batch mode capability. The use of STAMP is illustrated for the Nile river data which is analyzed throughout this issue, as well as by modeling a variety of oceanographic and climate related data sets. The analyses of the oceanographic and climate data illustrate the breadth of models available in STAMP, and that state-space methods produce results that provide new insights into important scientific problems.
Multivariable Wind Modeling in State Space
DEFF Research Database (Denmark)
Sichani, Mahdi Teimouri; Pedersen, B. J.
2011-01-01
Turbulence of the incoming wind field is of paramount importance to the dynamic response of wind turbines. Hence reliable stochastic models of the turbulence should be available from which time series can be generated for dynamic response and structural safety analysis. In the paper an empirical...... the succeeding state space and ARMA modeling of the turbulence rely on the positive definiteness of the cross-spectral density matrix, the problem with the non-positive definiteness of such matrices is at first addressed and suitable treatments regarding it are proposed. From the adjusted positive definite cross......-spectral density matrix a frequency response matrix is constructed which determines the turbulence vector as a linear filtration of Gaussian white noise. Finally, an accurate state space modeling method is proposed which allows selection of an appropriate model order, and estimation of a state space model...
Inequality Constrained State Space Models
Qian, Hang
2015-01-01
The standard Kalman filter cannot handle inequality constraints imposed on the state variables, as state truncation induces a non-linear and non-Gaussian model. We propose a Rao-Blackwellised particle filter with the optimal importance function for forward filtering and the likelihood function evaluation. The particle filter effectively enforces the state constraints when the Kalman filter violates them. We find substantial Monte Carlo variance reduction by using the optimal importance functi...
Population coding of visual space: modeling
Directory of Open Access Journals (Sweden)
Sidney R Lehky
2011-02-01
Full Text Available We examine how the representation of space is affected by receptive field (RF characteristics of the encoding population. Spatial responses were defined by overlapping Gaussian RFs. These responses were analyzed using multidimensional scaling to extract the representation of global space implicit in population activity. Spatial representations were based purely on firing rates, which were not labeled with receptive field characteristics (tuning curve peak location, for example, differentiating this approach from many other population coding models. Because responses were unlabeled, this model represents space using intrinsic coding, extracting relative positions amongst stimuli, rather than extrinsic coding where known RF characteristics provide a reference frame for extracting absolute positions. Two parameters were particularly important: RF diameter and RF dispersion, where dispersion indicates how broadly RF centers are spread out from the fovea. For large RFs, the model was able to form metrically accurate representations of physical space on low-dimensional manifolds embedded within the high-dimensional neural population response space, suggesting that in some cases the neural representation of space may be dimensionally isomorphic with 3D physical space. Smaller RF sizes degraded and distorted the spatial representation, with the smallest RF sizes (present in early visual areas being unable to recover even a topologically consistent rendition of space on low-dimensional manifolds. Finally, although positional invariance of stimulus responses has long been associated with large receptive fields in object recognition models, we found RF dispersion rather than RF diameter to be the critical parameter. In fact, at a population level, the modeling suggests that higher ventral stream areas with highly restricted RF dispersion would be unable to achieve positionally-invariant representations beyond this narrow region around fixation.
A continuous-time neural model for sequential action.
Kachergis, George; Wyatte, Dean; O'Reilly, Randall C; de Kleijn, Roy; Hommel, Bernhard
2014-11-01
Action selection, planning and execution are continuous processes that evolve over time, responding to perceptual feedback as well as evolving top-down constraints. Existing models of routine sequential action (e.g. coffee- or pancake-making) generally fall into one of two classes: hierarchical models that include hand-built task representations, or heterarchical models that must learn to represent hierarchy via temporal context, but thus far lack goal-orientedness. We present a biologically motivated model of the latter class that, because it is situated in the Leabra neural architecture, affords an opportunity to include both unsupervised and goal-directed learning mechanisms. Moreover, we embed this neurocomputational model in the theoretical framework of the theory of event coding (TEC), which posits that actions and perceptions share a common representation with bidirectional associations between the two. Thus, in this view, not only does perception select actions (along with task context), but actions are also used to generate perceptions (i.e. intended effects). We propose a neural model that implements TEC to carry out sequential action control in hierarchically structured tasks such as coffee-making. Unlike traditional feedforward discrete-time neural network models, which use static percepts to generate static outputs, our biological model accepts continuous-time inputs and likewise generates non-stationary outputs, making short-timescale dynamic predictions. PMID:25267830
A continuous-time neural model for sequential action.
Kachergis, George; Wyatte, Dean; O'Reilly, Randall C; de Kleijn, Roy; Hommel, Bernhard
2014-11-01
Action selection, planning and execution are continuous processes that evolve over time, responding to perceptual feedback as well as evolving top-down constraints. Existing models of routine sequential action (e.g. coffee- or pancake-making) generally fall into one of two classes: hierarchical models that include hand-built task representations, or heterarchical models that must learn to represent hierarchy via temporal context, but thus far lack goal-orientedness. We present a biologically motivated model of the latter class that, because it is situated in the Leabra neural architecture, affords an opportunity to include both unsupervised and goal-directed learning mechanisms. Moreover, we embed this neurocomputational model in the theoretical framework of the theory of event coding (TEC), which posits that actions and perceptions share a common representation with bidirectional associations between the two. Thus, in this view, not only does perception select actions (along with task context), but actions are also used to generate perceptions (i.e. intended effects). We propose a neural model that implements TEC to carry out sequential action control in hierarchically structured tasks such as coffee-making. Unlike traditional feedforward discrete-time neural network models, which use static percepts to generate static outputs, our biological model accepts continuous-time inputs and likewise generates non-stationary outputs, making short-timescale dynamic predictions.
In-Space Chemical Propulsion System Model
Byers, David C.; Woodcock, Gordon; Benfield, Michael P. J.
2004-01-01
Multiple, new technologies for chemical systems are becoming available and include high temperature rockets, very light propellant tanks and structures, new bipropellant and monopropellant options, lower mass propellant control components, and zero boil off subsystems. Such technologies offer promise of increasing the performance of in-space chemical propulsion for energetic space missions. A mass model for pressure-fed, Earth and space-storable, advanced chemical propulsion systems (ACPS) was developed in support of the NASA MSFC In-Space Propulsion Program. Data from flight systems and studies defined baseline system architectures and subsystems and analyses were formulated for parametric scaling relationships for all ACPS subsystem. The paper will first provide summary descriptions of the approaches used for the systems and the subsystems and then present selected analyses to illustrate use of the model for missions with characteristics of current interest.
Developing Viable Financing Models for Space Tourism
Eilingsfeld, F.; Schaetzler, D.
2002-01-01
Increasing commercialization of space services and the impending release of government's control of space access promise to make space ventures more attractive. Still, many investors shy away from going into the space tourism market as long as they do not feel secure that their return expectations will be met. First and foremost, attracting investors from the capital markets requires qualifying financing models. Based on earlier research on the cost of capital for space tourism, this paper gives a brief run-through of commercial, technical and financial due diligence aspects. After that, a closer look is taken at different valuation techniques as well as alternative ways of streamlining financials. Experience from earlier ventures has shown that the high cost of capital represents a significant challenge. Thus, the sophistication and professionalism of business plans and financial models needs to be very high. Special emphasis is given to the optimization of the debt-to-equity ratio over time. The different roles of equity and debt over a venture's life cycle are explained. Based on the latter, guidelines for the design of an optimized loan structure are given. These are then applied to simulating the financial performance of a typical space tourism venture over time, including the calculation of Weighted Average Cost of Capital (WACC) and Net Present Value (NPV). Based on a concluding sensitivity analysis, the lessons learned are presented. If applied properly, these will help to make space tourism economically viable.
Directory of Open Access Journals (Sweden)
Abdeldjallil eNaceri
2015-09-01
Full Text Available In our daily life experience, the angular size of an object correlates with its distance from the observer, provided that the physical size of the object remains constant. In this work, we investigated depth perception in action space (i.e., beyond the arm reach, while keeping the angular size of the target object constant. This was achieved by increasing the physical size of the target object as its distance to the observer increased. To the best of our knowledge, this is the first time that a similar protocol has been tested in action space, for distances to the observer ranging from 1.4 to 2.4m. We replicated the task in virtual and real environments and we found that the performance was significantly different between the two environments. In the real environment, all participants perceived the depth of the target object precisely. Whereas, in virtual reality the responses were significantly less precise, although, still above chance level in 16 of the 20 observers. The difference in the discriminability of the stimuli was likely due to different contributions of the convergence and the accommodation cues in the two environments. The values of Weber fractions estimated in our study were compared to those reported in previous studies in peripersonal and action space.
Making action-angle disc models for Gaia
McMillan, Paul J
2015-01-01
A brief review of recent work. I describe dynamical modelling of the Milky Way using action-angle coordinates. I explain what action-angle coordinates are, and what progress has been made in the past few years to ensuring they can be used in reasonably realistic Galactic potentials. I then describe recent modelling efforts, and progress they have made in constraining the potential of the Milky Way and the local dark matter density.
Institutional Model of Decentralization in Action
Azis, Iwan J.
2011-01-01
Applying the Institutional Model of Decentralization, the paper argues that the presumption that local democracy will impose accountability pressure on elected officials does not always hold. Even in a democratic system like in Indonesia, decentralization policy is welfare-enhancing only for the developed regions, not for all, exacerbating interregional welfare disparity. This "captured democracy" is largely due to the presence of "negative local capture". Where welfare has not improved, limi...
Habitability Concept Models for Living in Space
Ferrino, M.
2002-01-01
As growing trends show, living in "space" has acquired new meanings, especially considering the utilization of the International Space Station (ISS) with regard to group interaction as well as individual needs in terms of time, space and crew accommodations. In fact, for the crew, the Spaced Station is a combined Laboratory-Office/Home and embodies ethical, social, and cultural aspects as additional parameters to be assessed to achieve a user centered architectural design of crew workspace. Habitability Concept Models can improve the methods and techniques used to support the interior design and layout of space architectures and at the same time guarantee a human focused approach. This paper discusses and illustrates some of the results obtained for the interior design of a Habitation Module for the ISS. In this work, two different but complementary approaches are followed. The first is "object oriented" and based on Video Data (American and Russian) supported by Proxemic methods (Edward T. Hall, 1963 and Francesca Pregnolato, 1998). This approach offers flexible and adaptive design solutions. The second is "subject oriented" and based on a Virtual Reality environment. With this approach human perception and cognitive aspects related to a specific crew task are considered. Data obtained from these two approaches are used to verify requirements and advance the design of the Habitation Module for aspects related to man machine interfaces (MMI), ergonomics, work and free-time. It is expected that the results achieved can be applied to future space related projects.
Gauge invariant actions for string models
Energy Technology Data Exchange (ETDEWEB)
Banks, T.
1986-06-01
String models of unified interactions are elegant sets of Feynman rules for the scattering of gravitons, gauge bosons, and a host of massive excitations. The purpose of these lectures is to describe the progress towards a nonperturbative formulation of the theory. Such a formulation should make the geometrical meaning of string theory manifest and explain the many ''miracles'' exhibited by the string Feynman rules. There are some new results on gauge invariant observables, on the cosmological constant, and on the symmetries of interacting string field theory. 49 refs.
Gauge invariant actions for string models
International Nuclear Information System (INIS)
String models of unified interactions are elegant sets of Feynman rules for the scattering of gravitons, gauge bosons, and a host of massive excitations. The purpose of these lectures is to describe the progress towards a nonperturbative formulation of the theory. Such a formulation should make the geometrical meaning of string theory manifest and explain the many ''miracles'' exhibited by the string Feynman rules. There are some new results on gauge invariant observables, on the cosmological constant, and on the symmetries of interacting string field theory. 49 refs
Concepts of disability: the Activity Space Model.
Kopec, J A
1995-03-01
This paper describes a new conceptual framework for functional assessment, the Activity Space Model (ASM). According to this model, functional impairments may lead to restrictions in an individual's activity space, a multidimensional space that represents human potential for activity. For each elementary ability, restrictions in the corresponding dimension of the activity space can be evaluated by deriving a difficulty curve that depicts the relationship between the level of performance and the psychophysical cost of activity. The effect of disease on daily functioning is explained in terms of a tradeoff between the psychophysical cost and the value of each act of behavior to the disabled individual. These two constructs are measured on the same scale and expressed in units of difficulty. The location of each task within the activity space in relation to the difficulty curve determines whether it will be performed or avoided at a given point in time. The ASM has both theoretical and practical implications. It offers a new, integrated perspective on disability and suggests new strategies for developing and evaluating functional assessment measures.
A computational model of perception and action for cognitive robotics.
Haazebroek, Pascal; van Dantzig, Saskia; Hommel, Bernhard
2011-11-01
Robots are increasingly expected to perform tasks in complex environments. To this end, engineers provide them with processing architectures that are based on models of human information processing. In contrast to traditional models, where information processing is typically set up in stages (i.e., from perception to cognition to action), it is increasingly acknowledged by psychologists and robot engineers that perception and action are parts of an interactive and integrated process. In this paper, we present HiTEC, a novel computational (cognitive) model that allows for direct interaction between perception and action as well as for cognitive control, demonstrated by task-related attentional influences. Simulation results show that key behavioral studies can be readily replicated. Three processing aspects of HiTEC are stressed for their importance for cognitive robotics: (1) ideomotor learning of action control, (2) the influence of task context and attention on perception, action planning, and learning, and (3) the interaction between perception and action planning. Implications for the design of cognitive robotics are discussed.
Cosmological Models with Fractional Derivatives and Fractional Action Functional
Institute of Scientific and Technical Information of China (English)
V.K. Shchigolev
2011-01-01
Cosmological models of a scalar field with dynamical equations containing fractional derivatives or derived from the Einstein-Hilbert action of fractional order, are constructed. A number of exact solutions to those equations of fractional cosmological models in both eases is given.
Approximate Methods for State-Space Models
Koyama, Shinsuke; Shalizi, Cosma Rohilla; Kass, Robert E; 10.1198/jasa.2009.tm08326
2010-01-01
State-space models provide an important body of techniques for analyzing time-series, but their use requires estimating unobserved states. The optimal estimate of the state is its conditional expectation given the observation histories, and computing this expectation is hard when there are nonlinearities. Existing filtering methods, including sequential Monte Carlo, tend to be either inaccurate or slow. In this paper, we study a nonlinear filter for nonlinear/non-Gaussian state-space models, which uses Laplace's method, an asymptotic series expansion, to approximate the state's conditional mean and variance, together with a Gaussian conditional distribution. This {\\em Laplace-Gaussian filter} (LGF) gives fast, recursive, deterministic state estimates, with an error which is set by the stochastic characteristics of the model and is, we show, stable over time. We illustrate the estimation ability of the LGF by applying it to the problem of neural decoding and compare it to sequential Monte Carlo both in simulat...
Do absolutely irreducible group actions have odd dimensional fixed point spaces?
Lauterbach, Reiner
2010-01-01
In his volume [5] on "Symmetry Breaking for Compact Lie Groups" Mike Field quotes a private communication by Jorge Ize claiming that any bifurcation problem with absolutely irreducible group action would lead to bifurcation of steady states. The proof should come from the fact that any absolutely irreducible representation possesses an odd dimensional fixed point space. In this paper we show that there are many examples of groups which have absolutely irreducible representations but no odd dimensional fixed point space. This observation may be relevant also for some degree theoretic considerations concerning equivariant bifurcation. Moreover we show that our examples give rise to some interesting Hamiltonian dynamics and we show that despite some complications we can go a long way towards doing explicit computations and providing complete proofs. For some of the invariant theory needed we will depend on some computer aided computations. The work presented here greatly benefited from the computer algebra progr...
Lag space estimation in time series modelling
DEFF Research Database (Denmark)
Goutte, Cyril
1997-01-01
The purpose of this article is to investigate some techniques for finding the relevant lag-space, i.e. input information, for time series modelling. This is an important aspect of time series modelling, as it conditions the design of the model through the regressor vector a.k.a. the input layer i...... in a neural network. We give a rough description of the problem, insist on the concept of generalisation, and propose a generalisation-based method. We compare it to a non-parametric test, and carry out experiments, both on the well-known Henon map, and on a real data set...
Study on Strand Space Model Theory
Institute of Scientific and Technical Information of China (English)
JI QingGuang(季庆光); QING SiHan(卿斯汉); ZHOU YongBin(周永彬); FENG DengGuo(冯登国)
2003-01-01
The growing interest in the application of formal methods of cryptographic pro-tocol analysis has led to the development of a number of different ways for analyzing protocol. Inthis paper, it is strictly proved that if for any strand, there exists at least one bundle containingit, then an entity authentication protocol is secure in strand space model (SSM) with some smallextensions. Unfortunately, the results of attack scenario demonstrate that this protocol and the Yahalom protocol and its modification are de facto insecure. By analyzing the reasons of failure offormal inference in strand space model, some deficiencies in original SSM are pointed out. In orderto break through these limitations of analytic capability of SSM, the generalized strand space model(GSSM) induced by some protocol is proposed. In this model, some new classes of strands, oraclestrands, high order oracle strands etc., are developed, and some notions are formalized strictly in GSSM, such as protocol attacks, valid protocol run and successful protocol run. GSSM can thenbe used to further analyze the entity authentication protocol. This analysis sheds light on why thisprotocol would be vulnerable while it illustrates that GSSM not only can prove security protocolcorrect, but also can be efficiently used to construct protocol attacks. It is also pointed out thatusing other protocol to attack some given protocol is essentially the same as the case of using themost of protocol itself.
The Perception-Action Model: Counting Computational Mechanisms
DEFF Research Database (Denmark)
Grünbaum, Thor
2016-01-01
Milner and Goodale’s Two Visual Systems Hypothesis (TVSH) is regarded as common ground in recent discussions of visual consciousness. A central part of TVSH is a functional model of vision and action (a functional perception-action model, PAM for short). In this paper, I provide a brief overview...... of these current discussions and argue that PAM is ambiguous between a strong and a weak version. I argue that, given a standard way of individuating computational mechanisms, the available evidence cannot be used to distinguish between these versions. This not only has consequences for philosophical theories...
Modelling of Patterns in Space and Time
Murray, James
1984-01-01
This volume contains a selection of papers presented at the work shop "Modelling of Patterns in Space and Time", organized by the 80nderforschungsbereich 123, "8tochastische Mathematische Modelle", in Heidelberg, July 4-8, 1983. The main aim of this workshop was to bring together physicists, chemists, biologists and mathematicians for an exchange of ideas and results in modelling patterns. Since the mathe matical problems arising depend only partially on the particular field of applications the interdisciplinary cooperation proved very useful. The workshop mainly treated phenomena showing spatial structures. The special areas covered were morphogenesis, growth in cell cultures, competition systems, structured populations, chemotaxis, chemical precipitation, space-time oscillations in chemical reactors, patterns in flames and fluids and mathematical methods. The discussions between experimentalists and theoreticians were especially interesting and effective. The editors hope that these proceedings reflect ...
Generation of action plans for two mobile robots designed to operate in a space full of obstacles
International Nuclear Information System (INIS)
The paper describes a simulation study conducted on an action plan generator for two mobile robots designed to operate in a space full of obstacles. This plan generator should be able to convert an objective specified by a user into a series of elementary actions, thus reflecting the 'intelligent' behaviour of robots. These actions involve finding the optimum path, avoiding obstacles (for each robot), and solving navigational problems, namely detecting robot-robot collisions and critical situations. A model representing the environment in which the path has to be found is described. The course obtained is optimized by applying a variant of the 'branch and bound' A* algorithm, assigning to each section of the path a cost which is, in fact, the minimum distance to be covered. The navigation strategy is based on the analysis of the paths found and the application of the traffic rules. In order to do this, it was necessary to introduce a classification based on the risks of collision in areas referred to as 'static interference zones'. (author). 8 refs, 7 figs
Indian Academy of Sciences (India)
Debashish Goswami
2015-02-01
Let be one of the classical compact, simple, centre-less, connected Lie groups of rank with a maximal torus , the Lie algebra $\\mathcal{G}$ and let $\\{E_{i},F_{i},H_{i},i=1,\\ldots,n\\}$ be tha standard set of generators corresponding to a basis of the root system. Consider the adjoint-orbit space $M=\\{\\text{Ad}_{g}(H_{1}), g\\in G\\}$, identified with the homogeneous space / where $L=\\{g\\in G : \\text{Ad}_{g}(H_{1})=H_{1}\\}$. We prove that the coordinate functions $f_{i}(g):=_{i}(\\text{Ad}_{g}(H_{1}))$, $i=1,\\ldots,n$, where $\\{_{1},\\ldots,_{n}\\}$ is basis of $\\mathcal{G}'$ are `quadratically independent' in the sense that they do not satisfy any nontrivial homogeneous quadratic relations among them. Using this, it is proved that there is no genuine compact quantum group which can act faithfully on $C(M)$ such that the action leaves invariant the linear span of the above coordinate functions. As a corollary, it is also shown that any compact quantum group having a faithful action on the noncommutative manifold obtained by Rieffel deformation of satisfying a similar `linearity' condition must be a Rieffel-Wang type deformation of some compact group.
Data Model Management for Space Information Systems
Hughes, J. Steven; Crichton, Daniel J.; Ramirez, Paul; Mattmann, chris
2006-01-01
The Reference Architecture for Space Information Management (RASIM) suggests the separation of the data model from software components to promote the development of flexible information management systems. RASIM allows the data model to evolve independently from the software components and results in a robust implementation that remains viable as the domain changes. However, the development and management of data models within RASIM are difficult and time consuming tasks involving the choice of a notation, the capture of the model, its validation for consistency, and the export of the model for implementation. Current limitations to this approach include the lack of ability to capture comprehensive domain knowledge, the loss of significant modeling information during implementation, the lack of model visualization and documentation capabilities, and exports being limited to one or two schema types. The advent of the Semantic Web and its demand for sophisticated data models has addressed this situation by providing a new level of data model management in the form of ontology tools. In this paper we describe the use of a representative ontology tool to capture and manage a data model for a space information system. The resulting ontology is implementation independent. Novel on-line visualization and documentation capabilities are available automatically, and the ability to export to various schemas can be added through tool plug-ins. In addition, the ingestion of data instances into the ontology allows validation of the ontology and results in a domain knowledge base. Semantic browsers are easily configured for the knowledge base. For example the export of the knowledge base to RDF/XML and RDFS/XML and the use of open source metadata browsers provide ready-made user interfaces that support both text- and facet-based search. This paper will present the Planetary Data System (PDS) data model as a use case and describe the import of the data model into an ontology tool
Recommendations to Improve Space Projection Models and University Space Usage
Stigall, Sam W.
2007-01-01
In today"s economy, public university administrators need to reflect on current practices for reporting and projecting space requirements to government entities as the cost of constructing new facilities or renovating space rises while income from legislative appropriations diminishes. As stewards of public buildings and funds, institutions are…
Jointly structuring triadic spaces of meaning and action: book sharing from 3 months on.
Directory of Open Access Journals (Sweden)
Nicole eRossmanith
2014-12-01
Full Text Available This study explores the emergence of triadic interactions through the example of book sharing. As part of a naturalistic study, 10 infants were visited in their homes from 3-12 months. We report that (1 book sharing as a form of infant-caregiver-object interaction occurred from as early as 3 months. Using qualitative video analysis at a micro-level adapting methodologies from conversation and interaction analysis, we demonstrate that caregivers and infants practiced book sharing in a highly co-ordinated way, with caregivers carving out interaction units and shaping actions into action arcs and infants actively participating and co-ordinating their attention between mother and object from the beginning. We also (2 sketch a developmental trajectory of book sharing over the first year and show that the quality and dynamics of book sharing interactions underwent considerable change as the ecological situation was transformed in parallel with the infants' development of attention and motor skills. Social book sharing interactions reached an early peak at 6 months with the infants becoming more active in the coordination of attention between caregiver and book. From 7-9 months, the infants shifted their interest largely to solitary object exploration, in parallel with newly emerging postural and object manipulation skills, disrupting the social coordination and the cultural frame of book sharing. In the period from 9-12 months, social book interactions resurfaced, as infants began to effectively integrate object actions within the socially shared activity. In conclusion, to fully understand the development and qualities of triadic cultural activities such as book sharing, we need to look especially at the hitherto overlooked early period from 4-6 months, and investigate how shared spaces of meaning and action are structured together in and through interaction, creating the substrate for continuing cooperation and cultural learning.
A biologically plausible embodied model of action discovery
Directory of Open Access Journals (Sweden)
Rufino eBolado-Gomez
2013-03-01
Full Text Available During development, animals can spontaneously discover action-outcomepairings enabling subsequent achievement of their goals. We present abiologically plausible embodied model addressing key aspects of thisprocess. The biomimetic model core comprises the basal ganglia and itsloops through cortex and thalamus. We incorporate reinforcementlearning with phasic dopamine supplying a sensory prediction error,signalling 'surprising' outcomes. Phasic dopamine is used in acorticostriatal learning rule which is consistent with recent data. Wealso hypothesised that objects associated with surprising outcomesacquire 'novelty salience' contingent on the predicability of theoutcome. To test this idea we used a simple model of predictiongoverning the dynamics of novelty salience and phasic dopamine. Thetask of the virtual robotic agent mimicked an in vivo counterpart(Gancarz et al., 2011 and involved interaction with a target objectwhich caused a light flash, or a control object which did not.Learning took place according to two schedules. In one, the phasicoutcome was delivered after interaction with the target in anunpredictable way which emulated the in vivo protocol. Without noveltysalience, the model was unable to account for the experimental data.In the other schedule, the phasic outcome was reliably delivered andthe agent showed a rapid increase in the number of interactions withthe target which then decreased over subsequent sessions. We arguethis is precisely the kind of change in behaviour required torepeatedly present representations of context, action and outcome, toneural networks responsible for learning action-outcome contingency.The model also showed corticostriatal plasticity consistent withlearning a new action in basal ganglia. We conclude that actionlearning is underpinned by a complex interplay of plasticity andstimulus salience, and that our model contains many of the elementsfor biological action discovery to take place.
String states, loops and effective actions in noncommutative field theory and matrix models
Steinacker, Harold C.
2016-09-01
Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
String states, loops and effective actions in noncommutative field theory and matrix models
Directory of Open Access Journals (Sweden)
Harold C. Steinacker
2016-09-01
Full Text Available Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
String states, loops and effective actions in noncommutative field theory and matrix models
Steinacker, Harold C
2016-01-01
Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
Mathematical models for space shuttle ground systems
Tory, E. G.
1985-01-01
Math models are a series of algorithms, comprised of algebraic equations and Boolean Logic. At Kennedy Space Center, math models for the Space Shuttle Systems are performed utilizing the Honeywell 66/80 digital computers, Modcomp II/45 Minicomputers and special purpose hardware simulators (MicroComputers). The Shuttle Ground Operations Simulator operating system provides the language formats, subroutines, queueing schemes, execution modes and support software to write, maintain and execute the models. The ground systems presented consist primarily of the Liquid Oxygen and Liquid Hydrogen Cryogenic Propellant Systems, as well as liquid oxygen External Tank Gaseous Oxygen Vent Hood/Arm and the Vehicle Assembly Building (VAB) High Bay Cells. The purpose of math modeling is to simulate the ground hardware systems and to provide an environment for testing in a benign mode. This capability allows the engineers to check out application software for loading and launching the vehicle, and to verify the Checkout, Control, & Monitor Subsystem within the Launch Processing System. It is also used to train operators and to predict system response and status in various configurations (normal operations, emergency and contingent operations), including untried configurations or those too dangerous to try under real conditions, i.e., failure modes.
Edgeworth streaming model for redshift space distortions
Uhlemann, Cora
2015-01-01
We derive the Edgeworth streaming model (ESM) for the redshift space correlation function starting from an arbitrary distribution function for biased tracers of dark matter by considering its two-point statistics and show that it reduces to the Gaussian streaming model (GSM) when neglecting non-Gaussianities. We test the accuracy of the GSM and ESM independent of perturbation theory using the Horizon Run 2 N-body halo catalog. While the monopole of the redshift space halo correlation function is well described by the GSM, higher multipoles improve upon including the leading order non-Gaussian correction in the ESM: the GSM quadrupole breaks down on scales below 30 Mpc/h whereas the ESM stays accurate to 2% within statistical errors down to 10 Mpc/h. To predict the scale dependent functions entering the streaming model we employ Convolution Lagrangian perturbation theory (CLPT) based on the dust model and local Lagrangian bias. Since dark matter halos carry an intrinsic length scale given by their Lagrangian r...
Cognitive engineering models in space systems
Mitchell, Christine M.
1993-01-01
NASA space systems, including mission operations on the ground and in space, are complex, dynamic, predominantly automated systems in which the human operator is a supervisory controller. Models of cognitive functions in complex systems are needed to describe human performance and form the theoretical basis of operator workstation design, including displays, controls, and decision aids. Currently, there several candidate modeling methodologies. They include the Rasmussen abstraction/aggregation hierarchy and decision ladder, the goal-means network, the problem behavior graph, and the operator function model. The research conducted under the sponsorship of this grant focuses on the extension of the theoretical structure of the operator function model and its application to NASA Johnson mission operations and space station applications. The initial portion of this research consists of two parts. The first is a series of technical exchanges between NASA Johnson and Georgia Tech researchers. The purpose is to identify candidate applications for the current operator function model; prospects include mission operations and the Data Management System Testbed. The second portion will address extensions of the operator function model to tailor it to the specific needs of Johnson applications. At this point, we have accomplished two things. During a series of conversations with JSC researchers, we have defined the technical goal of the research supported by this grant to be the structural definition of the operator function model and its computer implementation, OFMspert. Both the OFM and OFMspert have matured to the point that they require infrastructure to facilitate use by researchers not involved in the evolution of the tools. The second accomplishment this year was the identification of the Payload Deployment and Retrieval System (PDRS) as a candidate system for the case study. In conjunction with government and contractor personnel in the Human-Computer Interaction Lab
Microblog Sentiment Analysis with Emoticon Space Model
Institute of Scientific and Technical Information of China (English)
姜飞; 刘奕群; 孙甲申; 朱璇; 张敏; 马少平
2015-01-01
Emoticons have been widely employed to express different types of moods, emotions, and feelings in microblog environments. They are therefore regarded as one of the most important signals for microblog sentiment analysis. Most existing studies use several emoticons that convey clear emotional meanings as noisy sentiment labels or similar sentiment indicators. However, in practical microblog environments, tens or even hundreds of emoticons are frequently adopted and all emoticons have their own unique emotional meanings. Besides, a considerable number of emoticons do not have clear emotional meanings. An improved sentiment analysis model should not overlook these phenomena. Instead of manually assigning sentiment labels to several emoticons that convey relatively clear meanings, we propose the emoticon space model (ESM) that leverages more emoticons to construct word representations from a massive amount of unlabeled data. By projecting words and microblog posts into an emoticon space, the proposed model helps identify subjectivity, polarity, and emotion in microblog environments. The experimental results for a public microblog benchmark corpus (NLP&CC 2013) indicate that ESM effectively leverages emoticon signals and outperforms previous state-of-the-art strategies and benchmark best runs.
Directory of Open Access Journals (Sweden)
Eleni Vasilaki
2009-12-01
Full Text Available Changes of synaptic connections between neurons are thought to be the physiological basis of learning. These changes can be gated by neuromodulators that encode the presence of reward. We study a family of reward-modulated synaptic learning rules for spiking neurons on a learning task in continuous space inspired by the Morris Water maze. The synaptic update rule modifies the release probability of synaptic transmission and depends on the timing of presynaptic spike arrival, postsynaptic action potentials, as well as the membrane potential of the postsynaptic neuron. The family of learning rules includes an optimal rule derived from policy gradient methods as well as reward modulated Hebbian learning. The synaptic update rule is implemented in a population of spiking neurons using a network architecture that combines feedforward input with lateral connections. Actions are represented by a population of hypothetical action cells with strong mexican-hat connectivity and are read out at theta frequency. We show that in this architecture, a standard policy gradient rule fails to solve the Morris watermaze task, whereas a variant with a Hebbian bias can learn the task within 20 trials, consistent with experiments. This result does not depend on implementation details such as the size of the neuronal populations. Our theoretical approach shows how learning new behaviors can be linked to reward-modulated plasticity at the level of single synapses and makes predictions about the voltage and spike-timing dependence of synaptic plasticity and the influence of neuromodulators such as dopamine. It is an important step towards connecting formal theories of reinforcement learning with neuronal and synaptic properties.
Vasilaki, Eleni; Frémaux, Nicolas; Urbanczik, Robert; Senn, Walter; Gerstner, Wulfram
2009-12-01
Changes of synaptic connections between neurons are thought to be the physiological basis of learning. These changes can be gated by neuromodulators that encode the presence of reward. We study a family of reward-modulated synaptic learning rules for spiking neurons on a learning task in continuous space inspired by the Morris Water maze. The synaptic update rule modifies the release probability of synaptic transmission and depends on the timing of presynaptic spike arrival, postsynaptic action potentials, as well as the membrane potential of the postsynaptic neuron. The family of learning rules includes an optimal rule derived from policy gradient methods as well as reward modulated Hebbian learning. The synaptic update rule is implemented in a population of spiking neurons using a network architecture that combines feedforward input with lateral connections. Actions are represented by a population of hypothetical action cells with strong mexican-hat connectivity and are read out at theta frequency. We show that in this architecture, a standard policy gradient rule fails to solve the Morris watermaze task, whereas a variant with a Hebbian bias can learn the task within 20 trials, consistent with experiments. This result does not depend on implementation details such as the size of the neuronal populations. Our theoretical approach shows how learning new behaviors can be linked to reward-modulated plasticity at the level of single synapses and makes predictions about the voltage and spike-timing dependence of synaptic plasticity and the influence of neuromodulators such as dopamine. It is an important step towards connecting formal theories of reinforcement learning with neuronal and synaptic properties. PMID:19997492
Integrated Space Asset Management Database and Modeling
Gagliano, L.; MacLeod, T.; Mason, S.; Percy, T.; Prescott, J.
The Space Asset Management Database (SAM-D) was implemented in order to effectively track known objects in space by ingesting information from a variety of databases and performing calculations to determine the expected position of the object at a specified time. While SAM-D performs this task very well, it is limited by technology and is not available outside of the local user base. Modeling and simulation can be powerful tools to exploit the information contained in SAM-D. However, the current system does not allow proper integration options for combining the data with both legacy and new M&S tools. A more capable data management infrastructure would extend SAM-D to support the larger data sets to be generated by the COI. A service-oriented architecture model will allow it to easily expand to incorporate new capabilities, including advanced analytics, M&S tools, fusion techniques and user interface for visualizations. Based on a web-centric approach, the entire COI will be able to access the data and related analytics. In addition, tight control of information sharing policy will increase confidence in the system, which would encourage industry partners to provide commercial data. SIMON is a Government off the Shelf information sharing platform in use throughout DoD and DHS information sharing and situation awareness communities. SIMON providing fine grained control to data owners allowing them to determine exactly how and when their data is shared. SIMON supports a micro-service approach to system development, meaning M&S and analytic services can be easily built or adapted. It is uniquely positioned to fill this need as an information-sharing platform with a proven track record of successful situational awareness system deployments. Combined with the integration of new and legacy M&S tools, a SIMON-based architecture will provide a robust SA environment for the NASA SA COI that can be extended and expanded indefinitely. First Results of Coherent Uplink from a
Dmitrievskiy, I.; Nechitailo, G.; Yurov, S.; Kuznetsov, A.
In space flights the biological objects are exposed to fields of different nature. Of all space flight factors we concentrated our attention on ionizing radiations the action of which was studied in experiments with bacteriophage T4B and with biological structures of the eye. In experiments with bacteriophages their viability and the mutagenic effect under the action of andronic radiation were studied. The effects of local action an phage particles expressed as an induction of deletions and a decrease in viability rate were revealed. We also present the biophysical mechanisms of occurrence of flashes in the eyes of cosmonauts during space flights. The well known hypotheses (Pazio G.G. et al., 1970; Charman W.N. et al, 1971) are based on the occurrence of Cherenkov radiation when a charged particle passes through the eye vitreous body and on a direct action of ionizing particles on the retina. A microdosimetric model was developed (Dmitrievskiy et al., 1982) to calculate the probability of a flash mechanisms. The calculate probability by the mechanism of direct action turned out to coincide with the experimental one and to be 3-4 orders of magnitude less by the mechanism of Cherenkov radiation. However, the experiments on an accelerator (Arodzero et al., 1987) showed that the contributions of the two mechanisms are roughly equal. This disagreement was eliminated due to taking into consideration the polarization of Cherenkov radiation and a highly efficient action of polarized light (established by us earlier) which is 103 - 104 times greater in the region of low intensities than the action of polarized light (Dmitrievskiy I.M., 1985). One more paradox- an increase of two orders of magnitude of visual acuity in cosmonauts watching in some cases terrestrial objects with the naked eye.
A probabilistic model of RNA conformational space
DEFF Research Database (Denmark)
Frellsen, Jes; Moltke, Ida; Thiim, Martin;
2009-01-01
The increasing importance of non-coding RNA in biology and medicine has led to a growing interest in the problem of RNA 3-D structure prediction. As is the case for proteins, RNA 3-D structure prediction methods require two key ingredients: an accurate energy function and a conformational sampling...... procedure. Both are only partly solved problems. Here, we focus on the problem of conformational sampling. The current state of the art solution is based on fragment assembly methods, which construct plausible conformations by stringing together short fragments obtained from experimental structures. However...... efficient sampling of RNA conformations in continuous space, and with associated probabilities. We show that the model captures several key features of RNA structure, such as its rotameric nature and the distribution of the helix lengths. Furthermore, the model readily generates native-like 3-D...
Merging linear discriminant analysis with Bag of Words model for human action recognition
Iosifidis, Alexandros; Tefas, Anastasios; Pitas, Ioannis
2016-01-01
In this paper we propose a novel method for human action recognition, that unifies discriminative Bag of Words (BoW)-based video representation and discriminant subspace learning. An iterative optimization scheme is proposed for sequential discriminant BoWs-based action representation and codebook adaptation based on action discrimination in a reduced dimensionality feature space where action classes are better discriminated. Experiments on four publicly available action recognition data sets...
Space weather: Modeling and forecasting ionospheric
International Nuclear Information System (INIS)
Full text: Space weather is the set of phenomena and interactions that take place in the interplanetary medium. It is regulated primarily by the activity originating in the Sun and affects both the artificial satellites that are outside of the protective cover of the Earth's atmosphere as the rest of the planets in the solar system. Among the phenomena that are of great relevance and impact on Earth are the auroras and geomagnetic storms , these are a direct result of irregularities in the flow of the solar wind and the interplanetary magnetic field . Given the high complexity of the physical phenomena involved (magnetic reconnection , particle inlet and ionizing radiation to the atmosphere) one of the great scientific challenges today is to forecast the state of plasmatic means either the interplanetary medium , the magnetosphere and ionosphere , for their importance to the development of various human activities such as radio , global positioning , navigation, etc. . It briefly address some of the international ionospheric modeling methods and contributions and participation that currently has the space group of the Institute of Geophysics Geophysics and Astronomy (IGA) in these activities of modeling and forecasting ionospheric. (author)
Directory of Open Access Journals (Sweden)
Stefano eTriberti
2016-01-01
Full Text Available Recent neuropsychological evidence suggest that a key role in linking perceptions and intentions is played by sense of presence. Despite this phenomenon having been studied primarily in the field of virtual reality (conceived as the illusion of being in the virtual space, recent research highlighted that it is a fundamental feature of everyday experience. Specifically, the function of presence as a cognitive process is to locate the Self in a physical space or situation, based on the perceived possibility to act in it; so, the variations in sense of presence allow one to continuously adapt his own action to the external environment. Indeed intentions, as the cognitive antecedents of action, are not static representations of the desired outcomes, but dynamic processes able to adjust their own representational content according to the opportunities/restrictions emerging in the environment. Focusing on the peculiar context of action mediated by interactive technologies, we here propose a theoretical model showing how each level of an intentional hierarchy (future-directed; present directed; and motor intentions can interlock with environmental affordances in order to promote a continuous stream of action and activity.
Triberti, Stefano; Riva, Giuseppe
2015-01-01
Recent neuropsychological evidence suggest that a key role in linking perceptions and intentions is played by sense of presence. Despite this phenomenon having been studied primarily in the field of virtual reality (conceived as the illusion of being in the virtual space), recent research highlighted that it is a fundamental feature of everyday experience. Specifically, the function of presence as a cognitive process is to locate the Self in a physical space or situation, based on the perceived possibility to act in it; so, the variations in sense of presence allow one to continuously adapt his own action to the external environment. Indeed intentions, as the cognitive antecedents of action, are not static representations of the desired outcomes, but dynamic processes able to adjust their own representational content according to the opportunities/restrictions emerging in the environment. Focusing on the peculiar context of action mediated by interactive technologies, we here propose a theoretical model showing how each level of an intentional hierarchy (future-directed; present directed; and motor intentions) can "interlock" with environmental affordances in order to promote a continuous stream of action and activity. PMID:26834670
Propagation of signals in spaces with affine connections and metrics as models of space-time
Manoff, Sawa
2003-01-01
The propagation of signals in space-time is considered on the basis of the notion of null (isotropic) vector field in spaces with affine connections and metrics as models of space or of space-time. The Doppler effect is generalized for these types of spaces. The notions of aberration, standard (longitudinal) Doppler effect, and transversal Doppler effect are considered. On their grounds, the Hubble effect appears as Doppler effect with explicit forms of the centrifugal (centripetal) and Corio...
Numerical Modeling of Ocular Dysfunction in Space
Nelson, Emily S.; Mulugeta, Lealem; Vera, J.; Myers, J. G.; Raykin, J.; Feola, A. J.; Gleason, R.; Samuels, B.; Ethier, C. R.
2014-01-01
Upon introduction to microgravity, the near-loss of hydrostatic pressure causes a marked cephalic (headward) shift of fluid in an astronaut's body. The fluid shift, along with other factors of spaceflight, induces a cascade of interdependent physiological responses which occur at varying time scales. Long-duration missions carry an increased risk for the development of the Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath, kinking of the optic nerve and potentially permanent degradation of visual function. In the cases of VIIP found to date, the initial onset of symptoms occurred after several weeks to several months of spaceflight, by which time the gross bodily fluid distribution is well established. We are developing a suite of numerical models to simulate the effects of fluid shift on the cardiovascular, central nervous and ocular systems. These models calculate the modified mean volumes, flow rates and pressures that are characteristic of the altered quasi-homeostatic state in microgravity, including intracranial and intraocular pressures. The results of the lumped models provide initial and boundary data to a 3D finite element biomechanics simulation of the globe, optic nerve head and retrobulbar subarachnoid space. The integrated set of models will be used to investigate the evolution of the biomechanical stress state in the ocular tissues due to long-term exposure to microgravity.
Exact solutions of SO(3) non-linear sigma model in a conic space background
Bezerra, V B; Romero, C
2005-01-01
We consider a nonlinear sigma model coupled to the metric of a conic space. We obtain restrictions for a nonlinear sigma model to be a source of the conic space. We then study nonlinear sigma model in the conic space background. We find coordinate transformations which reduce the chiral fields equations in the conic space background to field equations in Minkowski spacetime. This enables us to apply the same methods for obtaining exact solutions in Minkowski spacetime to the case of a conic spacetime. In the case the solutions depend on two spatial coordinates we employ Ivanov's geometrical ansatz. We give a general analysis and also present classes of solutions in which there is dependence on three and four coordinates. We discuss with special attention the intermediate instanton and meron solutions and their analogous in the conic space. We find differences in the total actions and topological charges of these solutions and discuss the role of the deficit angle.
Optimization using surrogate models - by the space mapping technique
DEFF Research Database (Denmark)
Søndergaard, Jacob
2003-01-01
conditions are satisfied. So hybrid methods, combining the space mapping technique with classical optimization methods, should be used if convergence to high accuracy is wanted. Approximation abilities of the space mapping surrogate are compared with those of a Taylor model of the expensive model. The space...... of the algorithms are hybrid algorithms. Convergence of a class of hybrid space mapping algorithms is proved.......Surrogate modelling and optimization techniques are intended for engineering design in the case where an expensive physical model is involved. This thesis provides a literature overview of the field of surrogate modelling and optimization. The space mapping technique is one such method...
Reputation and competition in a hidden action model.
Directory of Open Access Journals (Sweden)
Alessandro Fedele
Full Text Available The economics models of reputation and quality in markets can be classified in three categories. (i Pure hidden action, where only one type of seller is present who can provide goods of different quality. (ii Pure hidden information, where sellers of different types have no control over product quality. (iii Mixed frameworks, which include both hidden action and hidden information. In this paper we develop a pure hidden action model of reputation and Bertrand competition, where consumers and firms interact repeatedly in a market with free entry. The price of the good produced by the firms is contractible, whilst the quality is noncontractible, hence it is promised by the firms when a contract is signed. Consumers infer future quality from all available information, i.e., both from what they know about past quality and from current prices. According to early contributions, competition should make reputation unable to induce the production of high-quality goods. We provide a simple solution to this problem by showing that high quality levels are sustained as an outcome of a stationary symmetric equilibrium.
Reputation and competition in a hidden action model.
Fedele, Alessandro; Tedeschi, Piero
2014-01-01
The economics models of reputation and quality in markets can be classified in three categories. (i) Pure hidden action, where only one type of seller is present who can provide goods of different quality. (ii) Pure hidden information, where sellers of different types have no control over product quality. (iii) Mixed frameworks, which include both hidden action and hidden information. In this paper we develop a pure hidden action model of reputation and Bertrand competition, where consumers and firms interact repeatedly in a market with free entry. The price of the good produced by the firms is contractible, whilst the quality is noncontractible, hence it is promised by the firms when a contract is signed. Consumers infer future quality from all available information, i.e., both from what they know about past quality and from current prices. According to early contributions, competition should make reputation unable to induce the production of high-quality goods. We provide a simple solution to this problem by showing that high quality levels are sustained as an outcome of a stationary symmetric equilibrium. PMID:25329387
COST Action FP1005 ``Fibre suspension flow modelling''
Marchioli, Cristian
2013-11-01
Fibre suspensions are extremely complex solid-liquid systems since their components (fibres, flocs, air bubbles and additives) interact mutually in a complex way. The dynamics of fibre suspensions are crucial in many real-life applications, such as pulp and paper production. Current understanding of suspension flow dynamics remains poor and incomplete, resulting in conservative design of industrial equipments, low energy efficiency and equipment oversizing. In this paper, the most recent advancements in modelling and experimentation of fibre suspensions dynamics are presented. These advancements have been obtained in the framework of Action FP1005, funded by the COST Programme (European Cooperation in Science and Technology) to coordinate nationally-funded research on a European level. The Action aims at developing and validating numerical models for prediction of fibre suspensions as well as measurement techniques. The Action offers a forum to solve test cases and to compare simulated results to experiments, resulting in more reliable simulation tools to industry. Successfull introduction of such tool into industrial practice is crucial to innovate and increase competitivity of papermaking industry.
London, Leslie; Schneider, Helen
2012-01-01
While neoliberal globalisation is associated with increasing inequalities, global integration has simultaneously strengthened the dissemination of human rights discourse across the world. This paper explores the seeming contradiction that globalisation is conceived as disempowering nations states' ability to act in their population's interests, yet implementation of human rights obligations requires effective states to deliver socio-economic entitlements, such as health. Central to the actions required of the state to build a health system based on a human rights approach is the notion of accountability. Two case studies are used to explore the constraints on states meeting their human rights obligations regarding health, the first drawing on data from interviews with parliamentarians responsible for health in East and Southern Africa, and the second reflecting on the response to the HIV/AIDS epidemic in South Africa. The case studies illustrate the importance of a human rights paradigm in strengthening parliamentary oversight over the executive in ways that prioritise pro-poor protections and in increasing leverage for resources for the health sector within parliamentary processes. Further, a rights framework creates the space for civil society action to engage with the legislature to hold public officials accountable and confirms the importance of rights as enabling civil society mobilization, reinforcing community agency to advance health rights for poor communities. In this context, critical assessment of state incapacity to meet claims to health rights raises questions as to the diffusion of accountability rife under modern international aid systems. Such diffusion of accountability opens the door to 'cunning' states to deflect rights claims of their populations. We argue that human rights, as both a normative framework for legal challenges and as a means to create room for active civil society engagement provide a means to contest both the real and the
Integrability of geodesics and action-angle variables in Sasaki-Einstein space $T^{1,1}$
Visinescu, Mihai
2016-01-01
We briefly describe the construction of St\\"akel-Killing and Killing-Yano tensors on toric Sasaki-Einstein manifolds without working out intricate generalized Killing equations. The integrals of geodesic motions are expressed in terms of Killing vectors and Killing-Yano tensors of these spaces. We present the set of functionally independent integrals of motion for the homogeneous Sasaki-Einstein space $T^{1,1}$. We discuss the integrability of geodesics and construct explicitly the action-angle variables.
Modeling the reconstructed BAO in Fourier space
Seo, Hee-Jong; Beutler, Florian; Ross, Ashley J.; Saito, Shun
2016-08-01
The density field reconstruction technique, which partially reverses the non-linear degradation of the Baryon acoustic oscillation (BAO) feature in the galaxy redshift surveys, has been successful in substantially improving the cosmology constraints from recent surveys such as Baryon Oscillation Spectroscopic Survey (BOSS). We estimate the efficiency of the method as a function of various reconstruction details. To directly quantify the BAO information in non-linear density fields before and after reconstruction, we calculate the cross-correlations (i.e. propagators) of the pre(post)-reconstructed density field with the initial linear field using a mock sample that mimics the clustering of the BOSS galaxies. The results directly provide the BAO damping as a function of wavenumber that can be implemented into the Fisher matrix analysis. We focus on investigating the dependence of the propagator on a choice of smoothing filters and on two major different conventions of the redshift-space density field reconstruction that have been used in literature. By estimating the BAO signal to noise for each case, we predict constraints on the angular diameter distance and Hubble parameter using the Fisher matrix analysis. We thus determine an optimal Gaussian smoothing filter scale for the signal-to-noise level of the BOSS CMASS. We also present appropriate BAO fitting models for different reconstruction methods based on the first- and second-order Lagrangian perturbation theory in Fourier space. Using the mock data, we show that the modified BAO fitting model can substantially improve the accuracy of the BAO position in the best fits as well as the goodness of the fits.
Preliminaries to a Social-Semiotic Model of Communicative Action
Directory of Open Access Journals (Sweden)
Antonio SANDU
2015-12-01
Full Text Available The purpose of this article is to bring contributions to the elaboration of a social-semiotic model of social constructionism, which will make a synthesis between the theory of communicative action and the theories of social-constructionist semiotic model?, based on the postulation of a social universe in a network of communicative interdependencies developed on levels of reality. The interpretative model we propose comes to conceptualize the particularities of the sociological analysis of the transmodern society, seen as a knowledge-based society, placed at the interference with the postmodern society; that of generalized permissiveness. The model proposed aims at a constructionist-fractalic (al? analysis (of deconstruction-reconstruction type of the interpretative drift of social constructs, under the empire of different constructive instances.
Orland-Barak, Lily; Becher, Ayelet
2011-01-01
In this article we offer an extended reading of an action research model in the context of mentored learning in preservice education in Israel. Our reading attends both to how a particular form of action research plays out in participants' constructions of the practice of mentoring and mentored learning and how such constructions can be understood…
A dynamic appearance descriptor approach to facial actions temporal modeling.
Jiang, Bihan; Valstar, Michel; Martinez, Brais; Pantic, Maja
2014-02-01
Both the configuration and the dynamics of facial expressions are crucial for the interpretation of human facial behavior. Yet to date, the vast majority of reported efforts in the field either do not take the dynamics of facial expressions into account, or focus only on prototypic facial expressions of six basic emotions. Facial dynamics can be explicitly analyzed by detecting the constituent temporal segments in Facial Action Coding System (FACS) Action Units (AUs)-onset, apex, and offset. In this paper, we present a novel approach to explicit analysis of temporal dynamics of facial actions using the dynamic appearance descriptor Local Phase Quantization from Three Orthogonal Planes (LPQ-TOP). Temporal segments are detected by combining a discriminative classifier for detecting the temporal segments on a frame-by-frame basis with Markov Models that enforce temporal consistency over the whole episode. The system is evaluated in detail over the MMI facial expression database, the UNBC-McMaster pain database, the SAL database, the GEMEP-FERA dataset in database-dependent experiments, in cross-database experiments using the Cohn-Kanade, and the SEMAINE databases. The comparison with other state-of-the-art methods shows that the proposed LPQ-TOP method outperforms the other approaches for the problem of AU temporal segment detection, and that overall AU activation detection benefits from dynamic appearance information.
Chulaki, A.; Kuznetsova, M. M.; Rastaetter, L.; MacNeice, P. J.; Shim, J. S.; Pulkkinen, A. A.; Taktakishvili, A.; Mays, M. L.; Mendoza, A. M. M.; Zheng, Y.; Mullinix, R.; Collado-Vega, Y. M.; Maddox, M. M.; Pembroke, A. D.; Wiegand, C.
2015-12-01
Community Coordinated Modeling Center (CCMC) is a NASA affiliated interagency partnership with the primary goal of aiding the transition of modern space science models into space weather forecasting while supporting space science research. Additionally, over the past ten years it has established itself as a global space science education resource supporting undergraduate and graduate education and research, and spreading space weather awareness worldwide. A unique combination of assets, capabilities and close ties to the scientific and educational communities enable this small group to serve as a hub for raising generations of young space scientists and engineers. CCMC resources are publicly available online, providing unprecedented global access to the largest collection of modern space science models (developed by the international research community). CCMC has revolutionized the way simulations are utilized in classrooms settings, student projects, and scientific labs and serves hundreds of educators, students and researchers every year. Another major CCMC asset is an expert space weather prototyping team primarily serving NASA's interplanetary space weather needs. Capitalizing on its unrivaled capabilities and experiences, the team provides in-depth space weather training to students and professionals worldwide, and offers an amazing opportunity for undergraduates to engage in real-time space weather monitoring, analysis, forecasting and research. In-house development of state-of-the-art space weather tools and applications provides exciting opportunities to students majoring in computer science and computer engineering fields to intern with the software engineers at the CCMC while also learning about the space weather from the NASA scientists.
Linking knowledge and action through mental models of sustainable agriculture.
Hoffman, Matthew; Lubell, Mark; Hillis, Vicken
2014-09-01
Linking knowledge to action requires understanding how decision-makers conceptualize sustainability. This paper empirically analyzes farmer "mental models" of sustainability from three winegrape-growing regions of California where local extension programs have focused on sustainable agriculture. The mental models are represented as networks where sustainability concepts are nodes, and links are established when a farmer mentions two concepts in their stated definition of sustainability. The results suggest that winegrape grower mental models of sustainability are hierarchically structured, relatively similar across regions, and strongly linked to participation in extension programs and adoption of sustainable farm practices. We discuss the implications of our findings for the debate over the meaning of sustainability, and the role of local extension programs in managing knowledge systems.
Testing fermion actions. Scaling in the Schwinger model
International Nuclear Information System (INIS)
We test the scaling behaviour of Wilson, hypercube, maximally twisted mass and overlap fermion actions in dynamical simulations of the 2-dimensional massive Schwinger model. We also present possibilities to simulate overlap fermions dynamically by replacing the exact overlap operator by an approximate version. This approximation is used either as only the guidance Hamiltonian, keeping the exact overlap operator as the accept/reject Hamiltonian or for both, the guidance and accept/reject Hamiltonian in the Hybrid Monte Carlo algorithm. In the latter case we test whether the approximation error can be corrected for by computing the determinant ratio of the exact and the approximate overlap operators stochastically. (orig.)
The effective action approach applied to nuclear chiral sigma model
International Nuclear Information System (INIS)
The nuclear chiral sigma model of nuclear matter is considered by means of the Cornwall-Jackiw-tomboulis (CTJ) effective action. The method provides a very general framework for investigating many important problems: chiral symmetry in nuclear medium, energy density of nuclear ground state, nuclear Schwinger-Dyson (SD) equations, etc. It is shown that the SD equations for sigma-omega mixing are actually not present in this formalism. For numerical computation purposes the Hartree-Fock (HF) approximation for ground state energy density is also presented. (author). 26 refs
Gauge Potts model with generalized action: A Monte Carlo analysis
Energy Technology Data Exchange (ETDEWEB)
Fanchiotti, H.; Canal, C.A.G.; Sciutto, S.J.
1985-08-15
Results of a Monte Carlo calculation on the q-state gauge Potts model in d dimensions with a generalized action involving planar 1 x 1, plaquette, and 2 x 1, fenetre, loop interactions are reported. For d = 3 and q = 2, first- and second-order phase transitions are detected. The phase diagram for q = 3 presents only first-order phase transitions. For d = 2, a comparison with analytical results is made. Here also, the behavior of the numerical simulation in the vicinity of a second-order transition is analyzed.
The Diversity of Enterprise Modeling – a Taxonomy for Enterprise Modeling Actions
Directory of Open Access Journals (Sweden)
Ulf Seigerroth
2015-10-01
Full Text Available Both researchers and practitioners have recognized the need for developed knowledge about enterprise modeling. Therefore it is necessary to increase the understanding of various actions that are performed during enterprise modeling, their meaning, and their diversity. This paper proposes a taxonomy with a conceptual structure in two dimensions (hierarchy and process that could be used to increase the knowledge about enterprise modeling actions. The taxonomy introduces a terminology that enables a better understanding of the modeling actions for a clear purpose. One important aspect of the taxonomy is to create visibility and traceability of decisions made during enterprise modeling activities. These modeling decisions have previously been of a more tacit nature and the taxonomy is supposed to make the rationale behind different modeling decisions explicit and understandable.
Macro Level Simulation Model Of Space Shuttle Processing
2000-01-01
The contents include: 1) Space Shuttle Processing Simulation Model; 2) Knowledge Acquisition; 3) Simulation Input Analysis; 4) Model Applications in Current Shuttle Environment; and 5) Model Applications for Future Reusable Launch Vehicles (RLV's). This paper is presented in viewgraph form.
Complex Dynamic Thresholds and Generation of the Action Potentials in the Neural-Activity Model
Kirillov, S. Yu.; Nekorkin, V. I.
2016-05-01
This work is devoted to studying the processes of activation of the neurons whose excitation thresholds are not constant and vary in time (the so-called dynamic thresholds). The neuron dynamics is described by the FitzHugh-Nagumo model with nonlinear behavior of the recovery variable. The neuron response to the external pulsed activating action in the presence of a slowly varying synaptic current is studied within the framework of this model. The structure of the dynamic threshold is studied and its properties depending on the external-action parameters are established. It is found that the formation of the "folds" in the separatrix threshold manifold in the model phase space is a typical feature of the complex dynamic threshold. High neuron sensitivity to the action of the comparatively weak slow control signals is established. This explains the capability of the neurons to perform flexible tuning of their selective properties for detecting various external signals in sufficiently short times (of the order of duration of several spikes).
Weyl Action of Two-Column Mixed-Symmetry Field and Its Factorization Around (A)dS Space
Joung, Euihun
2016-01-01
We investigate the four-derivative free Weyl action for two-column mixed-symmetry field that makes use of maximal gauge symmetries. In flat space, the action can be uniquely determined from gauge and Weyl (trace shift) symmetry requirements. We show that there is a smooth and unique deformation of the flat action to (A)dS which keeps the same amount of gauge symmetries. This action admits a factorization into two distinct two-derivative actions having gauge parameters of different Young diagrams. Hence, this factorization pattern naturally extends that of the Weyl actions of symmetric higher spin fields to mixed-symmetry cases. The mass-deformation for these actions can be realized preserving one of the gauge symmetries. Although generically non-unitary, in special dimensions, unitarity is achieved selecting different mass deformations for dS and AdS. We consider particular examples of our construction such as New Massive Gravity in three dimensions, linearized bigravity in four dimensions and their arbitrary...
Evaluating model of frozen soil environment change under engineering actions
Institute of Scientific and Technical Information of China (English)
吴青柏; 朱元林; 刘永智
2002-01-01
The change of frozen soil environment is evaluated by permafrost thermal stability, thermal thaw sensibility and surface landscape stability and the quantitatively evaluating model of frozen soil environment is proposed in this paper. The evaluating model of frozen soil environment is calculated by 28 ground temperature measurements along Qinghai-Xizang Highway. The relationships of thermal thaw sensibility and freezing and thawing processes and seasonally thawing depth, thermal stability and permafrost table temperature, mean annual ground temperature and seasonally thawing depth, and surface landscape stability and freezing and thawing hazards and their forming possibility are analyzed. The results show that thermal stability, thermal thaw sensibility and surface landscape stability can be used to evaluate and predict the change of frozen soil environment under human engineering action.
Pressure wave model for action potential propagation in excitable cells
Rvachev, M M
2003-01-01
Speed of propagation of small-amplitude pressure waves through the cytoplasmic interior of myelinated and unmyelinated axons of different diameters is theoretically estimated and is found to generally agree with the action potential (AP) conduction velocities. This remarkable coincidence allows to surmise a model in which AP spread along axon is propelled not by straggling ionic currents as in the widely accepted local circuit theory, but by mechanoactivation of the membrane ion channels by a traveling pressure pulse. Hydraulic pulses propagating in the viscous axoplasm are calculated to decay over ~1 mm distances, and it is further hypothesized that it is the role of influxing during the AP calcium ions to activate membrane skeletal protein network attached to the membrane cytoplasmic side for a brief radial contraction amplifying the pressure pulse and preventing its decay. The model correctly predicts that the AP conduction velocity should vary as the one-half power of axon diameter for large unmyelinated ...
Phase lagging model of brain response to external stimuli - modeling of single action potential
Seetharaman, Karthik; Kulish, Vladimir V
2012-01-01
In this paper we detail a phase lagging model of brain response to external stimuli. The model is derived using the basic laws of physics like conservation of energy law. This model eliminates the paradox of instantaneous propagation of the action potential in the brain. The solution of this model is then presented. The model is further applied in the case of a single neuron and is verified by simulating a single action potential. The results of this modeling are useful not only for the fundamental understanding of single action potential generation, but also they can be applied in case of neuronal interactions where the results can be verified against the real EEG signal.
Vontiesenhausen, G. F.
1977-01-01
A program implementation model is presented which covers the in-space construction of certain large space systems from extraterrestrial materials. The model includes descriptions of major program elements and subelements and their operational requirements and technology readiness requirements. It provides a structure for future analysis and development.
Development and testing of a mouse simulated space flight model
Sonnenfeld, Gerald
1987-01-01
The development and testing of a mouse model for simulating some aspects of weightlessness that occurs during space flight, and the carrying out of immunological experiments on animals undergoing space flight is examined. The mouse model developed was an antiorthostatic, hypokinetic, hypodynamic suspension model similar to one used with rats. The study was divided into two parts. The first involved determination of which immunological parameters should be observed on animals flown during space flight or studied in the suspension model. The second involved suspending mice and determining which of those immunological parameters were altered by the suspension. Rats that were actually flown in Space Shuttle SL-3 were used to test the hypotheses.
DEFF Research Database (Denmark)
Clausen, Christian
2004-01-01
This contribution explores a range of social spaces where unions and workers have played or potential can play a role in the local social shaping of IT and work. It will mainly be based on the authors own research and experiences within Scandinavian research on technology and working from the past...... 30 years. The paper provides an overview of Scandinavian research within technology and working life form a Danish perspective. A major contribution is con-cerned with a variety of strategies employed by social actors involved in action research pro-jects and their role in the social shaping...... of technology. The point is made that no single strat-egy have proved to provide an uncontested route for union or workers influence. Instead the Scandinavian experiences indicate, that a range of spaces, players and positions have been developed, providing opportunities for addressing questions related...
Dynamic simulation of hydrodynamic model of drum level wave action and sloshing
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In order to build the model of the drum level wave action and sloshing, based on the method of modularization modeling,the hydrodynamic model of drum level wave action and sloshing was developed, and dynamic simulation researches were carried out based on the model. The results indicate that both drum level and drum length have functional relations with period of drum level wave action and sloshing. When the drum level decreases or drum length increases, the period of drum level wave action and sloshing increases, density of liquid and number of sub-module division have little influence on the period of drum level wave action and sloshing. The model was validated by the analytical solution theory of liquid's wave action and sloshing in cuboid container, and the 3D graphics of drum level wave action and sloshing was also obtained. The model can dynamically reflect the rules of wave action and sloshing of water in the container exactly.
Commentary : working across distant spaces : connecting participatory action research and teaching.
Pain, R.
2009-01-01
This commentary reflects on the key themes and goals of this symposium. It contextualizes the relationship between participatory action research (PAR) and teaching in the increasingly popular field of critical action-oriented geography. It considers a number of benefits to student learning from engagement with PAR, drawing on the papers in the collection, and raises some critical questions for future development.
A multidimensional decisions modeling framework for built space supply
Farooq, Bilal; Miller, Eric J.; Haider, Murtaza
2013-01-01
The spatial and temporal distribution of built space supply plays an important role in shaping urban form and thus the general travel pattern in an urban area. Within an integrated framework, we are interested in modeling the decisions of a builder in terms of when, where, what type, and how much built space to build. We present a multidimensional discrete-continuous model formulation for the built space supply decisions that are based on expected profit maximization. The framework is applied...
Vector space model for document representation in information retrieval
Directory of Open Access Journals (Sweden)
Dan MUNTEANU
2007-12-01
Full Text Available This paper presents the basics of information retrieval: the vector space model for document representation with Boolean and term weighted models, ranking methods based on the cosine factor and evaluation measures: recall, precision and combined measure.
Phase-space dynamics of Bianchi IX cosmological models
International Nuclear Information System (INIS)
The complex phase-space dynamical behaviour of a class of Biachi IX cosmological models is discussed, as the chaotic gravitational collapse due Poincare's homoclinic phenomena, and the n-furcation of periodic orbits and tori in the phase space of the models. Poincare maps which show this behaviour are constructed merically and applications are discussed. (Author)
Modelling Action Potential Generation and Propagation in Fibroblastic Cells
Torres, J. J.; Cornelisse, L. N.; Harks, E. G. A.; Theuvenet, A. P. R.; Ypey, D. L.
2003-04-01
Using a standard Hodgkin-Huxley (HH) formalism, we present a mathematical model for action potential (AP) generation and intercellular AP propagation in quiescent (serum-deprived) normal rat kidney (NRK) fibroblasts [1], based on the recent experimental identification of the ion channels involved [2]. The principal ion channels described are those of an inwardly rectifying K+ conductance (GKIR), an L-type calcium conductance (GCaL), an intracellular calcium activated Cl- conductance (GCl(Ca)), a residual leak conductance Gleak, and gap junctional channels between the cells (Ggj). The role of each one of these components in the particular shape of the AP wave-form has been analyzed and compared with experimental observations. In addition, we have studied the role of subcellular processes like intracellular calcium dynamics and calcium buffering in AP generation. AP propagation between cells was reconstructed in a hexagonal model of cells coupled by Ggj with physiological conductance values. The model revealed an excitability mechanism of quiescent NRK cells with a particular role of intracellular calcium dynamics. It allows further explorations of the mechanism of signal generation and transmission in NRK cell cultures and its dependence on growth conditions.
Space weather products at the Community Coordinated Modeling Center
Hesse, Michael
In addition to supporting space research in the international community, the Community Co-ordinated Modeling Center (CCMC) has as its second objective to bring to apply the power of modern research models toward space weather specification and forecasting. Initially motivated by the objective to test models and to ease the transition of research models to space weather forecasting organization, the CCMC has developed a number of real-time modeling systems, as well as large number of modeling and data products for space weather forecasting. Over time, these activities have evolved into tailored products for partners, as well as into a direct support of the space weather needs within NASA robotic mission community. Accessible through a customizable interface, users within the US or at partnering institutions internationally have access to space weather tools driven by the most advanced space research models. Through partnering with agencies and institutions in the US and abroad, the CCMC strives to set up further data sharing agreements to the benefit of all participating institutions. In this presen-tation, we provide an overview of existing CCMC space weather services and products, and we will explore additional avenues for international collaborations.
Motion Primitives for Action Recognition
DEFF Research Database (Denmark)
Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.
2007-01-01
The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent t...
Smooth spaces versus continuous spaces in models for synthetic differential geometry
Reyes, G.E.; Moerdijk, I.
1984-01-01
In topos models for synthetic differential geometry we study connections between smooth spaces (which interpret synthetic calculus) and continuous spaces (which interpret intuitionistic analysis). Our main tools are adjoint retractions of toposes and the standard map from the smooth reals to the con
A model for production, perception, and acquisition of actions in face-to-face communication.
Kröger, Bernd J; Kopp, Stefan; Lowit, Anja
2010-08-01
The concept of action as basic motor control unit for goal-directed movement behavior has been used primarily for private or non-communicative actions like walking, reaching, or grasping. In this paper, literature is reviewed indicating that this concept can also be used in all domains of face-to-face communication like speech, co-verbal facial expression, and co-verbal gesturing. Three domain-specific types of actions, i.e. speech actions, facial actions, and hand-arm actions, are defined in this paper and a model is proposed that elucidates the underlying biological mechanisms of action production, action perception, and action acquisition in all domains of face-to-face communication. This model can be used as theoretical framework for empirical analysis or simulation with embodied conversational agents, and thus for advanced human-computer interaction technologies. PMID:20012153
Modeling Geometric-Temporal Context With Directional Pyramid Co-Occurrence for Action Recognition.
Yuan, Chunfeng; Li, Xi; Hu, Weiming; Ling, Haibin; Maybank, Stephen J
2014-02-01
In this paper, we present a new geometric-temporal representation for visual action recognition based on local spatio-temporal features. First, we propose a modified covariance descriptor under the log-Euclidean Riemannian metric to represent the spatio-temporal cuboids detected in the video sequences. Compared with previously proposed covariance descriptors, our descriptor can be measured and clustered in Euclidian space. Second, to capture the geometric-temporal contextual information, we construct a directional pyramid co-occurrence matrix (DPCM) to describe the spatio-temporal distribution of the vector-quantized local feature descriptors extracted from a video. DPCM characterizes the co-occurrence statistics of local features as well as the spatio-temporal positional relationships among the concurrent features. These statistics provide strong descriptive power for action recognition. To use DPCM for action recognition, we propose a directional pyramid co-occurrence matching kernel to measure the similarity of videos. The proposed method achieves the state-of-the-art performance and improves on the recognition performance of the bag-of-visual-words (BOVWs) models by a large margin on six public data sets. For example, on the KTH data set, it achieves 98.78% accuracy while the BOVW approach only achieves 88.06%. On both Weizmann and UCF CIL data sets, the highest possible accuracy of 100% is achieved. PMID:26270910
A Quotient Space Approximation Model of Multiresolution Signal Analysis
Institute of Scientific and Technical Information of China (English)
Ling Zhang; Bo Zhang
2005-01-01
In this paper, we present a quotient space approximation model of multiresolution signal analysis and discuss the properties and characteristics of the model. Then the comparison between wavelet transform and the quotient space approximation is made. First, when wavelet transform is viewed from the new quotient space approximation perspective, it may help us to gain an insight into the essence of multiresolution signal analysis. Second, from the similarity between wavelet and quotient space approximations, it is possible to transfer the rich wavelet techniques into the latter so that a new way for multiresolution analysis may be found.
Manifestations of Isospin in Nearest Neighbor Spacing Distributions for the f-p Model Space
Quinonez, Michael; Zamick, Larry
2016-01-01
The strong interactions are charge independent. If we limit ourselves to the strong interactions, we have the isospin $T$ as a good quantum number. Here we consider the lack of level repulsion of states of different isospin and how this effect manifests in nearest neighbor spacing (NNS) histograms, which provide a visual and statistical context in which to study distributions of energy level spacings. In particular, we study nucleons in the f-p model space for the nucleus $^{44}$Ti. We also study the effect of the Coulomb interaction on the level spacing distribution.
Properties of Brownian Image Models in Scale-Space
DEFF Research Database (Denmark)
Pedersen, Kim Steenstrup
2003-01-01
law that apparently governs natural images. Furthermore, the distribution of Brownian images mapped into jet space is Gaussian and an analytical expression can be derived for the covariance matrix of Brownian images in jet space. This matrix is also a good approximation of the covariance matrix...... Brownian images) will be discussed in relation to linear scale-space theory, and it will be shown empirically that the second order statistics of natural images mapped into jet space may, within some scale interval, be modeled by the Brownian image model. This is consistent with the 1/f 2 power spectrum...... of natural images in jet space. The consequence of these results is that the Brownian image model can be used as a least committed model of the covariance structure of the distribution of natural images....
Kalu, A. E.
A model for Space Weather (SW) Circulation with Plasma Clouds as background radiation medium of Space Environment has been proposed and discussed. Major characteristics of the model are outlined and the model assumes a baroclinic Space Environment in view of observed pronounced horizontal electron temperature gradient with prevailing weak vertical temperature gradient. The primary objective of the study is to be able to monitor and realistically predict on real- or near real-time SW and Space Storms (SWS) affecting human economic systems on Earth as well as the safety and Physiologic comfort of human payload in Space Environment in relation to planned increase in human space flights especially with reference to the ISS Space Shuttle Taxi (ISST) Programme and other prolonged deep Space Missions. Although considerable discussions are now available in the literature on SW issues, routine Meteorological operational applications of SW forecast data and information for Space Environment are still yet to receive adequate attention. The paper attempts to fill this gap in the literature of SW. The paper examines the sensitivity and variability in 3-D continuum of Plasmas in response to solar radiation inputs into the magnetosphere under disturbed Sun condition. Specifically, the presence of plasma clouds in the form of Coronal Mass Ejections (CMEs) is stressed as a major source of danger to Space crews, spacecraft instrumentation and architecture charging problems as well as impacts on numerous radiation - sensitive human economic systems on Earth. Finally, the paper considers the application of model results in the form of effective monitoring of each of the two major phases of manned Spaceflights - take-off and re-entry phases where all-time assessment of spacecraft transient ambient micro-incabin and outside Space Environment is vital for all manned Spaceflights as recently evidenced by the loss of vital information during take-off of the February 1, 2003 US Columbia
Partial differential equations in action from modelling to theory
Salsa, Sandro
2015-01-01
The book is intended as an advanced undergraduate or first-year graduate course for students from various disciplines, including applied mathematics, physics and engineering. It has evolved from courses offered on partial differential equations (PDEs) over the last several years at the Politecnico di Milano. These courses had a twofold purpose: on the one hand, to teach students to appreciate the interplay between theory and modeling in problems arising in the applied sciences, and on the other to provide them with a solid theoretical background in numerical methods, such as finite elements. Accordingly, this textbook is divided into two parts. The first part, chapters 2 to 5, is more elementary in nature and focuses on developing and studying basic problems from the macro-areas of diffusion, propagation and transport, waves and vibrations. In turn the second part, chapters 6 to 11, concentrates on the development of Hilbert spaces methods for the variational formulation and the analysis of (mainly) linear bo...
Partial differential equations in action from modelling to theory
Salsa, Sandro
2016-01-01
The book is intended as an advanced undergraduate or first-year graduate course for students from various disciplines, including applied mathematics, physics and engineering. It has evolved from courses offered on partial differential equations (PDEs) over the last several years at the Politecnico di Milano. These courses had a twofold purpose: on the one hand, to teach students to appreciate the interplay between theory and modeling in problems arising in the applied sciences, and on the other to provide them with a solid theoretical background in numerical methods, such as finite elements. Accordingly, this textbook is divided into two parts. The first part, chapters 2 to 5, is more elementary in nature and focuses on developing and studying basic problems from the macro-areas of diffusion, propagation and transport, waves and vibrations. In turn the second part, chapters 6 to 11, concentrates on the development of Hilbert spaces methods for the variational formulation and the analysis of (mainly) linear bo...
Advancing Space Weather Modeling Capabilities at the CCMC
Mays, M. Leila; Kuznetsova, Maria; Boblitt, Justin; Chulaki, Anna; MacNeice, Peter; Mendoza, Michelle; Mullinix, Richard; Pembroke, Asher; Pulkkinen, Antti; Rastaetter, Lutz; Shim, Ja Soon; Taktakishvili, Aleksandre; Wiegand, Chiu; Zheng, Yihua
2016-04-01
The Community Coordinated Modeling Center (CCMC, http://ccmc.gsfc.nasa.gov) serves as a community access point to an expanding collection of state-of-the-art space environment models and as a hub for collaborative development on next generation of space weather forecasting systems. In partnership with model developers and the international research and operational communities, the CCMC integrates new data streams and models from diverse sources into end-to-end space weather predictive systems, identifies weak links in data-model & model-model coupling and leads community efforts to fill those gaps. The presentation will focus on the latest model installations at the CCMC and advances in CCMC-led community-wide model validation projects.
Development, validation and application of numerical space environment models
Honkonen, Ilja
2013-10-01
Currently the majority of space-based assets are located inside the Earth's magnetosphere where they must endure the effects of the near-Earth space environment, i.e. space weather, which is driven by the supersonic flow of plasma from the Sun. Space weather refers to the day-to-day changes in the temperature, magnetic field and other parameters of the near-Earth space, similarly to ordinary weather which refers to changes in the atmosphere above ground level. Space weather can also cause adverse effects on the ground, for example, by inducing large direct currents in power transmission systems. The performance of computers has been growing exponentially for many decades and as a result the importance of numerical modeling in science has also increased rapidly. Numerical modeling is especially important in space plasma physics because there are no in-situ observations of space plasmas outside of the heliosphere and it is not feasible to study all aspects of space plasmas in a terrestrial laboratory. With the increasing number of computational cores in supercomputers, the parallel performance of numerical models on distributed memory hardware is also becoming crucial. This thesis consists of an introduction, four peer reviewed articles and describes the process of developing numerical space environment/weather models and the use of such models to study the near-Earth space. A complete model development chain is presented starting from initial planning and design to distributed memory parallelization and optimization, and finally testing, verification and validation of numerical models. A grid library that provides good parallel scalability on distributed memory hardware and several novel features, the distributed cartesian cell-refinable grid (DCCRG), is designed and developed. DCCRG is presently used in two numerical space weather models being developed at the Finnish Meteorological Institute. The first global magnetospheric test particle simulation based on the
Combining search space partition and search Space partition and abstraction for LTL model checking
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The state space explosion problem is still the key obstacle for applying model checking to systems of industrial size.Abstraction-based methods have been particularly successful in this regard.This paper presents an approach based on refinement of search space partition and abstraction which combines these two techniques for reducing the complexity of model checking.The refinement depends on the representation of each portion of search space. Especially, search space can be refined stepwise to get a better reduction. As reported in the case study, the Integration of search space partition and abstraction improves the efficiencyof verification with respect to the requirement of memory and obtains significant advantage over the use of each of them in isolation.
Space Mapping Optimization of Microwave Circuits Exploiting Surrogate Models
DEFF Research Database (Denmark)
Bakr, M. H.; Bandler, J. W.; Madsen, Kaj;
2000-01-01
A powerful new space-mapping (SM) optimization algorithm is presented in this paper. It draws upon recent developments in both surrogate model-based optimization and modeling of microwave devices, SM optimization is formulated as a general optimization problem of a surrogate model. This model...
A FORMAL SPECIFICATION LANGUAGE FOR DYNAMIC STRAND SPACE MODEL
Institute of Scientific and Technical Information of China (English)
刘东喜; 李晓勇; 白英彩
2002-01-01
Specification language is used to provide enough information for the model of the cryptographic protocol. This paper first extends strand space model to dynamic strand model, and then a formal specification language for this model is defined by using BNF grammar. Compared with those in literatures, it is simpler because of only concerning the algebraic properties of cryptographic protocols.
Kelly, Jonathan W; Donaldson, Lisa S; Sjolund, Lori A; Freiberg, Jacob B
2013-10-01
Egocentric distances in virtual environments are commonly underperceived by up to 50 % of the intended distance. However, a brief period of interaction in which participants walk through the virtual environment while receiving visual feedback can dramatically improve distance judgments. Two experiments were designed to explore whether the increase in postinteraction distance judgments is due to perception-action recalibration or the rescaling of perceived space. Perception-action recalibration as a result of walking interaction should only affect action-specific distance judgments, whereas rescaling of perceived space should affect all distance judgments based on the rescaled percept. Participants made blind-walking distance judgments and verbal size judgments in response to objects in a virtual environment before and after interacting with the environment through either walking (Experiment 1) or reaching (Experiment 2). Size judgments were used to infer perceived distance under the assumption of size-distance invariance, and these served as an implicit measure of perceived distance. Preinteraction walking and size-based distance judgments indicated an underperception of egocentric distance, whereas postinteraction walking and size-based distance judgments both increased as a result of the walking interaction, indicating that walking through the virtual environment with continuous visual feedback caused rescaling of the perceived space. However, interaction with the virtual environment through reaching had no effect on either type of distance judgment, indicating that physical translation through the virtual environment may be necessary for a rescaling of perceived space. Furthermore, the size-based distance and walking distance judgments were highly correlated, even across changes in perceived distance, providing support for the size-distance invariance hypothesis. PMID:23839015
Parallel State Space Construction for Model-Checking
Garavel, Hubert; Mateescu, Radu; Smarandache, Irina
2001-01-01
The verification of concurrent finite-state systems by model-checking often requires to generate (a large part of) the state space of the system under analysis. Because of the state explosion problem, this may be a resource-consuming operation, both in terms of memory and CPU time. In this report, we aim at improving the performances of state space construction by using parallelization techniques. We present parallel algorithms for constructing state spaces (or Labeled Transition Systems) on ...
Space Science Cloud: a Virtual Space Science Research Platform Based on Cloud Model
Hu, Xiaoyan; Tong, Jizhou; Zou, Ziming
Through independent and co-operational science missions, Strategic Pioneer Program (SPP) on Space Science, the new initiative of space science program in China which was approved by CAS and implemented by National Space Science Center (NSSC), dedicates to seek new discoveries and new breakthroughs in space science, thus deepen the understanding of universe and planet earth. In the framework of this program, in order to support the operations of space science missions and satisfy the demand of related research activities for e-Science, NSSC is developing a virtual space science research platform based on cloud model, namely the Space Science Cloud (SSC). In order to support mission demonstration, SSC integrates interactive satellite orbit design tool, satellite structure and payloads layout design tool, payload observation coverage analysis tool, etc., to help scientists analyze and verify space science mission designs. Another important function of SSC is supporting the mission operations, which runs through the space satellite data pipelines. Mission operators can acquire and process observation data, then distribute the data products to other systems or issue the data and archives with the services of SSC. In addition, SSC provides useful data, tools and models for space researchers. Several databases in the field of space science are integrated and an efficient retrieve system is developing. Common tools for data visualization, deep processing (e.g., smoothing and filtering tools), analysis (e.g., FFT analysis tool and minimum variance analysis tool) and mining (e.g., proton event correlation analysis tool) are also integrated to help the researchers to better utilize the data. The space weather models on SSC include magnetic storm forecast model, multi-station middle and upper atmospheric climate model, solar energetic particle propagation model and so on. All the services above-mentioned are based on the e-Science infrastructures of CAS e.g. cloud storage and
Joint modeling of primary and secondary action in DBM
Koning, Ruud H.; Spring, P.N.; Wansbeek, T.J.
2002-01-01
In this paper we discuss the issue of primary and secondary actions to direct mail offers. Primary action refers to the first responses consumers make toward a direct offer or soliciation. It might represent an order for a product, a request for a catalog or credit card, or a pledge to donate to a c
The Reflective Teacher Leader: An Action Research Model
Furtado, Leena; Anderson, Dawnette
2012-01-01
This study presents four teacher reflections from action research projects ranging from kindergarten to adult school improvements. A teacher leadership matrix guided participants to connect teaching and learning theory to best practices by exploring uncharted territory within an iterative cycle of research and action. Teachers developed the…
Palmer, Christopher J; Bigelow, Carol; Van Emmerik, Richard E A
2013-01-01
Soldier equipment compromises task performance as temporal constraints during critical situations and load increase inertial and interactive forces during movement. Methods are necessary to optimise equipment that relate task performance to underlying coordination and perception-action coupling. Employing ecological task analysis and methods from dynamical systems theory, equipment load and coordination was examined during two sub-tasks embedded in combat performance, threat discrimination and dynamic marksmanship. Perception-action coupling was degraded with load during threat discrimination, leading to delays in functional reaction time. Reduced speed and accuracy during dynamic marksmanship under load was related to disrupted segmental coordination and adaptability during postural transitions between targets. These results show how reduced performance under load relates to coordination changes and perception-action coupling. These changes in functional capability are directly related to soldier survivability in combat. The methods employed may aid equipment design towards more optimised performance by modifying equipment or its distribution on humans. PMID:24028557
Bootstrapping Critical Ising Model on Three Dimensional Real Projective Space
Nakayama, Yu
2016-04-01
Given conformal data on a flat Euclidean space, we use crosscap conformal bootstrap equations to numerically solve the Lee-Yang model as well as the critical Ising model on a three dimensional real projective space. We check the rapid convergence of our bootstrap program in two dimensions from the exact solutions available. Based on the comparison, we estimate that our systematic error on the numerically solved one-point functions of the critical Ising model on a three dimensional real projective space is less than 1%. Our method opens up a novel way to solve conformal field theories on nontrivial geometries.
A Learning State-Space Model for Image Retrieval
Directory of Open Access Journals (Sweden)
Lee Greg C
2007-01-01
Full Text Available This paper proposes an approach based on a state-space model for learning the user concepts in image retrieval. We first design a scheme of region-based image representation based on concept units, which are integrated with different types of feature spaces and with different region scales of image segmentation. The design of the concept units aims at describing similar characteristics at a certain perspective among relevant images. We present the details of our proposed approach based on a state-space model for interactive image retrieval, including likelihood and transition models, and we also describe some experiments that show the efficacy of our proposed model. This work demonstrates the feasibility of using a state-space model to estimate the user intuition in image retrieval.
Quantum-Dot Semiconductor Optical Amplifiers: State Space Model versus Rate Equation Model
Directory of Open Access Journals (Sweden)
Hussein Taleb
2013-01-01
Full Text Available A simple and accurate dynamic model for QD-SOAs is proposed. The proposed model is based on the state space theory, where by eliminating the distance dependence of the rate equation model of the QD-SOA; we derive a state space model for the device. A comparison is made between the rate equation model and the state space model under both steady state and transient regimes. Simulation results demonstrate that the derived state space model not only is much simpler and faster than the rate equation model, but also it is as accurate as the rate equation model.
Space-time modeling of traffic flow
Kamarianakis, Yiannis; Prastacos, Poulicos
2002-01-01
A key concern in transportation planning and traffic management is the ability to forecast traffic flows on a street network. Traffic flows forecasts can be transformed to obtain travel time estimates and then use these as input to travel demand models, dynamic route guidance and congestion management procedures. A variety of mathematical techniques have been proposed for modeling traffic flow on a street network. Briefly, the most widely used theories are: -Kinetic models based on partial di...
One-loop structure of the U(1) gauge model on the truncated Heisenberg space
Burić, Maja; Prekrat, Dragan
2016-01-01
We calculate divergent one-loop corrections to the propagators of the U(1) gauge theory on the truncated Heisenberg space, which is one of the extensions of the Grosse-Wulkenhaar model. The model is purely geometric, based on the Yang-Mills action; the corresponding gauge-fixed theory is BRST invariant. We quantize perturbatively and, along with the usual wave-function and mass renormalizations, we find divergent nonlocal terms of the $\\Box^{-1}$ and $\\Box^{-2}$ type. We discuss the meaning of these terms and possible improvements of the model.
Zárate, Maria Rodó de
2015-01-01
Introduction In this paper I seek to contribute to feminist geographies of fear by analyzing the ways young feminists in a medium-sized non-metropolitan city of Catalonia manage fear and discomfort in public spaces. Through empirical and analytical methodologies that provide participatory insights to the intersectional and spatial experience of oppression and privilege, I examine their uses and experiences of public space focusing on the personal and collective strategies they develop to f...
A Rabbit Ventricular Action Potential Model Replicating Cardiac Dynamics at Rapid Heart Rates
Mahajan, Aman; Shiferaw, Yohannes; Sato, Daisuke; Baher, Ali; Olcese, Riccardo; Xie, Lai-Hua; Yang, Ming-Jim; Chen, Peng-Sheng; Restrepo, Juan G.; Karma, Alain; Garfinkel, Alan; Qu, Zhilin; Weiss, James N.
2008-01-01
Mathematical modeling of the cardiac action potential has proven to be a powerful tool for illuminating various aspects of cardiac function, including cardiac arrhythmias. However, no currently available detailed action potential model accurately reproduces the dynamics of the cardiac action potential and intracellular calcium (Cai) cycling at rapid heart rates relevant to ventricular tachycardia and fibrillation. The aim of this study was to develop such a model. Using an existing rabbit ven...
A Simulation and Modeling Framework for Space Situational Awareness
Energy Technology Data Exchange (ETDEWEB)
Olivier, S S
2008-09-15
This paper describes the development and initial demonstration of a new, integrated modeling and simulation framework, encompassing the space situational awareness enterprise, for quantitatively assessing the benefit of specific sensor systems, technologies and data analysis techniques. The framework is based on a flexible, scalable architecture to enable efficient, physics-based simulation of the current SSA enterprise, and to accommodate future advancements in SSA systems. In particular, the code is designed to take advantage of massively parallel computer systems available, for example, at Lawrence Livermore National Laboratory. The details of the modeling and simulation framework are described, including hydrodynamic models of satellite intercept and debris generation, orbital propagation algorithms, radar cross section calculations, optical brightness calculations, generic radar system models, generic optical system models, specific Space Surveillance Network models, object detection algorithms, orbit determination algorithms, and visualization tools. The use of this integrated simulation and modeling framework on a specific scenario involving space debris is demonstrated.
Space ecoliteracy- five informal education models for community empowerment
Venkataramaiah, Jagannatha; Jagannath, Sahana; J, Spandana; J, Sadhana; Jagannath, Shobha
Space ecoliteracy is a historical necessity and vital aspect of space age.Space Situational Awareness has taught lessons for mankind to look inward while stretching beyond cradle in human endeavours. Quality of life for every one on the only home of mankind-TERRA shall be a feasibility only after realizing Space ecoliteracy amongst all stakeholders in space quest. Objectives of Informal Environmental Education(UNESCO/UNEP/IEEP,1977) mandates awareness, attitude, knowledge, skill and participation at Individual and Community domains. Application of Space Technology at both Telecommunications and Remote Sensing domain have started making the fact that mankind has a challenge to learn and affirm earthmanship. Community empowerment focus after Earth Summit 1992 mandate of Sustainable Development has demonstrated a deluge of best practices in Agriculture,Urban, Industries and service sectors all over the globe. Further, deployment of Space technologies have proved the immense potential only after pre-empting the participatory approach at individual and community levels.Indian Space Programme with its 44th year of space service to national development has demonstrated self reliance in space technology for human development. Space technology for the most underdeveloped is a success story both in communication and information tools for quality of life. In this presentation Five Space Ecoliteracy models designed and validated since 1985 till date on informal environmental education namely 1) Ecological Environmental Studies by Students-EESS (1988): cited as one of the 20 best eco -education models by Earth Day Network,2)Community Eco Literacy Campaign-CEL,(2000): cited as a partner under Clean Up the World Campaign,UN, 3) Space Eco Literacy(2011)-an informa 8 week space eco literacy training reported at 39th COSPAR 12 assembly and 4) Space Eco Literacy by Practice(2014)- interface with formal education at institutions and 5) Space Ecoliteracy Mission as a space out reach in
Background independent effective action from D=1 matrix model
International Nuclear Information System (INIS)
We derive the background independent form of the Das-Jevicki action. The tachyon terms are given to all orders by a generally covariant form of the Das-Jevicki action. The graviton-dilaton sector is the usual low energy effective action. This enables us to examine questions such as the back reaction of the tachyon on the metric. In particular the reason why the usual Liouville term is an exact solution of the conformal invariance conditions, as well as the fact that it has no back reaction, become manifest. We comment on the propagation of a tachyonic perturbation in the background of a black-hole metric. (orig.)
Nonlinear Sigma Models with Compact Hyperbolic Target Spaces
Gubser, Steven; Schoenholz, Samuel S; Stoica, Bogdan; Stokes, James
2015-01-01
We explore the phase structure of nonlinear sigma models with target spaces corresponding to compact quotients of hyperbolic space, focusing on the case of a hyperbolic genus-2 Riemann surface. The continuum theory of these models can be approximated by a lattice spin system which we simulate using Monte Carlo methods. The target space possesses interesting geometric and topological properties which are reflected in novel features of the sigma model. In particular, we observe a topological phase transition at a critical temperature, above which vortices proliferate, reminiscent of the Kosterlitz-Thouless phase transition in the $O(2)$ model. Unlike in the $O(2)$ case, there are many different types of vortices, suggesting a possible analogy to the Hagedorn treatment of statistical mechanics of a proliferating number of hadron species. Below the critical temperature the spins cluster around six special points in the target space known as Weierstrass points. The diversity of compact hyperbolic manifolds suggest...
Computerised analysis of sulphate action on model concrete piles
Digital Repository Service at National Institute of Oceanography (India)
Deshmukh, A.M.; Balasubramanian, S.; Venugopal, C.
Sulphate action severely affects the durability of marine structures. It is imperative to study precisely the effects of magnesium sulphate on pile foundations in the marine environment. In the present paper an attempt is made to assess and analyse...
A Situative Space Model for Mobile Mixed-Reality Computing
DEFF Research Database (Denmark)
Pederson, Thomas; Janlert, Lars-Erik; Surie, Dipak
2011-01-01
This article proposes a situative space model that links the physical and virtual realms and sets the stage for complex human-computer interaction defined by what a human agent can see, hear, and touch, at any given point in time.......This article proposes a situative space model that links the physical and virtual realms and sets the stage for complex human-computer interaction defined by what a human agent can see, hear, and touch, at any given point in time....
A reference model for space data system interconnection services
Pietras, John; Theis, Gerhard
1993-03-01
The widespread adoption of standard packet-based data communication protocols and services for spaceflight missions provides the foundation for other standard space data handling services. These space data handling services can be defined as increasingly sophisticated processing of data or information received from lower-level services, using a layering approach made famous in the International Organization for Standardization (ISO) Open System Interconnection Reference Model (OSI-RM). The Space Data System Interconnection Reference Model (SDSI-RM) incorporates the conventions of the OSIRM to provide a framework within which a complete set of space data handling services can be defined. The use of the SDSI-RM is illustrated through its application to data handling services and protocols that have been defined by, or are under consideration by, the Consultative Committee for Space Data Systems (CCSDS).
Hypersurface-deformation algebroids and effective space-time models
Bojowald, Martin; Buyukcam, Umut; D'Ambrosio, Fabio
2016-01-01
In canonical gravity, covariance is implemented by brackets of hypersurface-deformation generators forming a Lie algebroid. Lie algebroid morphisms therefore allow one to relate different versions of the brackets that correspond to the same space-time structure. An application to examples of modified brackets found mainly in models of loop quantum gravity can in some cases map the space-time structure back to the classical Riemannian form after a field redefinition. For one type of quantum corrections (holonomies), signature change appears to be a generic feature of effective space-time, and is shown here to be a new quantum space-time phenomenon which cannot be mapped to an equivalent classical structure. In low-curvature regimes, our constructions prove the existence of classical space-time structures assumed elsewhere in models of loop quantum cosmology, but also shows the existence of additional quantum corrections that have not always been included.
Action Algebras and Model Algebras in Denotational Semantics
Guedes, Luiz Carlos Castro; Haeusler, Edward Hermann
the same way as that for functional denotational types. For example, PASCAL arrays belong to the “language inherent” aspect, while the Store domain seems to belong to the “model dependent” aspect. This distinction was important because it focussed attention on optimizing the model dependent semantic domains to obtain a more efficient implementation.) The research led to a nice conclusion: The guidelines of Action Semantics induce a clear separation of the model and language inherent aspects of a language’s semantics. A good implementation of facets, particularly the model dependent ones, leads to generation of an efficient compiler. In this article we discuss the separation of the language inherent and model-inherent domains at the theoretical and conceptual level. In doing so, the authors hope to show how Professor Mosses’s influence extended beyond his technical advice to his professional and personal examples on the supervision of PhD research.
A space-averaged model of branched structures
Lopez, Diego; Michelin, Sébastien
2014-01-01
Many biological systems and artificial structures are ramified, and present a high geometric complexity. In this work, we propose a space-averaged model of branched systems for conservation laws. From a one-dimensional description of the system, we show that the space-averaged problem is also one-dimensional, represented by characteristic curves, defined as streamlines of the space-averaged branch directions. The geometric complexity is then captured firstly by the characteristic curves, and secondly by an additional forcing term in the equations. This model is then applied to mass balance in a pipe network and momentum balance in a tree under wind loading.
Hacyan, Shahen
2006-11-01
Since the famous Einstein-Podolsky-Rosen (EPR) paper, it is clear that there is a serious incompatibility between local realism and quantum mechanics. Einstein believed that a complete quantum theory should be free of what he once called "spooky actions at distance". However, all experiments in quantum optics and atomic physics performed in the last two decades confirm the existence of quantum correlations that seem to contradict local realism. According to Bohr, the apparent contradictions disclose only the inadequacy of our customary concepts for the description of the quantum world. Are space and time such customary concepts? In this presentation, I argue that the Copenhagen interpretation is compatible with Kant's transcendental idealism and that, in particular, EPR type paradoxes are consistent with Kant's transcendental aesthetics, according to which space and time have no objective reality but are pure forms of sensible intuition.
2008-01-01
This audit was initiated in response to a hotline complaint regarding the review, approval, and release of scientific and technical information (STI) at Johnson Space Center. The complainant alleged that Johnson personnel conducting export control reviews of STI were not fully qualified to conduct those reviews and that the reviews often did not occur until after the STI had been publicly released. NASA guidance requires that STI, defined as the results of basic and applied scientific, technical, and related engineering research and development, undergo certain reviews prior to being released outside of NASA or to audiences that include foreign nationals. The process includes technical, national security, export control, copyright, and trade secret (e.g., proprietary data) reviews. The review process was designed to preclude the inappropriate dissemination of sensitive information while ensuring that NASA complies with a requirement of the National Aeronautics and Space Act of 1958 (the Space Act)1 to provide for the widest practicable and appropriate dissemination of information resulting from NASA research activities. We focused our audit on evaluating the STI review process: specifically, determining whether the roles and responsibilities for the review, approval, and release of STI were adequately defined and documented in NASA and Center-level guidance and whether that guidance was effectively implemented at Goddard Space Flight Center, Johnson Space Center, Langley Research Center, and Marshall Space Flight Center. Johnson was included in the review because it was the source of the initial complaint, and Goddard, Langley, and Marshall were included because those Centers consistently produce significant amounts of STI.
Numerical modelling of elastic space tethers
DEFF Research Database (Denmark)
Kristiansen, Kristian Uldall; Palmer, P. L.; Roberts, R. M.
2012-01-01
In this paper the importance of the ill-posedness of the classical, non-dissipative massive tether model on an orbiting tether system is studied numerically. The computations document that via the regularisation of bending resistance a more reliable numerical integrator can be produced. Furthermo...
Interactions In Space For Archaeological Models
Evans, T S; Knappett, C
2011-01-01
In this article we examine a variety of quantitative models for describing archaeological networks, with particular emphasis on the maritime networks of the Aegean Middle Bronze Age. In particular, we discriminate between those gravitational networks that are most likely (maximum entropy) and most efficient (best cost/benefit outcomes).
Solvable Models on Noncommutative Spaces with Minimal Length Uncertainty Relations
Dey, Sanjib
2014-01-01
Our main focus is to explore different models in noncommutative spaces in higher dimensions. We provide a procedure to relate a three dimensional q-deformed oscillator algebra to the corresponding algebra satisfied by canonical variables describing non-commutative spaces. The representations for the corresponding operators obey algebras whose uncertainty relations lead to minimal length, areas and volumes in phase space, which are in principle natural candidates of many different approaches of quantum gravity. We study some explicit models on these types of noncommutative spaces, first by utilising the perturbation theory, later in an exact manner. In many cases the operators are not Hermitian, therefore we use PT -symmetry and pseudo-Hermiticity property, wherever applicable, to make them self-consistent. Apart from building mathematical models, we focus on the physical implications of noncommutative theories too. We construct Klauder coherent states for the perturbative and nonperturbative noncommutative ha...
Spreading models in the duals of Schlumprecht-type spaces
Beanland, Kevin
2009-01-01
We show that the dual of Schlumprecht's space $S^*$ and the dual of Gowers and Maurey's HI space each contain a $c_0$ spreading model and that for each $1 < p < \\infty$ and $1/p+1/q=1$, the dual of the $p$-convexification of Schlumprecht's space and the dual of its HI counterpart, constructed by Neil Dew, each contain an $\\ell_q$ spreading model. The existence of a $c_0$ spreading model in $S^*$ solves a problem of S. A. Argyros. We also give a general criteria for the existence of a bounded non-compact operator and use this to show that there exist strictly singular non-compact operators on each of these spaces.
A Modeler's Perspective on Space Weather Forecasting (Invited)
Wiltberger, M. J.
2010-12-01
Space physics is moving into a new era where numerical models originally developed for answering science questions are used as the basis for making operational space weather forecasts. Answering this challenge requires developments on multiple fronts requiring collaborations across space physics disciplines and between the research and operations communities. Since space weather in geospace is driven by the solar wind conditions a natural solution to improving the forecast lead time is to couple geospace models to heliospheric models. The quality of these forecast is dependent upon the ability of the heliospheric models to accurately model IMF Bz. Another challenge presented by moving into the forecasting arena is preparing the models for real-time operation which includes both computational performance and data redundancy issues. Moving into operations also presents modelers with an opportunity to assess their models performance over calculation intervals unprecedented duration. A key collaboration in the transition of models to operation is the discussion between forecasters and developers on what forecast parameters can accurately be predicted by the current generation of numerical models. This collaboration naturally includes a discussion of the definition of the best metrics to be used in quantitatively assessing performance.
The Four Space-times Model of Reality
Fontana, G
2004-01-01
We live in a 3+1 space-time that is intended as a description of the universe with three space dimensions and one time dimension. Space-time dimensionality seems so natural that it is rarely criticized. Experiments and the highly successful relativistic theories teach us that there are four fundamental dimensions, among them is time that is treated as a special dimension. The specialty of time can be removed, leading to the concept that time is simply a function of four new fundamental dimensions, which have now identical properties, in combination with Lorentz invariance. A model is deduced in which a 4-space, characterized by four space-like coordinates, may host four "equivalent but orthogonal" space-times, each with three spatial coordinates and one temporal coordinate. Coordinates are shared; therefore the 4-space and the four space-times are all in one. Electromagnetic interaction is confined in each space-time and the role of the speed of light appears to be that of a barrier for the electromagnetic in...
Einstein, the reality of space, and the action-reaction principle
Brown, Harvey R
2013-01-01
Einstein regarded as one of the triumphs of his 1915 theory of gravity --- the general theory of relativity --- that it vindicated the action--reaction principle, while Newtonian mechanics as well as his 1905 special theory of relativity supposedly violated it. In this paper we examine why Einstein came to emphasise this position several years after the development of general relativity. Several key considerations are relevant to the story: the connection Einstein originally saw between Mach's analysis of inertia and both the equivalence principle and the principle of general covariance, the waning of Mach's influence owing to de Sitter's 1917 results, and Einstein's detailed correspondence with Moritz Schlick in 1920.
Diffusion Resonances in Action Space for an Atom Optics Kicked Rotor with Decoherence
Daley, A J; Leonhardt, R; Tan, S M
2001-01-01
We numerically investigate momentum diffusion rates for the pulse kicked rotor across the quantum to classical transition as the dynamics are made more macroscopic by increasing the total system action. For initial and late time rates we observe an enhanced diffusion peak which shifts and scales with changing kick strength, and we also observe distinctive peaks around quantum resonances. Our investigations take place in the context of a system of ultracold atoms which is coupled to its environment via spontaneous emission decoherence, and the effects should be realisable in ongoing experiments.
Frank, M.J.; Scheres, A.P.J.; Sherman, S.J.
2007-01-01
Models of natural action selection implicate fronto-striatal circuits in both motor and cognitive 'actions'. Dysfunction of these circuits leads to decision-making deficits in various populations. We review how computational models provide insights into the mechanistic basis for these deficits in Pa
Community projects as liminal spaces for climate action and sustainability practices in Scotland
Meyerricks, Svenja
2015-01-01
The potential of communities for sustainability learning and governance has generated substantial interest in sustainability discourses, but their specific roles and remits are not always critically examined. This thesis' original contribution to these discourses lies in the analysis of community projects as liminal spaces for pro-sustainable change that are limited in scope within wider political landscapes that do not sufficiently address wider challenges of an unravelling biosphere. The pa...
Fabert, Oliver
2007-01-01
Branched covers of orbit cylinders are the basic examples of holomorphic curves studied in symplectic field theory. Since all curves with Fredholm index one can never be regular for any choice of cylindrical almost complex structure, we generalize the obstruction bundle technique of Taubes for determining multiple cover contributions from Gromov-Witten theory to the case of moduli spaces with boundary. Our result proves that the differential in rational symplectic field theory and contact hom...
Listening to music primes space: pianists, but not novices, simulate heard actions.
Taylor, J Eric T; Witt, Jessica K
2015-03-01
Musicians sometimes report twitching in their fingers or hands while listening to music. This anecdote could be indicative of a tendency for auditory-motor co-representation in musicians. Here, we describe two studies showing that pianists (Experiment 1), but not novices (Experiment 2) automatically generate spatial representations that correspond to learned musical actions while listening to music. Participants made one-handed movements to the left or right from a central location in response to visual stimuli while listening to task-irrelevant auditory stimuli, which were scales played on a piano. These task-irrelevant scales were either ascending (compatible with rightward movements) or descending (compatible with leftward movements). Pianists were faster to respond when the scale direction was compatible with the direction of response movement, whereas novices' movements were unaffected by the scale. These results are in agreement with existing research on action-effect coupling in musicians, which draw heavily on common coding theory. In addition, these results show how intricate auditory stimuli (ascending or descending scales) evoke coarse, domain-general spatial representations.
Integral group actions on symmetric spaces and discrete duality symmetries of supergravity theories
International Nuclear Information System (INIS)
For G = G(ℝ), a split, simply connected, semisimple Lie group of rank n and K the maximal compact subgroup of G, we give a method for computing Iwasawa coordinates of K∖G using the Chevalley generators and the Steinberg presentation. When K∖G is a scalar coset for a supergravity theory in dimensions ≥3, we determine the action of the integral form G(ℤ) on K∖G. We give explicit results for the action of the discrete U-duality groups SL2(ℤ) and E7(ℤ) on the scalar cosets SO(2)∖SL2(ℝ) and [SU(8)/( ± Id)]∖E7(+7)(ℝ) for type IIB supergravity in ten dimensions and 11-dimensional supergravity reduced to D = 4 dimensions, respectively. For the former, we use this to determine the discrete U-duality transformations on the scalar sector in the Borel gauge and we describe the discrete symmetries of the dyonic charge lattice. We determine the spectrum-generating symmetry group for fundamental BPS solitons of type IIB supergravity in D = 10 dimensions at the classical level and we propose an analog of this symmetry at the quantum level. We indicate how our methods can be used to study the orbits of discrete U-duality groups in general
Integral group actions on symmetric spaces and discrete duality symmetries of supergravity theories
Energy Technology Data Exchange (ETDEWEB)
Carbone, Lisa [Mathematics Rutgers University, Hill Center-Busch Campus, 110 Frelinghuysen Rd., Piscataway, New Jersey 08854 (United States); Murray, Scott H. [Mathematics & Statistics, University of Canberra, ACT 2601 (Australia); Sati, Hisham [Department of Mathematics, University of Pittsburgh, 301 Thackeray Hall, Pittsburgh, Pennsylvania 15260 (United States)
2015-10-15
For G = G(ℝ), a split, simply connected, semisimple Lie group of rank n and K the maximal compact subgroup of G, we give a method for computing Iwasawa coordinates of K∖G using the Chevalley generators and the Steinberg presentation. When K∖G is a scalar coset for a supergravity theory in dimensions ≥3, we determine the action of the integral form G(ℤ) on K∖G. We give explicit results for the action of the discrete U-duality groups SL{sub 2}(ℤ) and E{sub 7}(ℤ) on the scalar cosets SO(2)∖SL{sub 2}(ℝ) and [SU(8)/( ± Id)]∖E{sub 7(+7)}(ℝ) for type IIB supergravity in ten dimensions and 11-dimensional supergravity reduced to D = 4 dimensions, respectively. For the former, we use this to determine the discrete U-duality transformations on the scalar sector in the Borel gauge and we describe the discrete symmetries of the dyonic charge lattice. We determine the spectrum-generating symmetry group for fundamental BPS solitons of type IIB supergravity in D = 10 dimensions at the classical level and we propose an analog of this symmetry at the quantum level. We indicate how our methods can be used to study the orbits of discrete U-duality groups in general.
Space-time modeling of electricity spot prices
DEFF Research Database (Denmark)
Abate, Girum Dagnachew; Haldrup, Niels
In this paper we derive a space-time model for electricity spot prices. A general spatial Durbin model that incorporates the temporal as well as spatial lags of spot prices is presented. Joint modeling of space-time effects is necessarily important when prices and loads are determined in a network...... of power exchange areas. We use data from the Nord Pool electricity power exchange area bidding markets. Different spatial weight matrices are considered to capture the structure of the spatial dependence process across different bidding markets and statistical tests show significant spatial dependence...
New results on mixture and exponential models by Orlicz spaces
Santacroce, Marina; Siri, Paola; Trivellato, Barbara
2016-01-01
New results and improvements in the study of nonparametric exponential and mixture models are proposed. In particular, different equivalent characterizations of maximal exponential models, in terms of open exponential arcs and Orlicz spaces, are given. Our theoretical results are supported by several examples and counterexamples and provide an answer to some open questions in the literature.
Modeling of Space-Time Focusing of Localized Nondiffracting Pulses
Zamboni-Rached, Michel
2015-01-01
In this paper we develop a method capable of modeling the space-time focusing of nondiffracting pulses. The new pulses can possess arbitrary peak velocities and, in addition to being resistant to diffraction, can have their peak intensities and focusing positions chosen a priori. More specifically, we can choose multiple locations (spatial ranges) of space/time focalization; also, the pulse intensities can be chosen in advance. The pulsed wave solutions presented here can have very interesting applications in many different fields, such as free-space optical communications, remote sensing, medical apparatus, etc.
Dimension invariants for groups admitting a cocompact model for proper actions
DEFF Research Database (Denmark)
Degrijse, Dieter Dries; Martínez-Pérez, Conchita
2016-01-01
Let G be a group that admits a cocompact classifying space for proper actions X. We derive a formula for the Bredon cohomological dimension for proper actions of G in terms of the relative cohomology with compact support of certain pairs of subcomplexes of X. We use this formula to compute...... the Bredon cohomological dimension for proper actions of fundamental groups of non-positively curved simple complexes of finite groups. As an application we show that if a virtually torsion-free group acts properly and chamber transitively on a building, its virtual cohomological dimension coincides with its...
A stochastic space-time model for intermittent precipitation occurrences
Sun, Ying
2016-01-28
Modeling a precipitation field is challenging due to its intermittent and highly scale-dependent nature. Motivated by the features of high-frequency precipitation data from a network of rain gauges, we propose a threshold space-time t random field (tRF) model for 15-minute precipitation occurrences. This model is constructed through a space-time Gaussian random field (GRF) with random scaling varying along time or space and time. It can be viewed as a generalization of the purely spatial tRF, and has a hierarchical representation that allows for Bayesian interpretation. Developing appropriate tools for evaluating precipitation models is a crucial part of the model-building process, and we focus on evaluating whether models can produce the observed conditional dry and rain probabilities given that some set of neighboring sites all have rain or all have no rain. These conditional probabilities show that the proposed space-time model has noticeable improvements in some characteristics of joint rainfall occurrences for the data we have considered.
Continuous-time discrete-space models for animal movement
Hanks, Ephraim M.; Hooten, Mevin B.; Alldredge, Mat W.
2015-01-01
The processes influencing animal movement and resource selection are complex and varied. Past efforts to model behavioral changes over time used Bayesian statistical models with variable parameter space, such as reversible-jump Markov chain Monte Carlo approaches, which are computationally demanding and inaccessible to many practitioners. We present a continuous-time discrete-space (CTDS) model of animal movement that can be fit using standard generalized linear modeling (GLM) methods. This CTDS approach allows for the joint modeling of location-based as well as directional drivers of movement. Changing behavior over time is modeled using a varying-coefficient framework which maintains the computational simplicity of a GLM approach, and variable selection is accomplished using a group lasso penalty. We apply our approach to a study of two mountain lions (Puma concolor) in Colorado, USA.
Modeling of space environment impact on nanostructured materials. General principles
Voronina, Ekaterina; Novikov, Lev
2016-07-01
In accordance with the resolution of ISO TC20/SC14 WG4/WG6 joint meeting, Technical Specification (TS) 'Modeling of space environment impact on nanostructured materials. General principles' which describes computer simulation methods of space environment impact on nanostructured materials is being prepared. Nanomaterials surpass traditional materials for space applications in many aspects due to their unique properties associated with nanoscale size of their constituents. This superiority in mechanical, thermal, electrical and optical properties will evidently inspire a wide range of applications in the next generation spacecraft intended for the long-term (~15-20 years) operation in near-Earth orbits and the automatic and manned interplanetary missions. Currently, ISO activity on developing standards concerning different issues of nanomaterials manufacturing and applications is high enough. Most such standards are related to production and characterization of nanostructures, however there is no ISO documents concerning nanomaterials behavior in different environmental conditions, including the space environment. The given TS deals with the peculiarities of the space environment impact on nanostructured materials (i.e. materials with structured objects which size in at least one dimension lies within 1-100 nm). The basic purpose of the document is the general description of the methodology of applying computer simulation methods which relate to different space and time scale to modeling processes occurring in nanostructured materials under the space environment impact. This document will emphasize the necessity of applying multiscale simulation approach and present the recommendations for the choice of the most appropriate methods (or a group of methods) for computer modeling of various processes that can occur in nanostructured materials under the influence of different space environment components. In addition, TS includes the description of possible
Orbital Optimization in the Active Space Decomposition Model
Kim, Inkoo; Shiozaki, Toru
2015-01-01
We report the derivation and implementation of orbital optimization algorithms for the active space decomposition (ASD) model, which are extensions of complete active space self-consistent field (CASSCF) and its occupation-restricted variants in the conventional multiconfiguration electronic-structure theory. Orbital rotations between active subspaces are included in the optimization, which allows us to unambiguously partition the active space into subspaces, enabling application of ASD to electron and exciton dynamics in covalently linked chromophores. One- and two-particle reduced density matrices, which are required for evaluation of orbital gradient and approximate Hessian elements, are computed from the intermediate tensors in the ASD energy evaluation. Numerical results on 4-(2-naphthylmethyl)-benzaldehyde and [3$_6$]cyclophane and model Hamiltonian analyses of triplet energy transfer processes in the Closs systems are presented. Furthermore model Hamiltonians for hole and electron transfer processes in...
Enhanced surrogate models for statistical design exploiting space mapping technology
DEFF Research Database (Denmark)
Koziel, Slawek; Bandler, John W.; Mohamed, Achmed S.;
2005-01-01
We present advances in microwave and RF device modeling exploiting Space Mapping (SM) technology. We propose new SM modeling formulations utilizing input mappings, output mappings, frequency scaling and quadratic approximations. Our aim is to enhance circuit models for statistical analysis...... and yield-driven design. We illustrate our results using a capacitively-loaded two-section impedance transformer, a single-resonator waveguide filter and a six-section H-plane waveguide filter....
Ventilation of a nuclear space: modelling, experimental validation and consequences
International Nuclear Information System (INIS)
The present problems raised by ventilation are stated, and a review is made of the models of contamination dispersion and calculation of the contaminant concentrations and their validity as to the data collected during radiological events. A model more suitable to the conditions prevailing in installations has been derived from these models in order to describe the evolution of contaminant concentrations in a ventilated space
Hybrid Acoustic Modelling of Historic Spaces Using Blender
Van Mourik, Jelle; Oxnard, Stephen; Foteinou, Aglaia; Murphy, Damian Thomas
2014-01-01
Historic spaces provide a challenge in terms of achieving accurate acoustic modelling and auralisation due to the large volumes typically involved, implying significant computational overhead, uncertainty in terms of the construction materials’ properties, and translating this into appropriate physically based boundary conditions. Hybrid acoustic modeling approaches seek to solve the computational problem through complementary assimilation of various modeling paradigms. SonicRender is such a ...
Nonlinear sigma models with compact hyperbolic target spaces
Gubser, Steven; Saleem, Zain H.; Schoenholz, Samuel S.; Stoica, Bogdan; Stokes, James
2016-06-01
We explore the phase structure of nonlinear sigma models with target spaces corresponding to compact quotients of hyperbolic space, focusing on the case of a hyperbolic genus-2 Riemann surface. The continuum theory of these models can be approximated by a lattice spin system which we simulate using Monte Carlo methods. The target space possesses interesting geometric and topological properties which are reflected in novel features of the sigma model. In particular, we observe a topological phase transition at a critical temperature, above which vortices proliferate, reminiscent of the Kosterlitz-Thouless phase transition in the O(2) model [1, 2]. Unlike in the O(2) case, there are many different types of vortices, suggesting a possible analogy to the Hagedorn treatment of statistical mechanics of a proliferating number of hadron species. Below the critical temperature the spins cluster around six special points in the target space known as Weierstrass points. The diversity of compact hyperbolic manifolds suggests that our model is only the simplest example of a broad class of statistical mechanical models whose main features can be understood essentially in geometric terms.
From Diagnosis to Action: An Automated Failure Advisor for Human Deep Space Missions
Colombano, Silvano; Spirkovska, Lilly; Baskaran, Vijayakumar; Morris, Paul; Mcdermott, William; Ossenfort, John; Bajwa, Anupa
2015-01-01
The major goal of current space system development at NASA is to enable human travel to deep space locations such as Mars and asteroids. At that distance, round trip communication with ground operators may take close to an hour, thus it becomes unfeasible to seek ground operator advice for problems that require immediate attention, either for crew safety or for activities that need to be performed at specific times for the attainment of scientific results. To achieve this goal, major reliance will need to be placed on automation systems capable of aiding the crew in detecting and diagnosing failures, assessing consequences of these failures, and providing guidance in repair activities that may be required. We report here on the most current step in the continuing development of such a system, and that is the addition of a Failure Response Advisor. In simple terms, we have a system in place the Advanced Caution and Warning System (ACAWS) to tell us what happened (failure diagnosis) and what happened because that happened (failure effects). The Failure Response Advisor will tell us what to do about it, how long until something must be done and why its important that something be done and will begin to approach the complex reasoning that is generally required for an optimal approach to automated system health management. This advice is based on the criticality and various timing elements, such as durations of activities and of component repairs, failure effects delay, and other factors. The failure advice is provided to operators (crew and mission controllers) together with the diagnostic and effects information. The operators also have the option to drill down for more information about the failure and the reasons for any suggested priorities.
Formulating state space models in R with focus on longitudinal regression models
DEFF Research Database (Denmark)
Dethlefsen, Claus; Lundbye-Christensen, Søren
We provide a language for formulating a range of state space models. The described methodology is implemented in the R -package sspir available from cran.r-project.org . A state space model is specified similarly to a generalized linear model in R , by marking the time-varying terms in the...
Formulating state space models in R with focus on longitudinal regression models
DEFF Research Database (Denmark)
Dethlefsen, Claus; Lundbye-Christensen, Søren
2006-01-01
We provide a language for formulating a range of state space models with response densities within the exponential family. The described methodology is implemented in the R-package sspir. A state space model is specified similarly to a generalized linear model in R, and then the time-varying terms...
Probabilistic Hybrid Action Models for Predicting Concurrent Percept-driven Robot Behavior
Beetz, M; 10.1613/jair.1565
2011-01-01
This article develops Probabilistic Hybrid Action Models (PHAMs), a realistic causal model for predicting the behavior generated by modern percept-driven robot plans. PHAMs represent aspects of robot behavior that cannot be represented by most action models used in AI planning: the temporal structure of continuous control processes, their non-deterministic effects, several modes of their interferences, and the achievement of triggering conditions in closed-loop robot plans. The main contributions of this article are: (1) PHAMs, a model of concurrent percept-driven behavior, its formalization, and proofs that the model generates probably, qualitatively accurate predictions; and (2) a resource-efficient inference method for PHAMs based on sampling projections from probabilistic action models and state descriptions. We show how PHAMs can be applied to planning the course of action of an autonomous robot office courier based on analytical and experimental results.
The space weather modeling framework. Progress and challenges
International Nuclear Information System (INIS)
Complete text of publication follows. The Space Weather Modeling Framework (SWMF) is a powerful tool for coupling regional models describing the space environment from the solar photosphere to the bottom of the ionosphere. Presently, SWMF contains 13 components: the solar corona (SC), eruptive event generator (EE), inner heliosphere (IE), outer heliosphere (OH), solar energetic particles (SE), global magnetosphere (GM), inner magnetosphere (IM), radiation belts (RB), plasmasphere (PS), ionospheric electrodynamics (IE), polar wind (PW), upper atmosphere (UA) and lower atmosphere (LA). This talk will present an overview of SWMF, new results obtained with improved physics (Hall MHD and multifluid MHD) as well as some validation studies.
Stochastic modelling of dissolved inorganic nitrogen in space and time
DEFF Research Database (Denmark)
Lophaven, Søren Nymand; Carstensen, Niels Jacob; Rootzen, Helle
2006-01-01
Environmental monitoring datasets often contain a large amount of missing values, and are characterized as being sampled over time on a distinct number of locations in the area of interest. This paper proposes a stochastic approach for modelling such data in space and time, by taking the spatial......, and as time series of DIN at three different locations. However, the model approach could be applied to any space-time point given by a location in the Kattegat area and a week in the 5-year period 1993-1997. The results can be interpreted from a biological and physical point of view. Thus for the specific...
SpaceWire model development technology for satellite architecture.
Energy Technology Data Exchange (ETDEWEB)
Eldridge, John M.; Leemaster, Jacob Edward; Van Leeuwen, Brian P.
2011-09-01
Packet switched data communications networks that use distributed processing architectures have the potential to simplify the design and development of new, increasingly more sophisticated satellite payloads. In addition, the use of reconfigurable logic may reduce the amount of redundant hardware required in space-based applications without sacrificing reliability. These concepts were studied using software modeling and simulation, and the results are presented in this report. Models of the commercially available, packet switched data interconnect SpaceWire protocol were developed and used to create network simulations of data networks containing reconfigurable logic with traffic flows for timing system distribution.
A Right Coprime Factorization of Neural State Space Models
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon
2007-01-01
In recent years, various methods for identification of nonlinear systems in closed loop using open-loop approaches have received considerable attention. However, these methods rely on differentially coprime factorizations of the nonlinear plants, which can be difficult to compute in practice....... To address this issue, this paper presents various technical results leading up to explicit formulae for right coprime factorizations of neural state space models, i.e., nonlinear system models represented in state space using neural networks, which satisfy a Bezout identity. ...
Kane Method Based Dynamics Modeling and Control Study for Space Manipulator Capturing a Space Target
Directory of Open Access Journals (Sweden)
Yanhua Han
2016-01-01
Full Text Available Dynamics modeling and control problem of a two-link manipulator mounted on a spacecraft (so-called carrier freely flying around a space target on earth’s circular orbit is studied in the paper. The influence of the carrier’s relative movement on its manipulator is considered in dynamics modeling; nevertheless, that of the manipulator on its carrier is neglected with the assumption that the mass and inertia moment of the manipulator is far less than that of the carrier. Meanwhile, we suppose that the attitude control system of the carrier guarantees its side on which the manipulator is mounted points accurately always the space target during approaching operation. The ideal constraint forces can be out of consideration in dynamics modeling as Kane method is used. The path functions of the manipulator’s end-effector approaching the space target as well as the manipulator’s joints control torque functions are programmed to meet the soft touch requirement that the end-effector’s relative velocity to the space target is zero at touch moment. Numerical simulation validation is conducted finally.
Action unit classification using active appearance models and conditional random fields
Van der Maaten, L.J.P.; Hendriks, E.A.
2011-01-01
In this paper, we investigate to what extent modern computer vision and machine learning techniques can assist social psychology research by automatically recognizing facial expressions. To this end, we develop a system that automatically recognizes the action units defined in the facial action coding system (FACS). The system uses a sophisticated deformable template, which is known as the active appearance model, to model the appearance of faces. The model is used to identify the location of...
Methodology of problem space modeling in industrial enterprise management system
Directory of Open Access Journals (Sweden)
V.V. Glushchevsky
2015-03-01
Full Text Available The aim of the article. The aim of the article is to develop methodological principles for building a problem space model which can be integrated into industrial enterprise management system. The results of the analysis. The author developed methodological principles for constructing the problem space of an industrial enterprise as a structural and functional model. These problems appear on enterprise business process network topology and can be solved by its management system. The centerpiece of the article is description of the main stages of implementation of modeling methodology of industrial enterprise typical management problems. These stages help to solve several units of organizational management system structure of enterprise within their functional competence. Author formulated an axiom system of structural and characteristic properties of modeling space problems elements, and interconnections between them. This system of axioms is actually a justification for the correctness and adequacy of the proposed modeling methodology and comes as theoretical basis in the construction of the structural and functional model of the management problems space. This model generalizes three basic structural components of the enterprise management system with the help of axioms system: a three-dimensional model of the management problem space (the first dimension is the enterprise business process network, the second dimension is a set of management problems, the third dimension is four vectors of measurable and qualitative characteristics of management problems, which can be analyzed and managed during enterprise functioning; a two-dimensional model of the cybernetic space of analytical problems, which are formalized form of management problems (multivariate model experiments can be implemented with the help of this model to solve wide range of problem situations and determine the most effective or optimal management solutions; a two-dimensional model
Pyle, E. J.
2013-12-01
The Next Generation Science Standards (NGSS) are a step forward in ensuring that future generations of students become scientifically literate. The NGSS document builds from the National Science Education Standards (1996) and the National Assessment of Educational Progress (NAEP) science framework of 2005. Design teams for the Curriculum Framework for K-12 Science Education were to outline the essential content necessary for students' science literacy, considering the foundational knowledge and the structure of each discipline in the context of learning progressions. Once draft standards were developed, two issues emerged from their review: (a) the continual need to prune 'cherished ideas' within the content, such that only essential ideas were represented, and (b) the potential for prior conceptions of Science & Engineering Practices (SEP) and cross-cutting concepts (CCC) to limit overly constrain performance expectations. With the release of the NGSS, several challenges are emerging for geoscience education. First, the traditional emphasis of Earth science in middle school has been augmented by new standards for high school that require major syntheses of concepts. Second, the integration of SEPs into performance expectations places an increased burden on teachers and curriculum developers to organize instruction around the nature of inquiry in the geosciences. Third, work is needed to define CCCs in Earth contexts, such that the unique structure of the geosciences is best represented. To ensure that the Earth & Space Science standards are implemented through grade 12, two supporting structures must be developed. In the past, many curricular materials claimed that they adhered to the NSES, but in some cases this match was a simple word match or checklist that bore only superficial resemblance to the standards. The structure of the performance expectations is of sufficient sophistication to ensure that adherence to the standards more than a casual exercise. Claims
Barrett-Crane spin foam model from generalized BF-type action for gravity
International Nuclear Information System (INIS)
We study a generalized action for gravity as a constrained BF theory, and its relationship with the Plebanski action. We analyze the discretization of the constraints and the spin foam quantization of the theory, showing that it leads naturally to the Barrett-Crane spin foam model for quantum gravity. Our analysis holds true in both the Euclidean and Lorentzian formulations
Empirical processes, typical sequences and coordinated actions in standard Borel spaces
Raginsky, Maxim
2010-01-01
This paper proposes a new notion of typical sequences on a wide class of abstract alphabets (so-called standard Borel spaces), which is based on approximations of memoryless sources by empirical distributions uniformly over a class of measurable "test functions." In the finite-alphabet case, we can take all uniformly bounded functions and recover the usual notion of strong typicality (or typicality under the total variation distance). For a general alphabet, however, this function class turns out to be too large, and must be restricted. With this in mind, we define typicality with respect to any Glivenko-Cantelli function class (i.e., a function class that admits a Uniform Law of Large Numbers) and demonstrate its power by giving simple derivations of the fundamental limits on the achievable rates in several source coding scenarios, in which the relevant operational criteria pertain to reproducing empirical averages of a general-alphabet stationary memoryless source with respect to a suitable function class.
Sol-Terra - AN Operational Space Weather Forecasting Model Framework
Bisi, M. M.; Lawrence, G.; Pidgeon, A.; Reid, S.; Hapgood, M. A.; Bogdanova, Y.; Byrne, J.; Marsh, M. S.; Jackson, D.; Gibbs, M.
2015-12-01
The SOL-TERRA project is a collaboration between RHEA Tech, the Met Office, and RAL Space funded by the UK Space Agency. The goal of the SOL-TERRA project is to produce a Roadmap for a future coupled Sun-to-Earth operational space weather forecasting system covering domains from the Sun down to the magnetosphere-ionosphere-thermosphere and neutral atmosphere. The first stage of SOL-TERRA is underway and involves reviewing current models that could potentially contribute to such a system. Within a given domain, the various space weather models will be assessed how they could contribute to such a coupled system. This will be done both by reviewing peer reviewed papers, and via direct input from the model developers to provide further insight. Once the models have been reviewed then the optimal set of models for use in support of forecast-based SWE modelling will be selected, and a Roadmap for the implementation of an operational forecast-based SWE modelling framework will be prepared. The Roadmap will address the current modelling capability, knowledge gaps and further work required, and also the implementation and maintenance of the overall architecture and environment that the models will operate within. The SOL-TERRA project will engage with external stakeholders in order to ensure independently that the project remains on track to meet its original objectives. A group of key external stakeholders have been invited to provide their domain-specific expertise in reviewing the SOL-TERRA project at critical stages of Roadmap preparation; namely at the Mid-Term Review, and prior to submission of the Final Report. This stakeholder input will ensure that the SOL-TERRA Roadmap will be enhanced directly through the input of modellers and end-users. The overall goal of the SOL-TERRA project is to develop a Roadmap for an operational forecast-based SWE modelling framework with can be implemented within a larger subsequent activity. The SOL-TERRA project is supported within
Initiation-promotion model of tumor prevalence in mice from space radiation exposures.
Cucinotta, F A; Wilson, J W
1995-08-01
Exposures in space consist of low-level background components from galactic cosmic rays (GCR), occasional intense-energetic solar-particle events, periodic passes through geomagnetic-trapped radiation, and exposure from possible onboard nuclear-propulsion engines. Risk models for astronaut exposure from such diverse components and modalities must be developed to assure adequate protection in future NASA missions. The low-level background exposures (GCR), including relativistic heavy ions (HZE), will be the ultimate limiting factor for astronaut career exposure. We consider herein a two-mutation, initiation-promotion, radiation-carcinogenesis model in mice in which the initiation stage is represented by a linear kinetics model of cellular repair/misrepair, including the track-structure model for heavy ion action cross-sections. The model is validated by comparison with the harderian gland tumor experiments of Alpen et al. for various ion beams. We apply the initiation-promotion model to exposures from galactic cosmic rays, using models of the cosmic-ray environment and heavy ion transport, and consider the effects of the age of the mice prior to and after the exposure and of the length of time in space on predictions of relative risk. Our results indicate that biophysical models of age-dependent radiation hazard will provide a better understanding of GCR risk than models that rely strictly on estimates of the initial slopes of these radiations.
Initiation-promotion model of tumor prevalence in mice from space radiation exposures.
Cucinotta, F A; Wilson, J W
1995-08-01
Exposures in space consist of low-level background components from galactic cosmic rays (GCR), occasional intense-energetic solar-particle events, periodic passes through geomagnetic-trapped radiation, and exposure from possible onboard nuclear-propulsion engines. Risk models for astronaut exposure from such diverse components and modalities must be developed to assure adequate protection in future NASA missions. The low-level background exposures (GCR), including relativistic heavy ions (HZE), will be the ultimate limiting factor for astronaut career exposure. We consider herein a two-mutation, initiation-promotion, radiation-carcinogenesis model in mice in which the initiation stage is represented by a linear kinetics model of cellular repair/misrepair, including the track-structure model for heavy ion action cross-sections. The model is validated by comparison with the harderian gland tumor experiments of Alpen et al. for various ion beams. We apply the initiation-promotion model to exposures from galactic cosmic rays, using models of the cosmic-ray environment and heavy ion transport, and consider the effects of the age of the mice prior to and after the exposure and of the length of time in space on predictions of relative risk. Our results indicate that biophysical models of age-dependent radiation hazard will provide a better understanding of GCR risk than models that rely strictly on estimates of the initial slopes of these radiations. PMID:7480628
Processing Approach of Non-linear Adjustment Models in the Space of Non-linear Models
Institute of Scientific and Technical Information of China (English)
LI Chaokui; ZHU Qing; SONG Chengfang
2003-01-01
This paper investigates the mathematic features of non-linear models and discusses the processing way of non-linear factors which contributes to the non-linearity of a nonlinear model. On the basis of the error definition, this paper puts forward a new adjustment criterion, SGPE.Last, this paper investigates the solution of a non-linear regression model in the non-linear model space and makes the comparison between the estimated values in non-linear model space and those in linear model space.
Multi-scale gravity field modeling in space and time
Wang, Shuo; Panet, Isabelle; Ramillien, Guillaume; Guilloux, Frédéric
2016-04-01
The Earth constantly deforms as it undergoes dynamic phenomena, such as earthquakes, post-glacial rebound and water displacement in its fluid envelopes. These processes have different spatial and temporal scales and are accompanied by mass displacements, which create temporal variations of the gravity field. Since 2002, the GRACE satellite missions provide an unprecedented view of the gravity field spatial and temporal variations. Gravity models built from these satellite data are essential to study the Earth's dynamic processes (Tapley et al., 2004). Up to present, time variations of the gravity field are often modelled using spatial spherical harmonics functions averaged over a fixed period, as 10 days or 1 month. This approach is well suited for modeling global phenomena. To better estimate gravity related to local and/or transient processes, such as earthquakes or floods, and adapt the temporal resolution of the model to its spatial resolution, we propose to model the gravity field using localized functions in space and time. For that, we build a model of the gravity field in space and time with a four-dimensional wavelet basis, well localized in space and time. First we design the 4D basis, then, we study the inverse problem to model the gravity field from the potential differences between the twin GRACE satellites, and its regularization using prior knowledge on the water cycle. Our demonstration of surface water mass signals decomposition in time and space is based on the use of synthetic along-track gravitational potential data. We test the developed approach on one year of 4D gravity modeling and compare the reconstructed water heights to those of the input hydrological model. Perspectives of this work is to apply the approach on real GRACE data, addressing the challenge of a realistic noise, to better describe and understand physical processus with high temporal resolution/low spatial resolution or the contrary.
Modeling situated abstraction : action coalescence via multidimensional coherence.
Energy Technology Data Exchange (ETDEWEB)
Sallach, D. L.; Decision and Information Sciences; Univ. of Chicago
2007-01-01
Situated social agents weigh dozens of priorities, each with its own complexities. Domains of interest are intertwined, and progress in one area either complements or conflicts with other priorities. Interpretive agents address these complexities through: (1) integrating cognitive complexities through the use of radial concepts, (2) recognizing the role of emotion in prioritizing alternatives and urgencies, (3) using Miller-range constraints to avoid oversimplified notions omniscience, and (4) constraining actions to 'moves' in multiple prototype games. Situated agent orientations are dynamically grounded in pragmatic considerations as well as intertwined with internal and external priorities. HokiPoki is a situated abstraction designed to shape and focus strategic agent orientations. The design integrates four pragmatic pairs: (1) problem and solution, (2) dependence and power, (3) constraint and affordance, and (4) (agent) intent and effect. In this way, agents are empowered to address multiple facets of a situation in an exploratory, or even arbitrary, order. HokiPoki is open to the internal orientation of the agent as it evolves, but also to the communications and actions of other agents.
Holographic Space-time Models of Anti-deSitter Space-times
Banks, Tom
2016-01-01
We study the constraints on HST models of AdS space-time. The causal diamonds of HST along time-like geodesics of AdS space-time, fit nicely into the FRW patch of AdS space. The coordinate singularity of the FRW patch is identified with the proper time at which the Hilbert space of the causal diamond becomes infinite dimensional. For diamonds much smaller than the AdS radius, RAdS, the time dependent Hamiltonians of HST are the same as those used to describe similar diamonds in Minkowski space. In particular, they are invariant under the fuzzy analog of volume preserving diffeomorphisms of the holographic screen, which leads to fast scrambling of perturbations on the horizon of a black hole of size smaller than RAdS. We argue that, in order to take a limit of this system which converges to a CFT, one must choose Hamiltonians, in a range of proper times of order RAdS, which break this invariance, and become local in a particular choice of basis for the variables. We show that, beginning with flat, sub-RAdS, pa...
Modeling irregularly spaced residual series as a continuous stochastic process
Von Asmuth, J.R.; Bierkens, M.F.P.
2005-01-01
In this paper, the background and functioning of a simple but effective continuous time approach for modeling irregularly spaced residual series is presented. The basic equations were published earlier by von Asmuth et al. (2002), who used them as part of a continuous time transfer function noise mo
Magnetic Testing, and Modeling, Simulation and Analysis for Space Applications
Boghosian, Mary; Narvaez, Pablo; Herman, Ray
2012-01-01
The Aerospace Corporation (Aerospace) and Lockheed Martin Space Systems (LMSS) participated with Jet Propulsion Laboratory (JPL) in the implementation of a magnetic cleanliness program of the NASA/JPL JUNO mission. The magnetic cleanliness program was applied from early flight system development up through system level environmental testing. The JUNO magnetic cleanliness program required setting-up a specialized magnetic test facility at Lockheed Martin Space Systems for testing the flight system and a testing program with facility for testing system parts and subsystems at JPL. The magnetic modeling, simulation and analysis capability was set up and performed by Aerospace to provide qualitative and quantitative magnetic assessments of the magnetic parts, components, and subsystems prior to or in lieu of magnetic tests. Because of the sensitive nature of the fields and particles scientific measurements being conducted by the JUNO space mission to Jupiter, the imposition of stringent magnetic control specifications required a magnetic control program to ensure that the spacecraft's science magnetometers and plasma wave search coil were not magnetically contaminated by flight system magnetic interferences. With Aerospace's magnetic modeling, simulation and analysis and JPL's system modeling and testing approach, and LMSS's test support, the project achieved a cost effective approach to achieving a magnetically clean spacecraft. This paper presents lessons learned from the JUNO magnetic testing approach and Aerospace's modeling, simulation and analysis activities used to solve problems such as remnant magnetization, performance of hard and soft magnetic materials within the targeted space system in applied external magnetic fields.
Dynamic State Space Partitioning for External Memory Model Checking
DEFF Research Database (Denmark)
Evangelista, Sami; Kristensen, Lars Michael
2009-01-01
We describe a dynamic partitioning scheme usable by model checking techniques that divide the state space into partitions, such as most external memory and distributed model checking algorithms. The goal of the scheme is to reduce the number of transitions that link states belonging to different ...... partitions, and thereby limit the amount of disk access and network communication. We report on several experiments made with our verification platform ASAP that implements the dynamic partitioning scheme proposed in this paper....
A Configuration-Space Equatorial Spread F Structure Model
Rino, C. L.; Carrano, C. S.; Retterer, J. M.
2014-12-01
Configuration-space models address the intermediate scale ESF structure range from hundreds of kilometers to hundreds of meters. It is well known that ESF structure is comprised of highly-elongated field-aligned striations. Striations are generated by physics-based ESF codes. Moreover, they are visually observable in twilight barium releases and air glow. Configuration-space models are derived from ensembles of field-aligned striations with specified radial profile functions, distributions of scale sizes, and distributions of clustered field-line starting locations. The model is intimately tied to underlying physics. The scale-dependent evolution of a field-aligned local plasma enhancement is a well posed plasma-physics problem. Local striation creation, evolution, and intensity is driven by the convective instability process. Successive bifurcation is often used to describe the Rayleigh-Taylor mechanism. The model makes no prior assumptions that ensure standard spectral decompositions. Indeed, the model shows that there is no possibility of constructing a consistent three-dimensional structure spectrum. The model does show that in planes intersecting field lines well removed from the meridian plane two-dimensional spectra can be constructed. There is a one-to-one relation between the striation size distribution and the index of the corresponding power-law segments. The profile shape controls the texture of the realizations. A critical number of randomly located striations are required to support a well-defined spectral characterization. The configuration space model is defined by a much smaller number of random variables than required to generate a realization of a process with specified spectral characteristics. Thus, it is feasible to generate a three-dimensional realization that can be used to simulate ESF and to interpret planned space-time Cubsat measurements. The theory will be reviewed and examples of model applications presented.
Applying Model Based Systems Engineering to NASA's Space Communications Networks
Bhasin, Kul; Barnes, Patrick; Reinert, Jessica; Golden, Bert
2013-01-01
System engineering practices for complex systems and networks now require that requirement, architecture, and concept of operations product development teams, simultaneously harmonize their activities to provide timely, useful and cost-effective products. When dealing with complex systems of systems, traditional systems engineering methodology quickly falls short of achieving project objectives. This approach is encumbered by the use of a number of disparate hardware and software tools, spreadsheets and documents to grasp the concept of the network design and operation. In case of NASA's space communication networks, since the networks are geographically distributed, and so are its subject matter experts, the team is challenged to create a common language and tools to produce its products. Using Model Based Systems Engineering methods and tools allows for a unified representation of the system in a model that enables a highly related level of detail. To date, Program System Engineering (PSE) team has been able to model each network from their top-level operational activities and system functions down to the atomic level through relational modeling decomposition. These models allow for a better understanding of the relationships between NASA's stakeholders, internal organizations, and impacts to all related entities due to integration and sustainment of existing systems. Understanding the existing systems is essential to accurate and detailed study of integration options being considered. In this paper, we identify the challenges the PSE team faced in its quest to unify complex legacy space communications networks and their operational processes. We describe the initial approaches undertaken and the evolution toward model based system engineering applied to produce Space Communication and Navigation (SCaN) PSE products. We will demonstrate the practice of Model Based System Engineering applied to integrating space communication networks and the summary of its
Neuro-Space Mapping for Modeling Heterojunction Bipolar Transistor
Institute of Scientific and Technical Information of China (English)
Yan Shuxia; Cheng Qianfu; Wu Haifeng; Zhang Qijun
2015-01-01
A neuro-space mapping(Neuro-SM) for modeling heterojunction bipolar transistor(HBT) is presented, which can automatically modify the input signals of the given model by neural network. The novel Neuro-SM formu-lations for DC and small-signal simulation are proposed to obtain the mapping network. Simulation results show that the errors between Neuro-SM models and the accurate data are less than 1%, demonstrating that the accurcy of the proposed method is higher than those of the existing models.
Nonlinear state space model identification of synchronous generators
Energy Technology Data Exchange (ETDEWEB)
Dehghani, M.; Nikravesh, S.K.Y. [Electrical Engineering Department, Amirkabir University of Technology, Tehran (Iran)
2008-05-15
A method for identification of a synchronous generator is suggested in this paper. The method uses the theoretical relations of machine parameters and the Prony method to find the state space model of the system. Such models are useful for controller design and stability tests. The proposed identification method is applied to a third order model of a synchronous generator. In this study, the field voltage is considered as the input and the active output power and the rotor angle are considered as the outputs of the synchronous generator. Simulation results show good accuracy of the identified model. (author)
Nechitailo, G.; Gordeev, A.
2004-01-01
The key role in increasing the resistance of plants to unfavorable space flight factors is assigned to biomembranes of root cells. It is these biomembranes in which numerous biochemical and biophysical processes determining the adaptive capacity of plant organisms occur. In the initial period of exposure to unfavorable space flight factors the adaptation reactions of the plant organism undoubtedly increase its resistance. But the intensification of removal of H + ions through the plasmalemma with an increase of the external influence sharply raises the quantity of cations leaving the cell, which leads to the accumulation of a considerable quantity of intracellular negative charges. These charges together with negative charges built in the membrane force protons to concentrate on the external surface of the membrane. Since protons have a very strong electric field, they form such a charge of which the electric field is about from several to hundreds of V/cm. The concentration of positive charges of protons entails the formation of a double electric field which extremely impedes the diffusion of other ions. Thus, a proton barrier is formed. Its length can be very considerable due to which the whole process of transmembrane energy and mass-transfer is disturbed. The proton barrier is easily destroyed by a weak electric field created in the root zone. In experiments on electrostimulation of different plants under space flight conditions at the orbital station MIR the absorption of nutrient elements by the root system increased to the optimal level, the ratio of physiologically active substances in the rhizosphere was normalized, the content of chlorophyll, carotin, and ascorbic acid in leaves corresponded to the ground-based control. Understanding of the mechanism of formation of a proton barrier on the plasmalemma of root cells as a result of the response of plants to the negative action of external factors (microgravity) is of great importance. It allows the
Seezink, Audrey; Poell, Rob; Kirschner, Paul A.
2009-01-01
Seezink, A., Poell, R. F., & Kirschner, P. A. (2009). Teachers' individual action theories about competence-based education: The value of the cognitive apprenticeship model. Journal of Vocational Education & Training, 61, 203-215.
Phase diagram of Model C in the parametric space of order parameter and space dimensions
Dudka, M.; Folk, R.; Holovatch, Yu.
2016-01-01
The scaling behavior of model C describing the dynamical behaviour of the $n$-component nonconserved order parameter coupled statically to a scalar conserved density is considered in $d$-dimensional space. Conditions for the realization of different types of scaling regimes in the $(n,d)$ plane are studied within the field-theoretical renormalization group approach. Borders separating these regions are calculated on the base of high-order RG functions using $\\epsilon$-expansions as well as by...
Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling
Directory of Open Access Journals (Sweden)
Amr Al Abed
2013-01-01
Full Text Available A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN, intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.
Space modeling with SolidWorks and NX
Duhovnik, Jože; Drešar, Primož
2015-01-01
Through a series of step-by-step tutorials and numerous hands-on exercises, this book aims to equip the reader with both a good understanding of the importance of space in the abstract world of engineers and the ability to create a model of a product in virtual space – a skill essential for any designer or engineer who needs to present ideas concerning a particular product within a professional environment. The exercises progress logically from the simple to the more complex; while SolidWorks or NX is the software used, the underlying philosophy is applicable to all modeling software. In each case, the explanation covers the entire procedure from the basic idea and production capabilities through to the real model; the conversion from 3D model to 2D manufacturing drawing is also clearly explained. Topics covered include modeling of prism, axisymmetric, symmetric, and sophisticated shapes; digitization of physical models using modeling software; creation of a CAD model starting from a physical model; free fo...
State space modeling of Memristor-based Wien oscillator
Talukdar, Abdul Hafiz Ibne
2011-12-01
State space modeling of Memristor based Wien \\'A\\' oscillator has been demonstrated for the first time considering nonlinear ion drift in Memristor. Time dependant oscillating resistance of Memristor is reported in both state space solution and SPICE simulation which plausibly provide the basis of realizing parametric oscillation by Memristor based Wien oscillator. In addition to this part Memristor is shown to stabilize the final oscillation amplitude by means of its nonlinear dynamic resistance which hints for eliminating diode in the feedback network of conventional Wien oscillator. © 2011 IEEE.
Space Object Tracking Method Based on a Snake Model
Zhan-wei, Xu; Xin, Wang
2016-04-01
In this paper, aiming at the problem of unstable tracking of low-orbit variable and bright space objects, adopting an active contour model, a kind of improved GVF (Gradient Vector Flow) - Snake algorithm is proposed to realize the real-time search of the real object contour on the CCD image. Combined with the Kalman filter for prediction, a new adaptive tracking method is proposed for space objects. Experiments show that this method can overcome the tracking error caused by the fixed window, and improve the tracking robustness.
A Model of Emergent Universe in Inhomogeneous Space-Time
Bhattacharya, Subhra
2016-01-01
A scenario of an emergent universe is constructed in the background of an inhomogeneous space-time model which is asymptotically (at spatial infinity) FRW space-time. The cosmic substratum consists of non-interacting two components, namely {\\bf a)} homogeneous and isotropic fluid but dissipative in nature and {\\bf b)} an inhomogeneous and anisotropic barotropic fluid. In non-equilibrium thermodynamic prescription (second order deviations), particle creation mechanism is considered the cause for the dissipative phenomena. It is found that for constant value of the particle creation rate parameter there exists a scenario of emergent universe.
Life sciences research in space: The requirement for animal models
Fuller, C. A.; Philips, R. W.; Ballard, R. W.
1987-01-01
Use of animals in NASA space programs is reviewed. Animals are needed because life science experimentation frequently requires long-term controlled exposure to environments, statistical validation, invasive instrumentation or biological tissue sampling, tissue destruction, exposure to dangerous or unknown agents, or sacrifice of the subject. The availability and use of human subjects inflight is complicated by the multiple needs and demands upon crew time. Because only living organisms can sense, integrate and respond to the environment around them, the sole use of tissue culture and computer models is insufficient for understanding the influence of the space environment on intact organisms. Equipment for spaceborne experiments with animals is described.
Improving active space telescope wavefront control using predictive thermal modeling
Gersh-Range, Jessica; Perrin, Marshall D.
2015-01-01
Active control algorithms for space telescopes are less mature than those for large ground telescopes due to differences in the wavefront control problems. Active wavefront control for space telescopes at L2, such as the James Webb Space Telescope (JWST), requires weighing control costs against the benefits of correcting wavefront perturbations that are a predictable byproduct of the observing schedule, which is known and determined in advance. To improve the control algorithms for these telescopes, we have developed a model that calculates the temperature and wavefront evolution during a hypothetical mission, assuming the dominant wavefront perturbations are due to changes in the spacecraft attitude with respect to the sun. Using this model, we show that the wavefront can be controlled passively by introducing scheduling constraints that limit the allowable attitudes for an observation based on the observation duration and the mean telescope temperature. We also describe the implementation of a predictive controller designed to prevent the wavefront error (WFE) from exceeding a desired threshold. This controller outperforms simpler algorithms even with substantial model error, achieving a lower WFE without requiring significantly more corrections. Consequently, predictive wavefront control based on known spacecraft attitude plans is a promising approach for JWST and other future active space observatories.
Model-based action planning involves cortico-cerebellar and basal ganglia networks
Fermin, Alan S. R.; Yoshida, Takehiko; Yoshimoto, Junichiro; Ito, Makoto; Tanaka, Saori C.; Doya, Kenji
2016-01-01
Humans can select actions by learning, planning, or retrieving motor memories. Reinforcement Learning (RL) associates these processes with three major classes of strategies for action selection: exploratory RL learns state-action values by exploration, model-based RL uses internal models to simulate future states reached by hypothetical actions, and motor-memory RL selects past successful state-action mapping. In order to investigate the neural substrates that implement these strategies, we conducted a functional magnetic resonance imaging (fMRI) experiment while humans performed a sequential action selection task under conditions that promoted the use of a specific RL strategy. The ventromedial prefrontal cortex and ventral striatum increased activity in the exploratory condition; the dorsolateral prefrontal cortex, dorsomedial striatum, and lateral cerebellum in the model-based condition; and the supplementary motor area, putamen, and anterior cerebellum in the motor-memory condition. These findings suggest that a distinct prefrontal-basal ganglia and cerebellar network implements the model-based RL action selection strategy. PMID:27539554
Model-based action planning involves cortico-cerebellar and basal ganglia networks.
Fermin, Alan S R; Yoshida, Takehiko; Yoshimoto, Junichiro; Ito, Makoto; Tanaka, Saori C; Doya, Kenji
2016-01-01
Humans can select actions by learning, planning, or retrieving motor memories. Reinforcement Learning (RL) associates these processes with three major classes of strategies for action selection: exploratory RL learns state-action values by exploration, model-based RL uses internal models to simulate future states reached by hypothetical actions, and motor-memory RL selects past successful state-action mapping. In order to investigate the neural substrates that implement these strategies, we conducted a functional magnetic resonance imaging (fMRI) experiment while humans performed a sequential action selection task under conditions that promoted the use of a specific RL strategy. The ventromedial prefrontal cortex and ventral striatum increased activity in the exploratory condition; the dorsolateral prefrontal cortex, dorsomedial striatum, and lateral cerebellum in the model-based condition; and the supplementary motor area, putamen, and anterior cerebellum in the motor-memory condition. These findings suggest that a distinct prefrontal-basal ganglia and cerebellar network implements the model-based RL action selection strategy. PMID:27539554
Data and models in Action. Methodological Issues in Production Ecology
Stein, A.; Penning, de F.W.T.
1999-01-01
This book addresses methodological issues of production ecology. A central issue is the combination of the agricultural model with reliable data in relation to scale. A model is developed with data from a single point, whereas decisions are to be made for areas of land. Such an approach requires the
Modeling of weak lensing statistics. II. Configuration-space statistics
Valageas, Patrick; Nishimichi, Takahiro
2011-01-01
We investigate the performance of an analytic model of the 3D matter distribution, which combines perturbation theory with halo models, for weak lensing configuration-space statistics. We compare our predictions for the weak lensing convergence two-point and three-point correlation functions with numerical simulations and fitting formulas proposed in previous works. We also consider the second and third-order moments of the smoothed convergence and of the aperture-mass. As in our previous study of Fourier-space weak lensing statistics, we find that our model provides better agreement with simulations than published fitting formulas. Moreover, we check that we recover the dependence on cosmology of these weak lensing statistics. This approach allows us to obtain the quantitative relationship between these integrated weak lensing statistics and the various contributions to the underlying 3D density fluctuations, decomposed over perturbative, 2-halo, or 1-halo terms.
Application of thermospheric general circulation models for space weather operations
Fuller-Rowell, T.; Minter, C.; Codrescu, M.
Solar irradiance is the dominant source of heat, ionization, and dissociation of the thermosphere, and to a large extent drives the global dynamics, and controls the neutral composition and density structure. Neutral composition is important for space weather applications because of its impact on ionospheric loss rates, and neutral density is critical for satellite drag prediction. The future for thermospheric general circulation models for space weather operations lies in their use as state propagators in data assimilation techniques. The physical models can match empirical models in accuracy provided accurate drivers are available, but their true value comes when combined with data in an optimal way. Two such applications have recently been developed. The first utilizes a Kalman filter to combine space-based observation of airglow with physical model predictions to produce global maps of neutral composition. The output of the filter will be used within the GAIM (Global Assimilation of Ionospheric Measurement) model developed under a parallel effort. The second filter uses satellite tracking and remote sensing data for specification of neutral density. Both applications rely on accurate estimates of the solar EUV and magnetospheric drivers.
The importance of understanding: Model space moderates goal specificity effects.
Kistner, Saskia; Burns, Bruce D; Vollmeyer, Regina; Kortenkamp, Ulrich
2016-01-01
The three-space theory of problem solving predicts that the quality of a learner's model and the goal specificity of a task interact on knowledge acquisition. In Experiment 1 participants used a computer simulation of a lever system to learn about torques. They either had to test hypotheses (nonspecific goal), or to produce given values for variables (specific goal). In the good- but not in the poor-model condition they saw torque depicted as an area. Results revealed the predicted interaction. A nonspecific goal only resulted in better learning when a good model of torques was provided. In Experiment 2 participants learned to manipulate the inputs of a system to control its outputs. A nonspecific goal to explore the system helped performance when compared to a specific goal to reach certain values when participants were given a good model, but not when given a poor model that suggested the wrong hypothesis space. Our findings support the three-space theory. They emphasize the importance of understanding for problem solving and stress the need to study underlying processes.
Wingate, Robert J.
2012-01-01
After the launch scrub of Space Shuttle mission STS-133 on November 5, 2010, large cracks were discovered in two of the External Tank intertank stringers. The NASA Marshall Space Flight Center, as managing center for the External Tank Project, coordinated the ensuing failure investigation and repair activities with several organizations, including the manufacturer, Lockheed Martin. To support the investigation, the Marshall Space Flight Center formed an ad-hoc stress analysis team to complement the efforts of Lockheed Martin. The team undertook six major efforts to analyze or test the structural behavior of the stringers. Extensive finite element modeling was performed to characterize the local stresses in the stringers near the region of failure. Data from a full-scale tanking test and from several subcomponent static load tests were used to confirm the analytical conclusions. The analysis and test activities of the team are summarized. The root cause of the stringer failures and the flight readiness rationale for the repairs that were implemented are discussed.
Nongenomic actions of cortisol in the teleost lactotroph model
DEFF Research Database (Denmark)
Borski, Russell J; Tipsmark, Christian Kølbæk; Mita, M
2006-01-01
of the present study was to investigate the role of phospholipase C (PLC)-IP3 in mediating cortisol's actions. During 30 min and 4-hour incubation, chicken GnRH-II induces a 2-4 fold increase in PRL release from the tilapia pituitary. The stimulatory effect of cGnRH-II was reduced by cortisol, cortisol-21......-hemisuccinate (HEF) and its membrane impermeant analog, HEF-BSA. Since GnRH induces PRL release, in part, via activation of PLC this suggests that cortisol may rapidly inhibit GnRH-induced PRL release by suppressing PLC activity. We also found that cortisol rapidly inhibits IP3 accumulation in tilapia RPD under...... stimulation by angiotensin II, a factor known to exert its cellular effects through stimulation of the PLC-IP3 pathway. Further studies demonstrate that cortisol reduces PLC activity (measured by the hydrolysis of 3H-PIP2) in a dose dependent manner from crude tilapia lactotroph membrane preparations. SRIF...
Foresight Model of Turkey's Defense Industries' Space Studies until 2040
Yuksel, Nurdan; Cifci, Hasan; Cakir, Serhat
2016-07-01
Being advanced in science and technology is inevitable reality in order to be able to have a voice in the globalized world. Therefore, for the countries, making policies in consistent with their societies' intellectual, economic and political infrastructure and attributing them to the vision having been embraced by all parties of the society is quite crucial for the success. The generated policies are supposed to ensure the usage of countries' resources in the most effective and fastest way, determine the priorities and needs of society and set their goals and related roadmaps. In this sense, technology foresight studies based on justified forecasting in science and technology have critical roles in the process of developing policies. In this article, Foresight Model of Turkey's Defense Industries' Space Studies, which is turned out to be the important part of community life and fundamental background of most technologies, up to 2040 is presented. Turkey got late in space technology studies. Hence, for being fast and efficient to use its national resources in a cost effective way and within national and international collaboration, it should be directed to its pre-set goals. By taking all these factors into consideration, the technology foresight model of Turkey's Defense Industry's Space Studies was presented in the study. In the model, the present condition of space studies in the World and Turkey was analyzed; literature survey and PEST analysis were made. PEST analysis will be the inputs of SWOT analysis and Delphi questionnaire will be used in the study. A two-round Delphi survey will be applied to the participants from universities, public and private organizations operating in space studies at Defense Industry. Critical space technologies will be distinguished according to critical technology measures determined by expert survey; space technology fields and goals will be established according to their importance and feasibility indexes. Finally, for the
Innovative Actions within the Business Models of European Companies
Georgeta Ilie
2014-01-01
Companies regularly reassess and reorganize their business models in order to create value and generate growth. They also reassess the price-performance correlation and new levels of capital efficiency. The new business models are frequently needed to provide goods at affordable prices through the adaptation of packaging strategies, pricing strategies, the product itself, and by helping to sustain financially the demand. In the context of current financial and economic difficulties, it reveal...
Motivation in action: A process model of L2 motivation
Dornyei, Zoltan; Otto, Istvan
1998-01-01
As part of a long-term project aimed at designing classroom interventions to motivate language learners, we have searched for a motivation model that could serve as a theoretical basis for the methodological applications. We have found that none of the existing models we considered were entirely adequate for our purpose for three reasons: (1) they did not provide a sufficiently comprehensive and detailed summary of all the relevant motivational influences on classroom behaviour; (2) they tend...
Action-based Dynamical Modelling for the Milky Way Disk
Trick, Wilma H; Rix, Hans-Walter
2016-01-01
We present RoadMapping, a full-likelihood dynamical modelling machinery that aims to recover the Milky Way's (MW) gravitational potential from large samples of stars in the Galactic disk. RoadMapping models the observed positions and velocities of stars with a parametrized, three-integral distribution function (DF) in a parametrized axisymmetric potential. We investigate through differential test cases with idealized mock data how the breakdown of model assumptions and data properties affect constraints on the potential and DF. Our key results are: (i) If the MW's true potential is not included in the assumed model potential family, we can - in the axisymmetric case - still find a robust estimate for the potential, with only <~ 10% difference in surface density within |z| <= 1.1 kpc inside the observed volume. (ii) Modest systematic differences between the true and model DF are inconsequential. E.g, when binning stars to define sub-populations with simple DFs, binning errors do not affect the modelling ...
A Trusted Host's Authentication Access and Control Model Faced on User Action
Institute of Scientific and Technical Information of China (English)
ZHANG Miao; XU Guoai; HU Zhengming; YANG Yixian
2006-01-01
The conception of trusted network connection (TNC) is introduced, and the weakness of TNC to control user's action is analyzed. After this, the paper brings out a set of secure access and control model based on access, authorization and control, and related authentication protocol. At last the security of this model is analyzed. The model can improve TNC's security of user control and authorization.
Stirling System Modeling for Space Nuclear Power Systems
Lewandowski, Edward J.; Johnson, Paul K.
2008-01-01
A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power, and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.
Modeling the Phase-Space Distribution around Massive Halos
Lam, Tsz Yan; Nishimichi, Takahiro; Takada, Masahiro
2013-01-01
The comparison between dynamical mass and lensing mass provides a targeted test for a wide range of modified gravity models. In our previous paper we showed, through numerical simulations, that the measurement of the line-of-sight velocity dispersion around stacked massive clusters whose lensing masses are known allows for stringent constraints on modified gravity on scales of 2 - 15 Mpc/h. In this work we develop a semi-analytical approach based on the halo model to describe the phase-space distribution and the line-of-sight velocity dispersion for different tracers. The model distinguishes contributions from the halo pairwise velocity and the virial velocity within halos. We also discuss observational complications, in particular the contribution from Hubble flow, and show how our model can incorporate these complications. We then incorporate the effects of modified gravity (specifically, f(R) and braneworld models), and show that the model predictions are in excellent agreement with modified gravity simula...
A phase-space model for Pleistocene ice volume
Imbrie, John Z; Lisiecki, Lorraine E
2011-01-01
We present a phase-space model that simulates Pleistocene ice volume changes based on Earth's orbital parameters. Terminations in the model are triggered by a combination of ice volume and orbital forcing and agree well with age estimates for Late Pleistocene terminations. The average phase at which model terminations begin is approximately 90 +/- 90 degrees before the maxima in all three orbital cycles. The large variability in phase is likely caused by interactions between the three cycles and ice volume. Unlike previous ice volume models, this model produces an orbitally driven increase in 100-kyr power during the mid-Pleistocene transition without any change in model parameters. This supports the hypothesis that Pleistocene variations in the 100-kyr power of glacial cycles could be caused, at least in part, by changes in Earth's orbital parameters, such as amplitude modulation of the 100-kyr eccentricity cycle, rather than changes within the climate system.
The modeling and simulation of the artifical space object
Gao, Sili; Tang, Xinyi; Yu, Yang; Xue, Fengting
2009-07-01
With a certain space-based low earth orbit satellite as its detecting target, after the author did a lot of research work and by experiential speculation, the paper initially gives simplified framework, shape and size of the satellite. Based on the different kinds of heat-control materials adopted by the satellite, the concerned material parameters were given out, such as emissivity, heat capacity, density and thermal conductivity etc. Based on the satellite's geometrical features, its 3D model was established via 3DS Max and was translated to customized-format model file which can be easily read-out by vc-program. The orbit of the satellite is a sun-synchronous orbit, its attitude control system was carried out by means of inertial directionality. According to the temperature of the surface given by a certain institute, the temperature of the satellite surface in the whole orbit period was gained by linear interpolation method. The infrared radiation model of the satellite was established based on the temperature and features of the proper materials. The motion model was established by two-body orbit motion formula which was based on the six orbital elements. At last, the infrared simulating images are provided under the system parameters such as detecting positions and detecting wavebands etc. The infrared scene simulation of space object can be achieved by this method and the base for the infrared detection of the space object is established.
Modeling and Capturing Users’ Actions in CSCL Systems for Collaboration Analysis Purposes
Directory of Open Access Journals (Sweden)
Manuel Ortega
2009-03-01
Full Text Available A significant number of CSCL (Computer-Supported Collaborative Learning environments support the learning of groups of students enabling their collaboration in solving problems. These collaborative environments usually need additional computational support to allow the automatic processing of both the actions carried out by the students and the end solution with the aim of studying the learning process and the validity of the solution proposed to the problem. This process, known as Collaboration and Interaction Analysis, is typically carried out in three phases: observation, abstraction and intervention. In this paper, we propose a methodological approach for the design of mechanisms for the observation phase. This approach provides a set of procedures enabling developers to design observation systems in CSCL environments that capture and model all the information required for comprehensive analyses of the collaboration process and the resulting solution to the problem. This methodological approach is put into practice by means of its use in the design of an observation system in the SPACE-DESIGN (SPecification and Automatic Construction of collaborative Environments of DESIGN collaborative environment.
Dispersion modeling of thermal power plant emissions on stochastic space
Gorle, J. M. R.; Sambana, N. R.
2016-05-01
This study aims to couple a deterministic atmospheric dispersion solver based on Gaussian model with a nonintrusive stochastic model to quantify the propagation of multiple uncertainties. The nonintrusive model is based on probabilistic collocation framework. The advantage of nonintrusive nature is to retain the existing deterministic plume dispersion model without missing the accuracy in extracting the statistics of stochastic solution. The developed model is applied to analyze the SO2 emission released from coal firing unit in the second stage of the National Thermal Power Corporation (NTPC) in Dadri, India using "urban" conditions. The entire application is split into two cases, depending on the source of uncertainty. In case 1, the uncertainties in stack gas exit conditions are used to construct the stochastic space while in case 2, meteorological conditions are considered as the sources of uncertainty. Both cases develop 2D uncertain random space in which the uncertainty propagation is quantified in terms of plume rise and pollutant concentration distribution under slightly unstable atmospheric stability conditions. Starting with deterministic Gaussian plume model demonstration and its application, development of stochastic collocation model, convergence study, error analysis, and uncertainty quantification are presented in this paper.
Aquatic blues: modeling depression and antidepressant action in zebrafish.
Nguyen, Michael; Stewart, Adam Michael; Kalueff, Allan V
2014-12-01
Depression is a serious psychiatric condition affecting millions of patients worldwide. Unipolar depression is characterized by low mood, anhedonia, social withdrawal and other severely debilitating psychiatric symptoms. Bipolar disorder manifests in alternating depressed mood and 'hyperactive' manic/hypomanic states. Animal experimental models are an invaluable tool for research into the pathogenesis of bipolar/unipolar depression, and for the development of potential treatments. Due to their high throughput value, genetic tractability, low cost and quick reproductive cycle, zebrafish (Danio rerio) have emerged as a promising new model species for studying brain disorders. Here, we discuss the developing utility of zebrafish for studying depression disorders, and outline future areas of research in this field. We argue that zebrafish represent a useful model organism for studying depression and its behavioral, genetic and physiological mechanisms, as well as for anti-depressant drug discovery.
Action-Based Dynamical Modeling for the Milky Way Disk
Trick, Wilma H.; Bovy, Jo; Rix, Hans-Walter
2016-10-01
We present RoadMapping, a full-likelihood dynamical modeling machinery that aims to recover the Milky Way’s (MW) gravitational potential from large samples of stars in the Galactic disk. RoadMapping models the observed positions and velocities of stars with a parameterized, three-integral distribution function (DF) in a parameterized axisymmetric potential. We investigate through differential test cases with idealized mock data how the breakdown of model assumptions and data properties affect constraints on the potential and DF. Our key results are: (i) If the MW’s true potential is not included in the assumed model potential family, we can—in the axisymmetric case—still find a robust estimate for the potential, with only ≲ 10 % difference in surface density within | z| ≤slant 1.1 {kpc} inside the observed volume. (ii) Modest systematic differences between the true and model DF are inconsequential. E.g., when binning stars to define sub-populations with simple DFs, binning errors do not affect the modeling as long as the DF parameters of neighboring bins differ by \\lt 20 % . In addition, RoadMapping ensures unbiased potential estimates for either (iii) small misjudgements of the spatial selection function (i.e., ≲ 15 % at the survey volume’s edge), (iv) if distances are known to within 10%, or (v) if proper motion uncertainties are known within 10% or are smaller than δ μ ≲ 1 {mas} {{yr}}-1. Challenges are the rapidly increasing computational costs for large sample sizes. Overall, RoadMapping is well suited to making precise new measurements of the MW’s potential with data from the upcoming Gaia releases.
Modeling Ships and Space Craft The Science and Art of Mastering the Oceans and Sky
Hagler, Gina
2013-01-01
Modeling Ships and Space Craft: The Science and Art of Mastering the Oceans and Sky begins with the theories of Aristotle and Archimedes, moving on to examine the work of Froude and Taylor, the early aviators and the Wright Brothers, Goddard and the other rocket men, and the computational fluid dynamic models of our time. It examines the ways each used fluid dynamic principles in the design of their vessels. In the process, this book covers the history of hydrodynamic (aero and fluid) theory and its progression – with some very accessible science examples – including seminal theories. Hydrodynamic principles in action are also explored with examples from nature and the works of man. This is a book for anyone interested in the history of technology – specifically the methods and science behind the use of scale models and hydrodynamic principles in the marine and aeronautical designs of today.
Computational Model of Primary Visual Cortex Combining Visual Attention for Action Recognition.
Directory of Open Access Journals (Sweden)
Na Shu
Full Text Available Humans can easily understand other people's actions through visual systems, while computers cannot. Therefore, a new bio-inspired computational model is proposed in this paper aiming for automatic action recognition. The model focuses on dynamic properties of neurons and neural networks in the primary visual cortex (V1, and simulates the procedure of information processing in V1, which consists of visual perception, visual attention and representation of human action. In our model, a family of the three-dimensional spatial-temporal correlative Gabor filters is used to model the dynamic properties of the classical receptive field of V1 simple cell tuned to different speeds and orientations in time for detection of spatiotemporal information from video sequences. Based on the inhibitory effect of stimuli outside the classical receptive field caused by lateral connections of spiking neuron networks in V1, we propose surround suppressive operator to further process spatiotemporal information. Visual attention model based on perceptual grouping is integrated into our model to filter and group different regions. Moreover, in order to represent the human action, we consider the characteristic of the neural code: mean motion map based on analysis of spike trains generated by spiking neurons. The experimental evaluation on some publicly available action datasets and comparison with the state-of-the-art approaches demonstrate the superior performance of the proposed model.
Joint Dynamics Modeling and Parameter Identification for Space Robot Applications
Directory of Open Access Journals (Sweden)
Adenilson R. da Silva
2007-01-01
Full Text Available Long-term mission identification and model validation for in-flight manipulator control system in almost zero gravity with hostile space environment are extremely important for robotic applications. In this paper, a robot joint mathematical model is developed where several nonlinearities have been taken into account. In order to identify all the required system parameters, an integrated identification strategy is derived. This strategy makes use of a robust version of least-squares procedure (LS for getting the initial conditions and a general nonlinear optimization method (MCS—multilevel coordinate search—algorithm to estimate the nonlinear parameters. The approach is applied to the intelligent robot joint (IRJ experiment that was developed at DLR for utilization opportunity on the International Space Station (ISS. The results using real and simulated measurements have shown that the developed algorithm and strategy have remarkable features in identifying all the parameters with good accuracy.
Dynamical 3-Space Gravity Theory: Effects on Polytropic Solar Models
Directory of Open Access Journals (Sweden)
May R. D.
2011-01-01
Full Text Available Numerous experiments and observations have confirmed the existence of a dynamical 3-space, detectable directly by light-speed anisotropy experiments, and indirectly by means of novel gravitational effects, such as bore hole g anomalies, predictable black hole masses, flat spiral-galaxy rotation curves, and the expansion of the universe, all without dark matter and dark energy. The dynamics for this 3-space follows from a unique generalisation of Newtonian gravity, once that is cast into a velocity formalism. This new theory of gravity is applied to the solar model of the sun to compute new density, pressure and temperature profiles, using polytrope modelling of the equation of state for the matter. These results should be applied to a re-analysis of solar neutrino production, and to stellar evolution in general.
Dynamical 3-Space Gravity Theory: Effects on Polytropic Solar Models
Directory of Open Access Journals (Sweden)
Cahill R. T.
2011-01-01
Full Text Available Numerous experiments and observations have confirmed the existence of a dynamical 3-space, detectable directly by light-speed anisotropy experiments, and indirectly by means of novel gravitational effects, such as bore hole g-anomalies, predictable black hole masses, flat spiral-galaxy rotation curves, and the expansion of the universe, all without dark matter and dark energy. The dynamics for this 3-space follows from a unique generalisation of Newtonian gravity, once that is cast into a velocity formalism. This new theory of gravity is applied to the solar model of the sun to compute new density, pressure and temperature profiles, using polytrope modelling of the equation of state for the matter. These results should be applied to a re-analysis of solar neutrino production, and to stellar evolution in general.
State space modelling and data analysis exercises in LISA Pathfinder
Nofrarias, M; Armano, M; Audley, H; Auger, G; Benedetti, M; Binetruy, P; Bogenstahl, J; Bortoluzzi, D; Bosetti, P; Brandt, N; Caleno, M; Cañizares, P; Cavalleri, A; Cesa, M; Chmeissani, M; Conchillo, A; Congedo, G; Cristofolin, I; Cruise, M; Danzmann, K; De Marchi, F; Diaz-Aguilo, M; Diepholz, I; Dixon, G; Dolesi, R; Dunbar, N; Fauste, J; Ferraioli, L; Fichter, V Ferroni W; Fitzsimons, E; Freschi, M; Marin, A García; Marirrodriga, C García; Gesa, R Gerndt L; Gibert, F; Giardini, D; Grimani, C; Grynagier, A; Guillaume, B; Guzmán, F; Harrison, I; Heinzel, G; Hernández, V; Hewitson, M; Hollington, D; Hough, J; Hoyland, D; Hueller, M; Huesler, J; Jennrich, O; Jetzer, P; Johlander, B; Killow, C; Llamas, X; Lloro, I; Lobo, A; Maarschalkerweerd, R; Madden, S; Mance, D; Mateos, I; McNamara, P W; Mendes, J; Mitchell, E; Monsky, A; Nicolini, D; Nicolodi, D; Pedersen, F; Perreur-Lloyd, M; Plagnol, E; Prat, P; Racca, G D; Ramos-Castro, J; Reiche, J; Perez, J A Romera; Robertson, D; Rozemeijer, H; Sanjuan, J; Schleicher, A; Schulte, M; Shaul, D; Stagnaro, L; Strandmoe, S; Steier, F; Sumner, T J; Taylor, A; Texier, D; Trenkel, C; Vitale, H-B Tu S; Wanner, G; Ward, H; Waschke, S; Wass, P; Weber, W J; Ziegler, T; Zweifel, P
2013-01-01
LISA Pathfinder is a mission planned by the European Space Agency to test the key technologies that will allow the detection of gravitational waves in space. The instrument on-board, the LISA Technology package, will undergo an exhaustive campaign of calibrations and noise characterisation campaigns in order to fully describe the noise model. Data analysis plays an important role in the mission and for that reason the data analysis team has been developing a toolbox which contains all the functionalities required during operations. In this contribution we give an overview of recent activities, focusing on the improvements in the modelling of the instrument and in the data analysis campaigns performed both with real and simulated data.
Community Reintegration: The Value of Educational-Action-Training Models.
Versluys, Hilda P.
1984-01-01
The article describes the principles that guide program development, the use of therapeutic and educational activities, and the components of transitional program models for disabled individuals re-entering the community following discharge from rehabilitation facilities. The role of the occupatonal therapist in successful reintegration is…
Modelling human actions on lightweight structures: experimental and numerical developments
Directory of Open Access Journals (Sweden)
Živanović S.
2015-01-01
Full Text Available This paper presents recent, numerical and experimental, developments in modelling dynamic loading generated by humans. As modern structures with exposure to human-induced loading, such as footbridges, building floors and grandstands, are becoming ever lighter and more slender, they are increasingly susceptible to vibration under human-induced dynamic excitation, such as walking, jumping, running and bobbing, and their vibration serviceability assessment is often a deciding factor in the design process. While simplified modelling of the human using a harmonic force was sufficient for assessment of vibration performance of more robust structures a few decades ago, the higher fidelity models are required in the contemporary design. These models are expected not only to describe both temporal and spectral features of the force signal more accurately, but also to capture the influence, psychological and physiological, of human-structure and human-human interaction mechanisms on the human kinematics, and consequently on the force generated and the resulting vibration response. Significant advances have been made in both the research studies and design guidance. This paper reports the key developments and identifies the scope for further research.
Characteristics of Effective Training: Developing a Model To Motivate Action.
Wise, Dena; Ezell, Patsy
2003-01-01
The Parenting and Consumer Education project identified effective models for training welfare-to-work facilitators. Premises were the importance of process, learner responsibility, and improvement of social networks. Effective training was learner focused, inspiring, and motivating; demonstrated productive behaviors and effective life skills; and…
A modeling investigation of vowel-to-vowel movement planning in acoustic and muscle spaces
Zandipour, Majid
The primary objective of this research was to explore the coordinate space in which speech movements are planned. A two dimensional biomechanical model of the vocal tract (tongue, lips, jaw, and pharynx) was constructed based on anatomical and physiological data from a subject. The model transforms neural command signals into the actions of muscles. The tongue was modeled by a 221-node finite element mesh. Each of the eight tongue muscles defined within the mesh was controlled by a virtual muscle model. The other vocal-tract components were modeled as simple 2nd-order systems. The model's geometry was adapted to a speaker, using MRI scans of the speaker's vocal tract. The vocal tract model, combined with an adaptive controller that consisted of a forward model (mapping 12-dimensional motor commands to a 64-dimensional acoustic spectrum) and an inverse model (mapping acoustic trajectories to motor command trajectories), was used to simulate and explore the implications of two planning hypotheses: planning in motor space vs. acoustic space. The acoustic, kinematic, and muscle activation (EMG) patterns of vowel-to-vowel sequences generated by the model were compared to data from the speaker whose acoustic, kinematic and EMG were also recorded. The simulation results showed that: (a) modulations of the motor commands effectively accounted for the effects of speaking rate on EMG, kinematic, and acoustic outputs; (b) the movement and acoustic trajectories were influenced by vocal tract biomechanics; and (c) both planning schemes produced similar articulatory movement, EMG, muscle length, force, and acoustic trajectories, which were also comparable to the subject's data under normal speaking conditions. In addition, the effects of a bite-block on measured EMG, kinematics and formants were simulated by the model. Acoustic planning produced successful simulations but motor planning did not. The simulation results suggest that with somatosensory feedback but no auditory
Transformation of Neural State Space Models into LFT Models for Robust Control Design
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2000-01-01
This paper considers the extraction of linear state space models and uncertainty models from neural networks trained as state estimators with direct application to robust control. A new method for writing a neural state space model in a linear fractional transformation form in a non......-conservative way is proposed, and it is demonstrated how a standard robust control law can be designed for a system described by means of a multi layer perceptron....
The Yukawa Model in One Space - One time Dimensions
Gouba, Laure
2016-01-01
The Yukawa Model is revisited in one space - one time dimensions in a complete different approach than the ones in the literature. We show that at the classical level it is a constrained system. We apply the Dirac method of quantization of constrained systems. Then by mean of the bosonization procedure we uniformize the Hamiltonian at the quantum level in terms of pseudo-scalar field and chiral components of a real scalar field.
Quantum-dot Semiconductor Optical Amplifiers in State Space Model
Institute of Scientific and Technical Information of China (English)
Hussein Taleb; Kambiz Abedi; Saeed Golmohammadi
2013-01-01
A state space model (SSM) is derived for quantum-dot semiconductor optical amplifiers (QD-SOAs).Rate equations of QD-SOA are formulated in the form of state update equations,where average occupation probabilities along QD-SOA cavity are considered as state variables of the system.Simulations show that SSM calculates QD-SOA's static and dynamic characteristics with high accuracy.
Space-time estimation of a particle system model
Guyon, Xavier; Pumo, Besnik
2007-01-01
13 pages Let X be a discrete time contact process (CP) on the discrete bidimensional lattice as define by Durett - Levin (1994) . We study estimation of the model based on space-time evolution on a finite subset of sites. For this, we make use of a marginal pseudo-likelihood. The estimator obtained is consistent and asymptoticaly normal for non-vanishing supercritical CP. Numerical studies confirm these results.
Mathematical analysis techniques for modeling the space network activities
Foster, Lisa M.
1992-01-01
The objective of the present work was to explore and identify mathematical analysis techniques, and in particular, the use of linear programming. This topic was then applied to the Tracking and Data Relay Satellite System (TDRSS) in order to understand the space network better. Finally, a small scale version of the system was modeled, variables were identified, data was gathered, and comparisons were made between actual and theoretical data.
Gaussian processes for state space models and change point detection
Turner, Ryan Darby
2012-01-01
This thesis details several applications of Gaussian processes (GPs) for enhanced time series modeling. We first cover different approaches for using Gaussian processes in time series problems. These are extended to the state space approach to time series in two different problems. We also combine Gaussian processes and Bayesian online change point detection (BOCPD) to increase the generality of the Gaussian process time series methods. These methodologies are evaluated on predict...
Exact energy spectrum for models with equally spaced point potentials
Caudrelier, V.; Crampe, N.
2006-01-01
We describe a non-perturbative method for computing the energy band structures of one-dimensional models with general point potentials sitting at equally spaced sites. This is done thanks to a Bethe ansatz approach and the method is applicable even when periodicity is broken, that is when Bloch's theorem is not valid any more. We derive the general equation governing the energy spectrum and illustrate its use in various situations. In particular, we get exact results for boundary effects. We ...
Holographic Space-time Models in $1 + 1$ Dimensions
Banks, T
2015-01-01
We construct Holographic Space-time models that reproduce the dynamics of $1 + 1$ dimensional string theory. The necessity for a dilaton field in the $1 + 1$ effective Lagrangian for classical geometry, the appearance of fermions, and even the form of the universal potential in the canonical $1$ matrix model, follow from general HST considerations. We note that 't Hooft's ansatz for the leading contribution to the black hole S-matrix, accounts for the entire S-matrix in these models in the limit that the string scale coincides with the Planck scale, up to transformations between near horizon and asymptotic coordinates. These $1 + 1$ dimensional models are describable as decoupling limits of the near horizon geometry of higher dimensional extremal black holes or black branes, and this suggests that deformations of the simplest model are equally physical. After proposing a notion of "relevant deformations", we describe deformations, which contain excitations corresponding to linear dilaton black holes, some of ...
Space radiation-associated lung injury in a murine model.
Christofidou-Solomidou, Melpo; Pietrofesa, Ralph A; Arguiri, Evguenia; Schweitzer, Kelly S; Berdyshev, Evgeny V; McCarthy, Maureen; Corbitt, Astrid; Alwood, Joshua S; Yu, Yongjia; Globus, Ruth K; Solomides, Charalambos C; Ullrich, Robert L; Petrache, Irina
2015-03-01
Despite considerable progress in identifying health risks to crewmembers related to exposure to galactic/cosmic rays and solar particle events (SPE) during space travel, its long-term effects on the pulmonary system are unknown. We used a murine risk projection model to investigate the impact of exposure to space-relevant radiation (SR) on the lung. C3H mice were exposed to (137)Cs gamma rays, protons (acute, low-dose exposure mimicking the 1972 SPE), 600 MeV/u (56)Fe ions, or 350 MeV/u (28)Si ions at the NASA Space Radiation Laboratory at Brookhaven National Laboratory. Animals were irradiated at the age of 2.5 mo and evaluated 23.5 mo postirradiation, at 26 mo of age. Compared with age-matched nonirradiated mice, SR exposures led to significant air space enlargement and dose-dependent decreased systemic oxygenation levels. These were associated with late mild lung inflammation and prominent cellular injury, with significant oxidative stress and apoptosis (caspase-3 activation) in the lung parenchyma. SR, especially high-energy (56)Fe or (28)Si ions markedly decreased sphingosine-1-phosphate levels and Akt- and p38 MAPK phosphorylation, depleted anti-senescence sirtuin-1 and increased biochemical markers of autophagy. Exposure to SR caused dose-dependent, pronounced late lung pathological sequelae consistent with alveolar simplification and cellular signaling of increased injury and decreased repair. The associated systemic hypoxemia suggested that this previously uncharacterized space radiation-associated lung injury was functionally significant, indicating that further studies are needed to define the risk and to develop appropriate lung-protective countermeasures for manned deep space missions. PMID:25526737
Tests of streaming models for redshift-space distortions
White, Martin; Chuang, Chia-Hsun; Tinker, Jeremy L; McBride, Cameron K; Prada, Francisco; Samushia, Lado
2014-01-01
Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. In preparation for analysis of redshift-space distortions from the Baryon Oscillation Spectroscopic Survey (BOSS) final data release we compare a number of analytic and phenomenological `streaming' models, specified in configuration space, to mock catalogs derived in different ways from several N-body simulations. The galaxies in each mock catalog have properties similar to those of the higher redshift galaxies measured by BOSS but differ in the details of how small-scale velocities and halo occupancy are determined. We find that all of the analytic models fit the simulations over a limited range of scales while failing at small scales. We discuss which models are most robust and on which scales they return reliable estimates of the rate of growth of structure: we find that...
A conceptual model for translating omic data into clinical action
Directory of Open Access Journals (Sweden)
Timothy M Herr
2015-01-01
Full Text Available Genomic, proteomic, epigenomic, and other "omic" data have the potential to enable precision medicine, also commonly referred to as personalized medicine. The volume and complexity of omic data are rapidly overwhelming human cognitive capacity, requiring innovative approaches to translate such data into patient care. Here, we outline a conceptual model for the application of omic data in the clinical context, called "the omic funnel." This model parallels the classic "Data, Information, Knowledge, Wisdom pyramid" and adds context for how to move between each successive layer. Its goal is to allow informaticians, researchers, and clinicians to approach the problem of translating omic data from bench to bedside, by using discrete steps with clearly defined needs. Such an approach can facilitate the development of modular and interoperable software that can bring precision medicine into widespread practice.
The Use of Evolution in a Central Action Selection Model
Directory of Open Access Journals (Sweden)
F. Montes-Gonzalez
2007-01-01
Full Text Available The use of effective central selection provides flexibility in design by offering modularity and extensibility. In earlier papers we have focused on the development of a simple centralized selection mechanism. Our current goal is to integrate evolutionary methods in the design of non-sequential behaviours and the tuning of specific parameters of the selection model. The foraging behaviour of an animal robot (animat has been modelled in order to integrate the sensory information from the robot to perform selection that is nearly optimized by the use of genetic algorithms. In this paper we present how selection through optimization finally arranges the pattern of presented behaviours for the foraging task. Hence, the execution of specific parts in a behavioural pattern may be ruled out by the tuning of these parameters. Furthermore, the intensive use of colour segmentation from a colour camera for locating a cylinder sets a burden on the calculations carried out by the genetic algorithm.
Special class of nonlinear damping models in flexible space structures
Hu, Anren; Singh, Ramendra P.; Taylor, Lawrence W.
1991-01-01
A special class of nonlinear damping models is investigated in which the damping force is proportional to the product of positive integer or the fractional power of the absolute values of displacement and velocity. For a one-degree-of-freedom system, the classical Krylov-Bogoliubov 'averaging' method is used, whereas for a distributed system, both an ad hoc perturbation technique and the finite difference method are employed to study the effects of nonlinear damping. The results are compared with linear viscous damping models. The amplitude decrement of free vibration for a single mode system with nonlinear models depends not only on the damping ratio but also on the initial amplitude, the time to measure the response, the frequency of the system, and the powers of displacement and velocity. For the distributed system, the action of nonlinear damping is found to reduce the energy of the system and to pass energy to lower modes.
Model-space nuclear matter calculations with the Bonn potential
Energy Technology Data Exchange (ETDEWEB)
Engvik, L.; Hjort-Jensen, M.; Osnes, E.; Kuo, T.T.S.
1992-08-01
In this work the authors have examined a model-space Brueckner-Hartree-Fock (MBHF) approach to the single-particle energies in nuclear matter, employing three recent versions of the Bonn meson-exchange potential model. The non-relativistic MBHF calculations form the well known ''Coester'' band, where the potential which exhibits the weakest tensor force yields the largest binding energy per nucleon. Correcting for relativistic effects, the MBHF calculations result in too little binding. The implications are discussed. 12 refs., 2 figs.
Model-space nuclear matter calculations with the Bonn potential
Energy Technology Data Exchange (ETDEWEB)
Engvik, L.; Hjort-Jensen, M.; Osnes, E.; Kuo, T.T.S.
1992-08-01
In this work the authors have examined a model-space Brueckner-Hartree-Fock (MBHF) approach to the single-particle energies in nuclear matter, employing three recent versions of the Bonn meson-exchange potential model. The non-relativistic MBHF calculations form the well known ``Coester`` band, where the potential which exhibits the weakest tensor force yields the largest binding energy per nucleon. Correcting for relativistic effects, the MBHF calculations result in too little binding. The implications are discussed. 12 refs., 2 figs.
DEFF Research Database (Denmark)
Fajstrup, Lisbeth; Goubault, Eric; Haucourt, Emmanuel;
2012-01-01
State-space reduction techniques, used primarily in model-checkers, all rely on the idea that some actions are independent, hence could be taken in any (respective) order while put in parallel, without changing the semantics. It is thus not necessary to consider all execution paths in the interle......State-space reduction techniques, used primarily in model-checkers, all rely on the idea that some actions are independent, hence could be taken in any (respective) order while put in parallel, without changing the semantics. It is thus not necessary to consider all execution paths...... of concurrent languages, where programs are interpreted as directed topological spaces, and study its properties in order to devise an algorithm for computing dihomotopy classes of execution paths. In particular, our algorithm is able to compute a control-flow graph for concurrent programs, possibly containing...
A model for thermal exchange in axons during action potential propagation.
Masson, Jean-Baptiste; Gallot, Guilhem
2008-01-01
International audience Several experiments have shown that during propagation of the action potential in axons, thermal energy is locally exchanged. In this paper, we use a simple model based on statistical physics to show that an important part of this exchange comes from the physics of the effusion. We evaluate, during the action potential propagation, the variation of internal energy and of the energy associated with the chemical potential of the effusion of water and ions to extract th...
Activators of potassium M currents have anticonvulsant actions in two rat models of encephalitis
Marylou V. Solbrig; Adrian, Russell; Wechsler, Steven L.; Koob, George F.
2006-01-01
Opioid systems in hippocampus regulate excitability and kappa opioids have a role in anticonvulsant protection, but their mechanisms of action are incompletely understood. We examined the ability of opioid and nonopioid agents with overlapping ionic mechanisms and actions similar to kappa opioid agonists, to block seizures in rat models of encephalitis due to Borna Disease virus and Herpes Simplex Virus Type-1. Naltrindole, a delta antagonist and thus a kappa opioid sparing agent, (10 mg/kg s...
Optimal State-Space Reduction for Pedigree Hidden Markov Models
Kirkpatrick, Bonnie
2012-01-01
To analyze whole-genome genetic data inherited in families, the likelihood is typically obtained from a Hidden Markov Model (HMM) having a state space of 2^n hidden states where n is the number of meioses or edges in the pedigree. There have been several attempts to speed up this calculation by reducing the state-space of the HMM. One of these methods has been automated in a calculation that is more efficient than the naive HMM calculation; however, that method treats a special case and the efficiency gain is available for only those rare pedigrees containing long chains of single-child lineages. The other existing state-space reduction method treats the general case, but the existing algorithm has super-exponential running time. We present three formulations of the state-space reduction problem, two dealing with groups and one with partitions. One of these problems, the maximum isometry group problem was discussed in detail by Browning and Browning. We show that for pedigrees, all three of these problems hav...
Directory of Open Access Journals (Sweden)
Marcos Antônio Silvestre Gomes
2015-07-01
Full Text Available This article discusses some aspects of the production of urban space considering the social agents actions. The methodology was based on literature searches, data surveys and interviews in public and private agencies, empirical observations and mapping of the urban area. The methodology was based on literature searches, data surveys and interviews in public and private agencies, empirical observations and mapping of the urban area. The objective is to present an analysis of state and real estate developers actions in the production and uneven valorization of urban space in Campos dos Goytacazes-RJ. The results of work indicate the intensification and complexification of actions of these agents with the advent of the oil economy. In the period 1981-2011 there was an intense valuation of South West-East axis of the city, with a vertiginous process of vertical integration and deployment of a high standard closed allotments, which has
Real Z2-bigradings, Majorana modules, and the standard model action
International Nuclear Information System (INIS)
The action functional of the standard model of particle physics is intimately related to a specific class of first order differential operators called Dirac operators of Pauli type ('Pauli-Dirac operators'). The aim of this article is to carefully analyze the geometrical structure of this class of Dirac operators on the basis of real Dirac operators of simple type. On the basis of simple type Dirac operators, it is shown how the standard model action (STM action) may be viewed as generalizing the Einstein-Hilbert action in a similar way that the Einstein-Hilbert action is generalized by a cosmological constant. Furthermore, we demonstrate how the geometrical scheme presented allows to naturally incorporate also Majorana mass terms within the standard model. For reasons of consistency, these Majorana mass terms are shown to dynamically contribute to the Einstein-Hilbert action by a 'true' cosmological constant. Due to its specific form, this cosmological constant can be very small. Nonetheless, this cosmological constant may provide a significant contribution to dark matter/energy. In the geometrical description presented, this possibility arises from a subtle interplay between Dirac and Majorana masses.
Bessel functions in mass action modeling of memories and remembrances
Energy Technology Data Exchange (ETDEWEB)
Freeman, Walter J. [Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3206 (United States); Capolupo, Antonio [Dipartimento di Fisica, E.R. Caianiello Universitá di Salerno, and INFN Gruppo collegato di Salerno, Fisciano 84084 (Italy); Kozma, Robert [Department of Mathematics, Memphis University, Memphis, TN 38152 (United States); Olivares del Campo, Andrés [The Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ (United Kingdom); Vitiello, Giuseppe, E-mail: vitiello@sa.infn.it [Dipartimento di Fisica, E.R. Caianiello Universitá di Salerno, and INFN Gruppo collegato di Salerno, Fisciano 84084 (Italy)
2015-10-02
Data from experimental observations of a class of neurological processes (Freeman K-sets) present functional distribution reproducing Bessel function behavior. We model such processes with couples of damped/amplified oscillators which provide time dependent representation of Bessel equation. The root loci of poles and zeros conform to solutions of K-sets. Some light is shed on the problem of filling the gap between the cellular level dynamics and the brain functional activity. Breakdown of time-reversal symmetry is related with the cortex thermodynamic features. This provides a possible mechanism to deduce lifetime of recorded memory. - Highlights: • We consider data from observations of impulse responses of cortex to electric shocks. • These data are fitted by Bessel functions which may be represented by couples of damped/amplified oscillators. • We study the data by using couples of damped/amplified oscillators. • We discuss lifetime and other properties of the considered brain processes.
THE MODEL CHARACTERISTICS OF JUMP ACTIONS STRUCTURE OF HIGH PERFORMANCE FEMALE VOLLEYBALL PLAYERS
Directory of Open Access Journals (Sweden)
Stech M.
2012-12-01
Full Text Available The purpose of this study was to develop generalized and individual models of the jump actions of skilled female volleyball players. The main prerequisite for the development of the jump actions models were the results of our earlier studies of factor structure of jump actions of 10 sportswomen of the Polish volleyball team "Gedania" (Premier League in the preparatory and competitive periods of the annual cycle of preparation. The athletes age was 22.0 +- 2.9 years, the sports experience - 8.1 +- 3.1 years, body height - 181.9 +- 8.4 years and body weight - 72.8 +- 10.8 kg. Mathematical and statistical processing of the data (the definition of M ± SD and significant differences between the samples was performed using a standard computer program "STATISTICA 7,0". Based on the analysis of the factor structure of 20 jump actions of skilled women volleyball players determined to within 5 of the most informative indexes and their tentative values recommended for the formation of a generalized model of this structure. Comparison of individual models of jump actions of skilled women volleyball players with their generalized models in different periods of preparation can be used for the rational choice of means and methods for the increasing of the training process efficiency.
Grassmann phase space theory and the Jaynes-Cummings model
Dalton, B. J.; Garraway, B. M.; Jeffers, J.; Barnett, S. M.
2013-07-01
The Jaynes-Cummings model of a two-level atom in a single mode cavity is of fundamental importance both in quantum optics and in quantum physics generally, involving the interaction of two simple quantum systems—one fermionic system (the TLA), the other bosonic (the cavity mode). Depending on the initial conditions a variety of interesting effects occur, ranging from ongoing oscillations of the atomic population difference at the Rabi frequency when the atom is excited and the cavity is in an n-photon Fock state, to collapses and revivals of these oscillations starting with the atom unexcited and the cavity mode in a coherent state. The observation of revivals for Rydberg atoms in a high-Q microwave cavity is key experimental evidence for quantisation of the EM field. Theoretical treatments of the Jaynes-Cummings model based on expanding the state vector in terms of products of atomic and n-photon states and deriving coupled equations for the amplitudes are a well-known and simple method for determining the effects. In quantum optics however, the behaviour of the bosonic quantum EM field is often treated using phase space methods, where the bosonic mode annihilation and creation operators are represented by c-number phase space variables, with the density operator represented by a distribution function of these variables. Fokker-Planck equations for the distribution function are obtained, and either used directly to determine quantities of experimental interest or used to develop c-number Langevin equations for stochastic versions of the phase space variables from which experimental quantities are obtained as stochastic averages. Phase space methods have also been developed to include atomic systems, with the atomic spin operators being represented by c-number phase space variables, and distribution functions involving these variables and those for any bosonic modes being shown to satisfy Fokker-Planck equations from which c-number Langevin equations are often
Phase transition in matrix model with logarithmic action: toy-model for gluons in baryons
International Nuclear Information System (INIS)
We study the competing effects of gluon self-coupling and their interactions with quarks in a baryon, using the very simple setting of a hermitian 1-matrix model with action trA4-log det (ν+A2). The logarithmic term comes from integrating out N quarks. The model is a caricature of 2d QCD coupled to adjoint scalars, which are the transversely polarized gluons in a dimensional reduction. ν is a dimensionless ratio of quark mass to coupling constant. The model interpolates between gluons in the vacuum (ν = ∞), gluons weakly coupled to heavy quarks (large ν) and strongly coupled to light quarks in a baryon (ν→0). Its solution in the large-N limit exhibits a phase transition from a weakly coupled 1-cut phase to a strongly coupled 2-cut phase as ν is decreased below νc = 0.27. Free energy and correlation functions are discontinuous in their third and second derivatives at νc. The transition to a two-cut phase forces eigenvalues of A away from zero, making glue-ring correlations grow as ν is decreased. In particular, they are enhanced in a baryon compared to the vacuum. This investigation is motivated by a desire to understand why half the proton's momentum is contributed by gluons
Operationalizing the Concept of Value--An Action Research-Based Model
Naslund, Dag; Olsson, Annika; Karlsson, Sture
2006-01-01
Purpose: While the importance of measuring customer satisfaction levels is well established, less research exists on how organizations operationalize such knowledge. The purpose of this paper is to describe an action research (AR) case study resulting in a workshop model to operationalize the concept of value. The model facilitates organizational…
Space Partitioning for Privacy Enabled 3D City Models
Filippovska, Y.; Wichmann, A.; Kada, M.
2016-10-01
Due to recent technological progress, data capturing and processing of highly detailed (3D) data has become extensive. And despite all prospects of potential uses, data that includes personal living spaces and public buildings can also be considered as a serious intrusion into people's privacy and a threat to security. It becomes especially critical if data is visible by the general public. Thus, a compromise is needed between open access to data and privacy requirements which can be very different for each application. As privacy is a complex and versatile topic, the focus of this work particularly lies on the visualization of 3D urban data sets. For the purpose of privacy enabled visualizations of 3D city models, we propose to partition the (living) spaces into privacy regions, each featuring its own level of anonymity. Within each region, the depicted 2D and 3D geometry and imagery is anonymized with cartographic generalization techniques. The underlying spatial partitioning is realized as a 2D map generated as a straight skeleton of the open space between buildings. The resulting privacy cells are then merged according to the privacy requirements associated with each building to form larger regions, their borderlines smoothed, and transition zones established between privacy regions to have a harmonious visual appearance. It is exemplarily demonstrated how the proposed method generates privacy enabled 3D city models.
On vector autoregressive modeling in space and time
di Giacinto, Valter
2010-06-01
Despite the fact that it provides a potentially useful analytical tool, allowing for the joint modeling of dynamic interdependencies within a group of connected areas, until lately the VAR approach had received little attention in regional science and spatial economic analysis. This paper aims to contribute in this field by dealing with the issues of parameter identification and estimation and of structural impulse response analysis. In particular, there is a discussion of the adaptation of the recursive identification scheme (which represents one of the more common approaches in the time series VAR literature) to a space-time environment. Parameter estimation is subsequently based on the Full Information Maximum Likelihood (FIML) method, a standard approach in structural VAR analysis. As a convenient tool to summarize the information conveyed by regional dynamic multipliers with a specific emphasis on the scope of spatial spillover effects, a synthetic space-time impulse response function (STIR) is introduced, portraying average effects as a function of displacement in time and space. Asymptotic confidence bands for the STIR estimates are also derived from bootstrap estimates of the standard errors. Finally, to provide a basic illustration of the methodology, the paper presents an application of a simple bivariate fiscal model fitted to data for Italian NUTS 2 regions.
A Bayesian state-space formulation of dynamic occupancy models.
Royle, J Andrew; Kéry, Marc
2007-07-01
Species occurrence and its dynamic components, extinction and colonization probabilities, are focal quantities in biogeography and metapopulation biology, and for species conservation assessments. It has been increasingly appreciated that these parameters must be estimated separately from detection probability to avoid the biases induced by non-detection error. Hence, there is now considerable theoretical and practical interest in dynamic occupancy models that contain explicit representations of metapopulation dynamics such as extinction, colonization, and turnover as well as growth rates. We describe a hierarchical parameterization of these models that is analogous to the state-space formulation of models in time series, where the model is represented by two components, one for the partially observable occupancy process and another for the observations conditional on that process. This parameterization naturally allows estimation of all parameters of the conventional approach to occupancy models, but in addition, yields great flexibility and extensibility, e.g., to modeling heterogeneity or latent structure in model parameters. We also highlight the important distinction between population and finite sample inference; the latter yields much more precise estimates for the particular sample at hand. Finite sample estimates can easily be obtained using the state-space representation of the model but are difficult to obtain under the conventional approach of likelihood-based estimation. We use R and WinBUGS to apply the model to two examples. In a standard analysis for the European Crossbill in a large Swiss monitoring program, we fit a model with year-specific parameters. Estimates of the dynamic parameters varied greatly among years, highlighting the irruptive population dynamics of that species. In the second example, we analyze route occupancy of Cerulean Warblers in the North American Breeding Bird Survey (BBS) using a model allowing for site
Modeling a Wireless Network for International Space Station
Alena, Richard; Yaprak, Ece; Lamouri, Saad
2000-01-01
This paper describes the application of wireless local area network (LAN) simulation modeling methods to the hybrid LAN architecture designed for supporting crew-computing tools aboard the International Space Station (ISS). These crew-computing tools, such as wearable computers and portable advisory systems, will provide crew members with real-time vehicle and payload status information and access to digital technical and scientific libraries, significantly enhancing human capabilities in space. A wireless network, therefore, will provide wearable computer and remote instruments with the high performance computational power needed by next-generation 'intelligent' software applications. Wireless network performance in such simulated environments is characterized by the sustainable throughput of data under different traffic conditions. This data will be used to help plan the addition of more access points supporting new modules and more nodes for increased network capacity as the ISS grows.
Liénard-type models for the simulation of the action potential of cardiac nodal cells
Podziemski, P.; Żebrowski, J. J.
2013-10-01
Existing models of cardiac cells which include multi-variable cardiac transmembrane current are too complex to simulate the long time dynamical properties of the heart rhythm. The large number of parameters that need to be defined and set for such models make them not only cumbersome to use but also require a large computing power. Consequently, the application of such models for the bedside analysis of heart rate of a specific patient may be difficult. Other ways of modelling need to be investigated. We consider the general problem of developing a model of cardiac pacemaker tissue that allows to combine the investigation of phenomena at a time scale of thousands of heart beats with the ability to reproduce realistic tissue-level characteristics of cell dynamics. We propose a modified van der Pol-Duffing equation-a Liénard-type oscillator-as a phenomenological model for cardiac nodal tissue, with certain important physiological similarities to ion-channel models of cardiac pacemaker cells. The model presented here is specifically designed to qualitatively reproduce mesoscopic characteristics of cell dynamics, including action potential duration (APD) restitution properties, phase response characteristics, and phase space structure. We show that these characteristics agree qualitatively with the extensive ionic models and experimental results in the literature [Anumonwo et al., 1991, [33], Cao et al., 1999, [49], Coster and Celler, 2003, [31], Qu, 2004, [45], Tsalikakis et al., 2007, [32], Inada et al., 2009, [14], Qu et al., 2010, [50
Molecular Dynamics Modeling of Tethered Organics in Confined Spaces
Energy Technology Data Exchange (ETDEWEB)
Waksburg, Avi [Monash University, Australia; Nguyen, M [Monash University, Australia; Chaffe, Alan [Monash University, Australia; Kidder, Michelle [ORNL; Buchanan III, A C [ORNL; Britt, Phillip F [ORNL
2011-01-01
A computational method for constructing and evaluating the dynamic behaviour of functionalised hexagonal mesoporous silica (HMS) MCM-41 models is reported. HMS with three pore diameters (1.7, 2.2 and 2.9 nm) were prepared, and, from these, two series of derivative structures were constructed - one with 1,3-diphenylpropyl (DPP) tethers and the other with smaller dimethylsilyl (DMS) tethers attached to the mesopores internal surfaces. Comparison with experimental data shows that simulation results correctly predict the maximum tether density that can be achieved for each tether and each pore diameter. For the smaller pore models, the extent of DPP functionalisation that can be achieved is limited by the available pore volume. However, for the larger pore model, the extent of functionalisation is limited by access to potentially reactive sites on the pore surface. The dynamic behaviour of the models was investigated over a range of temperatures (240-648 K). At lower temperatures (< 400 K), the mobility of DPP tethers in the 2.9 nm model is actually less than that observed in either the 2.2 nm model or the 1.7 nm model due to the extensive non-bonded interactions that are able to develop between tethers and the silica surface at this diameter. At higher temperatures, the free ends of these tethers break away from the surface, extend further into the pore space and the DPP mobility in the 2.9 nm model is higher than in the smaller pore systems.
Directory of Open Access Journals (Sweden)
Daniel Weiller
2010-05-01
Full Text Available Here we introduce a cognitive model capable to model a variety of behavioral domains and apply it to a navigational task. We used place cells as sensory representation, such that the cells’ place fields divided the environment into discrete states. The robot learns knowledge of the environment by memorizing the sensory outcome of its motor actions. This is composed of a central process, learning the probability of state-to-state transitions by motor actions and a distal processing routine, learning the extent to which these state-to-state transitions are caused by sensory-driven reflex behavior (obstacle avoidance. Navigational decision making integrates central and distal learned environmental knowledge to select an action that leads to a goal state. Differentiating distal and central processing increases the behavioral accuracy of the selected actions and the ability of behavioral adaptation to a changed environment. We propose that the system can canonically be expanded to model other behaviors, using alternative definitions of states and actions. The emphasis of this paper is to test this general cognitive model on a robot in a real world environment
Overview of NASA MSFC and UAH Space Weather Modeling and Data Efforts
Parker, Linda Neergaard
2016-01-01
Marshall Space Flight Center, along with its industry and academia neighbors, has a long history of space environment model development and testing. Space weather efforts include research, testing, model development, environment definition, anomaly investigation, and operational support. This presentation will highlight a few of the current space weather activities being performed at Marshall and through collaborative efforts with University of Alabama in Huntsville scientists.
Space Shuttle Model In The 16 Foot Transonic Tunnel
1978-01-01
What may appear at first glance to be a swimming shark is a wind tunnel model of the Space Shuttle Orbiter, being tested at NASA's Langley Research Center in Hampton,VA. The Orbiter model is 5.5 feet long (1/20th of the real Orbiter's length) and has remotely operated control surfaces. Inside Langley's 16 foot Transonic Wind Tunnel, the model simulated Orbiter re-entry into the Earth's atmosphere, when it must fly through the transonic speed range (the range that crosses the sound barrier). Information on Orbiter stability and control, collected and analyzed during the tests, were integrated with other data to become part of computerized flight simulation programs.
[Prognostic model of the space station contamination stage].
Zlotovol'skiĭ, V M; Smolenskaia, G S
1998-01-01
Forty two non-metallic materials, 8 human metabolites and a process liquid (ethylene glycol) were selected for development of a prognostic model of space station contamination by harmful trace admixtures (HTAs). Removal technologies made allowance for absorption by atmospheric condensate (AC) and filter adsorption. Calculations took in 18 HTAs representative of 8 classes of compounds. Simulation modeling allowed to determine HTA migration rates and percent ratio (1), calculate concentrations of contaminants in the atmosphere and atmospheric condensate (2), and to assess filter efficiency by comparison of loads on the filter and a refrigeration/drying set (3). Comparison of empirical and measured data permitted conclusions about adequacy of the model and its potentiality for predicting ramifications of nominal and contingency situations.
a New Einstein-Hilbert Action and a Superon-Graviton Model (sgm) of Nature
Shima, Kazunari; Tsuda, Motomu; Sawaguchi, Manabu
A nonlinear supersymmetric (NLSUSY) Einstein-Hilbert (EH)-type new action for the unity of nature is obtained by performing Einstein gravity analogue geometrical arguments in high symmetry spacetime inspired by NLSUSY. The new action is unstable and breaks down spontaneously into the EH action with matter in ordinary Riemann spacetime. All elementary particles except the graviton are composed of the fundamental fermion "superon" (the Nambu-Goldstone (NG) fermion of NLSUSY) and regarded as the eigenstates of SO(10) super-Poincaré (SP) algebra, called the superon-graviton model (SGM) of nature. Some phenomenological implications for low energy particle physics and cosmology are discussed. The linearization of NLSUSY including N=1 SGM action is attempted explicitly to obtain the linear SUSY local field theory, which is equivalent and renormalizable.
The Modeling Method of Forces Action Based on COADL%基于COADL兵力行动建模方法
Institute of Scientific and Technical Information of China (English)
张磊; 朱琳
2011-01-01
According to the desire of forces action modeling,designing a series of modeling language for forces action- COADL (Course Of Action Description Language), from the description of forces action modeling language,giving the outcome of forces action strategy. And as a basis, discussing the method of forces action modeling which based on COADL, concretely including : forces action basic modeling, phase action modeling, course of action modeling and forces action dynamic model.%根据兵力行动建模的需要,设计了一套兵力行动建模语言--COADL (Course Of Action Description Language),通过对兵力行动建模语言的描述,得到了兵力行动策略的产生,并以此为基础,讨论了基于COADL兵力行动的建模方法,具体包括:基本兵力行动建模,阶段行动方案建模,行动过程建模和兵力行动动态模型的构建.
A Knowledge Discovery from POS Data using State Space Models
Sato, Tadahiko; Higuchi, Tomoyuki
The number of competing-brands changes by new product's entry. The new product introduction is endemic among consumer packaged goods firm and is an integral component of their marketing strategy. As a new product's entry affects markets, there is a pressing need to develop market response model that can adapt to such changes. In this paper, we develop a dynamic model that capture the underlying evolution of the buying behavior associated with the new product. This extends an application of a dynamic linear model, which is used by a number of time series analyses, by allowing the observed dimension to change at some point in time. Our model copes with a problem that dynamic environments entail: changes in parameter over time and changes in the observed dimension. We formulate the model with framework of a state space model. We realize an estimation of the model using modified Kalman filter/fixed interval smoother. We find that new product's entry (1) decreases brand differentiation for existing brands, as indicated by decreasing difference between cross-price elasticities; (2) decreases commodity power for existing brands, as indicated by decreasing trend; and (3) decreases the effect of discount for existing brands, as indicated by a decrease in the magnitude of own-brand price elasticities. The proposed framework is directly applicable to other fields in which the observed dimension might be change, such as economic, bioinformatics, and so forth.
The Things You Do: Internal Models of Others’ Expected Behaviour Guide Action Observation
Schenke, Kimberley C.; Wyer, Natalie A.; Bach, Patric
2016-01-01
Predictions allow humans to manage uncertainties within social interactions. Here, we investigate how explicit and implicit person models–how different people behave in different situations–shape these predictions. In a novel action identification task, participants judged whether actors interacted with or withdrew from objects. In two experiments, we manipulated, unbeknownst to participants, the two actors action likelihoods across situations, such that one actor typically interacted with one object and withdrew from the other, while the other actor showed the opposite behaviour. In Experiment 2, participants additionally received explicit information about the two individuals that either matched or mismatched their actual behaviours. The data revealed direct but dissociable effects of both kinds of person information on action identification. Implicit action likelihoods affected response times, speeding up the identification of typical relative to atypical actions, irrespective of the explicit knowledge about the individual’s behaviour. Explicit person knowledge, in contrast, affected error rates, causing participants to respond according to expectations instead of observed behaviour, even when they were aware that the explicit information might not be valid. Together, the data show that internal models of others’ behaviour are routinely re-activated during action observation. They provide first evidence of a person-specific social anticipation system, which predicts forthcoming actions from both explicit information and an individuals’ prior behaviour in a situation. These data link action observation to recent models of predictive coding in the non-social domain where similar dissociations between implicit effects on stimulus identification and explicit behavioural wagers have been reported. PMID:27434265
Minow, Josep I.; Edwards, David L.
2008-01-01
Qualifying materials for use in the space environment is typically accomplished with laboratory exposures to simulated UV/EUV, atomic oxygen, and charged particle radiation environments with in-situ or subsequent measurements of material properties of interest to the particular application. Choice of environment exposure levels are derived from static design environments intended to represent either mean or extreme conditions that are anticipated to be encountered during a mission. The real space environment however is quite variable. Predictions of the on orbit performance of a material qualified to laboratory environments can be done using information on 'space weather' variations in the real environment. This presentation will first review the variability of space environments of concern for material degradation and then demonstrate techniques for using test data to predict material performance in a variety of space environments from low Earth orbit to interplanetary space using historical measurements and space weather models.
Documentation of a Model Action Plan to Deter Illicit Nuclear Trafficking
Energy Technology Data Exchange (ETDEWEB)
Smith, D; Kristo, M; Niemeyer, S; Dudder, G
2006-07-28
Theft, illegal possession, smuggling, or attempted unauthorized sale of nuclear and radiological materials remains a worldwide problem. The Nuclear Smuggling International Technical Working Group (ITWG) has adopted a model action plan to guide investigation of these cases through a systematic approach to nuclear forensics. The model action plan was recently documented and provides recommendations concerning incident response, collection of evidence in conformance with required legal standards, laboratory sampling and distribution of samples, radioactive materials analysis, including categorization and characterization of samples, forensics analysis of conventional evidence, and case development including interpretation of forensic signatures.
Directory of Open Access Journals (Sweden)
Stephane eGrade
2015-06-01
Full Text Available The perception of reachability (i.e., whether an object is within reach relies on body representations and action simulation. Similarly, egocentric distance estimation (i.e., the perception of the distance an object is from the self is thought to be partly derived from embodied action simulation. Although motor simulation is important for both, it is unclear whether the cognitive processes underlying these behaviors rely on the same motor processes. To investigate this, we measured the impact of a motor interference dual-task paradigm on reachability judgment, egocentric distance estimation, and allocentric length estimation (i.e., how distant two stimuli are from each other independent from the self used as a control task. Participants were required to make concurrent actions with either hand actions of foam ball grip squeezing or arm actions of weight lifting, or no concurrent actions. Results showed that concurrent squeeze actions significantly slowed response speed in the reachability judgment and egocentric distance estimation tasks, but that there was no impact of the concurrent actions on allocentric length estimation. Together, these results suggest that reachability and distance perception, both egocentric perspective tasks, and in contrast to the allocentric perspective task, involve action simulation cognitive processes. The results are discussed in terms of the implication of action simulation when evaluating the position of a target relative to the observer’s body, supporting an embodied view of spatial cognition.
Spectra of sigma models on semi-symmetric spaces
Energy Technology Data Exchange (ETDEWEB)
Cagnazzo, Alessandra; Schomerus, Volker; Tlapak, Vaclav [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2015-12-15
Sigma models on semi-symmetric spaces provide the central building block for string theories on AdS backgrounds. Under certain conditions on the global supersymmetry group they can be made one-loop conformal by adding an appropriate fermionic Wess-Zumino term. We determine the full one-loop dilation operator of the theory. It involves an interesting new XXZ-like interaction term. Eigenvalues of our dilation operator, i.e. the one-loop anomalous dimensions, are computed for a few examples.
Exact energy spectrum for models with equally spaced point potentials
Caudrelier, V.; Crampé, N.
2006-03-01
We describe a non-perturbative method for computing the energy band structures of one-dimensional models with general point potentials sitting at equally spaced sites. This is done thanks to a Bethe ansatz approach and the method is applicable even when periodicity is broken, that is when Bloch's theorem is not valid any more. We derive the general equation governing the energy spectrum and illustrate its use in various situations. In particular, we get exact results for boundary effects. We also study non-perturbatively the effects of impurities in such systems. Finally, we discuss the possibility of including interactions between the particles of these systems.
Calculating model of mass action concentrations for Ag-Au-Cu melts
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Based on phase diagrams and measured activities, the calculating model of mass action concentrations for heterogeneous melts Ag-Au-Cu was formulated. Calculated results agree with the improved results of recent research work.showing that the model formulated can reflect the structural characteristics of these melts. In this model, without the help of any empirical parameters, only three equilibrium constants are used, hence it is simple, lear, and favorable to the simplification of calculation.
An Ontological Model of Behaviour Theory to Generate Personalized Action Plans to Modify Behaviours.
Baig, Wasif; Abidi, Samina; Abidi, Syed Sibte Raza
2016-01-01
Behavior change approaches aim to assist patients in achieving self-efficacy in managing their condition. Social cognitive theory (SCT) stipulates self-efficacy as a central element to behavior change and provides constructs to achieve self-efficacy guided by person-specific action plans. In our work, to administer behaviour change in patient with chronic conditions, our approach entails the computerization of SCT-based self-efficacy constructs in order to generate personalized action plans that are suitable to an individual's current care scenario. We have taken a knowledge management approach, whereby we have computerized the SCT-based self-efficacy constructs in terms of a high-level SCT knowledge model that can be operationalized to generate personalized behaviour change action plans. We have collected and computerized behavior change content targeting healthy living and physical activity. Semantic web technologies have been used to develop the SCT knowledge model, represented in terms of an ontology and SWRL rules. The ontological SCT model can inferred to generate personalized self-management action plans for a given patient profile. We present formative evaluation of the clinical correctness and relevance of the generated personalized action plans for a range of test patient profiles. PMID:27577412
An Ontological Model of Behaviour Theory to Generate Personalized Action Plans to Modify Behaviours.
Baig, Wasif; Abidi, Samina; Abidi, Syed Sibte Raza
2016-01-01
Behavior change approaches aim to assist patients in achieving self-efficacy in managing their condition. Social cognitive theory (SCT) stipulates self-efficacy as a central element to behavior change and provides constructs to achieve self-efficacy guided by person-specific action plans. In our work, to administer behaviour change in patient with chronic conditions, our approach entails the computerization of SCT-based self-efficacy constructs in order to generate personalized action plans that are suitable to an individual's current care scenario. We have taken a knowledge management approach, whereby we have computerized the SCT-based self-efficacy constructs in terms of a high-level SCT knowledge model that can be operationalized to generate personalized behaviour change action plans. We have collected and computerized behavior change content targeting healthy living and physical activity. Semantic web technologies have been used to develop the SCT knowledge model, represented in terms of an ontology and SWRL rules. The ontological SCT model can inferred to generate personalized self-management action plans for a given patient profile. We present formative evaluation of the clinical correctness and relevance of the generated personalized action plans for a range of test patient profiles.
Cerba Diaconescu, Oxana; Schlomiuk, Dana; Vulpe, Nicolae
In this article, we consider the class QSL4{u +vc+w^c, ∞ } of all real quadratic differential systems (dx)/(dt) = p(x, y), (dy)/(dt) = q(x, y) with gcd(p, q) = 1, having invariant lines of total multiplicity four and two complex and one real infinite singularities. We first construct compactified canonical forms for the class QSL4{u +vc+w^c, ∞ } so as to include limit points in the 12-dimensional parameter space of this class. We next construct the bifurcation diagrams for these compactified canonical forms. These diagrams contain many repetitions of phase portraits and we show that these are due to many symmetries under the group action. To retain the essence of the dynamics we finally construct the quotient spaces under the action of the group G = Aff(2, ℝ) × ℝ* of affine transformations and time homotheties and we place the phase portraits in these quotient spaces. The final diagrams retain only the necessary information to capture the dynamics under the motion in the parameter space as well as under this group action. We also present here necessary and sufficient conditions for an affine line to be invariant of multiplicity k for a quadratic system.
Health Belief Model and Reasoned Action Theory in Predicting Water Saving Behaviors in Yazd, Iran
Directory of Open Access Journals (Sweden)
Mohammad Taghi Ghaneian
2012-12-01
Full Text Available Background: People's behaviors and intentions about healthy behaviors depend on their beliefs, values, and knowledge about the issue. Various models of health education are used in deter-mining predictors of different healthy behaviors but their efficacy in cultural behaviors, such as water saving behaviors, are not studied. The study was conducted to explain water saving beha-viors in Yazd, Iran on the basis of Health Belief Model and Reasoned Action Theory. Methods: The cross-sectional study used random cluster sampling to recruit 200 heads of households to collect the data. The survey questionnaire was tested for its content validity and reliability. Analysis of data included descriptive statistics, simple correlation, hierarchical multiple regression. Results: Simple correlations between water saving behaviors and Reasoned Action Theory and Health Belief Model constructs were statistically significant. Health Belief Model and Reasoned Action Theory constructs explained 20.80% and 8.40% of the variances in water saving beha-viors, respectively. Perceived barriers were the strongest Predictor. Additionally, there was a sta-tistically positive correlation between water saving behaviors and intention. Conclusion: In designing interventions aimed at water waste prevention, barriers of water saving behaviors should be addressed first, followed by people's attitude towards water saving. Health Belief Model constructs, with the exception of perceived severity and benefits, is more powerful than is Reasoned Action Theory in predicting water saving behavior and may be used as a framework for educational interventions aimed at improving water saving behaviors.
Modeling the dynamics of a compliant piano action mechanism impacting an elastic stiff string.
Vyasarayani, Chandrika P; Birkett, Stephen; McPhee, John
2009-06-01
A realistic model of the piano hammer-string interaction must treat the action mechanism and string as a single system. In this paper an elastic stiff string model is integrated with a dynamic model of a compliant action mechanism with flexible hammer shank. Action components represented as rotating bodies interact through felt-lined interfaces for which a specialized contact model with hysteretic damping and tangential friction was developed. The motion of the hammer during string contact is governed by the dynamics of the action mechanism, thereby providing a more sophisticated hammer-string interaction than a simple transverse impact hammer model with fixed contact location. Simulations have been used to compare mechanism response for impact on the elastic string as compared to a rigid stop. Hammer head scuffing along the string and time in contact were predicted to increase, while hammer shank vibration amplitude and peak contact force were decreased. Introducing hammer-string friction decreases the duration of contact and reduces the extent of scuffing. Finally, significant differences in hammer and string motion were predicted for a highly flexible hammer shank. Initial contact time and location, length of contact period and peak force, hammer vibration amplitude, scuffing extent, and string spectral content were all influenced. PMID:19507984
Directory of Open Access Journals (Sweden)
Gabriel A. Radvansky
2016-01-01
Full Text Available The Fluid Events Model is aimed at predicting changes in the actions people take on a moment-by-moment basis. In contrast with other research on action selection, this work does not investigate why some course of action was selected, but rather the likelihood of discontinuing the current course of action and selecting another in the near future. This is done using both task-based and experience-based factors. Prior work evaluated this model in the context of trial-by-trial, independent, interactive events, such as choosing how to copy a figure of a line drawing. In this paper, we extend this model to more covert event experiences, such as reading narratives, as well as to continuous interactive events, such as playing a video game. To this end, the model was applied to existing data sets of reading time and event segmentation for written and picture stories. It was also applied to existing data sets of performance in a strategy board game, an aerial combat game, and a first person shooter game in which a participant’s current state was dependent on prior events. The results revealed that the model predicted behavior changes well, taking into account both the theoretically defined structure of the described events, as well as a person’s prior experience. Thus, theories of event cognition can benefit from efforts that take into account not only how events in the world are structured, but also how people experience those events.
Radvansky, Gabriel A; D'Mello, Sidney K; Abbott, Robert G; Bixler, Robert E
2016-01-01
The Fluid Events Model is aimed at predicting changes in the actions people take on a moment-by-moment basis. In contrast with other research on action selection, this work does not investigate why some course of action was selected, but rather the likelihood of discontinuing the current course of action and selecting another in the near future. This is done using both task-based and experience-based factors. Prior work evaluated this model in the context of trial-by-trial, independent, interactive events, such as choosing how to copy a figure of a line drawing. In this paper, we extend this model to more covert event experiences, such as reading narratives, as well as to continuous interactive events, such as playing a video game. To this end, the model was applied to existing data sets of reading time and event segmentation for written and picture stories. It was also applied to existing data sets of performance in a strategy board game, an aerial combat game, and a first person shooter game in which a participant's current state was dependent on prior events. The results revealed that the model predicted behavior changes well, taking into account both the theoretically defined structure of the described events, as well as a person's prior experience. Thus, theories of event cognition can benefit from efforts that take into account not only how events in the world are structured, but also how people experience those events. PMID:26858673
Modeling and simulation of ion channels and action potentials in taste receptor cells
Institute of Scientific and Technical Information of China (English)
CHEN PeiHua; LIU Xiaodong; ZHANG Wei; ZHOU Jun; WANG Ping; YANG Wei; LUO JianHong
2009-01-01
Based on patch clamp data on the ionic currents of rat taste receptor cells,a mathematical model of mammalian taste receptor cells was constructed to simulate the action potentials of taste receptor cells and their corresponding ionic components,including voltage-gated Na~+ currents and outward delayed rectifier K~+ currents.Our simulations reproduced the action potentials of taste receptor cells in response to electrical stimuli or sour tastants.The kinetics of ion channels and their roles in action potentials of taste receptor cells were also analyzed.Our prototype model of single taste receptor cell and simulation results presented in this paper provide the basis for the further study of taste information processing in the gustatory system.
Modeling and simulation of ion channels and action potentials in taste receptor cells
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Based on patch clamp data on the ionic currents of rat taste receptor cells, a mathematical model of mammalian taste receptor cells was constructed to simulate the action potentials of taste receptor cells and their corresponding ionic components, including voltage-gated Na+ currents and outward delayed rectifier K+ currents. Our simulations reproduced the action potentials of taste receptor cells in response to electrical stimuli or sour tastants. The kinetics of ion channels and their roles in action potentials of taste receptor cells were also analyzed. Our prototype model of single taste receptor cell and simulation results presented in this paper provide the basis for the further study of taste information processing in the gustatory system.
Two-loop low-energy effective action in Abelian supersymmetric Chern–Simons matter models
International Nuclear Information System (INIS)
We compute two-loop low-energy effective actions in Abelian Chern–Simons matter models with N=2 and N=3 supersymmetry up to four-derivative order. Calculations are performed with a slowly-varying gauge superfield background. Though the gauge superfield propagator depends on the gauge fixing parameter, it is shown that the obtained results are independent of this parameter. In the massless case the considered models are superconformal. We demonstrate that the superconformal symmetry strongly restricts the form of two-loop quantum corrections to the effective actions such that the obtained terms have simpler structure than the analogous ones in the effective action of three-dimensional supersymmetric electrodynamics (SQED) with vanishing topological mass
Community ACTION Boards: An Innovative Model for Effective Community–Academic Research Partnerships
James, Sherline; Arniella, Guedy; Bickell, Nina A.; Walker, Willie; Robinson, Virginia; Taylor, Barbara; Horowitz, Carol R.
2012-01-01
Background Community-based participatory research (CBPR) requires equitable partnerships between community stakeholders and academics. Traditionally, researchers relied on community advisory boards, but these boards often play a reactive role on a project-by-project basis. The East and Central Harlem Health Outcomes (ECHHO) Community Action Board (CAB), however, is an effective, proactive group. Objectives The ECHHO board sought to identify key strategies and tools to build and employ a partnership model, and to disseminate lessons learned to other community–academic partnerships. Methods Current and former board members were interviewed and a wide range of related documents was reviewed. Lessons Learned The board became effective when it prioritized action and relationship-building, across seven key domains: Shared priorities, diversity, participation, transparency, mutual respect and recognition, and personal connections. The model is depicted graphically. Conclusion Community advisory boards may benefit from attention to taking action, and to building relationships between academics and community members. PMID:22616207
Model of strong stationary vortex turbulence in space plasmas
Directory of Open Access Journals (Sweden)
G. D. Aburjania
2009-01-01
Full Text Available This paper investigates the macroscopic consequences of nonlinear solitary vortex structures in magnetized space plasmas by developing theoretical model of plasma turbulence. Strongly localized vortex patterns contain trapped particles and, propagating in a medium, excite substantial density fluctuations and thus, intensify the energy, heat and mass transport processes, i.e., such vortices can form strong vortex turbulence. Turbulence is represented as an ensemble of strongly localized (and therefore weakly interacting vortices. Vortices with various amplitudes are randomly distributed in space (due to collisions. For their description, a statistical approach is applied. It is supposed that a stationary turbulent state is formed by balancing competing effects: spontaneous development of vortices due to nonlinear twisting of the perturbations' fronts, cascading of perturbations into short scales (direct spectral cascade and collisional or collisionless damping of the perturbations in the short-wave domain. In the inertial range, direct spectral cascade occurs through merging structures via collisions. It is shown that in the magneto-active plasmas, strong turbulence is generally anisotropic Turbulent modes mainly develop in the direction perpendicular to the local magnetic field. It is found that it is the compressibility of the local medium which primarily determines the character of the turbulent spectra: the strong vortex turbulence forms a power spectrum in wave number space. For example, a new spectrum of turbulent fluctuations in k^{−8/3} is derived which agrees with available experimental data. Within the framework of the developed model particle diffusion processes are also investigated. It is found that the interaction of structures with each other and particles causes anomalous diffusion in the medium. The effective coefficient of diffusion has a square root dependence on the stationary level of noise.
Space Weathering of Olivine: Samples, Experiments and Modeling
Keller, L. P.; Berger, E. L.; Christoffersen, R.
2016-01-01
Olivine is a major constituent of chondritic bodies and its response to space weathering processes likely dominates the optical properties of asteroid regoliths (e.g. S- and many C-type asteroids). Analyses of olivine in returned samples and laboratory experiments provide details and insights regarding the mechanisms and rates of space weathering. Analyses of olivine grains from lunar soils and asteroid Itokawa reveal that they display solar wind damaged rims that are typically not amorphized despite long surface exposure ages, which are inferred from solar flare track densities (up to 10 (sup 7 y)). The olivine damaged rim width rapidly approaches approximately 120 nm in approximately 10 (sup 6 y) and then reaches steady-state with longer exposure times. The damaged rims are nanocrystalline with high dislocation densities, but crystalline order exists up to the outermost exposed surface. Sparse nanophase Fe metal inclusions occur in the damaged rims and are believed to be produced during irradiation through preferential sputtering of oxygen from the rims. The observed space weathering effects in lunar and Itokawa olivine grains are difficult to reconcile with laboratory irradiation studies and our numerical models that indicate that olivine surfaces should readily blister and amorphize on relatively short time scales (less than 10 (sup 3 y)). These results suggest that it is not just the ion fluence alone, but other variable, the ion flux that controls the type and extent of irradiation damage that develops in olivine. This flux dependence argues for caution in extrapolating between high flux laboratory experiments and the natural case. Additional measurements, experiments, and modeling are required to resolve the discrepancies among the observations and calculations involving solar wind processing of olivine.
The Harari Shupe preon model and nonrelativistic quantum phase space
Żenczykowski, P.
2008-03-01
We propose that the whole algebraic structure of the Harari-Shupe rishon model originates via a Dirac-like linearization of quadratic form x2 +p2, with position and momentum satisfying standard commutation relations. The scheme does not invoke the concept of preons as spin-1/2 subparticles, thus evading the problem of preon confinement, while fully explaining all symmetries emboded in the Harari-Shupe model. Furthermore, the concept of quark colour is naturally linked to the ordering of rishons. Our scheme leads to group U (1) ⊗ SU (3) combined with SU (2), with two of the SU (2) generators not commuting with reflections. An interpretation of intra-generation quark-lepton transformations in terms of genuine rotations and reflections in phase space is proposed.
A new mathematical model in space optimization: A case study
Abdullah, Kamilah; Kamis, Nor Hanimah; Sha'ari, Nor Shahida; Muhammad Halim, Nurul Suhada; Hashim, Syaril Naqiah
2013-04-01
Most of higher education institutions provide certain area known as learning centre for their students to study or having group discussions. However, some of the learning centers are not provided by optimum number of tables and seats to accommodate the students sufficiently. This study proposed a new mathematical model in optimizing the number of tables and seats at Laman Najib, Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA (UiTM) Shah Alam. An improvement of space capacity with maximum number of students who can facilitate the Laman Najib at the same time has been made by considering the type and size of tables that are appropriate for student's discussions. Our finding is compared with the result of Simplex method of linear programming to ensure that our new model is valid and consistent with other existing approaches. As a conclusion, we found that the round-type tables with six seats provide the maximum number of students who can use Laman Najib for their discussions or group studying. Both methods are also practical to use as alternative approaches in solving other space optimization problems.
Assembly interruptability robustness model with applications to Space Station Freedom
Wade, James William
1991-02-01
Interruptability robustness of a construction project together with its assembly sequence may be measured by calculating the probability of its survival and successful completion in the face of unplanned interruptions of the assembly process. Such an interruption may jeopardize the survival of the structure being assembled, the survival of the support equipment, and/or the safety of the members of the construction crew, depending upon the stage in the assembly sequence when the interruption occurs. The interruption may be due to a number of actors such as: machinery break-downs, environmental damage, worker emergency illness or injury, etc. Each source of interruption has a probability of occurring, and adds an associated probability of loss, schedule delay, and cost to the project. Several options may exist for reducing the consequences of an interruption at a given point in the assembly sequence, including altering the assembly sequence, adding extra components or equipment as interruptability 'insurance', increasing the capability of support facilities, etc. Each option may provide a different overall performance of the project as it relates to success, assembly time, and project cost. The Interruptability Robustness Model was devised and provides a method which allows the overall interruptability robustness of construction of a project design and its assembly sequence to be quantified. In addition, it identifies the susceptibility to interruptions for the assembly sequence at all points within the assembly sequence. The model is applied to the present problem of quantifying and improving interruptability robustness during the construction of Space Station Freedom. This application was used as a touchstone for devising the Interruptability Robustness Model. However, the model may be utilized to assist in the analysis of interruptability robustness for other space-related construction projects such as the lunar base and orbital assembly of the manned Mars
Cross-Compiler for Modeling Space-Flight Systems
James, Mark
2007-01-01
Ripples is a computer program that makes it possible to specify arbitrarily complex space-flight systems in an easy-to-learn, high-level programming language and to have the specification automatically translated into LibSim, which is a text-based computing language in which such simulations are implemented. LibSim is a very powerful simulation language, but learning it takes considerable time, and it requires that models of systems and their components be described at a very low level of abstraction. To construct a model in LibSim, it is necessary to go through a time-consuming process that includes modeling each subsystem, including defining its fault-injection states, input and output conditions, and the topology of its connections to other subsystems. Ripples makes it possible to describe the same models at a much higher level of abstraction, thereby enabling the user to build models faster and with fewer errors. Ripples can be executed in a variety of computers and operating systems, and can be supplied in either source code or binary form. It must be run in conjunction with a Lisp compiler.
Musser, George
2015-01-01
What is space? It isn't a question that most of us normally stop to ask. Space is the venue of physics; it's where things exist, where they move and take shape. Yet over the past few decades, physicists have discovered a phenomenon that operates outside the confines of space and time. The phenomenon, the ability of one particle to affect another instantly across the vastness of space appears to be almost magical. Einstein grappled with this oddity and couldn't quite resolve it, describing it as "spooky action at a distance." But this strange occurrence has direct connections to black holes, particle collisions, and even the workings of gravity. If space isn't what we thought it was, then what is it? In Spooky Action at a Distance, George Musser sets out to answer that question, offering a provocative exploration of non locality and a celebration of the scientists who are trying to understand it. Musser guides us on an epic journey of scientific discovery into the lives of experimental physicists observing par...
Terpstra, Teun; Lindell, Michael K.
2013-01-01
Although research indicates that adoption of flood preparations among Europeans is low, only a few studies have attempted to explain citizens' preparedness behavior. This article applies the Protective Action Decision Model (PADM) to explain flood preparedness intentions in the Netherlands. Survey data ("N" = 1,115) showed that…
Jarvis, Joy; Dickerson, Claire; Thomas, Kit; Graham, Sally
2014-01-01
This article presents the Action--Reflection--Modelling (ARM) pedagogical approach for teacher education developed during a Malaysia-UK collaborative project to construct a Bachelor of Education (Honours) degree programme in Primary Mathematics, with English and Health and Physical Education as minor subjects. The degree programme was written…
Using the Knowledge to Action Process Model to Incite Clinical Change
Petzold, Anita; Korner-Bitensky, Nicol; Menon, Anita
2010-01-01
Introduction: Knowledge translation (KT) has only recently emerged in the field of rehabilitation with attention on creating effective KT interventions to increase clinicians' knowledge and use of evidence-based practice (EBP). The uptake of EBP is a complex process that can be facilitated by the use of the Knowledge to Action Process model. This…
Teacher Educators' In-Action Mental Models in Different Teaching Situations
Mevorach, Miriam; Strauss, Sidney
2012-01-01
In previous studies on teachers' cognition, we discovered that teachers' teaching can be described via a general in-action mental model (IAMM) concerning the structure of the mind and the roles of teaching in fostering children's learning. The purpose of our study was to examine teacher educators' IAMM regarding student teachers' minds and…
Action and Language Mechanisms in the Brain: Data, Models and Neuroinformatics
DEFF Research Database (Denmark)
Arbib, Michael A.; Bonaiuto, James J.; Bornkessel-Schlesewsky, Ina;
2014-01-01
We assess the challenges of studying action and language mechanisms in the brain, both singly and in relation to each other to provide a novel perspective on neuroinformatics, integrating the development of databases for encoding - separately or together - neurocomputational models and empirical ...
Action and Language Mechanisms in the Brain: Data, Models and Neuroinformatics
Arbib, Michael A.; Bonaiuto, James J.; Bornkessel-Schlesewsky, Ina; Kemmerer, David; MacWhinney, Brian; Nielsen, Finn Årup; Oztop, Erhan
2014-01-01
We assess the challenges of studying action and language mechanisms in the brain, both singly and in relation to each other to provide a novel perspective on neuroinformatics, integrating the development of databases for encoding – separately or together – neurocomputational models and empirical data that serve systems and cognitive neuroscience.
Action and language mechanisms in the brain: data, models and neuroinformatics.
Arbib, Michael A; Bonaiuto, James J; Bornkessel-Schlesewsky, Ina; Kemmerer, David; MacWhinney, Brian; Nielsen, Finn Årup; Oztop, Erhan
2014-01-01
We assess the challenges of studying action and language mechanisms in the brain, both singly and in relation to each other to provide a novel perspective on neuroinformatics, integrating the development of databases for encoding – separately or together – neurocomputational models and empirical data that serve systems and cognitive neuroscience. PMID:24234916
The communicative action and information: a learning to learn transdisciplinary model
Márcia Marques
2015-01-01
This article is about the communicative action and information model for social networking in digital environments, a transdisciplinary articulation of knowledge and learning that guides the collective and collaborative construction of inclusive communication strategies and ongoing development of competencies to promote understanding between the players, members of a social network. Information Science, Communication itself and Information and Communication Technologies (ICT) promote this art...
Directory of Open Access Journals (Sweden)
Doroshenko E.Iu.
2013-10-01
Full Text Available The application of modeling of technical and tactical actions as one of the leading components of the control system of competitive activities of highly skilled volleyball players. It is show that the proposed modeling techniques can generate the optimum orientation of the training process with the use of specialized tools at different stages of the annual cycle of training. In a study based on official statistics volleyball tournament World League in 2012 years. It is recommended to be oriented on the followings model indexes of actions of command and sportsmen: general amount of the collected glasses (170 - 190; amount of glasses, collected in an attack (139 - 157; amount of glasses, collected at blocking (12 - 24; amount of glasses, collected from a serve (9 - 17; the middle index of efficiency is protective actions (at the reception of ball from a serve -58,29%. It is shown that the performance of technical and tactical actions can be used as a model in the management of the process of training and competitive volleyball elite athletes.
Human Factors Research for Space Exploration: Measurement, Modeling, and Mitigation
Kaiser, Mary K.; Allen, Christopher S.; Barshi, Immanuel; Billman, Dorrit; Holden, Kritina L.
2010-01-01
As part of NASA's Human Research Program, the Space Human Factors Engineering Project serves as the bridge between Human Factors research and Human Spaceflight applications. Our goal is to be responsive to the operational community while addressing issues at a sufficient level of abstraction to ensure that our tools and solutions generalize beyond the point design. In this panel, representatives from four of our research domains will discuss the challenges they face in solving current problems while also enabling future capabilities. Historically, engineering-dominated organizations have tended to view good Human Factors (HF) as a desire rather than a requirement in system design and development. Our field has made significant gains in the past decade, however; the Department of Defense, for example, now recognizes Human-System Integration (HSI), of which HF is a component, as an integral part of their divisions hardware acquisition processes. And our own agency was far more accepting of HF/HSI requirements during the most recent vehicle systems definition than in any prior cycle. Nonetheless, HF subject matter experts at NASA often find themselves in catch up mode... coping with legacy systems (hardware and software) and procedures that were designed with little regard for the human element, and too often with an attitude of we can deal with any operator issues during training. Our challenge, then, is to segregate the true knowledge gaps in Space Human Factors from the prior failures to incorporate best (or even good) HF design principles. Further, we strive to extract the overarching core HF issues from the point-design-specific concerns that capture the operators (and managers) attention. Generally, our approach embraces a 3M approach to Human Factors: Measurement, Modeling, and Mitigation. Our first step is to measure human performance, to move from subjective anecdotes to objective, quantified data. Next we model the phenomenon, using appropriate methods in
Romanov, Evgenii Dmitrievich
2016-08-01
A family of quasi-invariant measures on the special functional space of curves in a finite-dimensional Euclidean space with respect to the action of diffeomorphisms is constructed. The main result is an explicit expression for the Radon-Nikodym derivative of the transformed measure relative to the original one. The stochastic Ito integral allows to express the result in an invariant form for a wider class of diffeomorphisms. These measures can be used to obtain irreducible unitary representations of the diffeomorphisms group which will be studied in future research. A geometric interpretation of the action considered together with a generalization to the multidimensional case makes such representations applicable to problems of quantum mechanics.
Renormalization Group and Decoupling in Curved Space II. The Standard Model and Beyond
Gorbar, E V; Gorbar, Eduard V.; Shapiro, Ilya L.
2003-01-01
We continue the study of the renormalization group and decoupling of massive fields in curved space, started in the previous article and analyse the higher derivative sector of the vacuum metric-dependent action of the Standard Model. The QCD sector at low-energies is described in terms of the composite effective fields. For fermions and scalars the massless limit shows perfect correspondence with the conformal anomaly, but similar limit in a massive vector case requires an extra compensating scalar. In all three cases the decoupling goes smoothly and monotonic. A particularly interesting case is the renormalization group flow in the theory with broken supersymmetry, where the sign of one of the beta-functions changes on the way from the UV to IR.
Poss, J E
2001-06-01
This article discusses the development of a new model representing the synthesis of two models that are often used to study health behaviors: the Health Belief Model and the Theory of Reasoned Action. The new model was developed as the theoretic framework for an investigation of the factors affecting participation by Mexican migrant workers in tuberculosis screening. Development of the synthesized model evolved from the concern that models used to investigate health-seeking behaviors of mainstream Anglo groups in the United States might not be appropriate for studying migrant workers or persons from other cultural backgrounds.
Initial Condition Model from Imaginary Part of Action and the Information Loss
Nielsen, H B
2009-01-01
We review slightly a work by Horowitz and Maldecena solving the information loss problem for black holes by having inside the blackhole - near to the singularity - a boundary condition, as e.g the no boundary proposal by Hartle and Hawking. Here we propose to make this boundary condition come out of our imaginary action model (together with Masao Ninomiya). This model naturally begins effectively to set up boundaries - whether it be in future or past! - especially strongly whenever we reach to high energy physics regimes, such as near the black hole singularity, or in Higgs producing machines as LHC or SSC. In such cases one can say our model predicts miracles. The point is that you may say that the information loss problem, unless you solve it in other ways, call for such a violation of time causality as in our imaginary action model!
A Taxonomic Reduced-Space Pollen Model for Paleoclimate Reconstruction
Wahl, E. R.; Schoelzel, C.
2010-12-01
Paleoenvironmental reconstruction from fossil pollen often attempts to take advantage of the rich taxonomic diversity in such data. Here, a taxonomically "reduced-space" reconstruction model is explored that would be parsimonious in introducing parameters needing to be estimated within a Bayesian Hierarchical Modeling context. This work involves a refinement of the traditional pollen ratio method. This method is useful when one (or a few) dominant pollen type(s) in a region have a strong positive correlation with a climate variable of interest and another (or a few) dominant pollen type(s) have a strong negative correlation. When, e.g., counts of pollen taxa a and b (r >0) are combined with pollen types c and d (r binomial logistic generalized linear model (GLM). The GLM can readily model this relationship in the forward form, pollen = g(climate), which is more physically realistic than inverse models often used in paleoclimate reconstruction [climate = f(pollen)]. The specification of the model is: rnum Bin(n,p), where E(r|T) = p = exp(η)/[1+exp(η)], and η = α + β(T); r is the pollen ratio formed as above, rnum is the ratio numerator, n is the ratio denominator (i.e., the sum of pollen counts), the denominator-specific count is (n - rnum), and T is the temperature at each site corresponding to a specific value of r. Ecological and empirical screening identified the model (Spruce+Birch) / (Spruce+Birch+Oak+Hickory) for use in temperate eastern N. America. α and β were estimated using both "traditional" and Bayesian GLM algorithms (in R). Although it includes only four pollen types, the ratio model yields more explained variation ( 80%) in the pollen-temperature relationship of the study region than a 64-taxon modern analog technique (MAT). Thus, the new pollen ratio method represents an information-rich, reduced space data model that can be efficiently employed in a BHM framework. The ratio model can directly reconstruct past temperature by solving the GLM
Long-range planning cost model for support of future space missions by the deep space network
Sherif, J. S.; Remer, D. S.; Buchanan, H. R.
1990-01-01
A simple model is suggested to do long-range planning cost estimates for Deep Space Network (DSP) support of future space missions. The model estimates total DSN preparation costs and the annual distribution of these costs for long-range budgetary planning. The cost model is based on actual DSN preparation costs from four space missions: Galileo, Voyager (Uranus), Voyager (Neptune), and Magellan. The model was tested against the four projects and gave cost estimates that range from 18 percent above the actual total preparation costs of the projects to 25 percent below. The model was also compared to two other independent projects: Viking and Mariner Jupiter/Saturn (MJS later became Voyager). The model gave cost estimates that range from 2 percent (for Viking) to 10 percent (for MJS) below the actual total preparation costs of these missions.
Exporting the Buyers Health Care Action Group Purchasing Model: Lessons from Other Communities
Christianson, Jon B; Feldman, Roger
2005-01-01
When first implemented in Minneapolis and St. Paul, Minnesota, the Buyers Health Care Action Group's (BHCAG) purchasing approach received considerable attention as an employer-managed, consumer-driven health care model embodying many of the principles of managed competition. First BHCAG and, later, a for-profit management company attempted to export this model to other communities. Their efforts were met with resistance from local hospitals and, in many cases, apathy by employers who were exp...
Scalability of the Muscular Action in a Parametric 3D Model of the Index Finger
Sancho Brú, Joaquín Luís; Vergara Monedero, Margarita; Rodríguez Cervantes, Pablo Jesús; Giurintano, David J.; Pérez González, Antonio
2008-01-01
A method for scaling the muscle action is proposed and used to achieve a 3D inverse dynamic model of the human finger with all its components scalable. This method is based on scaling the PCSA (physiological cross-sectional area) in a Hill muscle model. Different anthropometric parameters and maximal grip force data have been measured and their correlations have been analysed and used for scaling the PCSA of each muscle. A linear relationship between the normalised PCSA and the pr...
An integrative neural model of social perception, action observation, and theory of mind
Yang, Daniel Y.-J.; Rosenblau, Gabriela; Keifer, Cara; Pelphrey, Kevin A.
2015-01-01
In the field of social neuroscience, major branches of research have been instrumental in describing independent components of typical and aberrant social information processing, but the field as a whole lacks a comprehensive model that integrates different branches. We review existing research related to the neural basis of three key neural systems underlying social information processing: social perception, action observation, and theory of mind. We propose an integrative model that unites ...
Health Belief Model and Reasoned Action Theory in Predicting Water Saving Behaviors in Yazd, Iran
Mohammad Taghi Ghaneian; Mahdieh Momayyezi; Mohammad Ali Morowatisharifabad
2012-01-01
Background: People's behaviors and intentions about healthy behaviors depend on their beliefs, values, and knowledge about the issue. Various models of health education are used in deter-mining predictors of different healthy behaviors but their efficacy in cultural behaviors, such as water saving behaviors, are not studied. The study was conducted to explain water saving beha-viors in Yazd, Iran on the basis of Health Belief Model and Reasoned Action Theory. Methods: The cross-sectional stud...
Numerical Models for Sound Propagation in Long Spaces
Lai, Chenly Yuen Cheung
Both reverberation time and steady-state sound field are the key elements for assessing the acoustic condition in an enclosed space. They affect the noise propagation, speech intelligibility, clarity index, and definition. Since the sound field in a long space is non diffuse, classical room acoustics theory does not apply in this situation. The ray tracing technique and the image source methods are two common models to fathom both reverberation time and steady-state sound field in long enclosures nowadays. Although both models can give an accurate estimate of reverberation times and steady-state sound field directly or indirectly, they often involve time-consuming calculations. In order to simplify the acoustic consideration, a theoretical formulation has been developed for predicting both steady-state sound fields and reverberation times in street canyons. The prediction model is further developed to predict the steady-state sound field in a long enclosure. Apart from the straight long enclosure, there are other variations such as a cross junction, a long enclosure with a T-intersection, an U-turn long enclosure. In the present study, an theoretical and experimental investigations were conducted to develop formulae for predicting reverberation times and steady-state sound fields in a junction of a street canyon and in a long enclosure with T-intersection. The theoretical models are validated by comparing the numerical predictions with published experimental results. The theoretical results are also compared with precise indoor measurements and large-scale outdoor experimental results. In all of previous acoustical studies related to long enclosure, most of the studies are focused on the monopole sound source. Besides non-directional noise source, many noise sources in long enclosure are dipole like, such as train noise and fan noise. In order to study the characteristics of directional noise sources, a review of available dipole source was conducted. A dipole was
International Nuclear Information System (INIS)
A small break loss-of-accident (SBLOCA) in a typical Babcock and Wilcox (B ampersand W) nuclear power plant was modeled using RELAP5/MOD3. This work was performed as part of the United States Regulatory Commission's (USNRC) Code, Scaling, Applicability and Uncertainty (CSAU) study. The break was initiated by severing one high pressure injection (HPI) line at the cold leg. Thus, the small break was further aggravated by reduced HPI flow. Comparisons between scoping runs with minimal operator action, and full operator action, clearly showed that the operator plays a key role in recovering the plant. Operator actions were modeled based on the emergency operating procedures (EOPs) and the Technical Bases Document for the EOPs. The sequence of operator actions modeled here is only one of several possibilities. Different sequences of operator actions are possible for a given accident because of the subjective decisions the operator must make when determining the status of the plant, hence, which branch of the EOP to follow. To assess the credibility of the modeled operator actions, these actions and results of the simulated accident scenario were presented to operator examiners who are familiar with B ampersand W nuclear power plants. They agreed that, in general, the modeled operator actions conform to the requirements set forth in the EOPs and are therefore plausible. This paper presents the method for modeling the operator actions and discusses the simulated accident scenario from the viewpoint of operator actions
Cognition in Space Workshop. 1; Metrics and Models
Woolford, Barbara; Fielder, Edna
2005-01-01
"Cognition in Space Workshop I: Metrics and Models" was the first in a series of workshops sponsored by NASA to develop an integrated research and development plan supporting human cognition in space exploration. The workshop was held in Chandler, Arizona, October 25-27, 2004. The participants represented academia, government agencies, and medical centers. This workshop addressed the following goal of the NASA Human System Integration Program for Exploration: to develop a program to manage risks due to human performance and human error, specifically ones tied to cognition. Risks range from catastrophic error to degradation of efficiency and failure to accomplish mission goals. Cognition itself includes memory, decision making, initiation of motor responses, sensation, and perception. Four subgoals were also defined at the workshop as follows: (1) NASA needs to develop a human-centered design process that incorporates standards for human cognition, human performance, and assessment of human interfaces; (2) NASA needs to identify and assess factors that increase risks associated with cognition; (3) NASA needs to predict risks associated with cognition; and (4) NASA needs to mitigate risk, both prior to actual missions and in real time. This report develops the material relating to these four subgoals.
Model Based Defect Detection in Multi-Dimensional Vector Spaces
Honda, Toshifumi; Obara, Kenji; Harada, Minoru; Igarashi, Hajime
A highly sensitive inspection algorithm is proposed that extracts defects in multidimensional vector spaces from multiple images. The proposed algorithm projects subtraction vectors calculated from test and reference images to control the noise by reducing the dimensionality of vector spaces. The linear projection vectors are optimized using a physical defect model, and the noise distribution is calculated from the images. Because the noise distribution varies with the intensity or texture of the pixels, the target image is divided into small regions and the noise distribution of the subtraction images are calculated for each divided region. The bidirectional local perturbation pattern matching (BD-LPPM) which is an enhanced version of the LPPM, is proposed to increase the sensitivity when calculating the subtraction vectors, especially when the reference image contains more high-frequency components than the test image. The proposed algorithm is evaluated using defect samples for three different scanning electron microscopy images. The results reveal that the proposed algorithm increases the signal-to-noise ratio by a factor of 1.32 relative to that obtained using the Mahalanobis distance algorithm.
On modelling of physical effects accompanying the propagation of action potentials in nerve fibres
Engelbrecht, Jüri; Tamm, Kert; Laasmaa, Martin; Vendelin, Marko
2016-01-01
The recent theoretical and experimental studies have revealed many details of signal propagation in nervous systems. In this paper an attempt is made to unify various mathematical models which describe the signal propagation in nerve fibres. The analysis of existing single models permits to select the leading physiological effects. As a result, a more general mathematical model is described based on the coupling of action potentials with mechanical waves in a nerve fibre. The crucial issue is how to model coupling effects which are strongly linked to the ion currents through biomembranes.
Action Recognition using Motion Primitives
DEFF Research Database (Denmark)
Moeslund, Thomas B.; Fihl, Preben; Holte, Michael Boelstoft
The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent...... the actions as a sequence of temporal isolated instances, denoted primitives. These primitives are each defined by four features extracted from motion images. The primitives are recognized in each frame based on a trained classifier resulting in a sequence of primitives. From this sequence we recognize...... different temporal actions using a probabilistic Edit Distance method. The method is tested on different actions with and without noise and the results show recognizing rates of 88.7% and 85.5%, respectively....
PRO-ECOLOGICAL ACTIONS AND CONSUMER CHOICES IN THE MODEL OF RESPONSIBLE BUSINESS
Directory of Open Access Journals (Sweden)
Katarzyna Olejniczak
2015-09-01
Full Text Available The current farming conditions cause that recent social and environmental aspects of management play an important role for the functioning of modern enterprises. This results from the fact that on the one hand the activities of modern enterprises are determined by the surroundings’ increasing complexity, on the other hand the growing demands of various groups of stakeholders build company’s success based not only on a quest to maximize their profi t, but primarily on taking the responsibility for the consequences of their actions. Additionally, the growing awareness of consumers makes more and more enterprises implement the concept of corporate social responsibility (CSR in their actions. For this reason, it is important to discuss about the actions and choices of consumers in the model of CSR. The aim of this article is to present the results of the research on customers‘s environmentally conscious activities and choices.
Energy Technology Data Exchange (ETDEWEB)
Davis JE, Eddy MJ, Sutton TM, Altomari TJ
2007-03-01
Solid modeling computer software systems provide for the design of three-dimensional solid models used in the design and analysis of physical components. The current state-of-the-art in solid modeling representation uses a boundary representation format in which geometry and topology are used to form three-dimensional boundaries of the solid. The geometry representation used in these systems is cubic B-spline curves and surfaces--a network of cubic B-spline functions in three-dimensional Cartesian coordinate space. Many Monte Carlo codes, however, use a geometry representation in which geometry units are specified by intersections and unions of half-spaces. This paper describes an algorithm for converting from a boundary representation to a half-space representation.
Directory of Open Access Journals (Sweden)
Smith Thomas A
2008-01-01
Full Text Available Abstract Background Quantifying heterogeneity in malaria transmission is a prerequisite for accurate predictive mathematical models, but the variance in field measurements of exposure overestimates true micro-heterogeneity because it is inflated to an uncertain extent by sampling variation. Descriptions of field data also suggest that the rate of Plasmodium falciparum infection is not proportional to the intensity of challenge by infectious vectors. This appears to violate the principle of mass action that is implied by malaria biology. Micro-heterogeneity may be the reason for this anomaly. It is proposed that the level of micro-heterogeneity can be estimated from statistical models that estimate the amount of variation in transmission most compatible with a mass-action model for the relationship of infection to exposure. Methods The relationship between the entomological inoculation rate (EIR for falciparum malaria and infection risk was reanalysed using published data for cohorts of children in Saradidi (western Kenya. Infection risk was treated as binomially distributed, and measurement-error (Poisson and negative binomial models were considered for the EIR. Models were fitted using Bayesian Markov chain Monte Carlo algorithms and model fit compared for models that assume either mass-action kinetics, facilitation, competition or saturation of the infection process with increasing EIR. Results The proportion of inocula that resulted in infection in Saradidi was inversely related to the measured intensity of challenge. Models of facilitation showed, therefore, a poor fit to the data. When sampling error in the EIR was neglected, either competition or saturation needed to be incorporated in the model in order to give a good fit. Negative binomial models for the error in exposure could achieve a comparable fit while incorporating the more parsimonious and biologically plausible mass action assumption. Models that assume negative binomial micro
Investigating Patterns for the Process-Oriented Modelling and Simulation of Space in Complex Systems
Sampson, Adam T.; Welch, Peter H.; Warren, Douglas N.; Andrews, Paul S.; Bjørndalen, John Markus; Stepney, Susan; Timmis, Jon
2008-01-01
Complex systems modelling and simulation is becoming increasingly important to numerous disciplines. The CoSMoS project aims to produce a unified infrastructure for modelling and simulating all sorts of complex systems, making use of design patterns and the process-oriented programming model. We provide a description of CoSMoS and present a case study into the modelling of space in complex systems. We describe how two models - absolute geometric space and relational network space - can be cap...
Estimation of HIV infection and incubation via state space models.
Tan, W Y; Ye, Z
2000-09-01
By using the state space model (Kalman filter model) of the HIV epidemic, in this paper we have developed a general Bayesian procedure to estimate simultaneously the HIV infection distribution, the HIV incubation distribution, the numbers of susceptible people, infective people and AIDS cases. The basic approach is to use the Gibbs sampling method combined with the weighted bootstrap method. We have applied this method to the San Francisco AIDS incidence data from January 1981 to December 1992. The results show clearly that both the probability density function of the HIV infection and the probability density function of the HIV incubation are curves with two peaks. The results of the HIV infection distribution are clearly consistent with the finding by Tan et al. [W.Y. Tan, S.C. Tang, S.R. Lee, Estimation of HIV seroconversion and effects of age in San Francisco homosexual populations, J. Appl. Stat. 25 (1998) 85]. The results of HIV incubation distribution seem to confirm the staged model used by Satten and Longini [G. Satten, I. Longini, Markov chain with measurement error: estimating the 'true' course of marker of the progression of human immunodeficiency virus disease, Appl. Stat. 45 (1996) 275]. PMID:10942785
Exploring the Model Design Space for Battery Health Management
Saha, Bhaskar; Quach, Cuong Chi; Goebel, Kai Frank
2011-01-01
Battery Health Management (BHM) is a core enabling technology for the success and widespread adoption of the emerging electric vehicles of today. Although battery chemistries have been studied in detail in literature, an accurate run-time battery life prediction algorithm has eluded us. Current reliability-based techniques are insufficient to manage the use of such batteries when they are an active power source with frequently varying loads in uncertain environments. The amount of usable charge of a battery for a given discharge profile is not only dependent on the starting state-of-charge (SOC), but also other factors like battery health and the discharge or load profile imposed. This paper presents a Particle Filter (PF) based BHM framework with plug-and-play modules for battery models and uncertainty management. The batteries are modeled at three different levels of granularity with associated uncertainty distributions, encoding the basic electrochemical processes of a Lithium-polymer battery. The effects of different choices in the model design space are explored in the context of prediction performance in an electric unmanned aerial vehicle (UAV) application with emulated flight profiles.
Application of Interval Predictor Models to Space Radiation Shielding
Crespo, Luis G.; Kenny, Sean P.; Giesy,Daniel P.; Norman, Ryan B.; Blattnig, Steve R.
2016-01-01
This paper develops techniques for predicting the uncertainty range of an output variable given input-output data. These models are called Interval Predictor Models (IPM) because they yield an interval valued function of the input. This paper develops IPMs having a radial basis structure. This structure enables the formal description of (i) the uncertainty in the models parameters, (ii) the predicted output interval, and (iii) the probability that a future observation would fall in such an interval. In contrast to other metamodeling techniques, this probabilistic certi cate of correctness does not require making any assumptions on the structure of the mechanism from which data are drawn. Optimization-based strategies for calculating IPMs having minimal spread while containing all the data are developed. Constraints for bounding the minimum interval spread over the continuum of inputs, regulating the IPMs variation/oscillation, and centering its spread about a target point, are used to prevent data over tting. Furthermore, we develop an approach for using expert opinion during extrapolation. This metamodeling technique is illustrated using a radiation shielding application for space exploration. In this application, we use IPMs to describe the error incurred in predicting the ux of particles resulting from the interaction between a high-energy incident beam and a target.
Surovyatkina, Elena; Egorchenkov, Roman; Ivanov, Guennady
2007-06-01
The coexistence of different dynamical regimes of cardiac cell-model at a fixed set of stimulation parameters, i.e. multistability, revealed by noise is presented in this paper. Numerical simulations are performed using Luo-Rudy (LR1) action potential model. Numerical experiments with LR1 model conducted via noisy periodical stimulation showed the coexistence of several periodic rhythms. Weak noise in period of stimulation causes a hopping process between all the (meta-) stable rhythms of cell-model. This process is reflected in several parallel branches of the bifurcation diagram: noise unveils new, invisible before, stable rhythms which could appear in this model at different initial conditions. The phenomenon of multistability is directly evidenced by other numerical experiments: we have established the multistability property of a cell consisting in the fact that different initial conditions of stimulation (different extrasystole application times) lead to different stable periodic rhythms. We have obtained the shaping of attraction basins on the action potential curves. Such basins of attraction contain a set of initial conditions which determinate a stable periodic rhythm. We have found a close association between the attraction basins of the complex rhythms on the curves of action potential and the cardiac vulnerable windows on ECG record, during which extra stimuli can induce life threatening arrhythmias. Obtained results allow us to make a conclusion that multistability is very important for the electrical conduction system of the heart from the cell level to the integrated function of the heart.
Messina, Irene; Sambin, Marco; Beschoner, Petra; Viviani, Roberto
2016-08-01
Influential neurobiological models of the mechanism of action of psychotherapy attribute its success to increases of activity in prefrontal areas and decreases in limbic areas, interpreted as the successful and adaptive recruitment of controlled processes to achieve emotion regulation. In this article, we review the behavioral and neuroscientific evidence in support of this model and its applicability to explain the mechanism of action of psychotherapy. Neuroimaging studies of explicit emotion regulation, evidence on the neurobiological substrates of implicit emotion regulation, and meta-analyses of neuroimaging studies of the effect of psychotherapy consistently suggest that areas implicated in coding semantic representations play an important role in emotion regulation not covered by existing models based on controlled processes. We discuss the findings that implicate these same areas in supporting working memory, in encoding preferences and the prospective outcome of actions taken in rewarding or aversive contingencies, and show how these functions may be integrated into process models of emotion regulation that depend on elaborate semantic representations for their effectiveness. These alternative models also appear to be more consistent with internal accounts in the psychotherapeutic literature of how psychotherapy works. PMID:27351671
NASA 3D Models: James Webb Space Telescope
National Aeronautics and Space Administration — The James Webb Space Telescope (JWST) will be a large infrared telescope with a 6.5-meter primary mirror. The project is working to a 2018 launch date. The JWST...
Simulating Emerging Space Industries with Agent-Based Modeling Project
National Aeronautics and Space Administration — The Vision for Space Exploration (VSE) calls for encouraging commercial participation as a top-level objective. Given current and future commercial activities, how...
Rauterberg, M
1993-11-01
To support the human factors engineer in designing a good user interface, a method has been developed to analyse the empirical data of the interactive user behaviour traced in a finite discrete state space. The sequences of actions produced by the user contain valuable information about the mental model of this user, the individual problem solution strategies for a given task and the hierarchical structure of the task-subtasks relationships. The presented method, AMME, can analyse the action sequences and automatically generate (1) a net description of the task dependent model of the user, (2) a complete state transition matrix, and (3) various quantitative measures of the user's task solving process. The behavioural complexity of task-solving processes carried out by novices has been found to be significantly larger than the complexity of task-solving processes carried out by experts.
Energy Technology Data Exchange (ETDEWEB)
Cichy, Krzysztof [DESY, Zeuthen (Germany). NIC; Adam Mickiewicz Univ., Poznan (Poland). Faculty of Physics; Jansen, Karl [DESY, Zeuthen (Germany). NIC; Korcyl, Piotr [DESY, Zeuthen (Germany). NIC; Jagiellonian Univ., Krakow (Poland). M. Smoluchowski Inst. of Physics
2012-07-15
We present results of a lattice QCD application of a coordinate space renormalization scheme for the extraction of renormalization constants for flavour non-singlet bilinear quark operators. The method consists in the analysis of the small-distance behaviour of correlation functions in Euclidean space and has several theoretical and practical advantages, in particular: it is gauge invariant, easy to implement and has relatively low computational cost. The values of renormalization constants in the X-space scheme can be converted to the MS scheme via 4-loop continuum perturbative formulae. Our results for N{sub f}=2 maximally twisted mass fermions with tree-level Symanzik improved gauge action are compared to the ones from the RI-MOM scheme and show full agreement with this method. (orig.)
Cichy, Krzysztof; Korcyl, Piotr
2012-01-01
We present results of a lattice QCD application of a coordinate space renormalization scheme for the extraction of renormalization constants for flavour non-singlet bilinear quark operators. The method consists in the analysis of the small-distance behaviour of correlation functions in Euclidean space and has several theoretical and practical advantages, in particular: it is gauge invariant, easy to implement and has relatively low computational cost. The values of renormalization constants in the X-space scheme can be converted to the MSbar scheme via 4-loop continuum perturbative formulae. Our results for $N_f=2$ maximally twisted mass fermions with tree-level Symanzik improved gauge action are compared to the ones from the RI-MOM scheme and show full agreement with this method.
A phantom axon setup for validating models of action potential recordings.
Rossel, Olivier; Soulier, Fabien; Bernard, Serge; Guiraud, David; Cathébras, Guy
2016-08-01
Electrode designs and strategies for electroneurogram recordings are often tested first by computer simulations and then by animal models, but they are rarely implanted for long-term evaluation in humans. The models show that the amplitude of the potential at the surface of an axon is higher in front of the nodes of Ranvier than at the internodes; however, this has not been investigated through in vivo measurements. An original experimental method is presented to emulate a single fiber action potential in an infinite conductive volume, allowing the potential of an axon to be recorded at both the nodes of Ranvier and the internodes, for a wide range of electrode-to-fiber radial distances. The paper particularly investigates the differences in the action potential amplitude along the longitudinal axis of an axon. At a short radial distance, the action potential amplitude measured in front of a node of Ranvier is two times larger than in the middle of two nodes. Moreover, farther from the phantom axon, the measured action potential amplitude is almost constant along the longitudinal axis. The results of this new method confirm the computer simulations, with a correlation of 97.6 %. PMID:27016364
International Nuclear Information System (INIS)
Continuous action hydrogeological model (CAHM) is a special complex intended for multivariant forecasts of the underground water conditions. CAHM makes it possible to ground optimal arrangement and running of water supply and environmental control measures. CAHM takes into consideration surface storm run-off, vertical moisture and salt transfer in aeration zone soils and filtration model. Presented are mathematical models describing those phenomena. Calculation net of a regional CAHM is given. There is a map of forecasted set levels and heads of the underground water in case of functioning Yanovskij, Novoshepelichevskij and Chernobylskij water intakes at maximum flow rate. 1 refs.; 3 figs
Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles
International Nuclear Information System (INIS)
The objective of our research work is to provide -- with the aid of biophysical models of radiation action -- information on human risks following exposure to radon alpha particles. The approach proposed consists of (1) developing appropriate models (parametric and non-parametric) for alpha radiation induction of relevant end points (survival, cellular transformation), (2) providing an accurate physical characterization of the particle tracks in terms of nanodosimetric distributions, (3) supporting the models by detailed, molecular studies of the direct and indirect effects of alpha particles on DNA. Activities in the second year of this project are described
Modeling Approach/Strategy for Corrective Action Unit 97, Yucca Flat and Climax Mine , Revision 0
Energy Technology Data Exchange (ETDEWEB)
Janet Willie
2003-08-01
The objectives of the UGTA corrective action strategy are to predict the location of the contaminant boundary for each CAU, develop and implement a corrective action, and close each CAU. The process for achieving this strategy includes modeling to define the maximum extent of contaminant transport within a specified time frame. Modeling is a method of forecasting how the hydrogeologic system, including the underground test cavities, will behave over time with the goal of assessing the migration of radionuclides away from the cavities and chimneys. Use of flow and transport models to achieve the objectives of the corrective action strategy is specified in the FFACO. In the Yucca Flat/Climax Mine system, radionuclide migration will be governed by releases from the cavities and chimneys, and transport in alluvial aquifers, fractured and partially fractured volcanic rock aquifers and aquitards, the carbonate aquifers, and in intrusive units. Additional complexity is associated with multiple faults in Yucca Flat and the need to consider reactive transport mechanisms that both reduce and enhance the mobility of radionuclides. A summary of the data and information that form the technical basis for the model is provided in this document.
Probability boxes on totally preordered spaces for multivariate modelling
Troffaes, Matthias C M; 10.1016/j.ijar.2011.02.001
2011-01-01
A pair of lower and upper cumulative distribution functions, also called probability box or p-box, is among the most popular models used in imprecise probability theory. They arise naturally in expert elicitation, for instance in cases where bounds are specified on the quantiles of a random variable, or when quantiles are specified only at a finite number of points. Many practical and formal results concerning p-boxes already exist in the literature. In this paper, we provide new efficient tools to construct multivariate p-boxes and develop algorithms to draw inferences from them. For this purpose, we formalise and extend the theory of p-boxes using Walley's behavioural theory of imprecise probabilities, and heavily rely on its notion of natural extension and existing results about independence modeling. In particular, we allow p-boxes to be defined on arbitrary totally preordered spaces, hence thereby also admitting multivariate p-boxes via probability bounds over any collection of nested sets. We focus on t...
Oblique corrections from less-Higgsless models in warped space
Hatanaka, Hisaki
2015-01-01
The Higgsless model in warped extra dimension is reexamined. Dirichlet boundary conditions on the TeV brane are replaced with Robin boundary conditions which are parameterized by a mass parameter $M$. We calculate the Peskin-Takeuchi precision parameters $S$, $T$ and $U$ at tree level. We find that to satisfy the constraints on the precision parameters at $99 \\%$ [$95 \\%$] confidence level (CL) the first Kaluza-Klein excited $Z$ boson, $Z'$, should be heavier than 5 TeV [8 TeV]. The Magnitude of $M$, which is infinitely large in the original model, should be smaller than 200 GeV (70 GeV) for the curvature of the warped space $R^{-1}=10^{16}$ GeV ($10^{8}$ GeV) at $95\\%$ CL. If the Robin boundary conditions are induced by the mass terms localized on the TeV brane, from the $99\\%$ [$95\\%$] bound we find that the brane mass interactions account for more than $97\\%$ [$99\\%$] of the masses of $Z$ and $W$ bosons. Such a brane mass term is naturally interpreted as a vacuum expectation value of the Higgs scalar field...
Photochemical formation of oligopepides in the space processes modeling experiments
Gontareva, N.; Kuzicheva, E.
The origin of life may be considered as a sequence of events, each of which adds to the molecular complexity and order. Abundance of chemical building blocks synthesized previously is a prerequisite for the beginning of the next evolutionary step. That's why the availability of chemical building blocks for peptides and nucleic acids, their formation and resistance towards destructive impacts should not be underestimated. At the number of our previous publications it was reported about the oligopeptides and nucleotides formation promoted by cosmic energy sources at the terrestrial orbit. The next important question to solve was whether mineral beds could have protected these biological important substances from the destructive action of space radiation. Minerals of extraterrestrial origin, such as lunar soil, Allende and Murchison meteorites, were tested with respect of their protective properties. UV radiation of short wavelength (the most abundant and powerful source of energy during the period of early chemical evolution) was taken as the energy supplier triggering the solid phase synthesis process. Solid films consisting out of two aminoacids (Gly + Phe) were irradiated by UV 254 in course of the experiment - free or associat ed with minerals. As the result of exposure process, both dipeptides and tripeptides of certain aminoacids were identified. Presence of inorganic beds during irradiation increased the yield of oligopeptides. For lunar soil, the yield increased by 3.8 times, while in case of meteorite beds the rate between free and associated with clay samples was 1.4. These data correlate with our previous results on VUV 145 irradiation of the same mixture (Gly + Phe), irradiation dose 2.12*106 J m-2. The same set of products was traced in both experimental cases, while the quantitative yield of products was one order of magnitude less for the case of UV254 and the relevant irradiation dosage much higher - 2.64*107 J m -2. It should be considered, that at
Representative Model of the Learning Process in Virtual Spaces Supported by ICT
Capacho, José
2014-01-01
This paper shows the results of research activities for building the representative model of the learning process in virtual spaces (e-Learning). The formal basis of the model are supported in the analysis of models of learning assessment in virtual spaces and specifically in Dembo´s teaching learning model, the systemic approach to evaluating…
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
Space-mapping (SM) technique is applied for the modeling and design optimization of photonic devices. A mapping is established between the parameter spaces of the fast but approximate coarse model and the time-intensive yet accurate fine model. Two different applications of the SM techniques, i.e., design optimization and design modeling of photonic devices, are illustrated by way of examples.
Modeling the Mass Action Dynamics of Metabolism with Fluctuation Theorems and Maximum Entropy
Cannon, William; Thomas, Dennis; Baxter, Douglas; Zucker, Jeremy; Goh, Garrett
The laws of thermodynamics dictate the behavior of biotic and abiotic systems. Simulation methods based on statistical thermodynamics can provide a fundamental understanding of how biological systems function and are coupled to their environment. While mass action kinetic simulations are based on solving ordinary differential equations using rate parameters, analogous thermodynamic simulations of mass action dynamics are based on modeling states using chemical potentials. The latter have the advantage that standard free energies of formation/reaction and metabolite levels are much easier to determine than rate parameters, allowing one to model across a large range of scales. Bridging theory and experiment, statistical thermodynamics simulations allow us to both predict activities of metabolites and enzymes and use experimental measurements of metabolites and proteins as input data. Even if metabolite levels are not available experimentally, it is shown that a maximum entropy assumption is quite reasonable and in many cases results in both the most energetically efficient process and the highest material flux.
Institute of Scientific and Technical Information of China (English)
JIN Xuexiang; SU Yuelong; ZHANG Yi; WEI Zheng; LI Li
2009-01-01
The modeling of headway/spacing between two consecutive vehicles in a queue has many appli-cations in traffic flow theory and transport practice. Most known approaches have only studied vehicles on freeways. This paper presents a model for the spacing distribution of queuing vehicles at a signalized junc-tion based on random-matrix theory. The spacing distribution of a Gaussian symplectic ensemble (GSE) fits well with recently measured spacing distribution data. These results are also compared with measured spacing distribution observed for the car parking problem. Vehicle stationary queuing and vehicle parking have different spacing distributions due to different driving patterns.
Motion Primitives and Probabilistic Edit Distance for Action Recognition
DEFF Research Database (Denmark)
Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.
2009-01-01
The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent t...
State space model extraction of thermohydraulic systems Part I: a linear graph approach
Uren, Kenneth Richard; Schoor, George van
2013-01-01
This second paper in a two part series presents the application of a developed state space model extraction methodology applied to a Brayton cycle-based PCU (power conversion unit) of a PBMR (pebble bed modular reactor). The goal is to investigate if the state space extraction methodology can cope with larger and more complex thermohydraulic systems. In Part I the state space model extraction methodology for the purpose of control was described in detail and a state space represen...
DEFF Research Database (Denmark)
Ehnfors, Margareta; Angermo, Lilly Marit; Berring, Lene;
2006-01-01
. In most cases, the recipient of care is implicit. Expressions for the aim of an action are absent from the ISO model. By this mapping we identified areas for future development of the VIPS model and the experience from nursing terminology work in Scandinavia can contribute to the international......The aims of this study were to analyze the coherence between the concepts for nursing interventions in the Swedish VIPS model for nursing recording and the ISO Reference Terminology Model for Nursing Actions and to identify areas in the two models for further development. Seven Scandinavian experts...... analyzed the VIPS model's concepts for nursing interventions using prototypical examples of nursing actions, involving 233 units of analyses, and collaborated in mapping the two models. All nursing interventions in the VIPS model comprise actions and targets, but a few lack explicit expressions of means...
Numerical Model Related to Impact Fluid / Solid Under the action of an Electric Field
Freifer Somia; Alla Hocine
2013-01-01
The electrowetting is an area of significant interest. Many experimental studies have been conducted to find the relationship that binds the physical parameters of said phenomenon: the percentage of the white area inside the pixels of different sizes depending on the applied voltage etc. Our study is to develop a CFD model to validate the experimental results for the behavior of fluids (oil colored) within the reflector screens under the action of electric field.
MODELING OF THE HIGH CONCENTRATION LAYER OF COHESIVE SEDIMENT UNDER THE ACTION OF WAVES AND CURRENTS
Institute of Scientific and Technical Information of China (English)
Qinghe ZHANG; Yongsheng WU; Jijian LIAN; Pingxing DING
2001-01-01
High concentration layer of cohesive sediment frequently occurs in muddy estuaries and coastal zones, and causes rapid siltation of the waterways. A one dimensional vertical coupled model describing the interactions between waves, currents and suspended cohesive sediment is developed in the present paper. The numerical results and analyses with field measurements reveal the mechanism of the formation and transport behaviors of the layer under the action of waves and currents.
The languages of actions, formal grammars and qualitive modeling of companies
Kovchegov, Vladislav B.
2016-01-01
In this paper we discuss methods of using the language of actions, formal languages, and grammars for qualitative conceptual linguistic modeling of companies as technological and human institutions. The main problem following the discussion is the problem to find and describe a language structure for external and internal flow of information of companies. We anticipate that the language structure of external and internal base flows determine the structure of companies. In the structure modeli...
Variety of the Wave Change in Compound Muscle Action Potential in an Animal Model
ITO, ZENYA; Imagama, Shiro; Ando, Kei; Muramoto, Akio; Kobayashi, Kazuyoshi; Hida, Tetsuro; Ito, Kenyu; Ishikawa, Yoshimoto; Tsushima, Mikito; Matsumoto, Akiyuki; Tanaka, Satoshi; Morozumi, Masayoshi; Matsuyama, Yukihiro; Ishiguro, Naoki
2015-01-01
Study Design Animal study. Purpose To review the present warning point criteria of the compound muscle action potential (CMAP) and investigate new criteria for spinal surgery safety using an animal model. Overview of Literature Little is known about correlation palesis and amplitude of spinal cord monitoring. Methods After laminectomy of the tenth thoracic spinal lamina, 2-140 g force was delivered to the spinal cord with a tension gage to create a bilateral contusion injury. The study morpho...
Directory of Open Access Journals (Sweden)
Lida Zhu
Full Text Available Identifying patients most responsive to specific chemotherapy agents in neoadjuvant settings can help to maximize the benefits of treatment and minimize unnecessary side effects. Metagene approaches that predict response based on gene expression signatures derived from an associative analysis of clinical data can identify chance associations caused by the heterogeneity of a tumor, leading to reproducibility issues in independent validations. In this study, to incorporate information from drug mechanisms of action, we explore the potential of microRNA regulation networks as a new feature space for identifying predictive markers. We introduce a measure we term the CoMi (Context-specific-miRNA-regulation pattern to represent a descriptive feature of the miRNA regulation network in the transcriptome. We examine whether the modifications to the CoMi pattern on specific biological processes are a useful representation of drug action by predicting the response to neoadjuvant Paclitaxel treatment in breast cancer and show that the drug counteracts the CoMi network dysregulation induced by tumorigenesis. We then generate a quantitative testbed to investigate the ability of the CoMi pattern to distinguish FDA approved breast cancer drugs from other FDA approved drugs not related to breast cancer. We also compare the ability of the CoMi and metagene methods to predict response to neoadjuvant Paclitaxel treatment in clinical cohorts. We find the CoMi method outperforms the metagene method, achieving area under curve (AUC values of 0.78 and 0.66 respectively. Furthermore, several of the predicted CoMi features highlight the network-based mechanism of drug resistance. Thus, our study suggests that explicitly modeling the drug action using network biology provides a promising approach for predictive marker discovery.
Validating global hydrological models by ground and space gravimetry
Institute of Scientific and Technical Information of China (English)
ZHOU JiangCun; SUN HePing; XU JianQiao
2009-01-01
The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth's tides and variations in the Earth's rotation, the gravity residuals are used to describe the seasonal fluctuations in gravity field. Meanwhile, the gravity changes due to the air pressure loading are theoretically modeled from the measurements of the local air pressure, and those due to land water and nontidal ocean loading are also calculated according to the corresponding numerical models. The numerical results show that the gravity changes due to both the air pressure and land water loading are as large as 100×10-9 m s-2 in magnitude, and about 10×10-9 m s-2 for those due to the nontidal ocean loading in the coastal area. On the other hand, the monthly-averaged gravity variations over the area surrounding the stations are derived from the spherical harmonic coefficients of the GRACE-recovered gravity fields, by using Gaussian smoothing technique in which the radius is set to be 600 km. Compared the land water induced gravity variations, the SG observations after removal of tides, polar motion effects, air pressure and nontidal ocean loading effects and the GRACE-derived gravity variations with each other, it is inferred that both the ground- and space-based gravity observations can effectively detect the seasonal gravity variations with a magnitude of 100×10-9 m s-2 induced by the land water loading. This implies that high precision gravimetry is an effective technique to validate the reliabilities of the hydrological models.
Duality in Phase Space and Complex Dynamics of an Integrated Pest Management Network Model
Yuan, Baoyin; Tang, Sanyi; Cheke, Robert A.
Fragmented habitat patches between which plants and animals can disperse can be modeled as networks with varying degrees of connectivity. A predator-prey model with network structures is proposed for integrated pest management (IPM) with impulsive control actions. The model was analyzed using numerical methods to investigate how factors such as the impulsive period, the releasing constant of natural enemies and the mode of connections between the patches affect pest outbreak patterns and the success or failure of pest control. The concept of the cluster as defined by Holland and Hastings is used to describe variations in results ranging from global synchrony when all patches have identical fluctuations to n-cluster solutions with all patches having different dynamics. Heterogeneity in the initial densities of either pest or natural enemy generally resulted in a variety of cluster oscillations. Surprisingly, if n > 1, the clusters fall into two groups one with low amplitude fluctuations and the other with high amplitude fluctuations (i.e. duality in phase space), implying that control actions radically alter the system's characteristics by inducing duality and more complex dynamics. When the impulsive period is small enough, i.e. the control strategy is undertaken frequently, the pest can be eradicated. As the period increases, the pest's dynamics shift from a steady state to become chaotic with periodic windows and more multicluster oscillations arise for heterogenous initial density distributions. Period-doubling bifurcation and periodic halving cascades occur as the releasing constant of the natural enemy increases. For the same ecological system with five differently connected networks, as the randomness of the connectedness increases, the transient duration becomes smaller and the probability of multicluster oscillations appearing becomes higher.
Directory of Open Access Journals (Sweden)
Maziar Nekovee
2010-01-01
Full Text Available Cognitive radio is being intensively researched as the enabling technology for license-exempt access to the so-called TV White Spaces (TVWS, large portions of spectrum in the UHF/VHF bands which become available on a geographical basis after digital switchover. Both in the US, and more recently, in the UK the regulators have given conditional endorsement to this new mode of access. This paper reviews the state-of-the-art in technology, regulation, and standardisation of cognitive access to TVWS. It examines the spectrum opportunity and commercial use cases associated with this form of secondary access.
Man in space: The use of animal models
Ballard, Rodney W.; Souza, Kenneth A.
Animals have traditionally preceded man into space. During animal and human travels in space over the past almost 30 years, numerous anatomical, physiological, and biochemical changes have been observed. In order to safely qualify humans for extended duration space missions, scientific research needs to be performed. It may be possible to achieve many of these research goals with flight crews serving as experimental subjects; however, to do this with human subjects alone is impractical. Therefore, the use of animal surrogates as experimental subjects is essential to provide the missing information on the effects of spaceflights, to validate countermeasures, and to test medical treatment techniques which will be necessary for long duration missions. This research to assure human health, safety, and productivity in future extended duration space flights will include flights on NASA's Space Shuttle, unmanned biosatellites, and the Space Station Freedom.
A Symplectic Multi-Particle Tracking Model for Self-Consistent Space-Charge Simulation
Qiang, Ji
2016-01-01
Symplectic tracking is important in accelerator beam dynamics simulation. So far, to the best of our knowledge, there is no self-consistent symplectic space-charge tracking model available in the accelerator community. In this paper, we present a two-dimensional and a three-dimensional symplectic multi-particle spectral model for space-charge tracking simulation. This model includes both the effect from external fields and the effect of self-consistent space-charge fields using a split-operator method. Such a model preserves the phase space structure and shows much less numerical emittance growth than the particle-in-cell model in the illustrative examples.
Caenorhabditis elegans - A model system for space biology studies
Johnson, Thomas E.; Nelson, Gregory A.
1991-01-01
The utility of the nematode Caenorhabditis elegans in studies spanning aspects of development, aging, and radiobiology is reviewed. These topics are interrelated via cellular and DNA repair processes especially in the context of oxidative stress and free-radical metabolism. The relevance of these research topics to problems in space biology is discussed and properties of the space environment are outlined. Exposure to the space-flight environment can induce rapid changes in living systems that are similar to changes occurring during aging; manipulation of these environmental parameters may represent an experimental strategy for studies of development and senescence. The current and future opportunities for such space-flight experimentation are presented.
Anomalies of Minimal N=(0, 1) and N=(0, 2) Sigma Models on Homogeneous Spaces
Chen, Jin; Shifman, Mikhail; Vainshtein, Arkady
2015-01-01
We study chiral anomalies in $\\mathcal N=(0, 1)$ and $(0, 2)$ two-dimensional minimal sigma models defined on generic homogeneous spaces $G/H$. Such minimal theories contain only (left) chiral fermions and in certain cases are inconsistent because of "incurable" anomalies. We explicitly calculate the anomalous fermionic effective action and show how to remedy it by adding a series of local counter-terms. In this procedure, we derive a local anomaly matching condition, which is demonstrated to be equivalent to the well-known global topological constraint on $p_1(G/H)$. More importantly, we show that these local counter-terms further modify and constrain "curable" chiral models, some of which, for example, flow to nontrivial infrared superconformal fixed point. Finally, we also observe an interesting relation between $\\mathcal N=(0, 1)$ and $(0, 2)$ two-dimensional minimal sigma models and supersymmetric gauge theories. This paper generalizes and extends the results of our previous publication arXiv:1510.04324.
A cosmological model with compact space sections and low mass density
International Nuclear Information System (INIS)
A general relativistic cosmological model is presented, which has closed space sections and mass density below a critical density similar to that of Friedmann's models. The model may predict double images of cosmic sources. (Author)
Kinetics of drug action in disease states: towards physiology-based pharmacodynamic (PBPD) models.
Danhof, Meindert
2015-10-01
Gerhard Levy started his investigations on the "Kinetics of Drug Action in Disease States" in the fall of 1980. The objective of his research was to study inter-individual variation in pharmacodynamics. To this end, theoretical concepts and experimental approaches were introduced, which enabled assessment of the changes in pharmacodynamics per se, while excluding or accounting for the cofounding effects of concomitant changes in pharmacokinetics. These concepts were applied in several studies. The results, which were published in 45 papers in the years 1984-1994, showed considerable variation in pharmacodynamics. These initial studies on kinetics of drug action in disease states triggered further experimental research on the relations between pharmacokinetics and pharmacodynamics. Together with the concepts in Levy's earlier publications "Kinetics of Pharmacologic Effects" (Clin Pharmacol Ther 7(3): 362-372, 1966) and "Kinetics of pharmacologic effects in man: the anticoagulant action of warfarin" (Clin Pharmacol Ther 10(1): 22-35, 1969), they form a significant impulse to the development of physiology-based pharmacodynamic (PBPD) modeling as novel discipline in the pharmaceutical sciences. This paper reviews Levy's research on the "Kinetics of Drug Action in Disease States". Next it addresses the significance of his research for the evolution of PBPD modeling as a scientific discipline. PBPD models contain specific expressions to characterize in a strictly quantitative manner processes on the causal path between exposure (in terms of concentration at the target site) and the drug effect (in terms of the change in biological function). Pertinent processes on the causal path are: (1) target site distribution, (2) target binding and activation and (3) transduction and homeostatic feedback.
Space Weather Education: Learning to Forecast at the Community Coordinated Modeling Center
Wold, A.
2015-12-01
Enhancing space weather education is important to space science endeavors. While participating in the Space Weather Research, Education and Development Initiative (SW REDI) Bootcamp and working as a Space Weather Analyst Intern, several innovative technologies and tools were integral to my learning and understanding of space weather analysis and forecasting. Two of the tools utilized in learning about space weather were the Integrated Space Weather Analysis System (iSWA) and the Space Weather Database Of Notifications, Knowledge, Information (DONKI). iSWA, a web-based dissemination system, hosts many state-of-the-art space weather models as well as real time space weather data from spacecraft such as Solar Dynamics Observatory and the Advanced Composition Explorer. As a customizable tool that operates in real-time while providing access also to historical data, iSWA proved essential in my understanding the drivers and impacts of space weather. DONKI was instrumental in accessing historical space weather events to understand the connections between solar phenomena and their effects on Earth environments. DONKI operates as a database of space weather events including linkages between causes and effects of space weather events. iSWA and DONKI are tools available also to the public. They not only enrich the space weather learning process but also allow researchers and model developers access to essential heliophysics and magnetospheric data.
A model for emergence of space and time
Directory of Open Access Journals (Sweden)
J. Ambjørn
2015-10-01
Full Text Available We study string field theory (third quantization of the two-dimensional model of quantum geometry called generalized CDT (“causal dynamical triangulations”. Like in standard non-critical string theory the so-called string field Hamiltonian of generalized CDT can be associated with W-algebra generators through the string mode expansion. This allows us to define an “absolute” vacuum. “Physical” vacua appear as coherent states created by vertex operators acting on the absolute vacuum. Each coherent state corresponds to specific values of the coupling constants of generalized CDT. The cosmological “time” only exists relatively to a given “physical” vacuum and comes into existence before space, which is created because the “physical” vacuum is unstable. Thus each CDT “universe” is created as a “Big Bang” from the absolute vacuum, its time evolution is governed by the CDT string field Hamiltonian with given coupling constants, and one can imagine interactions between CDT universes with different coupling constants (“fourth quantization”
Information space models for data integration, and entity resolution
Porter, Reid; Collins, Linn; Powell, James; Rivenburgh, Reid
2012-06-01
Geospatial information systems provide a unique frame of reference to bring together a large and diverse set of data from a variety of sources. However, automating this process remains a challenge since: 1) data (particularly from sensors) is error prone and ambiguous, 2) analysis and visualization tools typically expect clean (or exact) data, and 3) it is difficult to describe how different data types and modalities relate to each other. In this paper we describe a data integration approach that can help address some of these challenges. Specifically we propose a light weight ontology for an Information Space Model (ISM). The ISM is designed to support functionality that lies between data catalogues and domain ontologies. Similar to data catalogues, the ISM provides metadata for data discovery across multiple, heterogeneous (often legacy) data sources e.g. maps servers, satellite images, social networks, geospatial blogs. Similar to domain ontologies, the ISM describes the functional relationship between these systems with respect to entities relevant to an application e.g. venues, actors and activities. We suggest a minimal set of ISM objects, and attributes for describing data sources and sensors relevant to data integration. We present a number of statistical relational learning techniques to represent and leverage the combination of deterministic and probabilistic dependencies found within the ISM. We demonstrate how the ISM provides a flexible language for data integration where unknown or ambiguous relationships can be mitigated.
The modeling of hemispherical resonator gyro and its space applications
Wang, Xu; Wu, Wenqi; Lou, Bing; Li, Yun
2011-12-01
The hemispherical resonator gyroscope (HRG) is a new vibration gyro, which first appeared in the 1960s. It has a feature of high accuracy, long life span, no wear-out and great reliability. With its excellent performances, the HRG can be used for spacecraft and satellite stabilization, precision pointing, aircraft navigation, strategic accuracy systems, oil borehole exploration and planetary exploration. Compared with traditional mechanical gyro and optical gyro, HRG has no rotators or movement parts. The resonator of HRG is made from quartz with low damping and stable temperature. The resonator Q factor exceeds 5,000,000 and it is placed under vacuum cap with residual pressure about 1×10-6 atm. The principium of HRG sensing the rotation relies on a transverse stress wave in the solid resonator. The stable material character of resonator and simple structure make the gyro high reliability, long lifetime, anti-radiation, anti-shock and high accuracy. Two working modes of the HRG which is the whole angle mode and force to rebalance mode are respectively analyzed, besides, the control loops applied in the gyro are illuminated in the paper. The basic kinetic model of the HRG is investigated in the paper, from which the principle and exhibition of the error existing in the device could be obtained clearly. At last, the HRG space applications are displayed and the result of the 100% mission success has demonstrated it is the best candidate for critical and high value missions.
State-space reduction and equivalence class sampling for a molecular self-assembly model.
Packwood, Daniel M; Han, Patrick; Hitosugi, Taro
2016-07-01
Direct simulation of a model with a large state space will generate enormous volumes of data, much of which is not relevant to the questions under study. In this paper, we consider a molecular self-assembly model as a typical example of a large state-space model, and present a method for selectively retrieving 'target information' from this model. This method partitions the state space into equivalence classes, as identified by an appropriate equivalence relation. The set of equivalence classes H, which serves as a reduced state space, contains none of the superfluous information of the original model. After construction and characterization of a Markov chain with state space H, the target information is efficiently retrieved via Markov chain Monte Carlo sampling. This approach represents a new breed of simulation techniques which are highly optimized for studying molecular self-assembly and, moreover, serves as a valuable guideline for analysis of other large state-space models. PMID:27493765
Tools and Products of Real-Time Modeling: Opportunities for Space Weather Forecasting
Hesse, Michael
2009-01-01
The Community Coordinated Modeling Center (CCMC) is a US inter-agency activity aiming at research in support of the generation of advanced space weather models. As one of its main functions, the CCMC provides to researchers the use of space science models, even if they are not model owners themselves. The second CCMC activity is to support Space Weather forecasting at national Space Weather Forecasting Centers. This second activity involves model evaluations, model transitions to operations, and the development of draft Space Weather forecasting tools. This presentation will focus on the last element. Specifically, we will discuss present capabilities, and the potential to derive further tools. These capabilities will be interpreted in the context of a broad-based, bootstrapping activity for modern Space Weather forecasting.
Representative Model Of The Learning Process In Virtual Spaces Supported By Ict
CAPACHO, José
2014-01-01
This paper shows the results of research activities for building the representative model of the learning process in virtual spaces (e-Learning). The formal basis of the model are supported in the analysis of models of learning assessment in virtual spaces and specifically in Dembo´s teaching learning model, the systemic approach to evaluating virtual learning by Badrul H. Khan, and the Cybernetic model for evaluating virtual learning environments. The e-Learning model is syste...
Representative Model of the Learning Process in Virtual Spaces Supported by ICT
CAPACHO, José
2015-01-01
This paper shows the results of research activities for building the representative model of the learning process in virtual spaces (e-Learning). The formal basis of the model are supported in the analysis of models of learning assessment in virtual spaces and specifically in Dembo´s teaching learning model, the systemic approach to evaluating virtual learning by Badrul H. Khan, and the Cybernetic model for evaluating virtual learning environments. The e-Learning model is systemic and of feed...
Neuronal chains for actions in the parietal lobe: a computational model.
Directory of Open Access Journals (Sweden)
Fabian Chersi
Full Text Available The inferior part of the parietal lobe (IPL is known to play a very important role in sensorimotor integration. Neurons in this region code goal-related motor acts performed with the mouth, with the hand and with the arm. It has been demonstrated that most IPL motor neurons coding a specific motor act (e.g., grasping show markedly different activation patterns according to the final goal of the action sequence in which the act is embedded (grasping for eating or grasping for placing. Some of these neurons (parietal mirror neurons show a similar selectivity also during the observation of the same action sequences when executed by others. Thus, it appears that the neuronal response occurring during the execution and the observation of a specific grasping act codes not only the executed motor act, but also the agent's final goal (intention.In this work we present a biologically inspired neural network architecture that models mechanisms of motor sequences execution and recognition. In this network, pools composed of motor and mirror neurons that encode motor acts of a sequence are arranged in form of action goal-specific neuronal chains. The execution and the recognition of actions is achieved through the propagation of activity bursts along specific chains modulated by visual and somatosensory inputs.The implemented spiking neuron network is able to reproduce the results found in neurophysiological recordings of parietal neurons during task performance and provides a biologically plausible implementation of the action selection and recognition process.Finally, the present paper proposes a mechanism for the formation of new neural chains by linking together in a sequential manner neurons that represent subsequent motor acts, thus producing goal-directed sequences.
Accounting for anthropogenic actions in modeling of stream flow at the regional scale
David, C. H.; Famiglietti, J. S.
2013-12-01
The modeling of the horizontal movement of water from land to coasts at scales ranging from 10^5 km^2 to 10^6 km^2 has benefited from extensive research within the past two decades. In parallel, community technology for gathering/sharing surface water observations and datasets for describing the geography of terrestrial water bodies have recently had groundbreaking advancements. Yet, the fields of computational hydrology and hydroinformatics have barely started to work hand-in-hand, and much research remains to be performed before we can better understand the anthropogenic impact on surface water through combined observations and models. Here, we build on our existing river modeling approach that leverages community state-of-the-art tools such as atmospheric data from the second phase of the North American Land Data Assimilation System (NLDAS2), river networks from the enhanced National Hydrography Dataset (NHDPlus), and observations from the U.S. Geological Survey National Water Information System (NWIS) obtained through CUAHSI webservices. Modifications are made to our integrated observational/modeling system to include treatment for anthropogenic actions such as dams, pumping and divergences in river networks. Initial results of a study focusing on the entire State of California suggest that availability of data describing human alterations on natural river networks associated with proper representation of such actions in our models could help advance hydrology further. Snapshot from an animation of flow in California river networks. The full animation is available at: http://www.ucchm.org/david/rapid.htm.
Impact evaluation ofwelfare actions over a community in Colombia, using a data correlated model
Directory of Open Access Journals (Sweden)
Juan C. Salazar U
2010-04-01
Full Text Available The impact evaluation of a communitarian program sometimes is based on statistical techniques such as linear regression models analysis when the goal is usually to quantify its effects on both social and welfare characteristics of a community. This involves the study of mental health and social variables which effects could not be easily quantified due to the presence of correlation structures among the observations within a particular subject. For this reason it is advisable to use linear mixed models to this kind of study. Objective: To calculate the impact of the effects produced by actions of the Instituto de Deportes y Recreación de Medellín (i n d e r on the participant population. Methodology: from a sample collected by i n d e r back in 2007, about participants and no participants of its programs, generalized linear models were estimated to explain the behavior of both social and psychological variables. Then, by using a logistic regression model a matching procedure was performed to identify the subjects and their repeated measures that will serve as inputs to measure the impact of the intervention of the welfare activities on the community by means of a linear mixed model. Results: The linear mixed estimation process identified important interaction variables that favor the intervention welfare actions. Conclusions:from the participation in the i n d e r activities, an improvement of variables related with social capital was found.
A class of exact pp-wave string models with interacting light-cone gauge actions
International Nuclear Information System (INIS)
We find a general class of pp-wave string solutions with NS-NS H3 or R-R F3 field strengths, which are analogous to solutions with non-constant F5 recently considered by Maldacena and Maoz (hep-th/0207284). We show that: (i) all pp-wave solutions supported by non-constant H3 or Fp fields are exact type II superstring solutions to all orders in α'; (ii) the corresponding light-cone gauge Green-Schwarz actions are non-linear in bosons but always quadratic in fermions, and describe UV finite 2-d theories; (iii) the pp-wave backgrounds supported by non-constant F3 field do not have, in contrast to their F5-field counterparts, 'supernumerary' supersymmetries and thus the associated light-cone GS actions do not possess 2-d supersymmetry. We consider a specific example where the pp-wave F3 background is parametrized by an arbitrary holomorphic function of one complex bosonic coordinate. The corresponding GS action has the same bosonic part, similar Yukawa terms but twice as many interacting world-sheet fermions as the (2,2) supersymmetric model originating from the analogous F5 background. We also discuss the structure of massless scalar vertex operators in the models related to N=2 super sine-Gordon and N=2 super Liouville theories. (author)
Action versus result-oriented schemes in a grassland agroecosystem: a dynamic modelling approach.
Directory of Open Access Journals (Sweden)
Rodolphe Sabatier
Full Text Available Effects of agri-environment schemes (AES on biodiversity remain controversial. While most AES are action-oriented, result-oriented and habitat-oriented schemes have recently been proposed as a solution to improve AES efficiency. The objective of this study was to compare action-oriented, habitat-oriented and result-oriented schemes in terms of ecological and productive performance as well as in terms of management flexibility. We developed a dynamic modelling approach based on the viable control framework to carry out a long term assessment of the three schemes in a grassland agroecosystem. The model explicitly links grazed grassland dynamics to bird population dynamics. It is applied to lapwing conservation in wet grasslands in France. We ran the model to assess the three AES scenarios. The model revealed the grazing strategies respecting ecological and productive constraints specific to each scheme. Grazing strategies were assessed by both their ecological and productive performance. The viable control approach made it possible to obtain the whole set of viable grazing strategies and therefore to quantify the management flexibility of the grassland agroecosystem. Our results showed that habitat and result-oriented scenarios led to much higher ecological performance than the action-oriented one. Differences in both ecological and productive performance between the habitat and result-oriented scenarios were limited. Flexibility of the grassland agroecosystem in the result-oriented scenario was much higher than in that of habitat-oriented scenario. Our model confirms the higher flexibility as well as the better ecological and productive performance of result-oriented schemes. A larger use of result-oriented schemes in conservation may also allow farmers to adapt their management to local conditions and to climatic variations.
Action versus result-oriented schemes in a grassland agroecosystem: a dynamic modelling approach.
Sabatier, Rodolphe; Doyen, Luc; Tichit, Muriel
2012-01-01
Effects of agri-environment schemes (AES) on biodiversity remain controversial. While most AES are action-oriented, result-oriented and habitat-oriented schemes have recently been proposed as a solution to improve AES efficiency. The objective of this study was to compare action-oriented, habitat-oriented and result-oriented schemes in terms of ecological and productive performance as well as in terms of management flexibility. We developed a dynamic modelling approach based on the viable control framework to carry out a long term assessment of the three schemes in a grassland agroecosystem. The model explicitly links grazed grassland dynamics to bird population dynamics. It is applied to lapwing conservation in wet grasslands in France. We ran the model to assess the three AES scenarios. The model revealed the grazing strategies respecting ecological and productive constraints specific to each scheme. Grazing strategies were assessed by both their ecological and productive performance. The viable control approach made it possible to obtain the whole set of viable grazing strategies and therefore to quantify the management flexibility of the grassland agroecosystem. Our results showed that habitat and result-oriented scenarios led to much higher ecological performance than the action-oriented one. Differences in both ecological and productive performance between the habitat and result-oriented scenarios were limited. Flexibility of the grassland agroecosystem in the result-oriented scenario was much higher than in that of habitat-oriented scenario. Our model confirms the higher flexibility as well as the better ecological and productive performance of result-oriented schemes. A larger use of result-oriented schemes in conservation may also allow farmers to adapt their management to local conditions and to climatic variations.
Orr, Mark G; Thrush, Roxanne; Plaut, David C.
2013-01-01
The reasoned action approach, although ubiquitous in health behavior theory (e.g., Theory of Reasoned Action/Planned Behavior), does not adequately address two key dynamical aspects of health behavior: learning and the effect of immediate social context (i.e., social influence). To remedy this, we put forth a computational implementation of the Theory of Reasoned Action (TRA) using artificial-neural networks. Our model re-conceptualized behavioral intention as arising from a dynamic constrain...
Spatio-temporal tumour model for analysis and mechanism of action of intracellular drug accumulation
Indian Academy of Sciences (India)
Somna Mishra; V K Katiyar
2008-09-01
We have developed a one-dimensional tumour simulator to describe the biodistribution of chemotherapeutic drugs to a tumoral lesion and the tumour cell’s response to therapy. A three-compartment model is used for drug dynamics within the tumour. The first compartment represents the extracellular space in which cells move, the second corresponds to the intracellular fluid space (including cell membrane) which is in direct equilibrium with the extracellular space, and the third is a non-exchangeable compartment that represents sequestered drug which is trapped in the nucleus to damage the cellular DNA, directly triggering cell death. Analytical and numerical techniques (Finite Element Method) are used to describe the tumour’s response to therapy and the effect of parameter variation on the drug concentration profiles in the three compartments.
Miki, Kei
2016-07-01
Highest weight modules for U q ( g l 2 ̂ ) are endowed with a structure of modules for the quantum toriodal algebra U κ of type sl2. Using this, we define U κ actions on the space of vertex operators for irreducible highest weight U q ( g l 2 ̂ ) modules. Highest or lowest weight vectors of the thus obtained U κ modules are expressed in terms of an intertwiner for U q ( s l 2 ̂ ) modules and an extra boson. The submodules generated by these vectors are investigated.
Theories of reasoned action and planned behavior as models of condom use: a meta-analysis.
Albarracín, D; Johnson, B T; Fishbein, M; Muellerleile, P A
2001-01-01
To examine how well the theories of reasoned action and planned behavior predict condom use, the authors synthesized 96 data sets (N = 22,594) containing associations between the models' key variables. Consistent with the theory of reasoned action's predictions, (a) condom use was related to intentions (weighted mean r. = .45), (b) intentions were based on attitudes (r. = .58) and subjective norms (r. = .39), and (c) attitudes were associated with behavioral beliefs (r. = .56) and norms were associated with normative beliefs (r. = .46). Consistent with the theory of planned behavior's predictions, perceived behavioral control was related to condom use intentions (r. = .45) and condom use (r. = .25), but in contrast to the theory, it did not contribute significantly to condom use. The strength of these associations, however, was influenced by the consideration of past behavior. Implications of these results for HIV prevention efforts are discussed.
Theories of reasoned action and planned behavior as models of condom use: a meta-analysis.
Albarracín, D; Johnson, B T; Fishbein, M; Muellerleile, P A
2001-01-01
To examine how well the theories of reasoned action and planned behavior predict condom use, the authors synthesized 96 data sets (N = 22,594) containing associations between the models' key variables. Consistent with the theory of reasoned action's predictions, (a) condom use was related to intentions (weighted mean r. = .45), (b) intentions were based on attitudes (r. = .58) and subjective norms (r. = .39), and (c) attitudes were associated with behavioral beliefs (r. = .56) and norms were associated with normative beliefs (r. = .46). Consistent with the theory of planned behavior's predictions, perceived behavioral control was related to condom use intentions (r. = .45) and condom use (r. = .25), but in contrast to the theory, it did not contribute significantly to condom use. The strength of these associations, however, was influenced by the consideration of past behavior. Implications of these results for HIV prevention efforts are discussed. PMID:11271752
An interplay model for authorities' actions and rumor spreading in emergency event
Huo, Liang-an; Huang, Peiqing; Fang, Xing
2011-10-01
Rumor spreading influences how rational individuals assess risks and evaluate needs, especially, it affects authorities to make decisions in an emergency-affected environments. Conversely, authorities' response to emergency will induct public opinions as well. In this paper, we present a simple model to describe the interplay between rumor spreading and authorities' actions in emergency situation based on utility theory. By drawing from differential equations we found that it is possible to minimize negative social utility of rumor spreading in the control of situation. At the same time, authorities' proactive actions can improve rumor management in emergency situation and yield positive social utility. Finally, we outline strategies for authorities that can contribute to rumor management in an emergency event.
DEFF Research Database (Denmark)
Smets, Barth F.; Lardon, Laurent
2009-01-01
Predicting the fate of horizontally transmissible elements in extant microbial communities might be facilitated by the availability of suitable mathematical models. Since the mid-1970s, mass action models have been introduced to describe the transfer of conjugal and mobilizable genetic elements....... This chapter will summarize and explain the assumptions behind spatially homogenous models, and show the predictions by these models under typical scenarios, such as evaluating existence conditions of conjugal plasmids under chemostat or seasonal growth conditions. Special attention is given to the sensitivity...... of the outcomes to the various plasmid dynamic parameters. For our analysis, we developed a set of user-friendly MatLab® routines, which are deposited in the public domain. We hope that the availability of these routines will encourage the computationally untrained microbiologist to make use of these mathematical...
Scalability of the muscular action in a parametric 3D model of the index finger.
Sancho-Bru, Joaquín L; Vergara, Margarita; Rodríguez-Cervantes, Pablo-Jesús; Giurintano, David J; Pérez-González, Antonio
2008-01-01
A method for scaling the muscle action is proposed and used to achieve a 3D inverse dynamic model of the human finger with all its components scalable. This method is based on scaling the physiological cross-sectional area (PCSA) in a Hill muscle model. Different anthropometric parameters and maximal grip force data have been measured and their correlations have been analyzed and used for scaling the PCSA of each muscle. A linear relationship between the normalized PCSA and the product of the length and breadth of the hand has been finally used for scaling, with a slope of 0.01315 cm(-2), with the length and breadth of the hand expressed in centimeters. The parametric muscle model has been included in a parametric finger model previously developed by the authors, and it has been validated reproducing the results of an experiment in which subjects from different population groups exerted maximal voluntary forces with their index finger in a controlled posture.
[A dynamic model of the extravehicular (correction of extravehicuar) activity space suit].
Yang, Feng; Yuan, Xiu-gan
2002-12-01
Objective. To establish a dynamic model of the space suit base on the particular configuration of the space suit. Method. The mass of the space suit components, moment of inertia, mobility of the joints of space suit, as well as the suit-generated torques, were considered in this model. The expressions to calculate the moment of inertia were developed by simplifying the geometry of the space suit. A modified Preisach model was used to mathematically describe the hysteretic torque characteristics of joints in a pressurized space suit, and it was implemented numerically basing on the observed suit parameters. Result. A dynamic model considering mass, moment of inertia and suit-generated torques was established. Conclusion. This dynamic model provides some elements for the dynamic simulation of the astronaut extravehicular activity.
Directory of Open Access Journals (Sweden)
Mohamad Tabatabaei Nasab
2014-03-01
Full Text Available With the emergence of high speed wireless network technologies and the increasing market penetration of cell phones the global advertising industry’s interest in using this medium as a means of marketing communication is rising. However, in spite of the increasing number of companies investing in mobile marketing campaigns, there is, as yet, little academic research on this topic and the nature and implications of this channel are not yet understood fully.Mobile advertising refers to advertisements delivered through a mobile device in form of text message. Current research is considered as applied objectively and its methodology is descriptive-analytical. Research data is gathered through distribution of questionnaire among a sample of 578 Yazd university students. To study users' attitude and intention, Technology Acceptance Model and theory of reasoned action are applied for accepting mobile advertising. Also SPSS16 and Lisrel 850 softwares are used for data analysis and research models are compared according to goodness of fit indices. On the basis of Lisrel structural equation results, both aforementioned models of mobile advertising acceptance were well-fitted and it is proved that the theory of reasoned action was fitted better than Technology Acceptance Model.
Correlation of ground tests and analyses of a dynamically scaled Space Station model configuration
Javeed, Mehzad; Edighoffer, Harold H.; Mcgowan, Paul E.
1993-01-01
Verification of analytical models through correlation with ground test results of a complex space truss structure is demonstrated. A multi-component, dynamically scaled space station model configuration is the focus structure for this work. Previously established test/analysis correlation procedures are used to develop improved component analytical models. Integrated system analytical models, consisting of updated component analytical models, are compared with modal test results to establish the accuracy of system-level dynamic predictions. Design sensitivity model updating methods are shown to be effective for providing improved component analytical models. Also, the effects of component model accuracy and interface modeling fidelity on the accuracy of integrated model predictions is examined.
Integrated Modeling, Analysis, and Verification for Space Missions Project
National Aeronautics and Space Administration — This project will further MBSE technology in fundamental ways by strengthening the link between SysML tools and framework engineering execution environments....
Exploring the Model Design Space for Battery Health Management
National Aeronautics and Space Administration — Battery Health Management (BHM) is a core enabling technology for the success and widespread adoption of the emerging electric vehicles of today. Although battery...
Directory of Open Access Journals (Sweden)
Mingbo eCai
2012-11-01
Full Text Available When observers experience a constant delay between their motor actions and sensory feedback, their perception of the temporal order between actions and sensations adapt (Stetson et al., 2006a. We present here a novel neural model that can explain temporal order judgments (TOJs and their recalibration. Our model employs three ubiquitous features of neural systems: 1 information pooling, 2 opponent processing, and 3 synaptic scaling. Specifically, the model proposes that different populations of neurons encode different delays between motor-sensory events, the outputs of these populations feed into rivaling neural populations (encoding before and after, and the activity difference between these populations determines the perceptual judgment. As a consequence of synaptic scaling of input weights, motor acts which are consistently followed by delayed sensory feedback will cause the network to recalibrate its point of subjective simultaneity. The structure of our model raises the possibility that recalibration of TOJs is a temporal analogue to the motion aftereffect. In other words, identical neural mechanisms may be used to make perceptual determinations about both space and time. Our model captures behavioral recalibration results for different numbers of adapting trials and different adapting delays. In line with predictions of the model, we additionally demonstrate that temporal recalibration can last through time, in analogy to storage of the motion aftereffect.
Simple Core-SOL-Divertor model and its application to operational space of HT-7U
International Nuclear Information System (INIS)
We develop a simple Core-SOL-Divertor (C-S-D) model to investigate qualitatively the overall features of the operational space for the integrated core and edge plasma. To construct the simple C-S-D model, a simple core plasma model of ITER physics guidelines and a two-point SOL-divertor model are used. The simple C-S-D model is applied to the study of the HT-7U operational space with lower hybrid current drive experiments under various kinds of trade-off for the basic plasma parameters. Effective methods for extending the operation space are also presented. From this study for the HT-7U operation space, it is shown that the C-S-D model is a useful tool to understand qualitatively the overall features of the plasma operation space
Overall feature of EAST operation space by using simple Core-SOL-Divertor model
International Nuclear Information System (INIS)
We have developed a simple Core-SOL-Divertor (C-S-D) model to investigate qualitatively the overall features of the operational space for the integrated core and edge plasma. To construct the simple C-S-D model, a simple core plasma model of ITER physics guidelines and a two-point SOL-divertor model are used. The simple C-S-D model is applied to the study of the EAST operational space with lower hybrid current drive experiments under various kinds of trade-off for the basic plasma parameters. Effective methods for extending the operation space are also presented. As shown by this study for the EAST operation space, it is evident that the C-S-D model is a useful tool to understand qualitatively the overall features of the plasma operation space. (author)
Mass action realizations of reaction kinetic system models on various time scales
Energy Technology Data Exchange (ETDEWEB)
Hangos, K M; Szederkenyi, G, E-mail: hangos@scl.sztaki.hu, E-mail: szeder@scl.sztaki.hu [Process Control Research Group, Computer and Automation Reseach Institute, Kende u. 13-17, H-1111 Budapest (Hungary)
2011-01-01
Complex chemical reaction networks often exhibit different dynamic behaviour on different time scales. A combined approach is proposed in this work for determining physically meaningful mass action realizations of complex chemical reaction networks that describe its dynamic behaviour on different time scales. This is achieved by appropriately reducing the detailed overall mass action kinetic scheme using quasi steady state assumptions fit to the particular time scale, and then searching for an optimal realization using mixed integer linear programing. Furthermore, the relationship between the properties (reversibility, deficiency, stability) of the obtained realizations of the same system on different time scales are also investigated and related to the same properties of the detailed overall model. It is shown that the reduced models obtained by quasi steady state assumptions may show exotic nonlinear behaviour, such as oscillations, when the original detailed is globally asymptotically stable. The proposed methods are illustrated by using a simple Michaelis-Menten type reaction kinetic example. The simplified versions of the well known Brusselator model have also been investigated and presented as a case study.
Affordance-based perception-action dynamics: A model of visually guided braking.
Harrison, Henry S; Turvey, Michael T; Frank, Till D
2016-04-01
Behavioral dynamics is a framework for understanding adaptive behavior as arising from the self-organizing interaction between animal and environment. The methods of nonlinear dynamics provide a language for describing behavior that is both stable and flexible. Behavioral dynamics has been criticized for ignoring the animal's sensitivity to its own capabilities, leading to the development of an alternative framework: affordance-based control. Although it is theoretically sound and empirically motivated, affordance-based control has resisted characterization in terms of nonlinear dynamics. Here, we provide a dynamical description of affordance-based control, extending behavioral dynamics to meet its criticisms. We propose a general modeling strategy consistent with both theories. We use visually guided braking as a representative behavior and construct a novel dynamical model. This model demonstrates the possibility of understanding visually guided action as respecting the limits of the actor's capabilities, while still being guided by informational variables associated with desired states of affairs. In addition to such "hard" constraints on behavior, our framework allows for the influence of "soft" constraints such as preference and comfort, opening a new area of inquiry in perception-action dynamics. PMID:26881694
Comparison of Space Debris Environment Models: ORDEM2000, MASTER-2001, MASTER-2005 and MASTER-2009
Kanemitsu, Yuki; 赤星, 保浩; Akahoshi, Yasuhiro; 鳴海, 智博; Narumi, Tomohiro; Faure, Pauline; 松本, 晴久; Matsumoto, Haruhisa; 北澤, 幸人; Kitazawa, Yukihito
2012-01-01
Hypervelocity impact by space debris on spacecraft is one of the most important issues for space development and operation, especially considering the growing amount of space debris in recent years. It is therefore important for spacecraft design to evaluate the impact risk by using environment models. In this paper, the authors compared the results of the debris impact flux in low Earth orbit, as calculated by four debris environment engineering models -NASA's ORDEM2000 and ESA's MASTER-2001...
Hall, Michael L.; Doster, Joseph M.
1986-01-01
Many proposed space reactor designs employ heat pipes as a means of conveying heat. Previous researchers have been concerned with steady state operation, but the transient operation is of interest in space reactor applications due to the necessity of remote startup and shutdown. A model is being developed to study the dynamic behavior of high temperature heat pipes during startup, shutdown and normal operation under space environments. Model development and preliminary results for a hypothetical design of the system are presented.
Institute of Scientific and Technical Information of China (English)
Nie Yong'an; Yao Lanyu
2010-01-01
The paper first studies the analytical expression of electrical potential by a point current source in a uniform half-space medium,and then focuses on the distribution of electrical potential in a horizontally layered half-space model by a point current source within the surface layer or the bottom layer.Finally,the electrical potential by a source electrode in any layer of a layered half-space model is presented.
Barnaud, Marie-Lou; Morgado, Nicolas; Palluel-Germain, Richard; Diard, Julien; Spalanzani, Anne
2014-01-01
International audience In order to navigate in a social environment, a robot must be aware of social spaces, which include proximity and interaction-based constraints. Previous models of interaction and personal spaces have been inspired by studies in social psychology but not systematically grounded and validated with respect to experimental data. We propose to implement personal and interaction space models in order to replicate a classical psychology experiment. Our robotic simulations ...
On Symmetries of Target Space for $\\sigma$-model of p-brane Origin
Ivashchuk, V D
1998-01-01
The target space M for the sigma-model appearing in theories with p-branes is considered. It is proved that M is a homogeneous space G/H. It is symmetric if and only if the U-vectors governing the sigma-model metric are either coinciding or mutually orthogonal. For nonzero noncoinciding U-vectors the Killing equations are solved. Using a block-orthogonal decomposition of the set of the U-vectors it is shown that under rather general assumptions the algebra of Killing vectors is a direct sum of several copies of sl(2,R) algebras (corresponding to 1-vector blocks), several solvable Lie algebras (corresponding to multivector blocks) and the Killing algebra of a flat space. The target space manifold is decomposed in a product of R^m, several 2-dimensional spaces of constant curvature (e.g. Lobachevsky space, part of de Sitter space) and several solvable Lie group manifolds.
Space Weather Forecasting and Research at the Community Coordinated Modeling Center
Aronne, M.
2015-12-01
The Space Weather Research Center (SWRC), within the Community Coordinated Modeling Center (CCMC), provides experimental research forecasts and analysis for NASA's robotic mission operators. Space weather conditions are monitored to provide advance warning and forecasts based on observations and modeling using the integrated Space Weather Analysis Network (iSWA). Space weather forecasters come from a variety of backgrounds, ranging from modelers to astrophysicists to undergraduate students. This presentation will discuss space weather operations and research from an undergraduate perspective. The Space Weather Research, Education, and Development Initiative (SW REDI) is the starting point for many undergraduate opportunities in space weather forecasting and research. Space weather analyst interns play an active role year-round as entry-level space weather analysts. Students develop the technical and professional skills to forecast space weather through a summer internship that includes a two week long space weather boot camp, mentorship, poster session, and research opportunities. My unique development of research projects includes studying high speed stream events as well as a study of 20 historic, high-impact solar energetic particle events. This unique opportunity to combine daily real-time analysis with related research prepares students for future careers in Heliophysics.
Modelling dendritic ecological networks in space: anintegrated network perspective
Peterson, Erin E.; Ver Hoef, Jay M.; Isaak, Dan J.; Falke, Jeffrey A.; Fortin, Marie-Josée; Jordon, Chris E.; McNyset, Kristina; Monestiez, Pascal; Ruesch, Aaron S.; Sengupta, Aritra; Som, Nicholas; Steel, E. Ashley; Theobald, David M.; Torgersen, Christian E.; Wenger, Seth J.
2013-01-01
Dendritic ecological networks (DENs) are a unique form of ecological networks that exhibit a dendritic network topology (e.g. stream and cave networks or plant architecture). DENs have a dual spatial representation; as points within the network and as points in geographical space. Consequently, some analytical methods used to quantify relationships in other types of ecological networks, or in 2-D space, may be inadequate for studying the influence of structure and connectivity on ecological processes within DENs. We propose a conceptual taxonomy of network analysis methods that account for DEN characteristics to varying degrees and provide a synthesis of the different approaches within
Improved Space Charge Modeling for Simulation and Design of Photoinjectors
Energy Technology Data Exchange (ETDEWEB)
Robert H. Jackson, Thuc Bui, John Verboncoeur
2010-04-19
Photoinjectors in advanced high-energy accelerators reduce beam energy spreads and enhance undulator photon fluxes. Photoinjector design is difficult because of the substantial differences in time and spatial scales. This Phase I program explored an innovative technique, the local Taylor polynomial (LTP) formulation, for improving finite difference analysis of photoinjectors. This included improved weighting techniques, systematic formula for high order interpolation and electric field computation, and improved handling of space charge. The Phase I program demonstrated that the approach was powerful, accurate, and efficient. It handles space charge gradients better than currently available technology.
Making Faces - State-Space Models Applied to Multi-Modal Signal Processing
DEFF Research Database (Denmark)
Lehn-Schiøler, Tue
2005-01-01
The two main focus areas of this thesis are State-Space Models and multi modal signal processing. The general State-Space Model is investigated and an addition to the class of sequential sampling methods is proposed. This new algorithm is denoted as the Parzen Particle Filter. Furthermore...... optimizer can be applied to speed up convergence. The linear version of the State-Space Model, the Kalman Filter, is applied to multi modal signal processing. It is demonstrated how a State-Space Model can be used to map from speech to lip movements. Besides the State-Space Model and the multi modal...... application an information theoretic vector quantizer is also proposed. Based on interactions between particles, it is shown how a quantizing scheme based on an analytic cost function can be derived....
Development of an Antimicrobial Stewardship Intervention Using a Model of Actionable Feedback
Directory of Open Access Journals (Sweden)
Sameer J. Patel
2012-01-01
Full Text Available We describe the development of an audit and feedback intervention to improve antibiotic prescribing in the neonatal intensive care unit (NICU using a theoretical framework. Participants included attending physicians, neonatal fellows, pediatric residents, and nurse practitioners. The intervention was based on the “model of actionable feedback” which emphasizes that feedback should be timely, individualized, nonpunitive, and customized to be effective. We found that real-time feedback could not be provided for the parameters established in this study, as we had to collect and analyze numerous data elements to assess appropriate initiation and continuation of antibiotics and required longer intervals to examine trends in antibiotic use. We learned during focus groups that NICU clinicians strongly resisted assigning individual responsibility for antibiotic prescribing as they viewed this as a shared responsibility informed by each patient's laboratory data and clinical course. We were able to create a non-punitive atmosphere thanks to written informed consent from NICU attendings and assurance from leadership that prescribing practices would not be used to assess job performance. We provided customized, meaningful feedback integrating input from the participants. Adapting the principles of the “model of actionable feedback” to provide feedback for antimicrobial prescribing practices proved challenging in the NICU setting.
International Nuclear Information System (INIS)
We generalize the worldline variational approach to field theory by introducing a trial action which allows for anisotropic terms to be induced by external 4-momenta of Green's functions. By solving the ensuing variational equations numerically we demonstrate that within the (quenched) scalar Wick-Cutkosky model considerable improvement can be achieved over results obtained previously with isotropic actions. In particular, the critical coupling associated with the instability of the model is lowered, in accordance with expectations from Baym's proof of the instability in the unquenched theory. The physical picture associated with a different quantum mechanical motion of the dressed particle along and perpendicular to its classical momentum is discussed. Indeed, we find that for large couplings the dressed particle is strongly distorted in the direction of its four-momentum. In addition, we obtain an exact relation between the renormalized coupling of the theory and the propagator. Along the way we introduce new and efficient methods to evaluate the averages needed in the variational approach and apply them to the calculation of the 2-point function. (orig.)
White, Martin; Reid, Beth; Chuang, Chia-Hsun; Tinker, Jeremy L.; McBride, Cameron K.; Prada, Francisco; Samushia, Lado
2015-02-01
Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. In preparation for analysis of redshift-space distortions from the Baryon Oscillation Spectroscopic Survey (BOSS) final data release, we compare a number of analytic and phenomenological models, specified in configuration space, to mock catalogues derived in different ways from several N-body simulations. The galaxies in each mock catalogue have properties similar to those of the higher redshift galaxies measured by BOSS but differ in the details of how small-scale velocities and halo occupancy are determined. We find that all of the analytic models fit the simulations over a limited range of scales while failing at small scales. We discuss which models are most robust and on which scales they return reliable estimates of the rate of growth of structure: we find that models based on some form of resummation can fit our N-body data for BOSS-like galaxies above 30 h-1 Mpc well enough to return unbiased parameter estimates.
Using Online Space Weather Modeling Resources in a Capstone Undergraduate Course
Liemohn, M.
2012-04-01
The University of Michigan offers a senior-undergraduate-level course entitled, "Space Weather Modeling," taken by all of the space weather concentration students in the Atmospheric, Oceanic, and Space Sciences department. This is the capstone course of our undergraduate series, using the foundational knowledge from the previous courses towards an integrative large-scale numerical modeling study. A fraction of the graduate students also take this course. Because the state-of-the-art modeling capabilities are well beyond what is possible in a single term of programming, this course uses available online model resources, in particular the Community Coordinated Modeling Center (CCMC), a multi-agency facility hosted by NASA's Goddard Space Flight Center. Students learn not only how to use the codes, but also the various options of what equations to solve to model a specific region of space and the various numerical approaches for implementing the equations within a code. The course is project-based, consisting of multiple written reports and oral presentations, and the technical communication skills are an important component of the grading rubric. Students learn how to conduct a numerical modeling study by critiquing several space weather modeling journal articles, and then carry out their our studies with several of the available codes. In the end, they are familiarized with the available models to know the ranges of validity and applicability for a wide array of space weather applications.
A Toy Model for Black Hole in Noncommutative Spaces
Demetrian, M.; Presnajder, P.
2006-01-01
We present a new point of view on the problem of the Schwarzschild black hole in the noncommutative spaces, proposed recently by F. Nasseri. We apply our treatment also to the case of the 2+1 dimensional Ba\\~ nados-Teitelboim-Zanelli black hole.
Structural simulation and modeling for assembly in real space
International Nuclear Information System (INIS)
FIESTA (Finite Element Structural analysis for Assembly) is a large scale simulation, which concerns a simulation space to bring real world in digital space, such as so named either virtual reality or virtual facility. In order to establish a huge and complex object like nuclear facilities of a real world, there are lack of methodology and technology for reproducing facilities in digital space. FIESTA attempts to realize an assembly structural analysis for supplying one of the methodologies to reproduce facilities in digital space. The first attempt of the structural analysis for assembly is accomplished by finite element analysis by integrating parts of facilities. Since the structural analysis for assembly requests massive calculation, parallel and distributed computing was applied for the computational environment. It has been practiced numerical experiments for a test reactor driven by JAEA. The structural analysis for assembly by finite element method is confirmed to be able to analyze a huge and complex facility and show results of numerical experiment by applying to a test reactor driven by JAEA. (author)
Petit, Alexis; Lemaitre, Anne
2016-06-01
New tools are necessary to deal with more than hundred thousands of space debris, thus our aim is to develop software able to propagate numerous trajectories and manage collisions or fragmentations. Specifically in low orbits Earth, gravity and atmospheric drag are the two main forces that affect the dynamics of the artificial satellites or space debris. NIMASTEP, the local orbit propagator, initially designed for high altitudes, has been adapted to low altitude orbits. To study the future debris environment, we propose a suitable model of space weather and we compare three different atmospheric density models (Jacchia-Bowman 2008, DTM-2013, and TD-88) able to propagate with accuracy and efficiency a large population of space debris on long time scales. We compare the results in different altitudes and during the reentry regime; we show, with a ballistic coefficient constant, a trend to underestimate or overestimate the decrease of the semi-major axis, specifically during the periods of high solar activity. We parallelize our software and use the calculation power of a computing cluster, we propagate a huge cloud of debris and we show that its global evolution is in agreement with the observations on several years.
Curvature and gravity actions for matrix models: II. The case of general Poisson structures
International Nuclear Information System (INIS)
We study the geometrical meaning of higher order terms in matrix models of Yang-Mills type in the semi-classical limit, generalizing recent results (Blaschke and Steinacker 2010 Class. Quantum Grav. 27 165010 (arXiv:1003.4132)) to the case of four-dimensional spacetime geometries with general Poisson structure. Such terms are expected to arise e.g. upon quantization of the IKKT-type models. We identify terms which depend only on the intrinsic geometry and curvature, including modified versions of the Einstein-Hilbert action as well as terms which depend on the extrinsic curvature. Furthermore, a mechanism is found which implies that the effective metric G on the spacetime brane M subset of RD 'almost' coincides with the induced metric g. Deviations from G = g are suppressed, and characterized by the would-be U(1) gauge field.
Walrus Bayesian State-space Model Output from the Bering Sea and Chukchi Sea, 2008-2012
U.S. Geological Survey, Department of the Interior — State-space models offer researchers an objective approach to modeling complex animal location datasets, and state-space model behavior classifications are often...