Action detection by double hierarchical multi-structure space-time statistical matching model
Han, Jing; Zhu, Junwei; Cui, Yiyin; Bai, Lianfa; Yue, Jiang
2018-03-01
Aimed at the complex information in videos and low detection efficiency, an actions detection model based on neighboring Gaussian structure and 3D LARK features is put forward. We exploit a double hierarchical multi-structure space-time statistical matching model (DMSM) in temporal action localization. First, a neighboring Gaussian structure is presented to describe the multi-scale structural relationship. Then, a space-time statistical matching method is proposed to achieve two similarity matrices on both large and small scales, which combines double hierarchical structural constraints in model by both the neighboring Gaussian structure and the 3D LARK local structure. Finally, the double hierarchical similarity is fused and analyzed to detect actions. Besides, the multi-scale composite template extends the model application into multi-view. Experimental results of DMSM on the complex visual tracker benchmark data sets and THUMOS 2014 data sets show the promising performance. Compared with other state-of-the-art algorithm, DMSM achieves superior performances.
Tracking in Object Action Space
DEFF Research Database (Denmark)
Krüger, Volker; Herzog, Dennis
2013-01-01
the 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...
Zolesi, B.; Cander, Lj. R.; Altadill, D.
The ionospheric community has long been aware that co-operative research on an international basis is essential to deal with temporal and spatial changes in the ionosphere that influence the performance of terrestrial and Earth-space radio systems. The EU COST (Co-operation in the field of Scientific and Technical Research) 271 Action on "Effects of the Upper Atmosphere on Terrestrial and Earth-space Communications" has had during the period of October 2000-August 2004 the following main objectives: (1) to evaluate the influence of upper atmospheric conditions on terrestrial and Earth-space communications, (2) to develop methods and techniques to improve ionospheric models over Europe for telecommunication and navigation applications and (3) 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. At the beginning of 2005 the new 296 Action in the COST Telecommunications, Information Science and Technology domain on "Mitigation of Ionospheric Effects on Radio Systems (MIERS)" was approved for the period 2005-2009. The main objectives of the MIERS are: (a) to support and enhanced the existing European facilities for historical and real-time digital ionospheric data collection and exchange; (b) to develop an integrated approach to ionospheric modelling, create the mechanism needed to ingest processed data into models, extend and develop suitable mitigation models and define the protocols needed to link models together; and (c) to strengthen the areas of expertise that already exist by stimulating closer cooperation between scientists and users, focusing the scope of all the previous COST ionospheric related studies to the mitigation of ionospheric effects on radio systems. This paper summarises briefly how the major objectives of the COST271 Action have been achieved and what are the most important
Bernal-Gamboa, Rodolfo; Gámez, A Matías; Nieto, Javier
2018-06-01
Instrumental extinction has been proposed as a model for understanding the suppression of problematic voluntary actions. Consequently, it has been suggested that response recovery after extinction could model relapse. Four experiments with rats used a free operant procedure to explore the impact of spacing extinction sessions on spontaneous recovery, renewal, reinstatement, and rapid reacquisition of extinguished lever-pressing. Initially, in all experiments, hungry rats were trained to perform two responses (R1 and R2) for food. Then, all responses underwent extinction. For R1, rats experienced a longer intersession interval (72 h) than for R2 (24 h). During the final restoration test, it was observed that using spaced extinction sessions reduced spontaneous recovery, renewal, and reinstatement. However, implementing a longer intersession interval throughout extinction exposure did not slow the rate of reacquisition of operant responses. The present findings suggest that in most cases extinction is more enduring when the extinction sessions are spaced. Since expanding the intersession interval during extinction might be interpreted as conducting extinction in multiple temporal contexts, the overall pattern of results was explained based on contextual modulation. Copyright © 2018 Elsevier B.V. All rights reserved.
Maximum entropy perception-action space: a Bayesian model of eye movement selection
Colas , Francis; Bessière , Pierre; Girard , Benoît
2010-01-01
International audience; In this article, we investigate the issue of the selection of eye movements in a free-eye Multiple Object Tracking task. We propose a Bayesian model of retinotopic maps with a complex logarithmic mapping. This model is structured in two parts: a representation of the visual scene, and a decision model based on the representation. We compare different decision models based on different features of the representation and we show that taking into account uncertainty helps...
Switching Reinforcement Learning for Continuous Action Space
Nagayoshi, Masato; Murao, Hajime; Tamaki, Hisashi
Reinforcement Learning (RL) attracts much attention as a technique of realizing computational intelligence such as adaptive and autonomous decentralized systems. In general, however, it is not easy to put RL into practical use. This difficulty includes a problem of designing a suitable action space of an agent, i.e., satisfying two requirements in trade-off: (i) to keep the characteristics (or structure) of an original search space as much as possible in order to seek strategies that lie close to the optimal, and (ii) to reduce the search space as much as possible in order to expedite the learning process. In order to design a suitable action space adaptively, we propose switching RL model to mimic a process of an infant's motor development in which gross motor skills develop before fine motor skills. Then, a method for switching controllers is constructed by introducing and referring to the “entropy”. Further, through computational experiments by using robot navigation problems with one and two-dimensional continuous action space, the validity of the proposed method has been confirmed.
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
Topology of actions and homogeneous spaces
International Nuclear Information System (INIS)
Kozlov, Konstantin L
2013-01-01
Topologization of a group of homeomorphisms and its action provide additional possibilities for studying the topological space, the group of homeomorphisms, and their interconnections. The subject of the paper is the use of the property of d-openness of an action (introduced by Ancel under the name of weak micro-transitivity) in the study of spaces with various forms of homogeneity. It is proved that a d-open action of a Čech-complete group is open. A characterization of Polish SLH spaces using d-openness is given, and it is established that any separable metrizable SLH space has an SLH completion that is a Polish space. Furthermore, the completion is realized in coordination with the completion of the acting group with respect to the two-sided uniformity. A sufficient condition is given for extension of a d-open action to the completion of the space with respect to the maximal equiuniformity with preservation of d-openness. A result of van Mill is generalized, namely, it is proved that any homogeneous CDH metrizable compactum is the only G-compactification of the space of rational numbers for the action of some Polish group. Bibliography: 39 titles.
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)
Learning Actions Models: Qualitative Approach
DEFF Research Database (Denmark)
Bolander, Thomas; Gierasimczuk, Nina
2015-01-01
In dynamic epistemic logic, actions are described using action models. In this paper we introduce a framework for studying learnability of action models from observations. We present first results concerning propositional action models. First we check two basic learnability criteria: finite ident...
Modeling intentional inhibition of actions
Thilakarathne, D.J.; Treur, J.
2015-01-01
Inspired by cognitive and neurological literature on action ownership and action awareness, in this paper a computational cognitive model for intentional inhibition (i.e.; the capacity to voluntarily suspend or inhibit an action) is introduced. The interplay between (positive) potential selection of
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...
DEFF Research Database (Denmark)
Juhl, Joakim
This thesis is about mathematical modelling and technology development. While mathematical modelling has become widely deployed within a broad range of scientific practices, it has also gained a central position within technology development. The intersection of mathematical modelling and technol...
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
Казыдуб, Надежда
2013-01-01
Discourse space is a complex structure that incorporates different levels and dimensions. The paper focuses on developing a multidisciplinary approach that is congruent to the complex character of the modern discourse. Two models of discourse space are proposed here. The Integrated Model reveals the interaction of different categorical mechanisms in the construction of the discourse space. The Evolutionary Model describes the historical roots of the modern discourse. It also reveals historica...
Production and action of cytokines in space
Chapes, Stephen K.; Morrison, Dennis R.; Guikema, James A.; Lewis, Marian L.; Spooner, Brian S.
1994-01-01
B6MP102 cells, a continuously cultured murine bone marrow macrophage cell line, were tested for secretion of tumor necrosis factor-alpha and Interleukin-1 during space flight. We found that B6MP102 cells secreted more tumor necrosis factor-alpha and interleukin-1 when stimulated in space with lipopolysaccharide than controls similarly stimulated on earth. This compared to increased secretion of interferon-beta and -gamma by lymphocytes that was measured on the same shuttle flights. Although space flight enhanced B6MP102 secretion of tumor necrosis factor-alpha, an experiment on a subsequent space flight (STS-50) found that cellular cytotoxicity, mediated by tumor necrosis factor-alpha, was inhibited.
DEFF Research Database (Denmark)
Grünbaum, Thor
2017-01-01
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...
Learning to Act: Qualitative Learning of Deterministic Action Models
DEFF Research Database (Denmark)
Bolander, Thomas; Gierasimczuk, Nina
2017-01-01
In this article we study learnability of fully observable, universally applicable action models of dynamic epistemic logic. We introduce a framework for actions seen as sets of transitions between propositional states and we relate them to their dynamic epistemic logic representations as action...... in the limit (inconclusive convergence to the right action model). We show that deterministic actions are finitely identifiable, while arbitrary (non-deterministic) actions require more learning power—they are identifiable in the limit. We then move on to a particular learning method, i.e. learning via update......, which proceeds via restriction of a space of events within a learning-specific action model. We show how this method can be adapted to learn conditional and unconditional deterministic action models. We propose update learning mechanisms for the afore mentioned classes of actions and analyse...
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.
Space for action: How practitioners influence environmental assessment
International Nuclear Information System (INIS)
Kågström, Mari; Richardson, Tim
2015-01-01
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
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 metho...
Reinforcement learning in continuous state and action spaces
H. P. van Hasselt (Hado); M.A. Wiering; M. van Otterlo
2012-01-01
textabstractMany 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
MHD dynamo action in space plasmas
International Nuclear Information System (INIS)
Faelthammar, C.G.
1984-05-01
Electric currents are now recognized to play a major role in the physical process of the Earths magnetosphere as well as in distant astrophysical plasmas. In driving these currents MHD dynamos as well as generators of a thermoelectric nature are important. The primary source of power for the Earths magnetospheric process is the solar wind, which supplies a voltage of the order of 200 kV across the magnetosphere. The direction of the large-scale solar wind electric field varies of many different time scales. The power input to the magnetosphere is closely correlated with the direction of the large-scale solar wind electric field in such a fashion as to mimick the response of a half-wave rectifier with a down-to-dusk conduction direction. Behind this apparently simple response there are complex plasma physical processes that are still very incompletely understood. They are intimately related to auroras, magnetic storms, radiation belts and changes in magnetospheric plasma populations. Similar dynamo actions should occur at other planets having magnetospheres. Recent observations seem to indicate that part of the power input to the Earths magnetosphere comes through MHD dynamo action of a forced plasma flow inside the flanks of the magnetopause and may play a role in other parts of the magnetosphere, too. An example of a cosmical MHD connected to a solid load is the corotating plasma of Jupiters inner magnetosphere, sweeping past the plants inner satelites. In particular the electric currents thereby driven to and from the satellite Io have attracted considerable interest.(author)
Application of Conformational Space Search in Drug Action | Adikwu ...
African Journals Online (AJOL)
The role of conformational space in drug action is presented. Two examples of molecules in different therapeutic groups are presented. Conformational space search will lead to isolating the exact conformation with the desired medicinal properties. Many conformations of a plant isolate may exist which are active, weakly ...
Quantum gravity boundary terms from the spectral action of noncommutative space.
Chamseddine, Ali H; Connes, Alain
2007-08-17
We study the boundary terms of the spectral action of the noncommutative space, defined by the spectral triple dictated by the physical spectrum of the standard model, unifying gravity with all other fundamental interactions. We prove that the spectral action predicts uniquely the gravitational boundary term required for consistency of quantum gravity with the correct sign and coefficient. This is a remarkable result given the lack of freedom in the spectral action to tune this term.
Safe Exploration of State and Action Spaces in Reinforcement Learning
Garcia, Javier; Fernandez, Fernando
2014-01-01
In this paper, we consider the important problem of safe exploration in reinforcement learning. While reinforcement learning is well-suited to domains with complex transition dynamics and high-dimensional state-action spaces, an additional challenge is posed by the need for safe and efficient exploration. Traditional exploration techniques are not particularly useful for solving dangerous tasks, where the trial and error process may lead to the selection of actions whose execution in some sta...
Response actions influence the categorization of directions in auditory space
Directory of Open Access Journals (Sweden)
Marcella de Castro Campos Velten
2015-08-01
Full Text Available Spatial region concepts such as front, back, left and right reflect our typical interaction with space, and the corresponding surrounding regions have different statuses in memory. We examined the representation of spatial directions in the auditory space, specifically in how far natural response actions, such as orientation movements towards a sound source, would affect the categorization of egocentric auditory space. While standing in the middle of a circle with 16 loudspeakers, participants were presented acoustic stimuli coming from the loudspeakers in randomized order, and verbally described their directions by using the concept labels front, back, left, right, front-right, front-left, back-right and back-left. Response actions varied in three blocked conditions: 1 facing front, 2 turning the head and upper body to face the stimulus, and 3 turning the head and upper body plus pointing with the hand and outstretched arm towards the stimulus. In addition to a protocol of the verbal utterances, motion capture and video recording generated a detailed corpus for subsequent analysis of the participants’ behavior. Chi-square tests revealed an effect of response condition for directions within the left and right sides. We conclude that movement-based response actions influence the representation of auditory space, especially within the sides’ regions.
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
Hähnel, Philipp; McLoughlin, Tristan
2017-12-01
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 Poincaré 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 conjecture anti-self-dual interaction terms which give an implicit definition of a twistor action for the full conformal higher spin theory.
Sigma models with purely Wess-Zumino-Witten actions
International Nuclear Information System (INIS)
Floreanini, R.; Percacci, R.; Sezgin, E.
1988-11-01
We study the dynamics of sigma models in arbitrary dimensions with purely Wess-Zumino-Witten actions (i.e. without kinetic terms), both from the Lagrangian and Hamiltonian point of view. These models have nontrivial gauge groups which contain the diffeomorphisms of space-time, as well as symmetry groups which in many cases turn out to be infinite dimensional. We give examples in 1,2,3 and 4 space-time dimensions.(author). 9 refs
Classical field theory in the space of reference frames. [Space-time manifold, action principle
Energy Technology Data Exchange (ETDEWEB)
Toller, M [Dipartimento di Matematica e Fisica, Libera Universita, Trento (Italy)
1978-03-11
The formalism of classical field theory is generalized by replacing the space-time manifold M by the ten-dimensional manifold S of all the local reference frames. The geometry of the manifold S is determined by ten vector fields corresponding to ten operationally defined infinitesimal transformations of the reference frames. The action principle is written in terms of a differential 4-form in the space S (the Lagrangian form). Densities and currents are represented by differential 3-forms in S. The field equations and the connection between symmetries and conservation laws (Noether's theorem) are derived from the action principle. Einstein's theory of gravitation and Maxwell's theory of electromagnetism are reformulated in this language. The general formalism can also be used to formulate theories in which charge, energy and momentum cannot be localized in space-time and even theories in which a space-time manifold cannot be defined exactly in any useful way.
Action Research as a Space for Transforming Learning Cultures
Directory of Open Access Journals (Sweden)
Elżbieta Wołodźko
2015-12-01
Full Text Available The article presents a three-year educational action research project on autonomous and reflective learning. Students and teachers, being actively engaged in many learning practices, were both participating in process(es of developing educational and research community. These interrelated processes framed a dynamic space for constructing and reconstructing the participants’ learning cultures. Thanks to linking educational and research aspects of students’ activity and to interpenetration of practice and reflection, action research generates particular conditions for learning cultures’ transformation, from “traditional” toward “new” ones, based on reflectivity, authenticity and empowerment. The dynamism of learning cultures was connected to various and conscious and reflective types of educational participation, which affected autonomy of studying (in its numerous dimensions and types, being in turn a constitutive element of participants’ learning cultures.
Cost Modeling for Space Telescope
Stahl, H. Philip
2011-01-01
Parametric cost models are an important tool for planning missions, compare concepts and justify technology investments. This paper presents on-going efforts to develop single variable and multi-variable cost models for space telescope optical telescope assembly (OTA). These models are based on data collected from historical space telescope missions. Standard statistical methods are used to derive CERs for OTA cost versus aperture diameter and mass. The results are compared with previously published models.
State Space Modeling Using SAS
Directory of Open Access Journals (Sweden)
Rajesh Selukar
2011-05-01
Full Text Available This article provides a brief introduction to the state space modeling capabilities in SAS, a well-known statistical software system. SAS provides state space modeling in a few different settings. SAS/ETS, the econometric and time series analysis module of the SAS system, contains many procedures that use state space models to analyze univariate and multivariate time series data. In addition, SAS/IML, an interactive matrix language in the SAS system, provides Kalman filtering and smoothing routines for stationary and nonstationary state space models. SAS/IML also provides support for linear algebra and nonlinear function optimization, which makes it a convenient environment for general-purpose state space modeling.
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
Nambu sigma model and effective membrane actions
Energy Technology Data Exchange (ETDEWEB)
Jurco, Branislav, E-mail: jurco@karlin.mff.cuni.cz [Mathematical Institute, Charles University, Prague 186 75 (Czech Republic); Schupp, Peter, E-mail: p.schupp@jacobs-university.de [Jacobs University Bremen, 28759 Bremen (Germany); Maxwell Institute for Mathematical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, Scotland (United Kingdom)
2012-07-09
We propose an effective action for a p{sup Prime }-brane with open p-branes ending on it. The action has dual descriptions similar to the commutative and non-commutative ones of the DBI action for D-branes and open strings. The Poisson structure governing the non-commutativity of the D-brane is replaced by a Nambu structure and the open-closed string relations are generalized to the case of p-branes utilizing a novel Nambu sigma model description of p-branes. In the case of an M5-brane our action interpolates between M5-actions already proposed in the literature and matrix-model like actions involving Nambu structures.
Nambu sigma model and effective membrane actions
International Nuclear Information System (INIS)
Jurčo, Branislav; Schupp, Peter
2012-01-01
We propose an effective action for a p ′ -brane with open p-branes ending on it. The action has dual descriptions similar to the commutative and non-commutative ones of the DBI action for D-branes and open strings. The Poisson structure governing the non-commutativity of the D-brane is replaced by a Nambu structure and the open-closed string relations are generalized to the case of p-branes utilizing a novel Nambu sigma model description of p-branes. In the case of an M5-brane our action interpolates between M5-actions already proposed in the literature and matrix-model like actions involving Nambu structures.
A neural network model of causative actions
Directory of Open Access Journals (Sweden)
Jeremy eLee-Hand
2015-06-01
Full Text Available A common idea in models of action representation is that actions are represented in terms of their perceptual effects (see e.g. Prinz, 1997; Hommel et al., 2001; Sahin et al., 2007; Umilta et al., 2008; Hommel et al., 2013. In this paper we extend existing models of effect-based action representations to account for a novel distinction. Some actions bring about effects that are independent events in their own right: for instance, if John 'smashes' a cup, he brings about the event of 'the cup smashing'. Other actions do not bring about such effects. For instance, if John 'grabs' a cup, this action does not cause the cup to 'do' anything: a grab action has well-defined perceptual effects, but these are not registered by the perceptual system that detects independent events involving external objects in the world. In our model, effect-based actions are implemented in several distinct neural circuits, which are organised into a hierarchy based on the complexity of their associated perceptual effects. The circuit at the top of this hierarchy is responsible for actions that bring about independently perceivable events. This circuit receives input from the perceptual module that recognises arbitrary events taking place in the world, and learns movements that reliably cause such events. We assess our model against existing experimental observations about effect-based motor representations, and make some novel experimental predictions. We also consider the possibility that the 'causative actions' circuit in our model can be identified with a motor pathway reported in other work, specialising in 'functional' actions on manipulable tools (Bub et al., 2008; Binkofski and Buxbaum, 2013.
A neural network model of causative actions.
Lee-Hand, Jeremy; Knott, Alistair
2015-01-01
A common idea in models of action representation is that actions are represented in terms of their perceptual effects (see e.g., Prinz, 1997; Hommel et al., 2001; Sahin et al., 2007; Umiltà et al., 2008; Hommel, 2013). In this paper we extend existing models of effect-based action representations to account for a novel distinction. Some actions bring about effects that are independent events in their own right: for instance, if John smashes a cup, he brings about the event of the cup smashing. Other actions do not bring about such effects. For instance, if John grabs a cup, this action does not cause the cup to "do" anything: a grab action has well-defined perceptual effects, but these are not registered by the perceptual system that detects independent events involving external objects in the world. In our model, effect-based actions are implemented in several distinct neural circuits, which are organized into a hierarchy based on the complexity of their associated perceptual effects. The circuit at the top of this hierarchy is responsible for actions that bring about independently perceivable events. This circuit receives input from the perceptual module that recognizes arbitrary events taking place in the world, and learns movements that reliably cause such events. We assess our model against existing experimental observations about effect-based motor representations, and make some novel experimental predictions. We also consider the possibility that the "causative actions" circuit in our model can be identified with a motor pathway reported in other work, specializing in "functional" actions on manipulable tools (Bub et al., 2008; Binkofski and Buxbaum, 2013).
Gershman, Samuel J; Pesaran, Bijan; Daw, Nathaniel D
2009-10-28
Humans and animals are endowed with a large number of effectors. Although this enables great behavioral flexibility, it presents an equally formidable reinforcement learning problem of discovering which actions are most valuable because of the high dimensionality of the action space. An unresolved question is how neural systems for reinforcement learning-such as prediction error signals for action valuation associated with dopamine and the striatum-can cope with this "curse of dimensionality." We propose a reinforcement learning framework that allows for learned action valuations to be decomposed into effector-specific components when appropriate to a task, and test it by studying to what extent human behavior and blood oxygen level-dependent (BOLD) activity can exploit such a decomposition in a multieffector choice task. Subjects made simultaneous decisions with their left and right hands and received separate reward feedback for each hand movement. We found that choice behavior was better described by a learning model that decomposed the values of bimanual movements into separate values for each effector, rather than a traditional model that treated the bimanual actions as unitary with a single value. A decomposition of value into effector-specific components was also observed in value-related BOLD signaling, in the form of lateralized biases in striatal correlates of prediction error and anticipatory value correlates in the intraparietal sulcus. These results suggest that the human brain can use decomposed value representations to "divide and conquer" reinforcement learning over high-dimensional action spaces.
IASM: Individualized activity space modeler
Hasanzadeh, Kamyar
2018-01-01
Researchers from various disciplines have long been interested in analyzing and describing human mobility patterns. Activity space (AS), defined as an area encapsulating daily human mobility and activities, has been at the center of this interest. However, given the applied nature of research in this field and the complexity that advanced geographical modeling can pose to its users, the proposed models remain simplistic and inaccurate in many cases. Individualized Activity Space Modeler (IASM) is a geographic information system (GIS) toolbox, written in Python programming language using ESRI's Arcpy module, comprising four tools aiming to facilitate the use of advanced activity space models in empirical research. IASM provides individual-based and context-sensitive tools to estimate home range distances, delineate activity spaces, and model place exposures using individualized geographical data. In this paper, we describe the design and functionality of IASM, and provide an example of how it performs on a spatial dataset collected through an online map-based survey.
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…
Space debris: modeling and detectability
Wiedemann, C.; Lorenz, J.; Radtke, J.; Kebschull, C.; Horstmann, A.; Stoll, E.
2017-01-01
High precision orbit determination is required for the detection and removal of space debris. Knowledge of the distribution of debris objects in orbit is necessary for orbit determination by active or passive sensors. The results can be used to investigate the orbits on which objects of a certain size at a certain frequency can be found. The knowledge of the orbital distribution of the objects as well as their properties in accordance with sensor performance models provide the basis for estimating the expected detection rates. Comprehensive modeling of the space debris environment is required for this. This paper provides an overview of the current state of knowledge about the space debris environment. In particular non-cataloged small objects are evaluated. Furthermore, improvements concerning the update of the current space debris model are addressed. The model of the space debris environment is based on the simulation of historical events, such as fragmentations due to explosions and collisions that actually occurred in Earth orbits. The orbital distribution of debris is simulated by propagating the orbits considering all perturbing forces up to a reference epoch. The modeled object population is compared with measured data and validated. The model provides a statistical distribution of space objects, according to their size and number. This distribution is based on the correct consideration of orbital mechanics. This allows for a realistic description of the space debris environment. Subsequently, a realistic prediction can be provided concerning the question, how many pieces of debris can be expected on certain orbits. To validate the model, a software tool has been developed which allows the simulation of the observation behavior of ground-based or space-based sensors. Thus, it is possible to compare the results of published measurement data with simulated detections. This tool can also be used for the simulation of sensor measurement campaigns. It is
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...... motivation stems from certain models for concurrent computation. So far, spaces of d-paths and their topological invariants have only been determined in cases that were elementary to overlook. In this paper, we develop a systematic approach describing spaces of directed paths - up to homotopy equivalence...
Viereck, R. A.; Azeem, S. I.
2017-12-01
One of the goals of the National Space Weather Action Plan is to establish extreme event benchmarks. These benchmarks are estimates of environmental parameters that impact technologies and systems during extreme space weather events. Quantitative assessment of anticipated conditions during these extreme space weather event will enable operators and users of affected technologies to develop plans for mitigating space weather risks and improve preparedness. The ionosphere is one of the most important regions of space because so many applications either depend on ionospheric space weather for their operation (HF communication, over-the-horizon radars), or can be deleteriously affected by ionospheric conditions (e.g. GNSS navigation and timing, UHF satellite communications, synthetic aperture radar, HF communications). Since the processes that influence the ionosphere vary over time scales from seconds to years, it continues to be a challenge to adequately predict its behavior in many circumstances. Estimates with large uncertainties, in excess of 100%, may result in operators of impacted technologies over or under preparing for such events. The goal of the next phase of the benchmarking activity is to reduce these uncertainties. In this presentation, we will focus on the sources of uncertainty in the ionospheric response to extreme geomagnetic storms. We will then discuss various research efforts required to better understand the underlying processes of ionospheric variability and how the uncertainties in ionospheric response to extreme space weather could be reduced and the estimates improved.
Diffeomorphisms as symplectomorphisms in history phase space: Bosonic string model
International Nuclear Information System (INIS)
Kouletsis, I.; Kuchar, K.V.
2002-01-01
The structure of the history phase space G of a covariant field system and its history group (in the sense of Isham and Linden) is analyzed on an example of a bosonic string. The history space G includes the time map T from the spacetime manifold (the two-sheet) Y to a one-dimensional time manifold T as one of its configuration variables. A canonical history action is posited on G such that its restriction to the configuration history space yields the familiar Polyakov action. The standard Dirac-ADM action is shown to be identical with the canonical history action, the only difference being that the underlying action is expressed in two different coordinate charts on G. The canonical history action encompasses all individual Dirac-ADM actions corresponding to different choices T of foliating Y. The history Poisson brackets of spacetime fields on G induce the ordinary Poisson brackets of spatial fields in the instantaneous phase space G 0 of the Dirac-ADM formalism. The canonical history action is manifestly invariant both under spacetime diffeomorphisms Diff Y and temporal diffeomorphisms Diff T. Both of these diffeomorphisms are explicitly represented by symplectomorphisms on the history phase space G. The resulting classical history phase space formalism is offered as a starting point for projection operator quantization and consistent histories interpretation of the bosonic string model
Computational Modeling of Space Physiology
Lewandowski, Beth E.; Griffin, Devon W.
2016-01-01
The Digital Astronaut Project (DAP), within NASAs Human Research Program, develops and implements computational modeling for use in the mitigation of human health and performance risks associated with long duration spaceflight. Over the past decade, DAP developed models to provide insights into space flight related changes to the central nervous system, cardiovascular system and the musculoskeletal system. Examples of the models and their applications include biomechanical models applied to advanced exercise device development, bone fracture risk quantification for mission planning, accident investigation, bone health standards development, and occupant protection. The International Space Station (ISS), in its role as a testing ground for long duration spaceflight, has been an important platform for obtaining human spaceflight data. DAP has used preflight, in-flight and post-flight data from short and long duration astronauts for computational model development and validation. Examples include preflight and post-flight bone mineral density data, muscle cross-sectional area, and muscle strength measurements. Results from computational modeling supplement space physiology research by informing experimental design. Using these computational models, DAP personnel can easily identify both important factors associated with a phenomenon and areas where data are lacking. This presentation will provide examples of DAP computational models, the data used in model development and validation, and applications of the model.
International Nuclear Information System (INIS)
Wald, H.B.
1990-01-01
The 'PATH' codes are used to design magnetic optics subsystems for neutral particle beam systems. They include a 2-1/2D and three 3-D space charge models, two of which have recently been added. This paper describes the 3-D models and reports on preliminary benchmark studies in which these models are checked for stability as the cloud size is varied and for consistency with each other. Differences between the models are investigated and the computer time requirements for running these models are established
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.
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 < 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. Journal of Microbiology & Biology Education.
A statistical model of future human actions
International Nuclear Information System (INIS)
Woo, G.
1992-02-01
A critical review has been carried out of models of future human actions during the long term post-closure period of a radioactive waste repository. Various Markov models have been considered as alternatives to the standard Poisson model, and the problems of parameterisation have been addressed. Where the simplistic Poisson model unduly exaggerates the intrusion risk, some form of Markov model may have to be introduced. This situation may well arise for shallow repositories, but it is less likely for deep repositories. Recommendations are made for a practical implementation of a computer based model and its associated database. (Author)
Simplicial models of trace spaces
DEFF Research Database (Denmark)
Raussen, Martin
2010-01-01
variation of the end points. The original motivation stems from certain models for concurrent computation. So far, homotopy types of spaces of d-paths and their topological invariants have only been determined in cases that were elementary to overlook. In this paper, we develop a systematic approach...
A composite model of the space-time and 'colors'
International Nuclear Information System (INIS)
Terazawa, Hidezumi.
1987-03-01
A pregeometric and pregauge model of the space-time and ''colors'' in which the space-time metric and ''color'' gauge fields are both composite is presented. By the non-triviality of the model, the number of space-time dimensions is restricted to be not larger than the number of ''colors''. The long conjectured space-color correspondence is realized in the model action of the Nambu-Goto type which is invariant under both general-coordinate and local-gauge transformations. (author)
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.
The effects of optical illusions in perception and action in peripersonal and extrapersonal space
Shim, J.; van der Kamp, J
While the two visual system hypothesis tells a fairly compelling story about perception and action in peripersonal space (i.e., within arm's reach), its validity for extrapersonal space is very limited and highly controversial. Hence, the present purpose was to assess whether perception and action
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...
AGAMA: Action-based galaxy modeling framework
Vasiliev, Eugene
2018-05-01
The AGAMA library models galaxies. It computes gravitational potential and forces, performs orbit integration and analysis, and can convert between position/velocity and action/angle coordinates. It offers a framework for finding best-fit parameters of a model from data and self-consistent multi-component galaxy models, and contains useful auxiliary utilities such as various mathematical routines. The core of the library is written in C++, and there are Python and Fortran interfaces. AGAMA may be used as a plugin for the stellar-dynamical software packages galpy (ascl:1411.008), AMUSE (ascl:1107.007), and NEMO (ascl:1010.051).
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
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....
Map-based model of the cardiac action potential
International Nuclear Information System (INIS)
Pavlov, Evgeny A.; Osipov, Grigory V.; Chan, C.K.; Suykens, Johan A.K.
2011-01-01
A simple computationally efficient model which is capable of replicating the basic features of cardiac cell action potential is proposed. The model is a four-dimensional map and demonstrates good correspondence with real cardiac cells. Various regimes of cardiac activity, which can be reproduced by the proposed model, are shown. Bifurcation mechanisms of these regimes transitions are explained using phase space analysis. The dynamics of 1D and 2D lattices of coupled maps which model the behavior of electrically connected cells is discussed in the context of synchronization theory. -- Highlights: → Recent experimental-data based models are complicated for analysis and simulation. → The simplified map-based model of the cardiac cell is constructed. → The model is capable for replication of different types of cardiac activity. → The spatio-temporal dynamics of ensembles of coupled maps are investigated. → Received data are analyzed in context of biophysical processes in the myocardium.
Map-based model of the cardiac action potential
Energy Technology Data Exchange (ETDEWEB)
Pavlov, Evgeny A., E-mail: genie.pavlov@gmail.com [Department of Computational Mathematics and Cybernetics, Nizhny Novgorod State University, 23, Gagarin Avenue, 603950 Nizhny Novgorod (Russian Federation); Osipov, Grigory V. [Department of Computational Mathematics and Cybernetics, Nizhny Novgorod State University, 23, Gagarin Avenue, 603950 Nizhny Novgorod (Russian Federation); Chan, C.K. [Institute of Physics, Academia Sinica, 128 Sec. 2, Academia Road, Nankang, Taipei 115, Taiwan (China); Suykens, Johan A.K. [K.U. Leuven, ESAT-SCD/SISTA, Kasteelpark Arenberg 10, B-3001 Leuven (Heverlee) (Belgium)
2011-07-25
A simple computationally efficient model which is capable of replicating the basic features of cardiac cell action potential is proposed. The model is a four-dimensional map and demonstrates good correspondence with real cardiac cells. Various regimes of cardiac activity, which can be reproduced by the proposed model, are shown. Bifurcation mechanisms of these regimes transitions are explained using phase space analysis. The dynamics of 1D and 2D lattices of coupled maps which model the behavior of electrically connected cells is discussed in the context of synchronization theory. -- Highlights: → Recent experimental-data based models are complicated for analysis and simulation. → The simplified map-based model of the cardiac cell is constructed. → The model is capable for replication of different types of cardiac activity. → The spatio-temporal dynamics of ensembles of coupled maps are investigated. → Received data are analyzed in context of biophysical processes in the myocardium.
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...
Directory of Open Access Journals (Sweden)
Narottam Maity
2016-01-01
Full Text Available Reflection of longitudinal displacement waves in a generalized thermoelastic half space under the action of uniform magnetic field has been investigated. The magnetic field is applied in such a direction that the problem can be considered as a two-dimensional one. The discussion is based on the three theories of generalized thermoelasticity: Lord-Shulman (L-S, Green-Lindsay (G-L, and Green-Naghdi (G-N with energy dissipation. We compute the possible wave velocities for different models. Amplitude ratios have been presented. The effects of magnetic field on various subjects of interest are discussed and shown graphically.
Pro-torus actions on Poincaré duality spaces
Indian Academy of Sciences (India)
duality spaces, Borel's dimension formula and topological splitting principle to local weights, hold if 'torus' is replaced by 'pro-torus'. Keywords. Pro-torus; Poincaré duality space; local weight. 1. Introduction. In the theory of linear representations of compact connected Lie groups, the crucial first step is restriction to the ...
Modeling volatility using state space models.
Timmer, J; Weigend, A S
1997-08-01
In time series problems, noise can be divided into two categories: dynamic noise which drives the process, and observational noise which is added in the measurement process, but does not influence future values of the system. In this framework, we show that empirical volatilities (the squared relative returns of prices) exhibit a significant amount of observational noise. To model and predict their time evolution adequately, we estimate state space models that explicitly include observational noise. We obtain relaxation times for shocks in the logarithm of volatility ranging from three weeks (for foreign exchange) to three to five months (for stock indices). In most cases, a two-dimensional hidden state is required to yield residuals that are consistent with white noise. We compare these results with ordinary autoregressive models (without a hidden state) and find that autoregressive models underestimate the relaxation times by about two orders of magnitude since they do not distinguish between observational and dynamic noise. This new interpretation of the dynamics of volatility in terms of relaxators in a state space model carries over to stochastic volatility models and to GARCH models, and is useful for several problems in finance, including risk management and the pricing of derivative securities. Data sets used: Olsen & Associates high frequency DEM/USD foreign exchange rates (8 years). Nikkei 225 index (40 years). Dow Jones Industrial Average (25 years).
The Space Laser Business Model
2005-01-01
Creating long-duration, high-powered lasers, for satellites, that can withstand the type of optical misalignment and damage dished out by the unforgiving environment of space, is work that is unique to NASA. It is complicated, specific work, where each step forward is into uncharted territory. In the 1990s, as this technology was first being created, NASA gave free reign to a group of "laser jocks" to develop their own business model and supply the Space Agency with the technology it needed. It was still to be a part of NASA as a division of Goddard Space Flight Center, but would operate independently out of a remote office. The idea for this satellite laboratory was based on the Skunk Works concept at Lockheed Martin Corporation. Formerly known as the Lockheed Corporation, in 1943, the aerospace firm, realizing that the type of advanced research it needed done could not be performed within the confines of a larger company, allowed a group of researchers and engineers to essentially run their own microbusiness without the corporate oversight. The Skunk Works project, in Burbank, California, produced America s first jet fighter, the world s most successful spy plane (U-2), the first 3-times-the-speed-of-sound surveillance aircraft, and the F-117A Nighthawk Stealth Fighter. Boeing followed suit with its Phantom Works, an advanced research and development branch of the company that operates independent of the larger unit and is responsible for a great deal of its most cutting-edge research. NASA s version of this advanced business model was the Space Lidar Technology Center (SLTC), just south of Goddard, in College Park, Maryland. Established in 1998 under a Cooperative Agreement between Goddard and the University of Maryland s A. James Clark School of Engineering, it was a high-tech laser shop where a small group of specialists, never more than 20 employees, worked all hours of the day and night to create the cutting- edge technology the Agency required of them. Drs
My Life with State Space Models
DEFF Research Database (Denmark)
Lundbye-Christensen, Søren
2007-01-01
. The conceptual idea behind the state space model is that the evolution over time in the object we are observing and the measurement process itself are modelled separately. My very first serious analysis of a data set was done using a state space model, and since then I seem to have been "haunted" by state space...
The standard model on non-commutative space-time
International Nuclear Information System (INIS)
Calmet, X.; Jurco, B.; Schupp, P.; Wohlgenannt, M.; Wess, J.
2002-01-01
We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter θ μν . No new particles are introduced; the structure group is SU(3) x SU(2) x U(1). We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order in θ μν we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the NCSM to the order considered. (orig.)
The standard model on non-commutative space-time
Energy Technology Data Exchange (ETDEWEB)
Calmet, X.; Jurco, B.; Schupp, P.; Wohlgenannt, M. [Sektion Physik, Universitaet Muenchen (Germany); Wess, J. [Sektion Physik, Universitaet Muenchen (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany)
2002-03-01
We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter {theta}{sup {mu}}{sup {nu}}. No new particles are introduced; the structure group is SU(3) x SU(2) x U(1). We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order in {theta}{sup {mu}}{sup {nu}} we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the NCSM to the order considered. (orig.)
The Effects of Optical Illusions in Perception and Action in Peripersonal and Extrapersonal Space.
Shim, Jaeho; van der Kamp, John
2017-09-01
While the two visual system hypothesis tells a fairly compelling story about perception and action in peripersonal space (i.e., within arm's reach), its validity for extrapersonal space is very limited and highly controversial. Hence, the present purpose was to assess whether perception and action differences in peripersonal space hold in extrapersonal space and are modulated by the same factors. To this end, the effects of an optic illusion in perception and action in both peripersonal and extrapersonal space were compared in three groups that threw balls toward a target at a distance under different target eccentricity (i.e., with the target fixated and in peripheral field), viewing (i.e., binocular and monocular viewing), and delay conditions (i.e., immediate and delayed action). The illusory bias was smaller in action than in perception in peripersonal space, but this difference was significantly reduced in extrapersonal space, primarily because of a weakening bias in perception. No systematic modulation of target eccentricity, viewing, and delay arose. The findings suggest that the two visual system hypothesis is also valid for extra personal space.
Classical model of the Dirac electron in curved space
International Nuclear Information System (INIS)
Barut, A.O.; Pavsic, M.
1987-01-01
The action for the classical model of the electron exhibiting Zitterbewegung is generalized to curved space by introducing a spin connection. The dynamical equations and the symplectic structure are given for several different choices of the variables. In particular, we obtain the equation of motion for spin and compare it with the Papapetrou equation. (author)
Modeling Space Radiation with Bleomycin
National Aeronautics and Space Administration — Space radiation is a mixed field of solar particle events (proton) and particles of Galactic Cosmic Rays (GCR) with different energy levels. These radiation events...
Gershman, Samuel J.; Pesaran, Bijan; Daw, Nathaniel D.
2009-01-01
Humans and animals are endowed with a large number of effectors. Although this enables great behavioral flexibility, it presents an equally formidable reinforcement learning problem of discovering which actions are most valuable, due to the high dimensionality of the action space. An unresolved question is how neural systems for reinforcement learning – such as prediction error signals for action valuation associated with dopamine and the striatum – can cope with this “curse of dimensionality...
Modeling nonstationarity in space and time.
Shand, Lyndsay; Li, Bo
2017-09-01
We propose to model a spatio-temporal random field that has nonstationary covariance structure in both space and time domains by applying the concept of the dimension expansion method in Bornn et al. (2012). Simulations are conducted for both separable and nonseparable space-time covariance models, and the model is also illustrated with a streamflow dataset. Both simulation and data analyses show that modeling nonstationarity in both space and time can improve the predictive performance over stationary covariance models or models that are nonstationary in space but stationary in time. © 2017, The International Biometric Society.
Additive action model for mixed irradiation
International Nuclear Information System (INIS)
Lam, G.K.Y.
1984-01-01
Recent experimental results indicate that a mixture of high and low LET radiation may have some beneficial features (such as lower OER but with skin sparing) for clinical use, and interest has been renewed in the study of mixtures of high and low LET radiation. Several standard radiation inactivation models can readily accommodate interaction between two mixed radiations, however, this is usually handled by postulating extra free parameters, which can only be determined by fitting to experimental data. A model without any free parameter is proposed to explain the biological effect of mixed radiations, based on the following two assumptions: (a) The combined biological action due to two radiations is additive, assuming no repair has taken place during the interval between the two irradiations; and (b) The initial physical damage induced by radiation develops into final biological effect (e.g. cell killing) over a relatively long period (hours) after irradiation. This model has been shown to provide satisfactory fit to the experiment results of previous studies
Brady, Vivienne; Lalor, Joan
2017-12-01
the aim of this research was to initiate active consultation with women and antenatal educators in the development and delivery of antenatal education that was mutually relevant. a Participatory Action Research approach influenced by feminist concerns was used to guide the research. Data were analysed by the researcher and participants using a Voice Centred Relational Method of Analysis. an Antenatal Education service in a consultant-led tertiary referral unit in Ireland. research findings revealed women's desires to build relationships through ANE to cope with anticipated loneliness and isolation after birth; however, environmental, structural, and organisational factors prohibited opportunity to build space for human connection. Participating women valued external and authoritative knowledge as truth, but concomitantly sought opportunity and space through classes to learn from the real life experiences of other mothers. Women lacked confidence in embodied knowing and their power to birth and demonstrated unquestioning acceptance of the predetermined nature of hospital birth and biomedical model of maternity care. in this research, we envisioned that hospital-based ANE, relevant and grounded in the needs and life experiences of women, could be developed, with a view to supporting women's decision-making processes, and understanding of pregnancy, birth and early motherhood. Participatory Action Research using a Voice Centred Relational Method of Analysis offered an opportunity to foster ethical and dialogic activity between learner and facilitator, underpinned by acknowledgement of the value of women's experiences; however, space for expression of new and useful knowledge in preparation for motherhood was limited by institutional context. Copyright © 2017 Elsevier Ltd. All rights reserved.
Modelling in vivo action potential propagation along a giant axon.
George, Stuart; Foster, Jamie M; Richardson, Giles
2015-01-01
A partial differential equation model for the three-dimensional current flow in an excitable, unmyelinated axon is considered. Where the axon radius is significantly below a critical value R(crit) (that depends upon intra- and extra-cellular conductivity and ion channel conductance) the resistance of the intracellular space is significantly higher than that of the extracellular space, such that the potential outside the axon is uniformly small whilst the intracellular potential is approximated by the transmembrane potential. In turn, since the current flow is predominantly axial, it can be shown that the transmembrane potential is approximated by a solution to the one-dimensional cable equation. It is noted that the radius of the squid giant axon, investigated by (Hodgkin and Huxley 1952e), lies close to R(crit). This motivates us to apply the three-dimensional model to the squid giant axon and compare the results thus found to those obtained using the cable equation. In the context of the in vitro experiments conducted in (Hodgkin and Huxley 1952e) we find only a small difference between the wave profiles determined using these two different approaches and little difference between the speeds of action potential propagation predicted. This suggests that the cable equation approximation is accurate in this scenario. However when applied to the it in vivo setting, in which the conductivity of the surrounding tissue is considerably lower than that of the axoplasm, there are marked differences in both wave profile and speed of action potential propagation calculated using the two approaches. In particular, the cable equation significantly over predicts the increase in the velocity of propagation as axon radius increases. The consequences of these results are discussed in terms of the evolutionary costs associated with increasing the speed of action potential propagation by increasing axon radius.
Job, Xavier E; de Fockert, Jan W; van Velzen, José
2016-08-01
Behavioural and electrophysiological evidence has demonstrated that preparation of goal-directed actions modulates sensory perception at the goal location before the action is executed. However, previous studies have focused on sensory perception in areas of peripersonal space. The present study investigated visual and tactile sensory processing at the goal location of upcoming movements towards the body, much of which is not visible, as well as visible peripersonal space. A motor task cued participants to prepare a reaching movement towards goals either in peripersonal space in front of them or personal space on the upper chest. In order to assess modulations of sensory perception during movement preparation, event-related potentials (ERPs) were recorded in response to task-irrelevant visual and tactile probe stimuli delivered randomly at one of the goal locations of the movements. In line with previous neurophysiological findings, movement preparation modulated visual processing at the goal of a movement in peripersonal space. Movement preparation also modulated somatosensory processing at the movement goal in personal space. The findings demonstrate that tactile perception in personal space is subject to similar top-down sensory modulation by motor preparation as observed for visual stimuli presented in peripersonal space. These findings show for the first time that the principles and mechanisms underlying adaptive modulation of sensory processing in the context of action extend to tactile perception in unseen personal space. Copyright © 2016 Elsevier Ltd. All rights reserved.
Pump Component Model in SPACE Code
International Nuclear Information System (INIS)
Kim, Byoung Jae; Kim, Kyoung Doo
2010-08-01
This technical report describes the pump component model in SPACE code. A literature survey was made on pump models in existing system codes. The models embedded in SPACE code were examined to check the confliction with intellectual proprietary rights. Design specifications, computer coding implementation, and test results are included in this report
A Hybrid 3D Indoor Space Model
Directory of Open Access Journals (Sweden)
A. Jamali
2016-10-01
Full Text Available GIS integrates spatial information and spatial analysis. An important example of such integration is for emergency response which requires route planning inside and outside of a building. Route planning requires detailed information related to indoor and outdoor environment. Indoor navigation network models including Geometric Network Model (GNM, Navigable Space Model, sub-division model and regular-grid model lack indoor data sources and abstraction methods. In this paper, a hybrid indoor space model is proposed. In the proposed method, 3D modeling of indoor navigation network is based on surveying control points and it is less dependent on the 3D geometrical building model. This research proposes a method of indoor space modeling for the buildings which do not have proper 2D/3D geometrical models or they lack semantic or topological information. The proposed hybrid model consists of topological, geometrical and semantical space.
Assessment of the NASA Space Shuttle Program's Problem Reporting and Corrective Action System
Korsmeryer, D. J.; Schreiner, J. A.; Norvig, Peter (Technical Monitor)
2001-01-01
This paper documents the general findings and recommendations of the Design for Safety Programs Study of the Space Shuttle Programs (SSP) Problem Reporting and Corrective Action (PRACA) System. The goals of this Study were: to evaluate and quantify the technical aspects of the SSP's PRACA systems, and to recommend enhancements addressing specific deficiencies in preparation for future system upgrades. The Study determined that the extant SSP PRACA systems accomplished a project level support capability through the use of a large pool of domain experts and a variety of distributed formal and informal database systems. This operational model is vulnerable to staff turnover and loss of the vast corporate knowledge that is not currently being captured by the PRACA system. A need for a Program-level PRACA system providing improved insight, unification, knowledge capture, and collaborative tools was defined in this study.
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.
Preliminary Cost Model for Space Telescopes
Stahl, H. Philip; Prince, F. Andrew; Smart, Christian; Stephens, Kyle; Henrichs, Todd
2009-01-01
Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. However, great care is required. Some space telescope cost models, such as those based only on mass, lack sufficient detail to support such analysis and may lead to inaccurate conclusions. Similarly, using ground based telescope models which include the dome cost will also lead to inaccurate conclusions. This paper reviews current and historical models. Then, based on data from 22 different NASA space telescopes, this paper tests those models and presents preliminary analysis of single and multi-variable space telescope cost models.
Cosmological models in the generalized Einstein action
International Nuclear Information System (INIS)
Arbab, A.I.
2007-12-01
We have studied the evolution of the Universe in the generalized Einstein action of the form R + β R 2 , 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 ∝ H 4 . In this scenario the cosmological constant varies quadratically with the energy density (ρ), i.e., Λ ∝ ρ 2 . 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 ∼ t n = 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 R 2 mimics a cosmic matter that could substitute the ordinary matter. (author)
Near-Earth Space Radiation Models
Xapsos, Michael A.; O'Neill, Patrick M.; O'Brien, T. Paul
2012-01-01
Review of models of the near-Earth space radiation environment is presented, including recent developments in trapped proton and electron, galactic cosmic ray and solar particle event models geared toward spacecraft electronics applications.
National Water Model: Providing the Nation with Actionable Water Intelligence
Aggett, G. R.; Bates, B.
2017-12-01
The National Water Model (NWM) provides national, street-level detail of water movement through time and space. Operating hourly, this flood of information offers enormous benefits in the form of water resource management, natural disaster preparedness, and the protection of life and property. The Geo-Intelligence Division at the NOAA National Water Center supplies forecasters and decision-makers with timely, actionable water intelligence through the processing of billions of NWM data points every hour. These datasets include current streamflow estimates, short and medium range streamflow forecasts, and many other ancillary datasets. The sheer amount of NWM data produced yields a dataset too large to allow for direct human comprehension. As such, it is necessary to undergo model data post-processing, filtering, and data ingestion by visualization web apps that make use of cartographic techniques to bring attention to the areas of highest urgency. This poster illustrates NWM output post-processing and cartographic visualization techniques being developed and employed by the Geo-Intelligence Division at the NOAA National Water Center to provide national actionable water intelligence.
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 ...
Defining Learning Space in a Serious Game in Terms of Operative and Resultant Actions
Martin, Michael W.; Shen, Yuzhong
2012-01-01
This paper explores the distinction between operative and resultant actions in games, and proposes that the learning space created by a serious game is a function of these actions. Further, it suggests a possible relationship between these actions and the forms of cognitive load imposed upon the game player. Association of specific types of cognitive load with respective forms of actions in game mechanics also presents some heuristics for integrating learning content into serious games. Research indicates that different balances of these types of actions are more suitable for novice or experienced learners. By examining these relationships, we can develop a few basic principles of game design which have an increased potential to promote positive learning outcomes.
The cohomology of orbit spaces of certain free circle group actions
Indian Academy of Sciences (India)
Abstract. Suppose that G = S1 acts freely on a finitistic space X whose (mod p) cohomology ring is isomorphic to that of a lens space L2m−1(p;q1,...,qm) or S1 ×. CPm−1. The mod p index of the action is defined to be the largest integer n such that αn = 0, where α ϵ H2(X/G; Zp) is the nonzero characteristic class of the S1-.
Modeling beams with elements in phase space
International Nuclear Information System (INIS)
Nelson, E.M.
1998-01-01
Conventional particle codes represent beams as a collection of macroparticles. An alternative is to represent the beam as a collection of current carrying elements in phase space. While such a representation has limitations, it may be less noisy than a macroparticle model, and it may provide insights about the transport of space charge dominated beams which would otherwise be difficult to gain from macroparticle simulations. The phase space element model of a beam is described, and progress toward an implementation and difficulties with this implementation are discussed. A simulation of an axisymmetric beam using 1d elements in phase space is demonstrated
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.
On discrete models of space-time
International Nuclear Information System (INIS)
Horzela, A.; Kempczynski, J.; Kapuscik, E.; Georgia Univ., Athens, GA; Uzes, Ch.
1992-02-01
Analyzing the Einstein radiolocation method we come to the conclusion that results of any measurement of space-time coordinates should be expressed in terms of rational numbers. We show that this property is Lorentz invariant and may be used in the construction of discrete models of space-time different from the models of the lattice type constructed in the process of discretization of continuous models. (author)
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.
Static, self-dual, finite action SU(3) gauge fields in the de Sitter space
International Nuclear Information System (INIS)
Chakrabarti, A.; Comtet, A.; Viswanathan, K.S.; Simon Fraser Univ., Burnaby, British Columbia
1980-01-01
Static, self-dual, finite action SU(3) gauge fields are constructed on the euclidean section of the positive curvature de Sitter metric with periodic time. Their relation to known time dependent flat space solutions is pointed out. Their significances and possible applications are indicated. (orig.)
Emulating a flexible space structure: Modeling
Waites, H. B.; Rice, S. C.; Jones, V. L.
1988-01-01
Control Dynamics, in conjunction with Marshall Space Flight Center, has participated in the modeling and testing of Flexible Space Structures. Through the series of configurations tested and the many techniques used for collecting, analyzing, and modeling the data, many valuable insights have been gained and important lessons learned. This paper discusses the background of the Large Space Structure program, Control Dynamics' involvement in testing and modeling of the configurations (especially the Active Control Technique Evaluation for Spacecraft (ACES) configuration), the results from these two processes, and insights gained from this work.
3D space analysis of dental models
Chuah, Joon H.; Ong, Sim Heng; Kondo, Toshiaki; Foong, Kelvin W. C.; Yong, Than F.
2001-05-01
Space analysis is an important procedure by orthodontists to determine the amount of space available and required for teeth alignment during treatment planning. Traditional manual methods of space analysis are tedious and often inaccurate. Computer-based space analysis methods that work on 2D images have been reported. However, as the space problems in the dental arch exist in all three planes of space, a full 3D analysis of the problems is necessary. This paper describes a visualization and measurement system that analyses 3D images of dental plaster models. Algorithms were developed to determine dental arches. The system is able to record the depths of the Curve of Spee, and quantify space liabilities arising from a non-planar Curve of Spee, malalignment and overjet. Furthermore, the difference between total arch space available and the space required to arrange the teeth in ideal occlusion can be accurately computed. The system for 3D space analysis of the dental arch is an accurate, comprehensive, rapid and repeatable method of space analysis to facilitate proper orthodontic diagnosis and treatment planning.
The manifold model for space-time
International Nuclear Information System (INIS)
Heller, M.
1981-01-01
Physical processes happen on a space-time arena. It turns out that all contemporary macroscopic physical theories presuppose a common mathematical model for this arena, the so-called manifold model of space-time. The first part of study is an heuristic introduction to the concept of a smooth manifold, starting with the intuitively more clear concepts of a curve and a surface in the Euclidean space. In the second part the definitions of the Csub(infinity) manifold and of certain structures, which arise in a natural way from the manifold concept, are given. The role of the enveloping Euclidean space (i.e. of the Euclidean space appearing in the manifold definition) in these definitions is stressed. The Euclidean character of the enveloping space induces to the manifold local Euclidean (topological and differential) properties. A suggestion is made that replacing the enveloping Euclidean space by a discrete non-Euclidean space would be a correct way towards the quantization of space-time. (author)
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...
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.
Parametric cost models for space telescopes
Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtnay
2017-11-01
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.
Causal fermion systems: A quantum space-time emerging from an action principle
Energy Technology Data Exchange (ETDEWEB)
Finster, Felix [Mathematics Department, University of Regensburg (Germany)
2013-07-01
Causal fermion systems provide a general framework for the formulation of relativistic quantum theory. A particular feature is that space-time is a secondary object which emerges by minimizing an action. The aim of the talk is to give a simple introduction, with an emphasis on conceptual issues. We begin with Dirac spinors in Minkowski space and explain how to formulate the system as a causal fermion system. As an example in curved space-time, we then consider spinors on a globally hyperbolic space-time. An example on a space-time lattice illustrates that causal fermion systems also allow for the description of discrete space-times. These examples lead us to the general definition of causal fermion systems. The causal action principle is introduced. We outline how for a given minimizer, one has notions of causality, connection and curvature, which generalize the classical notions and give rise to a proposal for a ''quantum geometry''. In the last part of the talk, we outline how quantum field theory can be described in this framework and discuss the relation to other approaches.
Observational modeling of topological spaces
International Nuclear Information System (INIS)
Molaei, M.R.
2009-01-01
In this paper a model for a multi-dimensional observer by using of the fuzzy theory is presented. Relative form of Tychonoff theorem is proved. The notion of topological entropy is extended. The persistence of relative topological entropy under relative conjugate relation is proved.
QSAR modeling and chemical space analysis of antimalarial compounds
Sidorov, Pavel; Viira, Birgit; Davioud-Charvet, Elisabeth; Maran, Uko; Marcou, Gilles; Horvath, Dragos; Varnek, Alexandre
2017-05-01
Generative topographic mapping (GTM) has been used to visualize and analyze the chemical space of antimalarial compounds as well as to build predictive models linking structure of molecules with their antimalarial activity. For this, a database, including 3000 molecules tested in one or several of 17 anti- Plasmodium activity assessment protocols, has been compiled by assembling experimental data from in-house and ChEMBL databases. GTM classification models built on subsets corresponding to individual bioassays perform similarly to the earlier reported SVM models. Zones preferentially populated by active and inactive molecules, respectively, clearly emerge in the class landscapes supported by the GTM model. Their analysis resulted in identification of privileged structural motifs of potential antimalarial compounds. Projection of marketed antimalarial drugs on this map allowed us to delineate several areas in the chemical space corresponding to different mechanisms of antimalarial activity. This helped us to make a suggestion about the mode of action of the molecules populating these zones.
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.
Predictive user modeling with actionable attributes
Zliobaite, I.; Pechenizkiy, M.
2013-01-01
Different machine learning techniques have been proposed and used for modeling individual and group user needs, interests and preferences. In the traditional predictive modeling instances are described by observable variables, called attributes. The goal is to learn a model for predicting the target
Preliminary Multivariable Cost Model for Space Telescopes
Stahl, H. Philip
2010-01-01
Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. Previously, the authors published two single variable cost models based on 19 flight missions. The current paper presents the development of a multi-variable space telescopes cost model. The validity of previously published models are tested. Cost estimating relationships which are and are not significant cost drivers are identified. And, interrelationships between variables are explored
Fritzon, K; Canter, D; Wilton, Z
2001-01-01
This article argues that criminal and deviant behaviour can be productively viewed through an action system framework. The idea is developed by considering two forms of destructive behaviour: arson and barricade-hostage terrorist incidents. Two studies are presented. The first study tests the hypothesis that different forms of arson will reflect the four dominant states that an action system can take; integrative, expressive, conservative, and adaptive. A smallest space analysis was performed on 46 variables describing 230 cases of arson and the results identified the four themes of action system functioning. An examination of the personal characteristics of the arsonists also produced four variable groupings and a combined analysis of the four action scales and four characteristics scales also supported the structural hypothesis of the action system model. The second study applied the action system model to the study acts of terrorist barricade-hostage incidents. A smallest space analysis of 44 variables coded from 41 incidents again revealed four distinct forms of activity, which were psychologically similar to the four modes of arson identified in study one. Overall, these two studies provide support for the appropriateness of the action system framework as a way of classifying different forms of deviant behaviour. Copyright 2001 John Wiley & Sons, Ltd.
Modeling Interdependent and Periodic Real-World Action Sequences
Kurashima, Takeshi; Althoff, Tim; Leskovec, Jure
2018-01-01
Mobile health applications, including those that track activities such as exercise, sleep, and diet, are becoming widely used. Accurately predicting human actions in the real world is essential for targeted recommendations that could improve our health and for personalization of these applications. However, making such predictions is extremely difficult due to the complexities of human behavior, which consists of a large number of potential actions that vary over time, depend on each other, and are periodic. Previous work has not jointly modeled these dynamics and has largely focused on item consumption patterns instead of broader types of behaviors such as eating, commuting or exercising. In this work, we develop a novel statistical model, called TIPAS, for Time-varying, Interdependent, and Periodic Action Sequences. Our approach is based on personalized, multivariate temporal point processes that model time-varying action propensities through a mixture of Gaussian intensities. Our model captures short-term and long-term periodic interdependencies between actions through Hawkes process-based self-excitations. We evaluate our approach on two activity logging datasets comprising 12 million real-world actions (e.g., eating, sleep, and exercise) taken by 20 thousand users over 17 months. We demonstrate that our approach allows us to make successful predictions of future user actions and their timing. Specifically, TIPAS improves predictions of actions, and their timing, over existing methods across multiple datasets by up to 156%, and up to 37%, respectively. Performance improvements are particularly large for relatively rare and periodic actions such as walking and biking, improving over baselines by up to 256%. This demonstrates that explicit modeling of dependencies and periodicities in real-world behavior enables successful predictions of future actions, with implications for modeling human behavior, app personalization, and targeting of health interventions. PMID
Effective hamiltonian calculations using incomplete model spaces
International Nuclear Information System (INIS)
Koch, S.; Mukherjee, D.
1987-01-01
It appears that the danger of encountering ''intruder states'' is substantially reduced if an effective hamiltonian formalism is developed for incomplete model spaces (IMS). In a Fock-space approach, the proof a ''connected diagram theorem'' is fairly straightforward with exponential-type of ansatze for the wave-operator W, provided the normalization chosen for W is separable. Operationally, one just needs a suitable categorization of the Fock-space operators into ''diagonal'' and ''non-diagonal'' parts that is generalization of the corresponding procedure for the complete model space. The formalism is applied to prototypical 2-electron systems. The calculations have been performed on the Cyber 205 super-computer. The authors paid special attention to an efficient vectorization for the construction and solution of the resulting coupled non-linear equations
A continuous-time neural model for sequential action.
Kachergis, George; Wyatte, Dean; O'Reilly, Randall C; de Kleijn, Roy; Hommel, Bernhard
2014-11-05
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. © 2014 The Author(s) Published by the Royal Society. All rights reserved.
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.
Decision modeling for analyzing fire action outcomes
Donald MacGregor; Armando Gonzalez-Caban
2008-01-01
A methodology for incident decomposition and reconstruction is developed based on the concept of an "event-frame model." The event-frame model characterizes a fire incident in terms of (a) environmental events that pertain to the fire and the fire context (e.g., fire behavior, weather, fuels) and (b) management events that represent responses to the fire...
Re-construction of action awareness depends on an internal model of action-outcome timing.
Stenner, Max-Philipp; Bauer, Markus; Machts, Judith; Heinze, Hans-Jochen; Haggard, Patrick; Dolan, Raymond J
2014-04-01
The subjective time of an instrumental action is shifted towards its outcome. This temporal binding effect is partially retrospective, i.e., occurs upon outcome perception. Retrospective binding is thought to reflect post-hoc inference on agency based on sensory evidence of the action - outcome association. However, many previous binding paradigms cannot exclude the possibility that retrospective binding results from bottom-up interference of sensory outcome processing with action awareness and is functionally unrelated to the processing of the action - outcome association. Here, we keep bottom-up interference constant and use a contextual manipulation instead. We demonstrate a shift of subjective action time by its outcome in a context of variable outcome timing. Crucially, this shift is absent when there is no such variability. Thus, retrospective action binding reflects a context-dependent, model-based phenomenon. Such top-down re-construction of action awareness seems to bias agency attribution when outcome predictability is low. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
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.
Qualitative models for space system engineering
Forbus, Kenneth D.
1990-01-01
The objectives of this project were: (1) to investigate the implications of qualitative modeling techniques for problems arising in the monitoring, diagnosis, and design of Space Station subsystems and procedures; (2) to identify the issues involved in using qualitative models to enhance and automate engineering functions. These issues include representing operational criteria, fault models, alternate ontologies, and modeling continuous signals at a functional level of description; and (3) to develop a prototype collection of qualitative models for fluid and thermal systems commonly found in Space Station subsystems. Potential applications of qualitative modeling to space-systems engineering, including the notion of intelligent computer-aided engineering are summarized. Emphasis is given to determining which systems of the proposed Space Station provide the most leverage for study, given the current state of the art. Progress on using qualitative models, including development of the molecular collection ontology for reasoning about fluids, the interaction of qualitative and quantitative knowledge in analyzing thermodynamic cycles, and an experiment on building a natural language interface to qualitative reasoning is reported. Finally, some recommendations are made for future research.
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'. Simulations...... are performed on recordings of 3-5 sec. video sequences with sentences from the Timit database. The model is able to construct an image sequence from an unknown noisy speech sequence fairly well even though the number of training examples are limited....
State-Space Modelling in Marine Science
DEFF Research Database (Denmark)
Albertsen, Christoffer Moesgaard
State-space models provide a natural framework for analysing time series that cannot be observed without error. This is the case for fisheries stock assessments and movement data from marine animals. In fisheries stock assessments, the aim is to estimate the stock size; however, the only data...... available is the number of fish removed from the population and samples on a small fraction of the population. In marine animal movement, accurate position systems such as GPS cannot be used. Instead, inaccurate alternative must be used yielding observations with large errors. Both assessment and individual...... animal movement models are important for management and conservation of marine animals. Consequently, models should be developed to be operational in a management context while adequately evaluating uncertainties in the models. This thesis develops state-space models using the Laplace approximation...
Physical models on discrete space and time
International Nuclear Information System (INIS)
Lorente, M.
1986-01-01
The idea of space and time quantum operators with a discrete spectrum has been proposed frequently since the discovery that some physical quantities exhibit measured values that are multiples of fundamental units. This paper first reviews a number of these physical models. They are: the method of finite elements proposed by Bender et al; the quantum field theory model on discrete space-time proposed by Yamamoto; the finite dimensional quantum mechanics approach proposed by Santhanam et al; the idea of space-time as lattices of n-simplices proposed by Kaplunovsky et al; and the theory of elementary processes proposed by Weizsaecker and his colleagues. The paper then presents a model proposed by the authors and based on the (n+1)-dimensional space-time lattice where fundamental entities interact among themselves 1 to 2n in order to build up a n-dimensional cubic lattice as a ground field where the physical interactions take place. The space-time coordinates are nothing more than the labelling of the ground field and take only discrete values. 11 references
Mouse infection models for space flight immunology
Chapes, Stephen Keith; Ganta, Roman Reddy; Chapers, S. K. (Principal Investigator)
2005-01-01
Several immunological processes can be affected by space flight. However, there is little evidence to suggest that flight-induced immunological deficits lead to illness. Therefore, one of our goals has been to define models to examine host resistance during space flight. Our working hypothesis is that space flight crews will come from a heterogeneous population; the immune response gene make-up will be quite varied. It is unknown how much the immune response gene variation contributes to the potential threat from infectious organisms, allergic responses or other long term health problems (e.g. cancer). This article details recent efforts of the Kansas State University gravitational immunology group to assess how population heterogeneity impacts host health, either in laboratory experimental situations and/or using the skeletal unloading model of space-flight stress. This paper details our use of several mouse strains with several different genotypes. In particular, mice with varying MHCII allotypes and mice on the C57BL background with different genetic defects have been particularly useful tools with which to study infections by Staphylococcus aureus, Salmonella typhimurium, Pasteurella pneumotropica and Ehrlichia chaffeensis. We propose that some of these experimental challenge models will be useful to assess the effects of space flight on host resistance to infection.
Quadratic adaptive algorithm for solving cardiac action potential models.
Chen, Min-Hung; Chen, Po-Yuan; Luo, Ching-Hsing
2016-10-01
An adaptive integration method is proposed for computing cardiac action potential models accurately and efficiently. Time steps are adaptively chosen by solving a quadratic formula involving the first and second derivatives of the membrane action potential. To improve the numerical accuracy, we devise an extremum-locator (el) function to predict the local extremum when approaching the peak amplitude of the action potential. In addition, the time step restriction (tsr) technique is designed to limit the increase in time steps, and thus prevent the membrane potential from changing abruptly. The performance of the proposed method is tested using the Luo-Rudy phase 1 (LR1), dynamic (LR2), and human O'Hara-Rudy dynamic (ORd) ventricular action potential models, and the Courtemanche atrial model incorporating a Markov sodium channel model. Numerical experiments demonstrate that the action potential generated using the proposed method is more accurate than that using the traditional Hybrid method, especially near the peak region. The traditional Hybrid method may choose large time steps near to the peak region, and sometimes causes the action potential to become distorted. In contrast, the proposed new method chooses very fine time steps in the peak region, but large time steps in the smooth region, and the profiles are smoother and closer to the reference solution. In the test on the stiff Markov ionic channel model, the Hybrid blows up if the allowable time step is set to be greater than 0.1ms. In contrast, our method can adjust the time step size automatically, and is stable. Overall, the proposed method is more accurate than and as efficient as the traditional Hybrid method, especially for the human ORd model. The proposed method shows improvement for action potentials with a non-smooth morphology, and it needs further investigation to determine whether the method is helpful during propagation of the action potential. Copyright © 2016 Elsevier Ltd. All rights
Gauge invariant actions for string models
International Nuclear Information System (INIS)
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
Space-time modeling of timber prices
Mo Zhou; Joseph Buongriorno
2006-01-01
A space-time econometric model was developed for pine sawtimber timber prices of 21 geographically contiguous regions in the southern United States. The correlations between prices in neighboring regions helped predict future prices. The impulse response analysis showed that although southern pine sawtimber markets were not globally integrated, local supply and demand...
New Skeletal-Space-Filling Models
Clarke, Frank H.
1977-01-01
Describes plastic, skeletal molecular models that are color-coded and can illustrate both the conformation and overall shape of small molecules. They can also be converted to space-filling counterparts by the additions of color-coded polystyrene spheres. (MLH)
Reliability models for Space Station power system
Singh, C.; Patton, A. D.; Kim, Y.; Wagner, H.
1987-01-01
This paper presents a methodology for the reliability evaluation of Space Station power system. The two options considered are the photovoltaic system and the solar dynamic system. Reliability models for both of these options are described along with the methodology for calculating the reliability indices.
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.
Model of dopant action in oxide cathodes
International Nuclear Information System (INIS)
Engelsen, Daniel den; Gaertner, Georg
2005-01-01
The paper describes an electrochemical model, which largely explains the formation of Ba in the oxide cathode at activation and normal operation. In a non-doped oxide cathode electrolysis of BaO is, besides the exchange reaction from the activators in the cathode nickel, an important source of Ba. By doping with rare earth oxides the conductivity of the oxide layer increases, which implies that the potential difference during current drawing over the oxide layer becomes lower and electrolysis of BaO is suppressed. This implies that the part of the electronic conductivity of the (Ba,Sr)O layer induced by the dopants also controls the sensitivity for poisoning: the higher the dopant level, the larger the sensitivity for poisoning. Furthermore, the suppression of electrolysis during normal operation largely explains why doped oxide cathodes have a better life performance than non-doped cathodes. Finally a hypothesis on the enhancement of sintering upon doping is presented
Legal and Political Implications of Offensive Actions from and Against the Space Segment
de Angelis, Iole M.
2002-01-01
deployment of strategic weapons, kinetic energy weapons and directed energy weapons are already contained within existing rules and such issues are being actively addressed by the international community. At the same time, the use of cyberwar and electronic warfare to counter space technology not only encounters a void of international rules, but it is a question that is very rarely taken into consideration while addressing to the issues of preventing space warfare. Finally, these techniques are easily available to non-state organisations - terrorist organisations and commercial companies - and individuals. In conclusion, the issues related to offensive actions towards and from space shall be taken into consideration not only in a military perspective, but also in a political perspective - terrorist actions against the space segment - and from an economical point of view.
Brown, Ronald; Higgins, Philip J.
2002-01-01
The main result is that the fundamental groupoid of the orbit space of a discontinuous action of a discrete group on a Hausdorff space which admits a universal cover is the orbit groupoid of the fundamental groupoid of the space. We also describe work of Higgins and of Taylor which makes this result usable for calculations. As an example, we compute the fundamental group of the symmetric square of a space. The main result, which is related to work of Armstrong, is due to Brown and Higgins in ...
Modeling and Analysis of Space Based Transceivers
Moore, Michael S.; Price, Jeremy C.; Abbott, Ben; Liebetreu, John; Reinhart, Richard C.; Kacpura, Thomas J.
2007-01-01
This paper presents the tool chain, methodology, and initial results of a study to provide a thorough, objective, and quantitative analysis of the design alternatives for space Software Defined Radio (SDR) transceivers. The approach taken was to develop a set of models and tools for describing communications requirements, the algorithm resource requirements, the available hardware, and the alternative software architectures, and generate analysis data necessary to compare alternative designs. The Space Transceiver Analysis Tool (STAT) was developed to help users identify and select representative designs, calculate the analysis data, and perform a comparative analysis of the representative designs. The tool allows the design space to be searched quickly while permitting incremental refinement in regions of higher payoff.
Women’s Voices in a Male World: Actions, Bodies, and Spaces Among the Ancient Maya
Directory of Open Access Journals (Sweden)
Elisa Perego
2007-11-01
Full Text Available Feminist archaeology has prompted scholars to reconsider gender roles in ancient Mesoamerica.Current research, however, tends to focus on elite women, classes and sites. Although I do not ignore the potential of these sources, in this paper I am mainly concerned with issues such as the phenomenology of bodies and spaces, subroyal ritual actions, and daily activities such as cooking and weaving. My aim is to offer an overview of the most recent studies on gender in Maya archaeology and to provide ideas for further research by emphasising the need to engender ritual and individuate female discourses in the archaeological record.
Adaptive Numerical Algorithms in Space Weather Modeling
Toth, Gabor; vanderHolst, Bart; Sokolov, Igor V.; DeZeeuw, Darren; Gombosi, Tamas I.; Fang, Fang; Manchester, Ward B.; Meng, Xing; Nakib, Dalal; Powell, Kenneth G.;
2010-01-01
Space weather describes the various processes in the Sun-Earth system that present danger to human health and technology. The goal of space weather forecasting is to provide an opportunity to mitigate these negative effects. Physics-based space weather modeling is characterized by disparate temporal and spatial scales as well as by different physics in different domains. A multi-physics system can be modeled by a software framework comprising of several components. Each component corresponds to a physics domain, and each component is represented by one or more numerical models. The publicly available Space Weather Modeling Framework (SWMF) can execute and couple together several components distributed over a parallel machine in a flexible and efficient manner. The framework also allows resolving disparate spatial and temporal scales with independent spatial and temporal discretizations in the various models. Several of the computationally most expensive domains of the framework are modeled by the Block-Adaptive Tree Solar wind Roe Upwind Scheme (BATS-R-US) code that can solve various forms of the magnetohydrodynamics (MHD) equations, including Hall, semi-relativistic, multi-species and multi-fluid MHD, anisotropic pressure, radiative transport and heat conduction. Modeling disparate scales within BATS-R-US is achieved by a block-adaptive mesh both in Cartesian and generalized coordinates. Most recently we have created a new core for BATS-R-US: the Block-Adaptive Tree Library (BATL) that provides a general toolkit for creating, load balancing and message passing in a 1, 2 or 3 dimensional block-adaptive grid. We describe the algorithms of BATL and demonstrate its efficiency and scaling properties for various problems. BATS-R-US uses several time-integration schemes to address multiple time-scales: explicit time stepping with fixed or local time steps, partially steady-state evolution, point-implicit, semi-implicit, explicit/implicit, and fully implicit numerical
Crane cabins' interior space multivariate anthropometric modeling.
Essdai, Ahmed; Spasojević Brkić, Vesna K; Golubović, Tamara; Brkić, Aleksandar; Popović, Vladimir
2018-01-01
Previous research has shown that today's crane cabins fail to meet the needs of a large proportion of operators. Performance and financial losses and effects on safety should not be overlooked as well. The first aim of this survey is to model the crane cabin interior space using up-to-date crane operator anthropometric data and to compare the multivariate and univariate method anthropometric models. The second aim of the paper is to define the crane cabin interior space dimensions that enable anthropometric convenience. To facilitate the cabin design, the anthropometric dimensions of 64 crane operators in the first sample and 19 more in the second sample were collected in Serbia. The multivariate anthropometric models, spanning 95% of the population on the basis of a set of 8 anthropometric dimensions, have been developed. The percentile method was also used on the same set of data. The dimensions of the interior space, necessary for the accommodation of the crane operator, are 1174×1080×1865 mm. The percentiles results for the 5th and 95th model are within the obtained dimensions. The results of this study may prove useful to crane cabin designers in eliminating anthropometric inconsistencies and improving the health of operators, but can also aid in improving the safety, performance and financial results of the companies where crane cabins operate.
A BRDF statistical model applying to space target materials modeling
Liu, Chenghao; Li, Zhi; Xu, Can; Tian, Qichen
2017-10-01
In order to solve the problem of poor effect in modeling the large density BRDF measured data with five-parameter semi-empirical model, a refined statistical model of BRDF which is suitable for multi-class space target material modeling were proposed. The refined model improved the Torrance-Sparrow model while having the modeling advantages of five-parameter model. Compared with the existing empirical model, the model contains six simple parameters, which can approximate the roughness distribution of the material surface, can approximate the intensity of the Fresnel reflectance phenomenon and the attenuation of the reflected light's brightness with the azimuth angle changes. The model is able to achieve parameter inversion quickly with no extra loss of accuracy. The genetic algorithm was used to invert the parameters of 11 different samples in the space target commonly used materials, and the fitting errors of all materials were below 6%, which were much lower than those of five-parameter model. The effect of the refined model is verified by comparing the fitting results of the three samples at different incident zenith angles in 0° azimuth angle. Finally, the three-dimensional modeling visualizations of these samples in the upper hemisphere space was given, in which the strength of the optical scattering of different materials could be clearly shown. It proved the good describing ability of the refined model at the material characterization as well.
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 ...
THE ACTION MODEL FOR MEASURING INFLUENCE IN ADVERTISING
Directory of Open Access Journals (Sweden)
Andrej Kovacic
2014-09-01
Full Text Available Despite the abundance of different theories there is little agreement on the suitable model that would explain how influence in advertising works. Historically, theoretical models have moved from including solely rational components towards including emotional components and from focusing on sequential processing towards hierarchy free processing models. Based on the existing literature, several most representative models are presented, described and evaluated. In a quest to explain a broader view on advertising influence we introduced the ACTION model (an acronym for Aim, Connection, Techniques, Identity, Opportunity and Numerous. Advantages, suggestions for future research and a critical discussion of using this model are further discussed.
Coello, Yann; Quesque, François; Gigliotti, Maria-Francesca; Ott, Laurent; Bruyelle, Jean-Luc
2018-01-01
Peripersonal space is a multisensory representation of the environment around the body in relation to the motor system, underlying the interactions with the physical and social world. Although changing body properties and social context have been shown to alter the functional processing of space, little is known about how changing the value of objects influences the representation of peripersonal space. In two experiments, we tested the effect of modifying the spatial distribution of reward-yielding targets on manual reaching actions and peripersonal space representation. Before and after performing a target-selection task consisting of manually selecting a set of targets on a touch-screen table, participants performed a two-alternative forced-choice reachability-judgment task. In the target-selection task, half of the targets were associated with a reward (change of colour from grey to green, providing 1 point), the other half being associated with no reward (change of colour from grey to red, providing no point). In Experiment 1, the target-selection task was performed individually with the aim of maximizing the point count, and the distribution of the reward-yielding targets was either 50%, 25% or 75% in the proximal and distal spaces. In Experiment 2, the target-selection task was performed in a social context involving cooperation between two participants to maximize the point count, and the distribution of the reward-yielding targets was 50% in the proximal and distal spaces. Results showed that changing the distribution of the reward-yielding targets or introducing the social context modified concurrently the amplitude of self-generated manual reaching actions and the representation of peripersonal space. Moreover, a decrease of the amplitude of manual reaching actions caused a reduction of peripersonal space when resulting from the distribution of reward-yielding targets, while this effect was not observed in a social interaction context. In that case, the
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
The approximate inverse in action: IV. Semi-discrete equations in a Banach space setting
International Nuclear Information System (INIS)
Schuster, T; Schöpfer, F; Rieder, A
2012-01-01
This article concerns the method of approximate inverse to solve semi-discrete, linear operator equations in Banach spaces. Semi-discrete means that we search for a solution in an infinite-dimensional Banach space having only a finite number of data available. In this sense the situation is applicable to a large variety of applications where a measurement process delivers a discretization of an infinite-dimensional data space. The method of approximate inverse computes scalar products of the data with pre-computed reconstruction kernels which are associated with mollifiers and the dual of the model operator. The convergence, approximation power and regularization property of this method when applied to semi-discrete operator equations in Hilbert spaces has been investigated in three prequels to this paper. Here we extend these results to a Banach space setting. We prove convergence and stability for general Banach spaces and reproduce the results specifically for the integration operator acting on the space of continuous functions. (paper)
Dynamic multibody modeling for tethered space elevators
Williams, Paul
2009-08-01
This paper presents a fundamental modeling strategy for dealing with powered and propelled bodies moving along space tethers. The tether is divided into a large number of discrete masses, which are connected by viscoelastic springs. The tether is subject to the full range of forces expected in Earth orbit in a relatively simple manner. Two different models of the elevator dynamics are presented. In order to capture the effect of the elevator moving along the tether, the elevator dynamics are included as a separate body in both models. One model treats the elevator's motion dynamically, where propulsive and friction forces are applied to the elevator body. The second model treats the elevator's motion kinematically, where the distance along the tether is determined by adjusting the lengths of tether on either side of the elevator. The tether model is used to determine optimal configurations for the space elevator. A modal analysis of two different configurations is presented which show that the fundamental mode of oscillation is a pendular one around the anchor point with a period on the order of 160 h for the in-plane motion, and 24 h for the out-of-plane motion. Numerical simulation results of the effects of the elevator moving along the cable are presented for different travel velocities and different elevator masses.
Animated pose templates for modeling and detecting human actions.
Yao, Benjamin Z; Nie, Bruce X; Liu, Zicheng; Zhu, Song-Chun
2014-03-01
This paper presents animated pose templates (APTs) for detecting short-term, long-term, and contextual actions from cluttered scenes in videos. Each pose template consists of two components: 1) a shape template with deformable parts represented in an And-node whose appearances are represented by the Histogram of Oriented Gradient (HOG) features, and 2) a motion template specifying the motion of the parts by the Histogram of Optical-Flows (HOF) features. A shape template may have more than one motion template represented by an Or-node. Therefore, each action is defined as a mixture (Or-node) of pose templates in an And-Or tree structure. While this pose template is suitable for detecting short-term action snippets in two to five frames, we extend it in two ways: 1) For long-term actions, we animate the pose templates by adding temporal constraints in a Hidden Markov Model (HMM), and 2) for contextual actions, we treat contextual objects as additional parts of the pose templates and add constraints that encode spatial correlations between parts. To train the model, we manually annotate part locations on several keyframes of each video and cluster them into pose templates using EM. This leaves the unknown parameters for our learning algorithm in two groups: 1) latent variables for the unannotated frames including pose-IDs and part locations, 2) model parameters shared by all training samples such as weights for HOG and HOF features, canonical part locations of each pose, coefficients penalizing pose-transition and part-deformation. To learn these parameters, we introduce a semi-supervised structural SVM algorithm that iterates between two steps: 1) learning (updating) model parameters using labeled data by solving a structural SVM optimization, and 2) imputing missing variables (i.e., detecting actions on unlabeled frames) with parameters learned from the previous step and progressively accepting high-score frames as newly labeled examples. This algorithm belongs to a
Space-time modeling of soil moisture
Chen, Zijuan; Mohanty, Binayak P.; Rodriguez-Iturbe, Ignacio
2017-11-01
A physically derived space-time mathematical representation of the soil moisture field is carried out via the soil moisture balance equation driven by stochastic rainfall forcing. The model incorporates spatial diffusion and in its original version, it is shown to be unable to reproduce the relative fast decay in the spatial correlation functions observed in empirical data. This decay resulting from variations in local topography as well as in local soil and vegetation conditions is well reproduced via a jitter process acting multiplicatively over the space-time soil moisture field. The jitter is a multiplicative noise acting on the soil moisture dynamics with the objective to deflate its correlation structure at small spatial scales which are not embedded in the probabilistic structure of the rainfall process that drives the dynamics. These scales of order of several meters to several hundred meters are of great importance in ecohydrologic dynamics. Properties of space-time correlation functions and spectral densities of the model with jitter are explored analytically, and the influence of the jitter parameters, reflecting variabilities of soil moisture at different spatial and temporal scales, is investigated. A case study fitting the derived model to a soil moisture dataset is presented in detail.
Modeling and control of flexible space structures
Wie, B.; Bryson, A. E., Jr.
1981-01-01
The effects of actuator and sensor locations on transfer function zeros are investigated, using uniform bars and beams as generic models of flexible space structures. It is shown how finite element codes may be used directly to calculate transfer function zeros. The impulse response predicted by finite-dimensional models is compared with the exact impulse response predicted by the infinite dimensional models. It is shown that some flexible structures behave as if there were a direct transmission between actuator and sensor (equal numbers of zeros and poles in the transfer function). Finally, natural damping models for a vibrating beam are investigated since natural damping has a strong influence on the appropriate active control logic for a flexible structure.
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.
Jointly structuring triadic spaces of meaning and action: book sharing from 3 months on.
Rossmanith, Nicole; Costall, Alan; Reichelt, Andreas F; López, Beatriz; Reddy, Vasudevi
2014-01-01
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 to 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 to 12 months, social book interactions resurfaced, as infants began to effectively integrate manual 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 to 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.
Can Participatory Action Research Create Value for Business Model Innovation?
DEFF Research Database (Denmark)
Sparre, Mogens; Rasmussen, Ole Horn; Fast, Alf Michael
Innovation (BMI)?” – has been investigated from five different perspectives based upon The Business Model Cube and The Where to Look Model. Using both established and newly developed tools the paper presents how. Theory and data from two cases are presented and it is demonstrated how industry increase......Abstract: Participatory Action Research (PAR) has a longer academic history compared with the idea of business models (BMs). This paper indicates how industries gain by using the combined methodology. The research question "Can participatory action research create value for Business Model...... their monetary and/or non-monetary value creation doing BMI based upon PAR. The process is essential and using the methodology of PAR creates meaning. Behind the process, the RAR methodology and its link to BM and BMI may contribute to theory construction and creation of a common language in academia around...
A probability space for quantum models
Lemmens, L. F.
2017-06-01
A probability space contains a set of outcomes, a collection of events formed by subsets of the set of outcomes and probabilities defined for all events. A reformulation in terms of propositions allows to use the maximum entropy method to assign the probabilities taking some constraints into account. The construction of a probability space for quantum models is determined by the choice of propositions, choosing the constraints and making the probability assignment by the maximum entropy method. This approach shows, how typical quantum distributions such as Maxwell-Boltzmann, Fermi-Dirac and Bose-Einstein are partly related with well-known classical distributions. The relation between the conditional probability density, given some averages as constraints and the appropriate ensemble is elucidated.
Integrated Space Asset Management Database and Modeling
MacLeod, Todd; Gagliano, Larry; Percy, Thomas; Mason, Shane
2015-01-01
Effective Space Asset Management is one key to addressing the ever-growing issue of space congestion. It is imperative that agencies around the world have access to data regarding the numerous active assets and pieces of space junk currently tracked in orbit around the Earth. At the center of this issues is the effective management of data of many types related to orbiting objects. As the population of tracked objects grows, so too should the data management structure used to catalog technical specifications, orbital information, and metadata related to those populations. Marshall Space Flight Center's Space Asset Management Database (SAM-D) was implemented in order to effectively catalog a broad set of data related to known objects in space by ingesting information from a variety of database and processing that data into useful technical information. Using the universal NORAD number as a unique identifier, the SAM-D processes two-line element data into orbital characteristics and cross-references this technical data with metadata related to functional status, country of ownership, and application category. The SAM-D began as an Excel spreadsheet and was later upgraded to an Access database. While SAM-D performs its task very well, it is limited by its current platform and is not available outside of the local user base. Further, while modeling and simulation can be powerful tools to exploit the information contained in SAM-D, the current system does not allow proper integration options for combining the data with both legacy and new M&S tools. This paper provides a summary of SAM-D development efforts to date and outlines a proposed data management infrastructure that extends SAM-D to support the larger data sets to be generated. A service-oriented architecture model using an information sharing platform named SIMON will allow it to easily expand to incorporate new capabilities, including advanced analytics, M&S tools, fusion techniques and user interface for
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
Energy Technology Data Exchange (ETDEWEB)
Steinacker, Harold C., E-mail: harold.steinacker@univie.ac.at
2016-09-15
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.
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...... for the vector turbulence process incorporating its phase spectrum in one stage, and its results are compared with a conventional ARMA modeling method....... 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...
A probabilistic model of RNA conformational space
DEFF Research Database (Denmark)
Frellsen, Jes; Moltke, Ida; Thiim, Martin
2009-01-01
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......, the discrete nature of the fragments necessitates the use of carefully tuned, unphysical energy functions, and their non-probabilistic nature impairs unbiased sampling. We offer a solution to the sampling problem that removes these important limitations: a probabilistic model of RNA structure that allows......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...
Numerical Modeling of Ophthalmic Response to Space
Nelson, E. S.; Myers, J. G.; Mulugeta, L.; Vera, J.; Raykin, J.; Feola, A.; Gleason, R.; Samuels, B.; Ethier, C. R.
2015-01-01
To investigate ophthalmic changes in spaceflight, we would like to predict the impact of blood dysregulation and elevated intracranial pressure (ICP) on Intraocular Pressure (IOP). Unlike other physiological systems, there are very few lumped parameter models of the eye. The eye model described here is novel in its inclusion of the human choroid and retrobulbar subarachnoid space (rSAS), which are key elements in investigating the impact of increased ICP and ocular blood volume. Some ingenuity was required in modeling the blood and rSAS compartments due to the lack of quantitative data on essential hydrodynamic quantities, such as net choroidal volume and blood flowrate, inlet and exit pressures, and material properties, such as compliances between compartments.
A discrete-space urban model with environmental amenities
Liaila Tajibaeva; Robert G. Haight; Stephen Polasky
2008-01-01
This paper analyzes the effects of providing environmental amenities associated with open space in a discrete-space urban model and characterizes optimal provision of open space across a metropolitan area. The discrete-space model assumes distinct neighborhoods in which developable land is homogeneous within a neighborhood but heterogeneous across neighborhoods. Open...
Sato, K. Y.; Tomko, D. L.; Levine, H. G.; Quincy, C. D.; Rayl, N. A.; Sowa, M. B.; Taylor, E. M.; Sun, S. C.; Kundrot, C. E.
2018-02-01
Model organisms are foundational for conducting physiological and systems biology research to define how life responds to the deep space environment. The organisms, areas of research, and Deep Space Gateway capabilities needed will be presented.
Directory of Open Access Journals (Sweden)
Carlos Coimbra-Araujo
2017-08-01
Full Text Available For several reasons, the Exact Sciences have been shown as one of the areas of scientific knowledge that most demand actions in non-formal spaces of education. One of the main reasons lies in the fact that Mathematics, Physics, Chemistry and Astronomy are traditionally addressed, within the school environment and in the formal curriculum, unrelated to the student reality. Such subjects are often seen as a set of inflexible and incomprehensible principles. In this aspect, the present work reviews the main problems surrounding the teaching of the mentioned scientific areas, highlighting non-formal tools for the teaching of Mathematics, Physics, Chemistry, Astronomy and, in particular, the modern virtual environments of teaching modeled by Computing Science. Other historical difficulties that the formal education of Exact Sciences has suffered in Brazil are also presented, as well some of the main non-formal resources sought to complement the curriculum that is usually presented in the classroom.
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...... parallel to the fibre axis. Consequently, they cannot easily evaluate the potential at the boundary nodes of a boundary-element electrode model. The Fourier-domain models employ axial-symmetric ring source models, and thereby provide higher accuracy that the line source model, where the source is lumped...... including anisotropy show that the spatial models require extreme care in the integration procedure owing to the singularity in the weighting functions. With adequate sampling, the spatial models can evaluate extracellular potentials with high accuracy....
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
Space Weather Action Plan Solar Radio Burst Phase 1 Benchmarks and the Steps to Phase 2
Biesecker, D. A.; White, S. M.; Gopalswamy, N.; Black, C.; Love, J. J.; Pierson, J.
2017-12-01
Solar radio bursts, when at the right frequency and when strong enough, can interfere with radar, communication, and tracking signals. In severe cases, radio bursts can inhibit the successful use of radio communications and disrupt a wide range of systems that are reliant on Position, Navigation, and Timing services on timescales ranging from minutes to hours across wide areas on the dayside of Earth. The White House's Space Weather Action Plan asked for solar radio burst intensity benchmarks for an event occurrence frequency of 1 in 100 years and also a theoretical maximum intensity benchmark. The benchmark team has developed preliminary (phase 1) benchmarks for the VHF (30-300 MHz), UHF (300-3000 MHz), GPS (1176-1602 MHz), F10.7 (2800 MHz), and Microwave (4000-20000) bands. The preliminary benchmarks were derived based on previously published work. Limitations in the published work will be addressed in phase 2 of the benchmark process. In addition, deriving theoretical maxima requires additional work, where it is even possible to, in order to meet the Action Plan objectives. In this presentation, we will present the phase 1 benchmarks, the basis used to derive them, and the limitations of that work. We will also discuss the work that needs to be done to complete the phase 2 benchmarks.
Using modeling to develop and evaluate a corrective action system
International Nuclear Information System (INIS)
Rodgers, L.
1995-01-01
At a former trucking facility in EPA Region 4, a corrective action system was installed to remediate groundwater and soil contaminated with gasoline and fuel oil products released from several underground storage tanks (USTs). Groundwater modeling was used to develop the corrective action plan and later used with soil vapor modeling to evaluate the systems effectiveness. Groundwater modeling was used to determine the effects of a groundwater recovery system on the water table at the site. Information gathered during the assessment phase was used to develop a three dimensional depiction of the subsurface at the site. Different groundwater recovery schemes were then modeled to determine the most effective method for recovering contaminated groundwater. Based on the modeling and calculations, a corrective action system combining soil vapor extraction (SVE) and groundwater recovery was designed. The system included seven recovery wells, to extract both soil vapor and groundwater, and a groundwater treatment system. Operation and maintenance of the system included monthly system sampling and inspections and quarterly groundwater sampling. After one year of operation the effectiveness of the system was evaluated. A subsurface soil gas model was used to evaluate the effects of the SVE system on the site contamination as well as its effects on the water table and groundwater recovery operations. Groundwater modeling was used in evaluating the effectiveness of the groundwater recovery system. Plume migration and capture were modeled to insure that the groundwater recovery system at the site was effectively capturing the contaminant plume. The two models were then combined to determine the effects of the two systems, acting together, on the remediation process
Model-Based Trade Space Exploration for Near-Earth Space Missions
Cohen, Ronald H.; Boncyk, Wayne; Brutocao, James; Beveridge, Iain
2005-01-01
We developed a capability for model-based trade space exploration to be used in the conceptual design of Earth-orbiting space missions. We have created a set of reusable software components to model various subsystems and aspects of space missions. Several example mission models were created to test the tools and process. This technique and toolset has demonstrated itself to be valuable for space mission architectural design.
Space Surveillance Network and Analysis Model (SSNAM) Performance Improvements
National Research Council Canada - National Science Library
Butkus, Albert; Roe, Kevin; Mitchell, Barbara L; Payne, Timothy
2007-01-01
... capacity by sensor, models for sensors yet to be created, user defined weather conditions, National Aeronautical and Space Administration catalog growth model including space debris, and solar flux just to name a few...
Modeling Physarum space exploration using memristors
International Nuclear Information System (INIS)
Ntinas, V; Sirakoulis, G Ch; Vourkas, I; Adamatzky, A I
2017-01-01
Slime mold Physarum polycephalum optimizes its foraging behaviour by minimizing the distances between the sources of nutrients it spans. When two sources of nutrients are present, the slime mold connects the sources, with its protoplasmic tubes, along the shortest path. We present a two-dimensional mesh grid memristor based model as an approach to emulate Physarum’s foraging strategy, which includes space exploration and reinforcement of the optimally formed interconnection network in the presence of multiple aliment sources. The proposed algorithmic approach utilizes memristors and LC contours and is tested in two of the most popular computational challenges for Physarum, namely maze and transportation networks. Furthermore, the presented model is enriched with the notion of noise presence, which positively contributes to a collective behavior and enables us to move from deterministic to robust results. Consequently, the corresponding simulation results manage to reproduce, in a much better qualitative way, the expected transportation networks. (paper)
Space weather: Modeling and forecasting ionospheric
International Nuclear Information System (INIS)
Calzadilla Mendez, A.
2008-01-01
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)
Space Weather Models at the CCMC And Their Capabilities
Hesse, Michael; Rastatter, Lutz; MacNeice, Peter; Kuznetsova, Masha
2007-01-01
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 focus of CCMC activities is on validation and verification of space weather models, and on the transition of appropriate models to space weather forecast centers. As part of the latter activity, the CCMC develops real-time simulation systems that stress models through routine execution. A by-product of these real-time calculations is the ability to derive model products, which may be useful for space weather operators. In this presentation, we will provide an overview of the community-provided, space weather-relevant, model suite, which resides at CCMC. We will discuss current capabilities, and analyze expected future developments of space weather related modeling.
International Space Station Model Correlation Analysis
Laible, Michael R.; Fitzpatrick, Kristin; Hodge, Jennifer; Grygier, Michael
2018-01-01
This paper summarizes the on-orbit structural dynamic data and the related modal analysis, model validation and correlation performed for the International Space Station (ISS) configuration ISS Stage ULF7, 2015 Dedicated Thruster Firing (DTF). The objective of this analysis is to validate and correlate the analytical models used to calculate the ISS internal dynamic loads and compare the 2015 DTF with previous tests. During the ISS configurations under consideration, on-orbit dynamic measurements were collected using the three main ISS instrumentation systems; Internal Wireless Instrumentation System (IWIS), External Wireless Instrumentation System (EWIS) and the Structural Dynamic Measurement System (SDMS). The measurements were recorded during several nominal on-orbit DTF tests on August 18, 2015. Experimental modal analyses were performed on the measured data to extract modal parameters including frequency, damping, and mode shape information. Correlation and comparisons between test and analytical frequencies and mode shapes were performed to assess the accuracy of the analytical models for the configurations under consideration. These mode shapes were also compared to earlier tests. Based on the frequency comparisons, the accuracy of the mathematical models is assessed and model refinement recommendations are given. In particular, results of the first fundamental mode will be discussed, nonlinear results will be shown, and accelerometer placement will be assessed.
Modelling of protective actions in the German Risk Study (FRG)
International Nuclear Information System (INIS)
Burkart, A.K.
1981-01-01
An emergency response model for nuclear accidents has to allow for a great number of widely different emergency conditions. In addition, it should be compatible with the pertinent laws, regulations, ordinances, guidelines, criteria and reference levels. The German (FRG) guidelines are basic and flexible rather than precise, many decisions being left to the emergency management. In the Risk Study these decisions had to be anticipated. After a brief discussion of the basis of the emergency response model employed in the German Risk Study (FRG), the essential requirements to be met are listed. The main part of the paper deals with the rationale and specification of protective actions. As a result of the calculations the numbers of persons and sizes of areas involved in protective actions are presented. The last section deals with the variation of input data. (author)
Re-modeling Chara action potential: II. The action potential form under salinity stress
Directory of Open Access Journals (Sweden)
Mary Jane Beilby
2017-04-01
Full Text Available In part I we established Thiel-Beilby model of the Chara action potential (AP. In part II the AP is investigated in detail at the time of saline stress. Even very short exposure of salt-sensitive Chara cells to artificial pond water with 50 mM NaCl (Saline APW modified the AP threshold and drastically altered the AP form. Detailed modeling of 14 saline APs from 3 cells established that both the Ca2+ pump and the Ca2+ channels on internal stores seem to be affected, with the changes sometimes cancelling and sometimes re-enforcing each other, leading to APs with long durations and very complex forms. The exposure to salinity offers further insights into AP mechanism and suggests future experiments. The prolonged APs lead to greater loss of chloride and potassium ions, compounding the effects of saline stress.
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.
Modeling, Analysis, and Optimization Issues for Large Space Structures
Pinson, L. D. (Compiler); Amos, A. K. (Compiler); Venkayya, V. B. (Compiler)
1983-01-01
Topics concerning the modeling, analysis, and optimization of large space structures are discussed including structure-control interaction, structural and structural dynamics modeling, thermal analysis, testing, and design.
A social identity model of pro-environmental action (SIMPEA).
Fritsche, Immo; Barth, Markus; Jugert, Philipp; Masson, Torsten; Reese, Gerhard
2018-03-01
Large-scale environmental crises are genuinely collective phenomena: they usually result from collective, rather than personal, behavior and how they are cognitively represented and appraised is determined by collectively shared interpretations (e.g., differing across ideological groups) and based on concern for collectives (e.g., humankind, future generations) rather than for individuals. Nevertheless, pro-environmental action has been primarily investigated as a personal decision-making process. We complement this research with a social identity perspective on pro-environmental action. Social identity is the human capacity to define the self in terms of "We" instead of "I," enabling people to think and act as collectives, which should be crucial given personal insufficiency to appraise and effectively respond to environmental crises. We propose a Social Identity Model of Pro-Environmental Action (SIMPEA) of how social identity processes affect both appraisal of and behavioral responses to large-scale environmental crises. We review related and pertinent research providing initial evidence for the role of 4 social identity processes hypothesized in SIMPEA. Specifically, we propose that ingroup identification, ingroup norms and goals, and collective efficacy determine environmental appraisals as well as both private and public sphere environmental action. These processes are driven by personal and collective emotions and motivations that arise from environmental appraisal and operate on both a deliberate and automatic processing level. Finally, we discuss SIMPEA's implications for the research agenda in environmental and social psychology and for interventions fostering pro-environmental action. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
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
Model space dimensionalities for multiparticle fermion systems
International Nuclear Information System (INIS)
Draayer, J.P.; Valdes, H.T.
1985-01-01
A menu driven program for determining the dimensionalities of fixed-(J) [or (J,T)] model spaces built by distributing identical fermions (electrons, neutrons, protons) or two distinguihable fermion types (neutron-proton and isospin formalisms) among any mixture of positive and negative parity spherical orbitals is presented. The algorithm, built around the elementary difference formula d(J)=d(M=J)-d(M=J+1), takes full advantage of M->-M and particle-hole symmetries. A 96 K version of the program suffices for as compilated a case as d[(+1/2, +3/2, + 5/2, + 7/2-11/2)sup(n-26)J=2 + ,T=7]=210,442,716,722 found in the 0hω valence space of 56 126 Ba 70 . The program calculates the total fixed-(Jsup(π)) or fixed-(Jsup(π),T) dimensionality of a model space generated by distributing a specified number of fermions among a set of input positive and negative parity (π) spherical (j) orbitals. The user is queried at each step to select among various options: 1. formalism - identical particle, neutron-proton, isospin; 2. orbits -bumber, +/-2*J of all orbits; 3. limits -minimum/maximum number of particles of each parity; 4. specifics - number of particles, +/-2*J (total), 2*T; 5. continue - same orbit structure, new case quit. Though designed for nuclear applications (jj-coupling), the program can be used in the atomic case (LS-coupling) so long as half integer spin values (j=l+-1/2) are input for the valnce orbitals. Mutiple occurrences of a given j value are properly taken into account. A minor extension provides labelling information for a generalized seniority classification scheme. The program logic is an adaption of methods used in statistical spectroscopy to evaluate configuration averages. Indeed, the need for fixed symmetry leve densities in spectral distribution theory motivated this work. The methods extend to other group structures where there are M-like additive quantum labels. (orig.)
Modelling of air-conditioned and heated spaces
Energy Technology Data Exchange (ETDEWEB)
Moehl, U
1987-01-01
A space represents a complex system involving numerous components, manipulated variables and disturbances which need to be described if dynamic behaviour of space air is to be determined. A justifiable amount of simulation input is determined by the application of adjusted modelling of the individual components. The determination of natural air exchange in heated spaces and of space-air flow in air-conditioned space are a primary source of uncertainties. (orig.).
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.
Percy-Smith, Barry; Carney, Clare
2011-01-01
This paper discusses learning from a project that set out to explore how the general public perceived the value of public art in the context of urban regeneration of a city centre space. Whilst not set up explicitly as an action research project, the paper discusses the way in which participatory public art projects of this kind can be understood…
Construction of fuzzy spaces and their applications to matrix models
Abe, Yasuhiro
Quantization of spacetime by means of finite dimensional matrices is the basic idea of fuzzy spaces. There remains an issue of quantizing time, however, the idea is simple and it provides an interesting interplay of various ideas in mathematics and physics. Shedding some light on such an interplay is the main theme of this dissertation. The dissertation roughly separates into two parts. In the first part, we consider rather mathematical aspects of fuzzy spaces, namely, their construction. We begin with a review of construction of fuzzy complex projective spaces CP k (k = 1, 2, · · ·) in relation to geometric quantization. This construction facilitates defining symbols and star products on fuzzy CPk. Algebraic construction of fuzzy CPk is also discussed. We then present construction of fuzzy S 4, utilizing the fact that CP3 is an S2 bundle over S4. Fuzzy S4 is obtained by imposing an additional algebraic constraint on fuzzy CP3. Consequently it is proposed that coordinates on fuzzy S4 are described by certain block-diagonal matrices. It is also found that fuzzy S8 can analogously be constructed. In the second part of this dissertation, we consider applications of fuzzy spaces to physics. We first consider theories of gravity on fuzzy spaces, anticipating that they may offer a novel way of regularizing spacetime dynamics. We obtain actions for gravity on fuzzy S2 and on fuzzy CP3 in terms of finite dimensional matrices. Application to M(atrix) theory is also discussed. With an introduction of extra potentials to the theory, we show that it also has new brane solutions whose transverse directions are described by fuzzy S 4 and fuzzy CP3. The extra potentials can be considered as fuzzy versions of differential forms or fluxes, which enable us to discuss compactification models of M(atrix) theory. In particular, compactification down to fuzzy S4 is discussed and a realistic matrix model of M-theory in four-dimensions is proposed.
On a Poisson homogeneous space of bilinear forms with a Poisson-Lie action
Chekhov, L. O.; Mazzocco, M.
2017-12-01
Let \\mathscr A be the space of bilinear forms on C^N with defining matrices A endowed with a quadratic Poisson structure of reflection equation type. The paper begins with a short description of previous studies of the structure, and then this structure is extended to systems of bilinear forms whose dynamics is governed by the natural action A\\mapsto B ABT} of the {GL}_N Poisson-Lie group on \\mathscr A. A classification is given of all possible quadratic brackets on (B, A)\\in {GL}_N× \\mathscr A preserving the Poisson property of the action, thus endowing \\mathscr A with the structure of a Poisson homogeneous space. Besides the product Poisson structure on {GL}_N× \\mathscr A, there are two other (mutually dual) structures, which (unlike the product Poisson structure) admit reductions by the Dirac procedure to a space of bilinear forms with block upper triangular defining matrices. Further generalisations of this construction are considered, to triples (B,C, A)\\in {GL}_N× {GL}_N× \\mathscr A with the Poisson action A\\mapsto B ACT}, and it is shown that \\mathscr A then acquires the structure of a Poisson symmetric space. Generalisations to chains of transformations and to the quantum and quantum affine algebras are investigated, as well as the relations between constructions of Poisson symmetric spaces and the Poisson groupoid. Bibliography: 30 titles.
One-loop effective action for non-local modified Gauss-Bonnet gravity in de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Cognola, Guido; Zerbini, Sergio [Universita di Trento (Italy); Istituto Nazionale di Fisica Nucleare Gruppo Collegato di Trento, Dipartimento di Fisica, Trento (Italy); Elizalde, Emilio [Consejo Superior de Investigaciones Cientificas (ICE/CSIC) and Institut d' Estudis Espacials de Catalunya (IEEC), Facultat Ciencies, Bellaterra (Barcelona) (Spain); Nojiri, Shin' ichi [Nagoya University, Department of Physics, Nagoya (Japan); Odintsov, Sergei D. [Consejo Superior de Investigaciones Cientificas (ICE/CSIC) and Institut d' Estudis Espacials de Catalunya (IEEC), Facultat Ciencies, Bellaterra (Barcelona) (Spain); ICREA, Barcelona (Spain); TSPU, Center of Theor. Phys., Tomsk (Russian Federation)
2009-12-15
We discuss the classical and quantum properties of non-local modified Gauss-Bonnet gravity in de Sitter space, using its equivalent representation via string-inspired local scalar-Gauss-Bonnet gravity with a scalar potential. A classical, multiple de Sitter universe solution is found where one of the de Sitter phases corresponds to the primordial inflationary epoch, while the other de Sitter space solution - the one with the smallest Hubble rate - describes the late-time acceleration of our universe. A Chameleon scenario for the theory under investigation is developed, and it is successfully used to show that the theory complies with gravitational tests. An explicit expression for the one-loop effective action for this non-local modified Gauss-Bonnet gravity in the de Sitter space is obtained. It is argued that this effective action might be an important step towards the solution of the cosmological constant problem. (orig.)
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.
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...
Spectral action for Bianchi type-IX cosmological models
International Nuclear Information System (INIS)
Fan, Wentao; Fathizadeh, Farzad; Marcolli, Matilde
2015-01-01
A rationality result previously proved for Robertson-Walker metrics is extended to a homogeneous anisotropic cosmological model, namely the Bianchi type-IX minisuperspace. It is shown that the Seeley-de Witt coefficients appearing in the expansion of the spectral action for the Bianchi type-IX geometry are expressed in terms of polynomials with rational coefficients in the cosmic evolution factors w_1(t),w_2(t),w_3(t), and their higher derivates with respect to time. We begin with the computation of the Dirac operator of this geometry and calculate the coefficients a_0,a_2,a_4 of the spectral action by using heat kernel methods and parametric pseudodifferential calculus. An efficient method is devised for computing the Seeley-de Witt coefficients of a geometry by making use of Wodzicki’s noncommutative residue, and it is confirmed that the method checks out for the cosmological model studied in this article. The advantages of the new method are discussed, which combined with symmetries of the Bianchi type-IX metric, yield an elegant proof of the rationality result.
Spectral action for Bianchi type-IX cosmological models
Energy Technology Data Exchange (ETDEWEB)
Fan, Wentao; Fathizadeh, Farzad; Marcolli, Matilde [Division of Physics, Mathematics and Astronomy, California Institute of Technology,1200 E. California Blvd., Pasadena, CA 91125 (United States)
2015-10-13
A rationality result previously proved for Robertson-Walker metrics is extended to a homogeneous anisotropic cosmological model, namely the Bianchi type-IX minisuperspace. It is shown that the Seeley-de Witt coefficients appearing in the expansion of the spectral action for the Bianchi type-IX geometry are expressed in terms of polynomials with rational coefficients in the cosmic evolution factors w{sub 1}(t),w{sub 2}(t),w{sub 3}(t), and their higher derivates with respect to time. We begin with the computation of the Dirac operator of this geometry and calculate the coefficients a{sub 0},a{sub 2},a{sub 4} of the spectral action by using heat kernel methods and parametric pseudodifferential calculus. An efficient method is devised for computing the Seeley-de Witt coefficients of a geometry by making use of Wodzicki’s noncommutative residue, and it is confirmed that the method checks out for the cosmological model studied in this article. The advantages of the new method are discussed, which combined with symmetries of the Bianchi type-IX metric, yield an elegant proof of the rationality result.
A general-model-space diagrammatic perturbation theory
International Nuclear Information System (INIS)
Hose, G.; Kaldor, U.
1980-01-01
A diagrammatic many-body perturbation theory applicable to arbitrary model spaces is presented. The necessity of having a complete model space (all possible occupancies of the partially-filled shells) is avoided. This requirement may be troublesome for systems with several well-spaced open shells, such as most atomic and molecular excited states, as a complete model space spans a very broad energy range and leaves out states within that range, leading to poor or no convergence of the perturbation series. The method presented here would be particularly useful for such states. The solution of a model problem (He 2 excited Σ + sub(g) states) is demonstrated. (Auth.)
Radicals excess in the retina: A model for light flashes in space
International Nuclear Information System (INIS)
Narici, L.; De Martino, A.; Brunetti, V.; Rinaldi, A.; Sannita, W.G.; Paci, M.
2009-01-01
The risk due to cosmic radiation is a major issue in planning future missions to the Moon or Mars and would be critical if inadequately addressed. Functional risks must also be considered. The perception of light flashes reported by astronauts in space, and ascribed mostly to the action of ionizing radiation in the eye (retina), is an evidence for radiation functional interaction. No detailed model of the ion/retina interaction is yet available. Here we present the first model for a generation mechanism compatible with light flashes in space, and the results of in vitro tests supporting it. The model can be a common end point for the interactions between ionizing radiation and visual system in space. It would also support the assessment of functional radiation risks in space.
Axiomatics of uniform space-time models
International Nuclear Information System (INIS)
Levichev, A.V.
1983-01-01
The mathematical statement of space-time axiomatics of the special theory of relativity is given; it postulates that the space-time M is the binding single boundary Hausedorf local-compact four-dimensional topological space with the given order. The theorem is proved: if the invariant order in the four-dimensional group M is given by the semi-group P, which contingency K contains inner points , then M is commutative. The analogous theorem is correct for the group of two and three dimensionalities
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...
Brain Functors: A Mathematical Model of Intentional Perception and Action
Directory of Open Access Journals (Sweden)
David Ellerman
2016-03-01
Full Text Available Category theory has foundational importance because it provides conceptual lenses to characterize what is important and universal in mathematics - with adjunctions being the primary lens. If adjunctions are so important in mathematics, then perhaps they will isolate concepts of some importance in the empirical sciences. But the applications of adjunctions have been hampered by an overly restrictive formulation that avoids heteromorphisms or hets. By reformulating an adjunction using hets, it is split into two parts, a left and a right semiadjunction. Semiadjunctions (essentially a formulation of universal mapping properties using hets can then be combined in a new way to define the notion of a brain functor that provides an abstract model of the intentionality of perception and action (as opposed to the passive reception of sense-data or the reflex generation of behavior.
Model Adaptation in Parametric Space for POD-Galerkin Models
Gao, Haotian; Wei, Mingjun
2017-11-01
The development of low-order POD-Galerkin models is largely motivated by the expectation to use the model developed with a set of parameters at their native values to predict the dynamic behaviors of the same system under different parametric values, in other words, a successful model adaptation in parametric space. However, most of time, even small deviation of parameters from their original value may lead to large deviation or unstable results. It has been shown that adding more information (e.g. a steady state, mean value of a different unsteady state, or an entire different set of POD modes) may improve the prediction of flow with other parametric states. For a simple case of the flow passing a fixed cylinder, an orthogonal mean mode at a different Reynolds number may stabilize the POD-Galerkin model when Reynolds number is changed. For a more complicated case of the flow passing an oscillatory cylinder, a global POD-Galerkin model is first applied to handle the moving boundaries, then more information (e.g. more POD modes) is required to predicate the flow under different oscillatory frequencies. Supported by ARL.
Phase-space dynamics of Bianchi IX cosmological models
International Nuclear Information System (INIS)
Soares, I.D.
1985-01-01
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) [pt
Therapeutic action of ghrelin in a mouse model of colitis.
Gonzalez-Rey, Elena; Chorny, Alejo; Delgado, Mario
2006-05-01
Ghrelin is a novel growth hormone-releasing peptide with potential endogenous anti-inflammatory activities ameliorating some pathologic inflammatory conditions. Crohn's disease is a chronic debilitating disease characterized by severe T helper cell (Th)1-driven inflammation of the colon. The aim of this study was to investigate the therapeutic effect of ghrelin in a murine model of colitis. We examined the anti-inflammatory action of ghrelin in the colitis induced by intracolonic administration of trinitrobenzene sulfonic acid. Diverse clinical signs of the disease were evaluated, including weight loss, diarrhea, colitis, and histopathology. We also investigated the mechanisms involved in the potential therapeutic effect of ghrelin, such as inflammatory cytokines and chemokines, Th1-type response, and regulatory factors. Ghrelin ameliorated significantly the clinical and histopathologic severity of the trinitrobenzene sulfonic acid-induced colitis; abrogating body weight loss, diarrhea, and inflammation; and increasing survival. The therapeutic effect was associated with down-regulation of both inflammatory and Th1-driven autoimmune response through the regulation of a wide spectrum of inflammatory mediators. In addition, a partial involvement of interluekin-10/transforming growth factor-beta1-secreting regulatory T cells in this therapeutic effect was demonstrated. Importantly, the ghrelin treatment was therapeutically effective in established colitis and avoided the recurrence of the disease. Our data demonstrate novel anti-inflammatory actions for ghrelin in the gastrointestinal tract, ie, the capacity to deactivate the intestinal inflammatory response and to restore mucosal immune tolerance at multiple levels. Consequently, ghrelin administration represents a novel possible therapeutic approach for the treatment of Crohn's disease and other Th1-mediated inflammatory diseases, such as rheumatoid arthritis and multiple sclerosis.
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...
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...
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 Br...
Directory of Open Access Journals (Sweden)
Philip Gemmell
Full Text Available Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K(+, inward rectifying K(+, L-type Ca(2+, and Na(+/K(+ pump currents in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al. at multiple cycle lengths (400, 600, 1,000 ms was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in
Gemmell, Philip; Burrage, Kevin; Rodriguez, Blanca; Quinn, T Alexander
2014-01-01
Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K(+), inward rectifying K(+), L-type Ca(2+), and Na(+)/K(+) pump currents) in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al.) at multiple cycle lengths (400, 600, 1,000 ms) was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in experimentally
Variational methods and effective actions in string models
International Nuclear Information System (INIS)
Dereli, T.; Tucker, R.W.
1987-01-01
Effective actions motivated by zero-order and first-order actions are examined. Particular attention is devoted to a variational procedure that is consistent with the structure equations involving the Lorentz connection. Attention is drawn to subtleties that can arise in varying higher-order actions and an efficient procedure developed to handle these cases using the calculus of forms. The effect of constrained variations on the field equations is discussed. (author)
The space-time model according to dimensional continuous space-time theory
International Nuclear Information System (INIS)
Martini, Luiz Cesar
2014-01-01
This article results from the Dimensional Continuous Space-Time Theory for which the introductory theoretician was presented in [1]. A theoretical model of the Continuous Space-Time is presented. The wave equation of time into absolutely stationary empty space referential will be described in detail. The complex time, that is the time fixed on the infinite phase time speed referential, is deduced from the New View of Relativity Theory that is being submitted simultaneously with this article in this congress. Finally considering the inseparable Space-Time is presented the duality equation wave-particle.
Space Particle Hazard Measurement and Modeling
2007-11-30
the spacecraft and perturbations of the environment generated by the spacecraft. Koons et al. (1999) compiled and studied all spacecraft anomalies...unrealistic for D12 than for Dα0p). However, unlike the stability problems associated with the original cross diffusion terms, they are quite manageable ...E), to mono-energetic beams of charged particles of known energies which enables one, in principle , to unfold the space environment spectrum, j(E
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.
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.
Heterotic non-linear sigma models with anti-de Sitter target spaces
International Nuclear Information System (INIS)
Michalogiorgakis, Georgios; Gubser, Steven S.
2006-01-01
We calculate the beta function of non-linear sigma models with S D+1 and AdS D+1 target spaces in a 1/D expansion up to order 1/D 2 and to all orders in α ' . This beta function encodes partial information about the spacetime effective action for the heterotic string to all orders in α ' . We argue that a zero of the beta function, corresponding to a worldsheet CFT with AdS D+1 target space, arises from competition between the one-loop and higher-loop terms, similarly to the bosonic and supersymmetric cases studied previously in [J.J. Friess, S.S. Gubser, Non-linear sigma models with anti-de Sitter target spaces, Nucl. Phys. B 750 (2006) 111-141]. Various critical exponents of the non-linear sigma model are calculated, and checks of the calculation are presented
Track structure model of cell damage in space flight
Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Shinn, Judy L.; Ngo, Duc M.
1992-01-01
The phenomenological track-structure model of cell damage is discussed. A description of the application of the track-structure model with the NASA Langley transport code for laboratory and space radiation is given. Comparisons to experimental results for cell survival during exposure to monoenergetic, heavy-ion beams are made. The model is also applied to predict cell damage rates and relative biological effectiveness for deep-space exposures.
Mathematical Model of the Public Understanding of Space Science
Prisniakov, V.; Prisniakova, L.
The success in deployment of the space programs now in many respects depends on comprehension by the citizens of necessity of programs, from "space" erudition of country. Purposefulness and efficiency of the "space" teaching and educational activity depend on knowledge of relationships between separate variables of such process. The empirical methods of ``space'' well-information of the taxpayers should be supplemented by theoretical models permitting to demonstrate a ways of control by these processes. Authors on the basis of their experience of educational activity during 50- years of among the students of space-rocket profession obtain an equation of ``space" state of the society determining a degree of its knowledge about Space, about achievements in its development, about indispensable lines of investigations, rates of informatization of the population. It is supposed, that the change of the space information consists of two parts: (1) - from going of the information about practical achievements, about development special knowledge requiring of independent financing, and (2) from intensity of dissemination of the ``free" information of a general educational line going to the population through mass-media, book, in family, in educational institutions, as a part of obligatory knowledge of any man, etc. In proposed model the level space well-information of the population depends on intensity of dissemination in the society of the space information, and also from a volume of financing of space-rocket technology, from a part of population of the employment in the space-rocket programs, from a factor of education of the population in adherence to space problems, from welfare and mentality of the people, from a rate of unemployment and material inequality. Obtained in the report on these principles the equation of a space state of the society corresponds to catastrophe such as cusp, the analysis has shown which one ways of control of the public understanding of space
Preliminary Multi-Variable Parametric Cost Model for Space Telescopes
Stahl, H. Philip; Hendrichs, Todd
2010-01-01
This slide presentation reviews creating a preliminary multi-variable cost model for the contract costs of making a space telescope. There is discussion of the methodology for collecting the data, definition of the statistical analysis methodology, single variable model results, testing of historical models and an introduction of the multi variable models.
Superfield Lax formalism of supersymmetric sigma model on symmetric spaces
International Nuclear Information System (INIS)
Saleem, U.; Hassan, M.
2006-01-01
We present a superfield Lax formalism of the superspace sigma model based on the target space G/H and show that a one-parameter family of flat superfield connections exists if the target space G/H is a symmetric space. The formalism has been related to the existence of an infinite family of local and non-local superfield conserved quantities. A few examples have been given to illustrate the results. (orig.)
Gravity mediated Dark Matter models in the de Sitter space
Vancea, Ion V.
2018-01-01
In this paper, we generalize the simplified Dark Matter models with graviton mediator to the curved space-time, in particular to the de Sitter space. We obtain the generating functional of the Green's functions in the Euclidean de Sitter space for the covariant free gravitons. We determine the generating functional of the interacting theory between Dark Matter particles and the covariant gravitons. Also, we calculate explicitly the 2-point and 3-point interacting Green's functions for the sym...
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
Validation of nuclear models used in space radiation shielding applications
International Nuclear Information System (INIS)
Norman, Ryan B.; Blattnig, Steve R.
2013-01-01
A program of verification and validation has been undertaken to assess the applicability of models to space radiation shielding applications and to track progress as these models are developed over time. In this work, simple validation metrics applicable to testing both model accuracy and consistency with experimental data are developed. The developed metrics treat experimental measurement uncertainty as an interval and are therefore applicable to cases in which epistemic uncertainty dominates the experimental data. To demonstrate the applicability of the metrics, nuclear physics models used by NASA for space radiation shielding applications are compared to an experimental database consisting of over 3600 experimental cross sections. A cumulative uncertainty metric is applied to the question of overall model accuracy, while a metric based on the median uncertainty is used to analyze the models from the perspective of model development by examining subsets of the model parameter space.
Payload maintenance cost model for the space telescope
White, W. L.
1980-01-01
An optimum maintenance cost model for the space telescope for a fifteen year mission cycle was developed. Various documents and subsequent updates of failure rates and configurations were made. The reliability of the space telescope for one year, two and one half years, and five years were determined using the failure rates and configurations. The failure rates and configurations were also used in the maintenance simulation computer model which simulate the failure patterns for the fifteen year mission life of the space telescope. Cost algorithms associated with the maintenance options as indicated by the failure patterns were developed and integrated into the model.
State-space prediction model for chaotic time series
Alparslan, A. K.; Sayar, M.; Atilgan, A. R.
1998-08-01
A simple method for predicting the continuation of scalar chaotic time series ahead in time is proposed. The false nearest neighbors technique in connection with the time-delayed embedding is employed so as to reconstruct the state space. A local forecasting model based upon the time evolution of the topological neighboring in the reconstructed phase space is suggested. A moving root-mean-square error is utilized in order to monitor the error along the prediction horizon. The model is tested for the convection amplitude of the Lorenz model. The results indicate that for approximately 100 cycles of the training data, the prediction follows the actual continuation very closely about six cycles. The proposed model, like other state-space forecasting models, captures the long-term behavior of the system due to the use of spatial neighbors in the state space.
Properties of Brownian Image Models in Scale-Space
DEFF Research Database (Denmark)
Pedersen, Kim Steenstrup
2003-01-01
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...... 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......In this paper it is argued that the Brownian image model is the least committed, scale invariant, statistical image model which describes the second order statistics of natural images. Various properties of three different types of Gaussian image models (white noise, Brownian and fractional...
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.
Coupled iterated map models of action potential dynamics in a one-dimensional cable of cardiac cells
International Nuclear Information System (INIS)
Wang Shihong; Xie Yuanfang; Qu Zhilin
2008-01-01
Low-dimensional iterated map models have been widely used to study action potential dynamics in isolated cardiac cells. Coupled iterated map models have also been widely used to investigate action potential propagation dynamics in one-dimensional (1D) coupled cardiac cells, however, these models are usually empirical and not carefully validated. In this study, we first developed two coupled iterated map models which are the standard forms of diffusively coupled maps and overcome the limitations of the previous models. We then determined the coupling strength and space constant by quantitatively comparing the 1D action potential duration profile from the coupled cardiac cell model described by differential equations with that of the coupled iterated map models. To further validate the coupled iterated map models, we compared the stability conditions of the spatially uniform state of the coupled iterated maps and those of the 1D ionic model and showed that the coupled iterated map model could well recapitulate the stability conditions, i.e. the spatially uniform state is stable unless the state is chaotic. Finally, we combined conduction into the developed coupled iterated map model to study the effects of coupling strength on wave stabilities and showed that the diffusive coupling between cardiac cells tends to suppress instabilities during reentry in a 1D ring and the onset of discordant alternans in a periodically paced 1D cable
Uncertainty Driven Action (UDA) model: A foundation for unifying perspectives on design activity
DEFF Research Database (Denmark)
Cash, Philip; Kreye, Melanie
2017-01-01
are linked via uncertainty perception. The foundations of the UDA model in the design literature are elaborated in terms of the three core actions and their links to designer cognition and behaviour, utilising definitions and concepts from Activity Theory. The practical relevance and theoretical......This paper proposes the Uncertainty Driven Action (UDA) model, which unifies the fragmented literature on design activity. The UDA model conceptualises design activity as a process consisting of three core actions: information action, knowledge-sharing action, and representation action, which...... contributions of the UDA model are discussed. This paper contributes to the design literature by offering a comprehensive formalisation of design activity of individual designers, which connects cognition and action, to provide a foundation for understanding previously disparate descriptions of design activity....
A Simulation and Modeling Framework for Space Situational Awareness
International Nuclear Information System (INIS)
Olivier, S.S.
2008-01-01
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
Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee
We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach,
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
Field space entanglement entropy, zero modes and Lifshitz models
Huffel, Helmuth; Kelnhofer, Gerald
2017-12-01
The field space entanglement entropy of a quantum field theory is obtained by integrating out a subset of its fields. We study an interacting quantum field theory consisting of massless scalar fields on a closed compact manifold M. To this model we associate its Lifshitz dual model. The ground states of both models are invariant under constant shifts. We interpret this invariance as gauge symmetry and subject the models to proper gauge fixing. By applying the heat kernel regularization one can show that the field space entanglement entropies of the massless scalar field model and of its Lifshitz dual are agreeing.
Field space entanglement entropy, zero modes and Lifshitz models
Directory of Open Access Journals (Sweden)
Helmuth Huffel
2017-12-01
Full Text Available The field space entanglement entropy of a quantum field theory is obtained by integrating out a subset of its fields. We study an interacting quantum field theory consisting of massless scalar fields on a closed compact manifold M. To this model we associate its Lifshitz dual model. The ground states of both models are invariant under constant shifts. We interpret this invariance as gauge symmetry and subject the models to proper gauge fixing. By applying the heat kernel regularization one can show that the field space entanglement entropies of the massless scalar field model and of its Lifshitz dual are agreeing.
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....... It is also shown that on the slow manifold the dynamics of the satellites are well-approximated by the finite dimensional slack-spring model....
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...
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 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
1993-01-01
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).
Space engineering modeling and optimization with case studies
Pintér, János
2016-01-01
This book presents a selection of advanced case studies that cover a substantial range of issues and real-world challenges and applications in space engineering. Vital mathematical modeling, optimization methodologies and numerical solution aspects of each application case study are presented in detail, with discussions of a range of advanced model development and solution techniques and tools. Space engineering challenges are discussed in the following contexts: •Advanced Space Vehicle Design •Computation of Optimal Low Thrust Transfers •Indirect Optimization of Spacecraft Trajectories •Resource-Constrained Scheduling, •Packing Problems in Space •Design of Complex Interplanetary Trajectories •Satellite Constellation Image Acquisition •Re-entry Test Vehicle Configuration Selection •Collision Risk Assessment on Perturbed Orbits •Optimal Robust Design of Hybrid Rocket Engines •Nonlinear Regression Analysis in Space Engineering< •Regression-Based Sensitivity Analysis and Robust Design ...
Validation of ecological state space models using the Laplace approximation
DEFF Research Database (Denmark)
Thygesen, Uffe Høgsbro; Albertsen, Christoffer Moesgaard; Berg, Casper Willestofte
2017-01-01
Many statistical models in ecology follow the state space paradigm. For such models, the important step of model validation rarely receives as much attention as estimation or hypothesis testing, perhaps due to lack of available algorithms and software. Model validation is often based on a naive...... for estimation in general mixed effects models. Implementing one-step predictions in the R package Template Model Builder, we demonstrate that it is possible to perform model validation with little effort, even if the ecological model is multivariate, has non-linear dynamics, and whether observations...... useful directions in which the model could be improved....
Modelling Dowel Action of Discrete Reinforcing Bars in Cracked Concrete Structures
International Nuclear Information System (INIS)
Kwan, A. K. H.; Ng, P. L.; Lam, J. Y. K.
2010-01-01
Dowel action is one of the component actions for shear force transfer in cracked reinforced concrete. In finite element analysis of concrete structures, the use of discrete representation of reinforcing bars is considered advantageous over the smeared representation due to the relative ease of modelling the bond-slip behaviour. However, there is very limited research on how to simulate the dowel action of discrete reinforcing bars. Herein, a numerical model for dowel action of discrete reinforcing bars crossing cracks in concrete is developed. The model features the derivation of dowel stiffness matrix based on beam-on-elastic-foundation theory and the direct assemblage of dowel stiffness into the concrete element stiffness matrices. The dowel action model is incorporated in a nonlinear finite element programme with secant stiffness formulation. Deep beams tested in the literature are analysed and it is found that the incorporation of dowel action model improves the accuracy of analysis.
Low-energy effective action in nonperturbative electrodynamics in curved space-time
International Nuclear Information System (INIS)
Avramidi, Ivan G.; Fucci, Guglielmo
2009-01-01
We study the heat kernel for the Laplace-type partial differential operator acting on smooth sections of a complex spin-tensor bundle over a generic n-dimensional Riemannian manifold. Assuming that the curvature of the U(1) connection (that we call the electromagnetic field) is constant, we compute the first two coefficients of the nonperturbative asymptotic expansion of the heat kernel which are of zero and the first order in Riemannian curvature and of arbitrary order in the electromagnetic field. We apply these results to the study of the effective action in nonperturbative electrodynamics in four dimensions and derive a generalization of the Schwinger's result for the creation of scalar and spinor particles in electromagnetic field induced by the gravitational field. We discover a new infrared divergence in the imaginary part of the effective action due to the gravitational corrections, which seems to be a new physical effect.
Phase space model for transmission of light beam
International Nuclear Information System (INIS)
Fu Shinian
1989-01-01
Based on Fermat's principle of ray optics, the Hamiltonian of an optical ray is derived by comparison with classical mechanics. A phase space model of light beam is proposed, assuming that the light beam, regarded as a group of rays, can be described by an ellipse in the μ-phase space. Therefore, the transmission of light beam is represented by the phase space matrix transformation. By means of this non-wave formulation, the same results are obtained as those from wave equation such as Kogelnik's ABCD law. As an example of the application on this model, the matching problem of optical cavity is solved
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.
Integrability of geodesics and action-angle variables in Sasaki-Einstein space T{sup 1,1}
Energy Technology Data Exchange (ETDEWEB)
Visinescu, Mihai [National Institute of Physics and Nuclear Engineering, Department Theoretical Physics, Magurele, Bucharest (Romania)
2016-09-15
We briefly describe the construction of Staekel-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 the homogeneous Sasaki-Einstein space T{sup 1,1}. We discuss the integrability of geodesics and construct explicitly the action-angle variables. Two pairs of frequencies of the geodesic motions are resonant giving way to chaotic behavior when the system is perturbed. (orig.)
Computational Fluid Dynamics Model for Saltstone Vault 4 Vapor Space
International Nuclear Information System (INIS)
Lee, Si Young
2005-01-01
Computational fluid dynamics (CFD) methods have been used to estimate the flow patterns for vapor space inside the Saltstone Vault No.4 under different operating scenarios. The purpose of this work is to examine the gas motions inside the vapor space under the current vault configurations. A CFD model took three-dimensional transient momentum-energy coupled approach for the vapor space domain of the vault. The modeling calculations were based on prototypic vault geometry and expected normal operating conditions as defined by Waste Solidification Engineering. The modeling analysis was focused on the air flow patterns near the ventilated corner zones of the vapor space inside the Saltstone vault. The turbulence behavior and natural convection mechanism used in the present model were benchmarked against the literature information and theoretical results. The verified model was applied to the Saltstone vault geometry for the transient assessment of the air flow patterns inside the vapor space of the vault region using the boundary conditions as provided by the customer. The present model considered two cases for the estimations of the flow patterns within the vapor space. One is the reference baseline case. The other is for the negative temperature gradient between the roof inner and top grout surface temperatures intended for the potential bounding condition. The flow patterns of the vapor space calculated by the CFD model demonstrate that the ambient air comes into the vapor space of the vault through the lower-end ventilation hole, and it gets heated up by the Benard-cell type circulation before leaving the vault via the higher-end ventilation hole. The calculated results are consistent with the literature information
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.
A Status of the Advanced Space Transportation Program from Planning to Action
Lyles, Garry; Griner, Carolyn
1998-01-01
A Technology Plan for Enabling Commercial Space Business was presented at the 48th International Astronautical Congress in Turin, Italy. This paper presents a status of the program's accomplishments. Technology demonstrations have progressed in each of the four elements of the program; (1) Low Cost Technology, (2) Advanced Reusable Technology, (3) Space Transfer Technology and (4) Space Transportation Research. The Low Cost Technology program element is primarily focused at reducing development and acquisition costs of aerospace hardware using a "design to cost" philosophy with robust margins, adapting commercial manufacturing processes and commercial off-the-shelf hardware. The attributes of this philosophy for small payload launch are being demonstrated at the component, sub-system, and system level. The X-34 "Fastrac" engine has progressed through major component and subsystem demonstrations. A propulsion system test bed has been implemented for system-level demonstration of component and subsystem technologies; including propellant tankage and feedlines, controls, pressurization, and engine systems. Low cost turbopump designs, commercial valves and a controller are demonstrating the potential for a ten-fold reduction in engine and propulsion system costs. The Advanced Reusable Technology program element is focused on increasing life through high strength-to-weight structures and propulsion components, highly integrated propellant tanks, automated checkout and health management and increased propulsion system performance. The validation of rocket based combined cycle (RBCC) propulsion is pro,-,ressing through component and subsystem testing. RBCC propulsion has the potential to provide performance margin over an all rocket system that could result in lower gross liftoff weight, a lower propellant mass fraction or a higher payload mass fraction. The Space Transfer Technology element of the program is pursuing technology that can improve performance and
Nuclear spectroscopy in large shell model spaces: recent advances
International Nuclear Information System (INIS)
Kota, V.K.B.
1995-01-01
Three different approaches are now available for carrying out nuclear spectroscopy studies in large shell model spaces and they are: (i) the conventional shell model diagonalization approach but taking into account new advances in computer technology; (ii) the recently introduced Monte Carlo method for the shell model; (iii) the spectral averaging theory, based on central limit theorems, in indefinitely large shell model spaces. The various principles, recent applications and possibilities of these three methods are described and the similarity between the Monte Carlo method and the spectral averaging theory is emphasized. (author). 28 refs., 1 fig., 5 tabs
Emergent gravity on covariant quantum spaces in the IKKT model
Energy Technology Data Exchange (ETDEWEB)
Steinacker, Harold C. [Faculty of Physics, University of Vienna,Boltzmanngasse 5, A-1090 Vienna (Austria)
2016-12-30
We study perturbations of 4-dimensional fuzzy spheres as backgrounds in the IKKT or IIB matrix model. Gauge fields and metric fluctuations are identified among the excitation modes with lowest spin, supplemented by a tower of higher-spin fields. They arise from an internal structure which can be viewed as a twisted bundle over S{sup 4}, leading to a covariant noncommutative geometry. The linearized 4-dimensional Einstein equations are obtained from the classical matrix model action under certain conditions, modified by an IR cutoff. Some one-loop contributions to the effective action are computed using the formalism of string states.
Forward modeling of space-borne gravitational wave detectors
International Nuclear Information System (INIS)
Rubbo, Louis J.; Cornish, Neil J.; Poujade, Olivier
2004-01-01
Planning is underway for several space-borne gravitational wave observatories to be built in the next 10 to 20 years. Realistic and efficient forward modeling will play a key role in the design and operation of these observatories. Space-borne interferometric gravitational wave detectors operate very differently from their ground-based counterparts. Complex orbital motion, virtual interferometry, and finite size effects complicate the description of space-based systems, while nonlinear control systems complicate the description of ground-based systems. Here we explore the forward modeling of space-based gravitational wave detectors and introduce an adiabatic approximation to the detector response that significantly extends the range of the standard low frequency approximation. The adiabatic approximation will aid in the development of data analysis techniques, and improve the modeling of astrophysical parameter extraction
Efficient Neural Network Modeling for Flight and Space Dynamics Simulation
Directory of Open Access Journals (Sweden)
Ayman Hamdy Kassem
2011-01-01
Full Text Available This paper represents an efficient technique for neural network modeling of flight and space dynamics simulation. The technique will free the neural network designer from guessing the size and structure for the required neural network model and will help to minimize the number of neurons. For linear flight/space dynamics systems, the technique can find the network weights and biases directly by solving a system of linear equations without the need for training. Nonlinear flight dynamic systems can be easily modeled by training its linearized models keeping the same network structure. The training is fast, as it uses the linear system knowledge to speed up the training process. The technique is tested on different flight/space dynamic models and showed promising results.
Modeling Trees with a Space Colonization Algorithm
Morell Higueras, Marc
2014-01-01
[CATALÀ] Aquest TFG tracta la implementació d'un algorisme de generació procedural que construeixi una estructura reminiscent a la d'un arbre de clima temperat, i també la implementació del pas de l'estructura a un model tridimensional, acompanyat de l'eina per a visualitzar el resultat i fer-ne l'exportació [ANGLÈS] This TFG consists of the implementation of a procedural generation algorithm that builds a structure reminiscent of that of a temperate climate tree, and also consists of the ...
SOFTCOST - DEEP SPACE NETWORK SOFTWARE COST MODEL
Tausworthe, R. C.
1994-01-01
The early-on estimation of required resources and a schedule for the development and maintenance of software is usually the least precise aspect of the software life cycle. However, it is desirable to make some sort of an orderly and rational attempt at estimation in order to plan and organize an implementation effort. The Software Cost Estimation Model program, SOFTCOST, was developed to provide a consistent automated resource and schedule model which is more formalized than the often used guesswork model based on experience, intuition, and luck. SOFTCOST was developed after the evaluation of a number of existing cost estimation programs indicated that there was a need for a cost estimation program with a wide range of application and adaptability to diverse kinds of software. SOFTCOST combines several software cost models found in the open literature into one comprehensive set of algorithms that compensate for nearly fifty implementation factors relative to size of the task, inherited baseline, organizational and system environment, and difficulty of the task. SOFTCOST produces mean and variance estimates of software size, implementation productivity, recommended staff level, probable duration, amount of computer resources required, and amount and cost of software documentation. Since the confidence level for a project using mean estimates is small, the user is given the opportunity to enter risk-biased values for effort, duration, and staffing, to achieve higher confidence levels. SOFTCOST then produces a PERT/CPM file with subtask efforts, durations, and precedences defined so as to produce the Work Breakdown Structure (WBS) and schedule having the asked-for overall effort and duration. The SOFTCOST program operates in an interactive environment prompting the user for all of the required input. The program builds the supporting PERT data base in a file for later report generation or revision. The PERT schedule and the WBS schedule may be printed and stored in a
ACTION-SPACE CLUSTERING OF TIDAL STREAMS TO INFER THE GALACTIC POTENTIAL
Energy Technology Data Exchange (ETDEWEB)
Sanderson, Robyn E.; Helmi, Amina [Kapteyn Astronomical Institute, P.O. Box 800, 9700 AV Groningen (Netherlands); Hogg, David W., E-mail: robyn@astro.columbia.edu [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)
2015-03-10
We present a new method for constraining the Milky Way halo gravitational potential by simultaneously fitting multiple tidal streams. This method requires three-dimensional positions and velocities for all stars to be fit, but does not require identification of any specific stream or determination of stream membership for any star. We exploit the principle that the action distribution of stream stars is most clustered when the potential used to calculate the actions is closest to the true potential. Clustering is quantified with the Kullback-Leibler Divergence (KLD), which also provides conditional uncertainties for our parameter estimates. We show, for toy Gaia-like data in a spherical isochrone potential, that maximizing the KLD of the action distribution relative to a smoother distribution recovers the input potential. The precision depends on the observational errors and number of streams; using K III giants as tracers, we measure the enclosed mass at the average radius of the sample stars accurate to 3% and precise to 20%-40%. Recovery of the scale radius is precise to 25%, biased 50% high by the small galactocentric distance range of stars in our mock sample (1-25 kpc, or about three scale radii, with mean 6.5 kpc). 20-25 streams with at least 100 stars each are required for a stable confidence interval. With radial velocities (RVs) to 100 kpc, all parameters are determined with ∼10% accuracy and 20% precision (1.3% accuracy for the enclosed mass), underlining the need to complete the RV catalog for faint halo stars observed by Gaia.
Inomata, Teppei; Kimura, Kouji; Hagiwara, Masafumi
Studies for video surveillance applications for preventing various crimes such as stealing and violence have become a hot topic. This paper proposes a new video surveillance system that can detect suspicious behaviors such as a car break-in and vandalization in an open space parking, and that is based on image processing. The proposed system has the following features: it 1)deals time series data flow, 2)recognizes “human elemental actions” using statistic features, and 3)detects suspicious behavior using Subspace method and AdaBoost. We conducted the experiments to test the performance of the proposed system using open space parking scenes. As a result, we obtained about 10.0% for false positive rate, and about 4.6% for false negative rate.
Modeling space charge in beams for heavy-ion fusion
International Nuclear Information System (INIS)
Sharp, W.M.
1995-01-01
A new analytic model is presented which accurately estimates the radially averaged axial component of the space-charge field of an axisymmetric heavy-ion beam in a cylindrical beam pipe. The model recovers details of the field near the beam ends that are overlooked by simpler models, and the results compare well to exact solutions of Poisson's equation. Field values are shown for several simple beam profiles and are compared with values obtained from simpler models
A probabilistic model of RNA conformational space
DEFF Research Database (Denmark)
Frellsen, Jes; Moltke, Ida; Thiim, Martin
2009-01-01
, the discrete nature of the fragments necessitates the use of carefully tuned, unphysical energy functions, and their non-probabilistic nature impairs unbiased sampling. We offer a solution to the sampling problem that removes these important limitations: a probabilistic model of RNA structure that allows...... conformations for 9 out of 10 test structures, solely using coarse-grained base-pairing information. In conclusion, the method provides a theoretical and practical solution for a major bottleneck on the way to routine prediction and simulation of RNA structure and dynamics in atomic detail.......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...
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.
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 form...... 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...
Action Relations. Basic Design Concepts for Behaviour Modelling and Refinement.
Quartel, Dick
This thesis presents basic design concepts, design methods and a basic design language for distributed system behaviours. This language is based on two basic concepts: the action concept and the causality relation concept. Our methods focus on behaviour refinement, which consists of replacing an
Exactly solvable string models of curved space-time backgrounds
Russo, J.G.; Russo, J G; Tseytlin, A A
1995-01-01
We consider a new 3-parameter class of exact 4-dimensional solutions in closed string theory and solve the corresponding string model, determining the physical spectrum and the partition function. The background fields (4-metric, antisymmetric tensor, two Kaluza-Klein vector fields, dilaton and modulus) generically describe axially symmetric stationary rotating (electro)magnetic flux-tube type universes. Backgrounds of this class include both the dilatonic Melvin solution and the uniform magnetic field solution discussed earlier as well as some singular space-times. Solvability of the string sigma model is related to its connection via duality to a much simpler looking model which is a "twisted" product of a flat 2-space and a space dual to 2-plane. We discuss some physical properties of this model as well as a number of generalizations leading to larger classes of exact 4-dimensional string solutions.
Modeling electron fractionalization with unconventional Fock spaces.
Cobanera, Emilio
2017-08-02
It is shown that certain fractionally-charged quasiparticles can be modeled on D-dimensional lattices in terms of unconventional yet simple Fock algebras of creation and annihilation operators. These unconventional Fock algebras are derived from the usual fermionic algebra by taking roots (the square root, cubic root, etc) of the usual fermionic creation and annihilation operators. If the fermions carry non-Abelian charges, then this approach fractionalizes the Abelian charges only. In particular, the mth-root of a spinful fermion carries charge e/m and spin 1/2. Just like taking a root of a complex number, taking a root of a fermion yields a mildly non-unique result. As a consequence, there are several possible choices of quantum exchange statistics for fermion-root quasiparticles. These choices are tied to the dimensionality [Formula: see text] of the lattice by basic physical considerations. One particular family of fermion-root quasiparticles is directly connected to the parafermion zero-energy modes expected to emerge in certain mesoscopic devices involving fractional quantum Hall states. Hence, as an application of potential mesoscopic interest, I investigate numerically the hybridization of Majorana and parafermion zero-energy edge modes caused by fractionalizing but charge-conserving tunneling.
Phase-Space Models of Solitary Electron Hoies
DEFF Research Database (Denmark)
Lynov, Jens-Peter; Michelsen, Poul; Pécseli, Hans
1985-01-01
Two different phase-space models of solitary electron holes are investigated and compared with results from computer simulations of an actual laboratory experiment, carried out in a strongly magnetized, cylindrical plasma column. In the two models, the velocity distribution of the electrons...
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...
Modeling Coastal Vulnerability through Space and Time.
Hopper, Thomas; Meixler, Marcia S
2016-01-01
Coastal ecosystems experience a wide range of stressors including wave forces, storm surge, sea-level rise, and anthropogenic modification and are thus vulnerable to erosion. Urban coastal ecosystems are especially important due to the large populations these limited ecosystems serve. However, few studies have addressed the issue of urban coastal vulnerability at the landscape scale with spatial data that are finely resolved. The purpose of this study was to model and map coastal vulnerability and the role of natural habitats in reducing vulnerability in Jamaica Bay, New York, in terms of nine coastal vulnerability metrics (relief, wave exposure, geomorphology, natural habitats, exposure, exposure with no habitat, habitat role, erodible shoreline, and surge) under past (1609), current (2015), and future (2080) scenarios using InVEST 3.2.0. We analyzed vulnerability results both spatially and across all time periods, by stakeholder (ownership) and by distance to damage from Hurricane Sandy. We found significant differences in vulnerability metrics between past, current and future scenarios for all nine metrics except relief and wave exposure. The marsh islands in the center of the bay are currently vulnerable. In the future, these islands will likely be inundated, placing additional areas of the shoreline increasingly at risk. Significant differences in vulnerability exist between stakeholders; the Breezy Point Cooperative and Gateway National Recreation Area had the largest erodible shoreline segments. Significant correlations exist for all vulnerability (exposure/surge) and storm damage combinations except for exposure and distance to artificial debris. Coastal protective features, ranging from storm surge barriers and levees to natural features (e.g. wetlands), have been promoted to decrease future flood risk to communities in coastal areas around the world. Our methods of combining coastal vulnerability results with additional data and across multiple time
Space - A unique environment for process modeling R&D
Overfelt, Tony
1991-01-01
Process modeling, the application of advanced computational techniques to simulate real processes as they occur in regular use, e.g., welding, casting and semiconductor crystal growth, is discussed. Using the low-gravity environment of space will accelerate the technical validation of the procedures and enable extremely accurate determinations of the many necessary thermophysical properties. Attention is given to NASA's centers for the commercial development of space; joint ventures of universities, industries, and goverment agencies to study the unique attributes of space that offer potential for applied R&D and eventual commercial exploitation.
Quantum metric spaces as a model for pregeometry
International Nuclear Information System (INIS)
Alvarez, E.; Cespedes, J.; Verdaguer, E.
1992-01-01
A new arena for the dynamics of spacetime is proposed, in which the basic quantum variable is the two-point distance on a metric space. The scaling dimension (that is, the Kolmogorov capacity) in the neighborhood of each point then defines in a natural way a local concept of dimension. We study our model in the region of parameter space in which the resulting spacetime is not too different from a smooth manifold
Spectral decomposition of model operators in de Branges spaces
International Nuclear Information System (INIS)
Gubreev, Gennady M; Tarasenko, Anna A
2011-01-01
The paper is devoted to studying a class of completely continuous nonselfadjoint operators in de Branges spaces of entire functions. Among other results, a class of unconditional bases of de Branges spaces consisting of values of their reproducing kernels is constructed. The operators that are studied are model operators in the class of completely continuous non-dissipative operators with two-dimensional imaginary parts. Bibliography: 22 titles.
Space Weather Action Plan Ionizing Radiation Benchmarks: Phase 1 update and plans for Phase 2
Talaat, E. R.; Kozyra, J.; Onsager, T. G.; Posner, A.; Allen, J. E., Jr.; Black, C.; Christian, E. R.; Copeland, K.; Fry, D. J.; Johnston, W. R.; Kanekal, S. G.; Mertens, C. J.; Minow, J. I.; Pierson, J.; Rutledge, R.; Semones, E.; Sibeck, D. G.; St Cyr, O. C.; Xapsos, M.
2017-12-01
Changes in the near-Earth radiation environment can affect satellite operations, astronauts in space, commercial space activities, and the radiation environment on aircraft at relevant latitudes or altitudes. Understanding the diverse effects of increased radiation is challenging, but producing ionizing radiation benchmarks will help address these effects. The following areas have been considered in addressing the near-Earth radiation environment: the Earth's trapped radiation belts, the galactic cosmic ray background, and solar energetic-particle events. The radiation benchmarks attempt to account for any change in the near-Earth radiation environment, which, under extreme cases, could present a significant risk to critical infrastructure operations or human health. The goal of these ionizing radiation benchmarks and associated confidence levels will define at least the radiation intensity as a function of time, particle type, and energy for an occurrence frequency of 1 in 100 years and an intensity level at the theoretical maximum for the event. In this paper, we present the benchmarks that address radiation levels at all applicable altitudes and latitudes in the near-Earth environment, the assumptions made and the associated uncertainties, and the next steps planned for updating the benchmarks.
A stochastic space-time model for intermittent precipitation occurrences
Sun, Ying; Stein, Michael L.
2016-01-01
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.
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.
NASA Space Radiation Program Integrative Risk Model Toolkit
Kim, Myung-Hee Y.; Hu, Shaowen; Plante, Ianik; Ponomarev, Artem L.; Sandridge, Chris
2015-01-01
NASA Space Radiation Program Element scientists have been actively involved in development of an integrative risk models toolkit that includes models for acute radiation risk and organ dose projection (ARRBOD), NASA space radiation cancer risk projection (NSCR), hemocyte dose estimation (HemoDose), GCR event-based risk model code (GERMcode), and relativistic ion tracks (RITRACKS), NASA radiation track image (NASARTI), and the On-Line Tool for the Assessment of Radiation in Space (OLTARIS). This session will introduce the components of the risk toolkit with opportunity for hands on demonstrations. The brief descriptions of each tools are: ARRBOD for Organ dose projection and acute radiation risk calculation from exposure to solar particle event; NSCR for Projection of cancer risk from exposure to space radiation; HemoDose for retrospective dose estimation by using multi-type blood cell counts; GERMcode for basic physical and biophysical properties for an ion beam, and biophysical and radiobiological properties for a beam transport to the target in the NASA Space Radiation Laboratory beam line; RITRACKS for simulation of heavy ion and delta-ray track structure, radiation chemistry, DNA structure and DNA damage at the molecular scale; NASARTI for modeling of the effects of space radiation on human cells and tissue by incorporating a physical model of tracks, cell nucleus, and DNA damage foci with image segmentation for the automated count; and OLTARIS, an integrated tool set utilizing HZETRN (High Charge and Energy Transport) intended to help scientists and engineers study the effects of space radiation on shielding materials, electronics, and biological systems.
Action Relations. Basic Design Concepts for Behaviour Modelling and Refinement.
Quartel, Dick
1998-01-01
This thesis presents basic design concepts, design methods and a basic design language for distributed system behaviours. This language is based on two basic concepts: the action concept and the causality relation concept. Our methods focus on behaviour refinement, which consists of replacing an abstract behaviour by a more concrete behaviour, such that the concrete behaviour conforms to the abstract behaviour. An important idea underlying this thesis is that an effective design methodology s...
Geodetic Space Weather Monitoring by means of Ionosphere Modelling
Schmidt, Michael
2017-04-01
The term space weather indicates physical processes and phenomena in space caused by radiation of energy mainly from the Sun. Manifestations of space weather are (1) variations of the Earth's magnetic field, (2) the polar lights in the northern and southern hemisphere, (3) variations within the ionosphere as part of the upper atmosphere characterized by the existence of free electrons and ions, (4) the solar wind, i.e. the permanent emission of electrons and photons, (5) the interplanetary magnetic field, and (6) electric currents, e.g. the van Allen radiation belt. It can be stated that ionosphere disturbances are often caused by so-called solar storms. A solar storm comprises solar events such as solar flares and coronal mass ejections (CMEs) which have different effects on the Earth. Solar flares may cause disturbances in positioning, navigation and communication. CMEs can effect severe disturbances and in extreme cases damages or even destructions of modern infrastructure. Examples are interruptions to satellite services including the global navigation satellite systems (GNSS), communication systems, Earth observation and imaging systems or a potential failure of power networks. Currently the measurements of solar satellite missions such as STEREO and SOHO are used to forecast solar events. Besides these measurements the Earth's ionosphere plays another key role in monitoring the space weather, because it responses to solar storms with an increase of the electron density. Space-geodetic observation techniques, such as terrestrial GNSS, satellite altimetry, space-borne GPS (radio occultation), DORIS and VLBI provide valuable global information about the state of the ionosphere. Additionally geodesy has a long history and large experience in developing and using sophisticated analysis and combination techniques as well as empirical and physical modelling approaches. Consequently, geodesy is predestinated for strongly supporting space weather monitoring via
Shell model in large spaces and statistical spectroscopy
International Nuclear Information System (INIS)
Kota, V.K.B.
1996-01-01
For many nuclear structure problems of current interest it is essential to deal with shell model in large spaces. For this, three different approaches are now in use and two of them are: (i) the conventional shell model diagonalization approach but taking into account new advances in computer technology; (ii) the shell model Monte Carlo method. A brief overview of these two methods is given. Large space shell model studies raise fundamental questions regarding the information content of the shell model spectrum of complex nuclei. This led to the third approach- the statistical spectroscopy methods. The principles of statistical spectroscopy have their basis in nuclear quantum chaos and they are described (which are substantiated by large scale shell model calculations) in some detail. (author)
Estimation methods for nonlinear state-space models in ecology
DEFF Research Database (Denmark)
Pedersen, Martin Wæver; Berg, Casper Willestofte; Thygesen, Uffe Høgsbro
2011-01-01
The use of nonlinear state-space models for analyzing ecological systems is increasing. A wide range of estimation methods for such models are available to ecologists, however it is not always clear, which is the appropriate method to choose. To this end, three approaches to estimation in the theta...... logistic model for population dynamics were benchmarked by Wang (2007). Similarly, we examine and compare the estimation performance of three alternative methods using simulated data. The first approach is to partition the state-space into a finite number of states and formulate the problem as a hidden...... Markov model (HMM). The second method uses the mixed effects modeling and fast numerical integration framework of the AD Model Builder (ADMB) open-source software. The third alternative is to use the popular Bayesian framework of BUGS. The study showed that state and parameter estimation performance...
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
Space-Based Telescopes for the Actionable Refinement of Ephemeris Systems and Test Engineering
2011-12-01
57 the properties of Spectrolab Ultra-Triple Junction (UTJ) solar cells. The solar panel interior-facing surfaces were modeled as basic panel...satellites, and, finally, a thermal model has been developed for on-orbit thermal performance evaluation. The STARE satellite is currently scheduled to be...a secondary payload mounted in the NPS CubeSat Launcher (NPSCuL), attached to the Atlas V Aft Bulkhead Carrier (ABC) on the Centaur upper stage. The
Structural Continuum Modeling of Space Shuttle External Tank Foam Insulation
Steeve, Brian; Ayala, Sam; Purlee, T. Eric; Shaw, Phillip
2006-01-01
This document is a viewgraph presentation reporting on work in modeling the foam insulation of the Space Shuttle External Tank. An analytical understanding of foam mechanics is required to design against structural failure. The Space Shuttle External Tank is covered primarily with closed cell foam to: Prevent ice, Protect structure from ascent aerodynamic and engine plume heating, and Delay break-up during re-entry. It is important that the foam does not shed unacceptable debris during ascent environment. Therefore a modeling of the foam insulation was undertaken.
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.
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...
Requirements for modeling airborne microbial contamination in space stations
Van Houdt, Rob; Kokkonen, Eero; Lehtimäki, Matti; Pasanen, Pertti; Leys, Natalie; Kulmala, Ilpo
2018-03-01
Exposure to bioaerosols is one of the facets that affect indoor air quality, especially for people living in densely populated or confined habitats, and is associated to a wide range of health effects. Good indoor air quality is thus vital and a prerequisite for fully confined environments such as space habitats. Bioaerosols and microbial contamination in these confined space stations can have significant health impacts, considering the unique prevailing conditions and constraints of such habitats. Therefore, biocontamination in space stations is strictly monitored and controlled to ensure crew and mission safety. However, efficient bioaerosol control measures rely on solid understanding and knowledge on how these bioaerosols are created and dispersed, and which factors affect the survivability of the associated microorganisms. Here we review the current knowledge gained from relevant studies in this wide and multidisciplinary area of bioaerosol dispersion modeling and biological indoor air quality control, specifically taking into account the specific space conditions.
Redshift space clustering of galaxies and cold dark matter model
Bahcall, Neta A.; Cen, Renyue; Gramann, Mirt
1993-01-01
The distorting effect of peculiar velocities on the power speturm and correlation function of IRAS and optical galaxies is studied. The observed redshift space power spectra and correlation functions of IRAS and optical the galaxies over the entire range of scales are directly compared with the corresponding redshift space distributions using large-scale computer simulations of cold dark matter (CDM) models in order to study the distortion effect of peculiar velocities on the power spectrum and correlation function of the galaxies. It is found that the observed power spectrum of IRAS and optical galaxies is consistent with the spectrum of an Omega = 1 CDM model. The problems that such a model currently faces may be related more to the high value of Omega in the model than to the shape of the spectrum. A low-density CDM model is also investigated and found to be consistent with the data.
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...... in the spot price dynamics. Estimation of the spatial Durbin model show that the spatial lag variable is as important as the temporal lag variable in describing the spot price dynamics. We use the partial derivatives impact approach to decompose the price impacts into direct and indirect effects and we show...... that price effects transmit to neighboring markets and decline with distance. In order to examine the evolution of the spatial correlation over time, a time varying parameters spot price spatial Durbin model is estimated using recursive estimation. It is found that the spatial correlation within the Nord...
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
Extended Cellular Automata Models of Particles and Space-Time
Beedle, Michael
2005-04-01
Models of particles and space-time are explored through simulations and theoretical models that use Extended Cellular Automata models. The expanded Cellular Automata Models consist go beyond simple scalar binary cell-fields, into discrete multi-level group representations like S0(2), SU(2), SU(3), SPIN(3,1). The propagation and evolution of these expanded cellular automatas are then compared to quantum field theories based on the "harmonic paradigm" i.e. built by an infinite number of harmonic oscillators, and with gravitational models.
Validated TRNSYS Model for Solar Assisted Space Heating System
International Nuclear Information System (INIS)
Abdalla, Nedal
2014-01-01
The present study involves a validated TRNSYS model for solar assisted space heating system as applied to a residential building in Jordan using new detailed radiation models of the TRNSYS 17.1 and geometric building model Trnsys3d for the Google SketchUp 3D drawing program. The annual heating load for a building (Solar House) which is located at the Royal ScientiFIc Society (RS5) in Jordan is estimated under climatological conditions of Amman. The aim of this Paper is to compare measured thermal performance of the Solar House with that modeled using TRNSYS. The results showed that the annual measured space heating load for the building was 6,188 kWh while the heati.ng load for the modeled building was 6,391 kWh. Moreover, the measured solar fraction for the solar system was 50% while the modeled solar fraction was 55%. A comparison of modeled and measured data resulted in percentage mean absolute errors for solar energy for space heating, auxiliary heating and solar fraction of 13%, 7% and 10%, respectively. The validated model will be useful for long-term performance simulation under different weather and operating conditions.(author)
Exactly solvable string models of curved space-time backgrounds
International Nuclear Information System (INIS)
Russo, J.G.
1995-01-01
We consider a new 3-parameter class of exact 4-dimensional solutions in closed string theory and solve the corresponding string model, determining the physical spectrum and the partition function. The background fields (4-metric, antisymmetric tensor, two Kaluza-Klein vector fields, dilaton and modulus) generically describe axially symmetric stationary rotating (electro)magnetic flux-tube type universes. Backgrounds of this class include both the ''dilatonic'' (a=1) and ''Kaluza-Klein'' (a=√(3)) Melvin solutions and the uniform magnetic field solution, as well as some singular space-times. Solvability of the string σ-model is related to its connection via duality to a simpler model which is a ''twisted'' product of a flat 2-space and a space dual to 2-plane. We discuss some physical properties of this model (tachyonic instabilities in the spectrum, gyromagnetic ratio, issue of singularities, etc.). It provides one of the first examples of a consistent solvable conformal string model with explicit D=4 curved space-time interpretation. (orig.)
Space-Charge-Limited Emission Models for Particle Simulation
Verboncoeur, J. P.; Cartwright, K. L.; Murphy, T.
2004-11-01
Space-charge-limited (SCL) emission of electrons from various materials is a common method of generating the high current beams required to drive high power microwave (HPM) sources. In the SCL emission process, sufficient space charge is extracted from a surface, often of complicated geometry, to drive the electric field normal to the surface close to zero. The emitted current is highly dominated by space charge effects as well as ambient fields near the surface. In this work, we consider computational models for the macroscopic SCL emission process including application of Gauss's law and the Child-Langmuir law for space-charge-limited emission. Models are described for ideal conductors, lossy conductors, and dielectrics. Also considered is the discretization of these models, and the implications for the emission physics. Previous work on primary and dual-cell emission models [Watrous et al., Phys. Plasmas 8, 289-296 (2001)] is reexamined, and aspects of the performance, including fidelity and noise properties, are improved. Models for one-dimensional diodes are considered, as well as multidimensional emitting surfaces, which include corners and transverse fields.
Grms or graphical representation of model spaces. Vol. I Basics
International Nuclear Information System (INIS)
Duch, W.
1986-01-01
This book presents a novel approach to the many-body problem in quantum chemistry, nuclear shell-theory and solid-state theory. Many-particle model spaces are visualized using graphs, each path of a graph labeling a single basis function or a subspace of functions. Spaces of a very high dimension are represented by small graphs. Model spaces have structure that is reflected in the architecture of the corresponding graphs, that in turn is reflected in the structure of the matrices corresponding to operators acting in these spaces. Insight into this structure leads to formulation of very efficient computer algorithms. Calculation of matrix elements is reduced to comparison of paths in a graph, without ever looking at the functions themselves. Using only very rudimentary mathematical tools graphical rules of matrix element calculation in abelian cases are derived, in particular segmentation rules obtained in the unitary group approached are rederived. The graphs are solutions of Diophantine equations of the type appearing in different branches of applied mathematics. Graphical representation of model spaces should find as many applications as has been found for diagramatical methods in perturbation theory
International Nuclear Information System (INIS)
Liu, Yanguo; Zhao, Yanyan; Sun, Hongyu; Zhang, Beibei; Cao, Sufeng; Xu, Xiaobin; Wang, Zhihong; Arandiyan, Hamidreza
2015-01-01
Multicomponent nanoframes (NFs) with a hollow structural character have shown the potential to be applied in many fields. Here we report a novel strategy to synthesize Zn_xCd_1_−_xS NFs via the synergistic actions of the graphene oxide (GO) confinement effect and oriented cation exchange. The obtained samples have been systematically characterized by x-ray diffractometry (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photospectroscopy (XPS) and Raman spectrometry. The results show that the two dimensional space confinement effect induced by GO and the oriented cation exchange reaction are responsible for the formation of the multicomponent NFs. The high photoelectrochemical activity and the low cost of the starting materials will make the multicomponent NFs applicable in photoelectronic and photoelectrocatalytic fields. (paper)
Seddig-Raufie, Djamila; Jansen, Ludger; Schober, Daniel; Boeker, Martin; Grewe, Niels; Schulz, Stefan
2012-09-21
Ontology Design Patterns (ODPs) are representational artifacts devised to offer solutions for recurring ontology design problems. They promise to enhance the ontology building process in terms of flexibility, re-usability and expansion, and to make the result of ontology engineering more predictable. In this paper, we analyze ODP repositories and investigate their relation with upper-level ontologies. In particular, we compare the BioTop upper ontology to the Action ODP from the NeOn an ODP repository. In view of the differences in the respective approaches, we investigate whether the Action ODP can be embedded into BioTop. We demonstrate that this requires re-interpreting the meaning of classes of the NeOn Action ODP in the light of the precepts of realist ontologies. As a result, the re-design required clarifying the ontological commitment of the ODP classes by assigning them to top-level categories. Thus, ambiguous definitions are avoided. Classes of real entities are clearly distinguished from classes of information artifacts. The proposed approach avoids the commitment to the existence of unclear future entities which underlies the NeOn Action ODP. Our re-design is parsimonious in the sense that existing BioTop content proved to be largely sufficient to define the different types of actions and plans. The proposed model demonstrates that an expressive upper-level ontology provides enough resources and expressivity to represent even complex ODPs, here shown with the different flavors of Action as proposed in the NeOn ODP. The advantage of ODP inclusion into a top-level ontology is the given predetermined dependency of each class, an existing backbone structure and well-defined relations. Our comparison shows that the use of some ODPs is more likely to cause problems for ontology developers, rather than to guide them. Besides the structural properties, the explanation of classification results were particularly hard to grasp for 'self-sufficient' ODPs as
Mathematical model of parking space unit for triangular parking area
Syahrini, Intan; Sundari, Teti; Iskandar, Taufiq; Halfiani, Vera; Munzir, Said; Ramli, Marwan
2018-01-01
Parking space unit (PSU) is an effective measure for the area size of a vehicle, including the free space and the width of the door opening of the vehicle (car). This article discusses a mathematical model for parking space of vehicles in triangular shape area. An optimization model for triangular parking lot is developed. Integer Linear Programming (ILP) method is used to determine the maximum number of the PSU. The triangular parking lot is in isosceles and equilateral triangles shape and implements four possible rows and five possible angles for each field. The vehicles which are considered are cars and motorcycles. The results show that the isosceles triangular parking area has 218 units of optimal PSU, which are 84 units of PSU for cars and 134 units of PSU for motorcycles. Equilateral triangular parking area has 688 units of optimal PSU, which are 175 units of PSU for cars and 513 units of PSU for motorcycles.
Interfacial and Wall Transport Models for SPACE-CAP Code
International Nuclear Information System (INIS)
Hong, Soon Joon; Choo, Yeon Joon; Han, Tae Young; Hwang, Su Hyun; Lee, Byung Chul; Choi, Hoon; Ha, Sang Jun
2009-01-01
The development project for the domestic design code was launched to be used for the safety and performance analysis of pressurized light water reactors. And CAP (Containment Analysis Package) code has been also developed for the containment safety and performance analysis side by side with SPACE. The CAP code treats three fields (gas, continuous liquid, and dispersed drop) for the assessment of containment specific phenomena, and is featured by its multidimensional assessment capabilities. Thermal hydraulics solver was already developed and now under testing of its stability and soundness. As a next step, interfacial and wall transport models was setup. In order to develop the best model and correlation package for the CAP code, various models currently used in major containment analysis codes, which are GOTHIC, CONTAIN2.0, and CONTEMPT-LT, have been reviewed. The origins of the selected models used in these codes have also been examined to find out if the models have not conflict with a proprietary right. In addition, a literature survey of the recent studies has been performed in order to incorporate the better models for the CAP code. The models and correlations of SPACE were also reviewed. CAP models and correlations are composed of interfacial heat/mass, and momentum transport models, and wall heat/mass, and momentum transport models. This paper discusses on those transport models in the CAP code
Interfacial and Wall Transport Models for SPACE-CAP Code
Energy Technology Data Exchange (ETDEWEB)
Hong, Soon Joon; Choo, Yeon Joon; Han, Tae Young; Hwang, Su Hyun; Lee, Byung Chul [FNC Tech., Seoul (Korea, Republic of); Choi, Hoon; Ha, Sang Jun [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)
2009-10-15
The development project for the domestic design code was launched to be used for the safety and performance analysis of pressurized light water reactors. And CAP (Containment Analysis Package) code has been also developed for the containment safety and performance analysis side by side with SPACE. The CAP code treats three fields (gas, continuous liquid, and dispersed drop) for the assessment of containment specific phenomena, and is featured by its multidimensional assessment capabilities. Thermal hydraulics solver was already developed and now under testing of its stability and soundness. As a next step, interfacial and wall transport models was setup. In order to develop the best model and correlation package for the CAP code, various models currently used in major containment analysis codes, which are GOTHIC, CONTAIN2.0, and CONTEMPT-LT, have been reviewed. The origins of the selected models used in these codes have also been examined to find out if the models have not conflict with a proprietary right. In addition, a literature survey of the recent studies has been performed in order to incorporate the better models for the CAP code. The models and correlations of SPACE were also reviewed. CAP models and correlations are composed of interfacial heat/mass, and momentum transport models, and wall heat/mass, and momentum transport models. This paper discusses on those transport models in the CAP code.
Statistical learning modeling method for space debris photometric measurement
Sun, Wenjing; Sun, Jinqiu; Zhang, Yanning; Li, Haisen
2016-03-01
Photometric measurement is an important way to identify the space debris, but the present methods of photometric measurement have many constraints on star image and need complex image processing. Aiming at the problems, a statistical learning modeling method for space debris photometric measurement is proposed based on the global consistency of the star image, and the statistical information of star images is used to eliminate the measurement noises. First, the known stars on the star image are divided into training stars and testing stars. Then, the training stars are selected as the least squares fitting parameters to construct the photometric measurement model, and the testing stars are used to calculate the measurement accuracy of the photometric measurement model. Experimental results show that, the accuracy of the proposed photometric measurement model is about 0.1 magnitudes.
State Space Reduction for Model Checking Agent Programs
S.-S.T.Q. Jongmans (Sung-Shik); K.V. Hindriks; M.B. van Riemsdijk; L. Dennis; O. Boissier; R.H. Bordini (Rafael)
2012-01-01
htmlabstractState space reduction techniques have been developed to increase the efficiency of model checking in the context of imperative programming languages. Unfortunately, these techniques cannot straightforwardly be applied to agents: the nature of states in the two programming paradigms
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.
Space Object Radiometric Modeling for Hardbody Optical Signature Database Generation
2009-09-01
Introduction This presentation summarizes recent activity in monitoring spacecraft health status using passive remote optical nonimaging ...Approved for public release; distribution is unlimited. Space Object Radiometric Modeling for Hardbody Optical Signature Database Generation...It is beneficial to the observer/analyst to understand the fundamental optical signature variability associated with these detection and
2PI effective action for the SYK model and tensor field theories
Benedetti, Dario; Gurau, Razvan
2018-05-01
We discuss the two-particle irreducible (2PI) effective action for the SYK model and for tensor field theories. For the SYK model the 2PI effective action reproduces the bilocal reformulation of the model without using replicas. In general tensor field theories the 2PI formalism is the only way to obtain a bilocal reformulation of the theory, and as such is a precious instrument for the identification of soft modes and for possible holographic interpretations. We compute the 2PI action for several models, and push it up to fourth order in the 1 /N expansion for the model proposed by Witten in [1], uncovering a one-loop structure in terms of an auxiliary bilocal action.
A Management Model for International Participation in Space Exploration Missions
George, Patrick J.; Pease, Gary M.; Tyburski, Timothy E.
2005-01-01
This paper proposes an engineering management model for NASA's future space exploration missions based on past experiences working with the International Partners of the International Space Station. The authors have over 25 years of combined experience working with the European Space Agency, Japan Aerospace Exploration Agency, Canadian Space Agency, Italian Space Agency, Russian Space Agency, and their respective contractors in the design, manufacturing, verification, and integration of their elements electric power system into the United States on-orbit segment. The perspective presented is one from a specific sub-system integration role and is offered so that the lessons learned from solving issues of technical and cultural nature may be taken into account during the formulation of international partnerships. Descriptions of the types of unique problems encountered relative to interactions between international partnerships are reviewed. Solutions to the problems are offered, taking into consideration the technical implications. Through the process of investigating each solution, the important and significant issues associated with working with international engineers and managers are outlined. Potential solutions are then characterized by proposing a set of specific methodologies to jointly develop spacecraft configurations that benefits all international participants, maximizes mission success and vehicle interoperability while minimizing cost.
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
Phase space analysis of some interacting Chaplygin gas models
Energy Technology Data Exchange (ETDEWEB)
Khurshudyan, M. [Academy of Sciences of Armenia, Institute for Physical Research, Ashtarak (Armenia); Tomsk State University of Control Systems and Radioelectronics, Laboratory for Theoretical Cosmology, Tomsk (Russian Federation); Tomsk State Pedagogical University, Department of Theoretical Physics, Tomsk (Russian Federation); Myrzakulov, R. [Eurasian National University, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan)
2017-02-15
In this paper we discuss a phase space analysis of various interacting Chaplygin gas models in general relativity. Linear and nonlinear sign changeable interactions are considered. For each case appropriate late time attractors of field equations are found. The Chaplygin gas is one of the dark fluids actively considered in modern cosmology due to the fact that it is a joint model of dark energy and dark matter. (orig.)
Model Experiments for the Determination of Airflow in Large Spaces
DEFF Research Database (Denmark)
Nielsen, Peter V.
Model experiments are one of the methods used for the determination of airflow in large spaces. This paper will discuss the formation of the governing dimensionless numbers. It is shown that experiments with a reduced scale often will necessitate a fully developed turbulence level of the flow....... Details of the flow from supply openings are very important for the determination of room air distribution. It is in some cases possible to make a simplified supply opening for the model experiment....
Space Environment Modelling with the Use of Artificial Intelligence Methods
Lundstedt, H.; Wintoft, P.; Wu, J.-G.; Gleisner, H.; Dovheden, V.
1996-12-01
Space based technological systems are affected by the space weather in many ways. Several severe failures of satellites have been reported at times of space storms. Our society also increasingly depends on satellites for communication, navigation, exploration, and research. Predictions of the conditions in the satellite environment have therefore become very important. We will here present predictions made with the use of artificial intelligence (AI) techniques, such as artificial neural networks (ANN) and hybrids of AT methods. We are developing a space weather model based on intelligence hybrid systems (IHS). The model consists of different forecast modules, each module predicts the space weather on a specific time-scale. The time-scales range from minutes to months with the fundamental time-scale of 1-5 minutes, 1-3 hours, 1-3 days, and 27 days. Solar and solar wind data are used as input data. From solar magnetic field measurements, either made on the ground at Wilcox Solar Observatory (WSO) at Stanford, or made from space by the satellite SOHO, solar wind parameters can be predicted and modelled with ANN and MHD models. Magnetograms from WSO are available on a daily basis. However, from SOHO magnetograms will be available every 90 minutes. SOHO magnetograms as input to ANNs will therefore make it possible to even predict solar transient events. Geomagnetic storm activity can today be predicted with very high accuracy by means of ANN methods using solar wind input data. However, at present real-time solar wind data are only available during part of the day from the satellite WIND. With the launch of ACE in 1997, solar wind data will on the other hand be available during 24 hours per day. The conditions of the satellite environment are not only disturbed at times of geomagnetic storms but also at times of intense solar radiation and highly energetic particles. These events are associated with increased solar activity. Predictions of these events are therefore
Preliminary Multi-Variable Cost Model for Space Telescopes
Stahl, H. Philip; Hendrichs, Todd
2010-01-01
Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. This paper reviews the methodology used to develop space telescope cost models; summarizes recently published single variable models; and presents preliminary results for two and three variable cost models. Some of the findings are that increasing mass reduces cost; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and technology development as a function of time reduces cost at the rate of 50% per 17 years.
A Parametric Computational Model of the Action Potential of Pacemaker Cells.
Ai, Weiwei; Patel, Nitish D; Roop, Partha S; Malik, Avinash; Andalam, Sidharta; Yip, Eugene; Allen, Nathan; Trew, Mark L
2018-01-01
A flexible, efficient, and verifiable pacemaker cell model is essential to the design of real-time virtual hearts that can be used for closed-loop validation of cardiac devices. A new parametric model of pacemaker action potential is developed to address this need. The action potential phases are modeled using hybrid automaton with one piecewise-linear continuous variable. The model can capture rate-dependent dynamics, such as action potential duration restitution, conduction velocity restitution, and overdrive suppression by incorporating nonlinear update functions. Simulated dynamics of the model compared well with previous models and clinical data. The results show that the parametric model can reproduce the electrophysiological dynamics of a variety of pacemaker cells, such as sinoatrial node, atrioventricular node, and the His-Purkinje system, under varying cardiac conditions. This is an important contribution toward closed-loop validation of cardiac devices using real-time heart models.
Alaa, Nour Eddine; Lefraich, Hamid; El Malki, Imane
2014-10-21
Cardiac arrhythmias are becoming one of the major health care problem in the world, causing numerous serious disease conditions including stroke and sudden cardiac death. Furthermore, cardiac arrhythmias are intimately related to the signaling ability of cardiac cells, and are caused by signaling defects. Consequently, modeling the electrical activity of the heart, and the complex signaling models that subtend dangerous arrhythmias such as tachycardia and fibrillation, necessitates a quantitative model of action potential (AP) propagation. Yet, many electrophysiological models, which accurately reproduce dynamical characteristic of the action potential in cells, have been introduced. However, these models are very complex and are very time consuming computationally. Consequently, a large amount of research is consecrated to design models with less computational complexity. This paper is presenting a new model for analyzing the propagation of ionic concentrations and electrical potential in space and time. In this model, the transport of ions is governed by Nernst-Planck flux equation (NP), and the electrical interaction of the species is described by a new cable equation. These set of equations form a system of coupled partial nonlinear differential equations that is solved numerically. In the first we describe the mathematical model. To realize the numerical simulation of our model, we proceed by a finite element discretization and then we choose an appropriate resolution algorithm. We give numerical simulations obtained for different input scenarios in the case of suicide substrate reaction which were compared to those obtained in literature. These input scenarios have been chosen so as to provide an intuitive understanding of dynamics of the model. By accessing time and space domains, it is shown that interpreting the electrical potential of cell membrane at steady state is incorrect. This model is general and applies to ions of any charge in space and time
[A Structural Equation Model of Pressure Ulcer Prevention Action in Clinical Nurses].
Lee, Sook Ja; Park, Ok Kyoung; Park, Mi Yeon
2016-08-01
The purpose of this study was to construct and test a structural equation model for pressure ulcer prevention action by clinical nurses. The Health Belief Model and the Theory of Planned Behavior were used as the basis for the study. A structured questionnaire was completed by 251 clinical nurses to analyze the relationships between concepts of perceived benefits, perceived barriers, attitude, subjective norm, perceived control, intention to perform action and behavior. SPSS 22.0 and AMOS 22.0 programs were used to analyze the efficiency of the hypothesized model and calculate the direct and indirect effects of factors affecting pressure ulcer prevention action among clinical nurses. The model fitness statistics of the hypothetical model fitted to the recommended levels. Attitude, subjective norm and perceived control on pressure ulcer prevention action explained 64.2% for intention to perform prevention action. The major findings of this study indicate that it is essential to recognize improvement in positive attitude for pressure ulcer prevention action and a need for systematic education programs to increase perceived control for prevention action.
Action selection in growing state spaces: control of network structure growth
International Nuclear Information System (INIS)
Thalmeier, Dominik; Kappen, Hilbert J; Gómez, Vicenç
2017-01-01
The dynamical processes taking place on a network depend on its topology. Influencing the growth process of a network therefore has important implications on such dynamical processes. We formulate the problem of influencing the growth of a network as a stochastic optimal control problem in which a structural cost function penalizes undesired topologies. We approximate this control problem with a restricted class of control problems that can be solved using probabilistic inference methods. To deal with the increasing problem dimensionality, we introduce an adaptive importance sampling method for approximating the optimal control. We illustrate this methodology in the context of formation of information cascades, considering the task of influencing the structure of a growing conversation thread, as in Internet forums. Using a realistic model of growing trees, we show that our approach can yield conversation threads with better structural properties than the ones observed without control. (paper)
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.
State space modeling of Memristor-based Wien oscillator
Talukdar, Abdul Hafiz Ibne; Radwan, Ahmed G.; Salama, Khaled N.
2011-01-01
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.
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.
Truncated conformal space approach to scaling Lee-Yang model
International Nuclear Information System (INIS)
Yurov, V.P.; Zamolodchikov, Al.B.
1989-01-01
A numerical approach to 2D relativstic field theories is suggested. Considering a field theory model as an ultraviolet conformal field theory perturbed by suitable relevant scalar operator one studies it in finite volume (on a circle). The perturbed Hamiltonian acts in the conformal field theory space of states and its matrix elements can be extracted from the conformal field theory. Truncation of the space at reasonable level results in a finite dimensional problem for numerical analyses. The nonunitary field theory with the ultraviolet region controlled by the minimal conformal theory μ(2/5) is studied in detail. 9 refs.; 17 figs
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...
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.
State-Space Modelling of Loudspeakers using Fractional Derivatives
DEFF Research Database (Denmark)
King, Alexander Weider; Agerkvist, Finn T.
2015-01-01
This work investigates the use of fractional order derivatives in modeling moving-coil loudspeakers. A fractional order state-space solution is developed, leading the way towards incorporating nonlinearities into a fractional order system. The method is used to calculate the response of a fractio......This work investigates the use of fractional order derivatives in modeling moving-coil loudspeakers. A fractional order state-space solution is developed, leading the way towards incorporating nonlinearities into a fractional order system. The method is used to calculate the response...... of a fractional harmonic oscillator, representing the mechanical part of a loudspeaker, showing the effect of the fractional derivative and its relationship to viscoelasticity. Finally, a loudspeaker model with a fractional order viscoelastic suspension and fractional order voice coil is fit to measurement data...
A growing social network model in geographical space
Antonioni, Alberto; Tomassini, Marco
2017-09-01
In this work we propose a new model for the generation of social networks that includes their often ignored spatial aspects. The model is a growing one and links are created either taking space into account, or disregarding space and only considering the degree of target nodes. These two effects can be mixed linearly in arbitrary proportions through a parameter. We numerically show that for a given range of the combination parameter, and for given mean degree, the generated network class shares many important statistical features with those observed in actual social networks, including the spatial dependence of connections. Moreover, we show that the model provides a good qualitative fit to some measured social networks.
Mapping from Speech to Images Using Continuous State Space Models
DEFF Research Database (Denmark)
Lehn-Schiøler, Tue; Hansen, Lars Kai; Larsen, Jan
2005-01-01
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...... a subjective point of view the model is able to construct an image sequence from an unknown noisy speech sequence even though the number of training examples are limited.......'. The performance of the system is critically dependent on the number of hidden variables, with too few variables the model cannot represent data, and with too many overfitting is noticed. Simulations are performed on recordings of 3-5 sec.\\$\\backslash\\$ video sequences with sentences from the Timit database. From...
A State Space Model for the Wood Chip Refining Model
Directory of Open Access Journals (Sweden)
David Di Ruscio
1997-07-01
Full Text Available A detailed dynamic model of the fibre size distribution between the refiner discs, distributed along the refiner radius, is presented. Both one- and two-dimensional descriptions for the fibre or shive geometry are given. It is shown that this model may be simplified and that analytic solutions exist under non-restrictive assumptions. A direct method for the recursive estimation of unknown parameters is presented. This method is applicable to linear or linearized systems which have a triangular structure.
Rodent Models of Non-classical Progesterone Action Regulating Ovulation
Directory of Open Access Journals (Sweden)
Melinda A. Mittelman-Smith
2017-07-01
Full Text Available It is becoming clear that steroid hormones act not only by binding to nuclear receptors that associate with specific response elements in the nucleus but also by binding to receptors on the cell membrane. In this newly discovered manner, steroid hormones can initiate intracellular signaling cascades which elicit rapid effects such as release of internal calcium stores and activation of kinases. We have learned much about the translocation and signaling of steroid hormone receptors from investigations into estrogen receptor α, which can be trafficked to, and signal from, the cell membrane. It is now clear that progesterone (P4 can also elicit effects that cannot be exclusively explained by transcriptional changes. Similar to E2 and its receptors, P4 can initiate signaling at the cell membrane, both through progesterone receptor and via a host of newly discovered membrane receptors (e.g., membrane progesterone receptors, progesterone receptor membrane components. This review discusses the parallels between neurotransmitter-like E2 action and the more recently investigated non-classical P4 signaling, in the context of reproductive behaviors in the rodent.
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...
Cusimano, N.; Gerardo-Giorda, L.
2018-06-01
Classical models of electrophysiology do not typically account for the effects of high structural heterogeneity in the spatio-temporal description of excitation waves propagation. We consider a modification of the Monodomain model obtained by replacing the diffusive term of the classical formulation with a fractional power of the operator, defined in the spectral sense. The resulting nonlocal model describes different levels of tissue heterogeneity as the fractional exponent is varied. The numerical method for the solution of the fractional Monodomain relies on an integral representation of the nonlocal operator combined with a finite element discretisation in space, allowing to handle in a natural way bounded domains in more than one spatial dimension. Numerical tests in two spatial dimensions illustrate the features of the model. Activation times, action potential duration and its dispersion throughout the domain are studied as a function of the fractional parameter: the expected peculiar behaviour driven by tissue heterogeneities is recovered.
Enhancing the Action Research Capacity of the International Model ...
International Development Research Centre (IDRC) Digital Library (Canada)
... the UNCED (United Nations Conference on Environment and Development) Rio ... an international network of working models of sustainable forest management ... countries in Africa, Asia, Canada, Europe, Latin America and the Caribbean, ...
Nonlinear sigma models with compact hyperbolic target spaces
International Nuclear Information System (INIS)
Gubser, Steven; Saleem, Zain H.; Schoenholz, Samuel S.; Stoica, Bogdan; Stokes, James
2016-01-01
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 V.L. Berezinskii, Destruction of long-range order in one-dimensional and two-dimensional systems having a continuous symmetry group II. Quantum systems, Sov. Phys. JETP 34 (1972) 610. J.M. Kosterlitz and D.J. Thouless, Ordering, metastability and phase transitions in two-dimensional systems, J. Phys. C 6 (1973) 1181 [http://inspirehep.net/search?p=find+J+%22J.Phys.,C6,1181%22]. . 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.
Nonlinear sigma models with compact hyperbolic target spaces
Energy Technology Data Exchange (ETDEWEB)
Gubser, Steven [Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (United States); Saleem, Zain H. [Department of Physics and Astronomy, University of Pennsylvania,Philadelphia, PA 19104 (United States); National Center for Physics, Quaid-e-Azam University Campus,Islamabad 4400 (Pakistan); Schoenholz, Samuel S. [Department of Physics and Astronomy, University of Pennsylvania,Philadelphia, PA 19104 (United States); Stoica, Bogdan [Walter Burke Institute for Theoretical Physics, California Institute of Technology,452-48, Pasadena, CA 91125 (United States); Stokes, James [Department of Physics and Astronomy, University of Pennsylvania,Philadelphia, PA 19104 (United States)
2016-06-23
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 V.L. Berezinskii, Destruction of long-range order in one-dimensional and two-dimensional systems having a continuous symmetry group II. Quantum systems, Sov. Phys. JETP 34 (1972) 610. J.M. Kosterlitz and D.J. Thouless, Ordering, metastability and phase transitions in two-dimensional systems, J. Phys. C 6 (1973) 1181 [http://inspirehep.net/search?p=find+J+%22J.Phys.,C6,1181%22]. . 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.
Adaptive Modeling of the International Space Station Electrical Power System
Thomas, Justin Ray
2007-01-01
Software simulations provide NASA engineers the ability to experiment with spacecraft systems in a computer-imitated environment. Engineers currently develop software models that encapsulate spacecraft system behavior. These models can be inaccurate due to invalid assumptions, erroneous operation, or system evolution. Increasing accuracy requires manual calibration and domain-specific knowledge. This thesis presents a method for automatically learning system models without any assumptions regarding system behavior. Data stream mining techniques are applied to learn models for critical portions of the International Space Station (ISS) Electrical Power System (EPS). We also explore a knowledge fusion approach that uses traditional engineered EPS models to supplement the learned models. We observed that these engineered EPS models provide useful background knowledge to reduce predictive error spikes when confronted with making predictions in situations that are quite different from the training scenarios used when learning the model. Evaluations using ISS sensor data and existing EPS models demonstrate the success of the adaptive approach. Our experimental results show that adaptive modeling provides reductions in model error anywhere from 80% to 96% over these existing models. Final discussions include impending use of adaptive modeling technology for ISS mission operations and the need for adaptive modeling in future NASA lunar and Martian exploration.
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
Classically integrable boundary conditions for symmetric-space sigma models
International Nuclear Information System (INIS)
MacKay, N.J.; Young, C.A.S.
2004-01-01
We investigate boundary conditions for the non-linear sigma model on the compact symmetric space G/H. The Poisson brackets and the classical local conserved charges necessary for integrability are preserved by boundary conditions which correspond to involutions which commute with the involution defining H. Applied to SO(3)/SO(2), the non-linear sigma model on S 2 , these yield the great circles as boundary submanifolds. Applied to GxG/G, they reproduce known results for the principal chiral model
Modeling Natural Space Ionizing Radiation Effects on External Materials
Alstatt, Richard L.; Edwards, David L.; Parker, Nelson C. (Technical Monitor)
2000-01-01
Predicting the effective life of materials for space applications has become increasingly critical with the drive to reduce mission cost. Programs have considered many solutions to reduce launch costs including novel, low mass materials and thin thermal blankets to reduce spacecraft mass. Determining the long-term survivability of these materials before launch is critical for mission success. This presentation will describe an analysis performed on the outer layer of the passive thermal control blanket of the Hubble Space Telescope. This layer had degraded for unknown reasons during the mission, however ionizing radiation (IR) induced embrittlement was suspected. A methodology was developed which allowed direct comparison between the energy deposition of the natural environment and that of the laboratory generated environment. Commercial codes were used to predict the natural space IR environment model energy deposition in the material from both natural and laboratory IR sources, and design the most efficient test. Results were optimized for total and local energy deposition with an iterative spreadsheet. This method has been used successfully for several laboratory tests at the Marshall Space Flight Center. The study showed that the natural space IR environment, by itself, did not cause the premature degradation observed in the thermal blanket.
State-space modeling to support management of brucellosis in the Yellowstone bison population
Hobbs, N. Thompson; Geremia, Chris; Treanor, John; Wallen, Rick; White, P.J.; Hooten, Mevin B.; Rhyan, Jack C.
2015-01-01
The bison (Bison bison) of the Yellowstone ecosystem, USA, exemplify the difficulty of conserving large mammals that migrate across the boundaries of conservation areas. Bison are infected with brucellosis (Brucella abortus) and their seasonal movements can expose livestock to infection. Yellowstone National Park has embarked on a program of adaptive management of bison, which requires a model that assimilates data to support management decisions. We constructed a Bayesian state-space model to reveal the influence of brucellosis on the Yellowstone bison population. A frequency-dependent model of brucellosis transmission was superior to a density-dependent model in predicting out-of-sample observations of horizontal transmission probability. A mixture model including both transmission mechanisms converged on frequency dependence. Conditional on the frequency-dependent model, brucellosis median transmission rate was 1.87 yr−1. The median of the posterior distribution of the basic reproductive ratio (R0) was 1.75. Seroprevalence of adult females varied around 60% over two decades, but only 9.6 of 100 adult females were infectious. Brucellosis depressed recruitment; estimated population growth rate λ averaged 1.07 for an infected population and 1.11 for a healthy population. We used five-year forecasting to evaluate the ability of different actions to meet management goals relative to no action. Annually removing 200 seropositive female bison increased by 30-fold the probability of reducing seroprevalence below 40% and increased by a factor of 120 the probability of achieving a 50% reduction in transmission probability relative to no action. Annually vaccinating 200 seronegative animals increased the likelihood of a 50% reduction in transmission probability by fivefold over no action. However, including uncertainty in the ability to implement management by representing stochastic variation in the number of accessible bison dramatically reduced the probability of
Application of parameters space analysis tools for empirical model validation
Energy Technology Data Exchange (ETDEWEB)
Paloma del Barrio, E. [LEPT-ENSAM UMR 8508, Talence (France); Guyon, G. [Electricite de France, Moret-sur-Loing (France)
2004-01-01
A new methodology for empirical model validation has been proposed in the framework of the Task 22 (Building Energy Analysis Tools) of the International Energy Agency. It involves two main steps: checking model validity and diagnosis. Both steps, as well as the underlying methods, have been presented in the first part of the paper. In this part, they are applied for testing modelling hypothesis in the framework of the thermal analysis of an actual building. Sensitivity analysis tools have been first used to identify the parts of the model that can be really tested on the available data. A preliminary diagnosis is then supplied by principal components analysis. Useful information for model behaviour improvement has been finally obtained by optimisation techniques. This example of application shows how model parameters space analysis is a powerful tool for empirical validation. In particular, diagnosis possibilities are largely increased in comparison with residuals analysis techniques. (author)
Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee
2015-09-01
We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004). Based on two proposed functions of social identity performance (Klein, Spears, & Reicher, 2007), we distinguished between the efficacy of collective action at consolidating the identity of a protest movement and its efficacy at achieving social change (political efficacy). We expected identity consolidation efficacy to positively predict collective action tendencies directly and indirectly via political efficacy. We also expected collective action tendencies to be positively predicted by moral outrage and by sympathy in response to disadvantaged outgroup's suffering. These hypotheses were supported in two surveys examining intentions to protest for Palestine in Britain (Study 1), and intentions to attend the June 4th vigil in Hong Kong to commemorate the Tiananmen massacre among a sample of Hong Kong citizens (Study 2). The contributions of these findings to research on the dual pathway model of collective action and the different functions of collective action are discussed. © 2014 The British Psychological Society.
International Nuclear Information System (INIS)
Fradkin, E.S.; Palchik, M.Ya.
1996-02-01
We study a family of exactly solvable models of conformally-invariant quantum field theory in D-dimensional space. We demonstrate the existence of D-dimensional analogs of primary and secondary fields. Under the action of energy-momentum tensor and conserved currents, the primary fields creates an infinite set of (tensor) secondary fields of different generations. The commutators of secondary fields with zero components of current and energy-momentum tensor include anomalous operator terms. We show that the Hilbert space of conformal theory has a special sector which structure is solely defined by the Ward identities independently on the choice of dynamical model. The states of this sector are constructed from secondary fields. Definite self-consistent conditions on the states of the latter sector fix the choice of the field model uniquely. In particular, Lagrangian models do belong to this class of models. The above self-consistent conditions are formulated as follows. Special superpositions Q s , s = 1,2,... of secondary fields are constructed. Each superposition is determined by the requirement that the form of its commutators with energy-momentum tensor and current (i.e. transformation properties) should be identical to that of a primary field. Each equation Q s (x) = 0 is consistent, and defines an exactly solvable model for D ≥ 3. The structure of these models are analogous to that of well-known two dimensional conformal models. The states Q s (x) modul 0> are analogous to the null-vectors of two dimensional theory. In each of these models one can obtain a closed set of differential equations for all the higher Green functions, as well as algebraic equations relating the scale dimension of fundamental field to the D-dimensional analog of a central charge. As an example, we present a detailed discussion of a pair of exactly solvable models in even-dimensional space D ≥ 4. (author). 28 refs
Modeling Growth and Yield of Schizolobium amazonicum under Different Spacings
Directory of Open Access Journals (Sweden)
Gilson Fernandes da Silva
2013-01-01
Full Text Available This study aimed to present an approach to model the growth and yield of the species Schizolobium amazonicum (Paricá based on a study of different spacings located in Pará, Brazil. Whole-stand models were employed, and two modeling strategies (Strategies A and B were tested. Moreover, the following three scenarios were evaluated to assess the accuracy of the model in estimating total and commercial volumes at five years of age: complete absence of data (S1; available information about the variables basal area, site index, dominant height, and number of trees at two years of age (S2; and this information available at five years of age (S3. The results indicated that the 3 × 2 spacing has a higher mortality rate than normal, and, in general, greater spacing corresponds to larger diameter and average height and smaller basal area and volume per hectare. In estimating the total and commercial volumes for the three scenarios tested, Strategy B seems to be the most appropriate method to estimate the growth and yield of Paricá plantations in the study region, particularly because Strategy A showed a significant bias in its estimates.
Discrete random walk models for space-time fractional diffusion
International Nuclear Information System (INIS)
Gorenflo, Rudolf; Mainardi, Francesco; Moretti, Daniele; Pagnini, Gianni; Paradisi, Paolo
2002-01-01
A physical-mathematical approach to anomalous diffusion may be based on generalized diffusion equations (containing derivatives of fractional order in space or/and time) and related random walk models. By space-time fractional diffusion equation we mean an evolution equation obtained from the standard linear diffusion equation by replacing the second-order space derivative with a Riesz-Feller derivative of order α is part of (0,2] and skewness θ (moduleθ≤{α,2-α}), and the first-order time derivative with a Caputo derivative of order β is part of (0,1]. Such evolution equation implies for the flux a fractional Fick's law which accounts for spatial and temporal non-locality. The fundamental solution (for the Cauchy problem) of the fractional diffusion equation can be interpreted as a probability density evolving in time of a peculiar self-similar stochastic process that we view as a generalized diffusion process. By adopting appropriate finite-difference schemes of solution, we generate models of random walk discrete in space and time suitable for simulating random variables whose spatial probability density evolves in time according to this fractional diffusion equation
Space, time, and the third dimension (model error)
Moss, Marshall E.
1979-01-01
The space-time tradeoff of hydrologic data collection (the ability to substitute spatial coverage for temporal extension of records or vice versa) is controlled jointly by the statistical properties of the phenomena that are being measured and by the model that is used to meld the information sources. The control exerted on the space-time tradeoff by the model and its accompanying errors has seldom been studied explicitly. The technique, known as Network Analyses for Regional Information (NARI), permits such a study of the regional regression model that is used to relate streamflow parameters to the physical and climatic characteristics of the drainage basin.The NARI technique shows that model improvement is a viable and sometimes necessary means of improving regional data collection systems. Model improvement provides an immediate increase in the accuracy of regional parameter estimation and also increases the information potential of future data collection. Model improvement, which can only be measured in a statistical sense, cannot be quantitatively estimated prior to its achievement; thus an attempt to upgrade a particular model entails a certain degree of risk on the part of the hydrologist.
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.
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.
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.
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.
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.
Latent Class Models in action: bridging social capital & Internet usage.
Neves, Barbara Barbosa; Fonseca, Jaime R S
2015-03-01
This paper explores how Latent Class Models (LCM) can be applied in social research, when the basic assumptions of regression models cannot be validated. We examine the usefulness of this method with data collected from a study on the relationship between bridging social capital and the Internet. Social capital is defined here as the resources that are potentially available in one's social ties. Bridging is a dimension of social capital, usually related to weak ties (acquaintances), and a source of instrumental resources such as information. The study surveyed a stratified random sample of 417 inhabitants of Lisbon, Portugal. We used LCM to create the variable bridging social capital, but also to estimate the relationship between bridging social capital and Internet usage when we encountered convergence problems with the logistic regression analysis. We conclude by showing a positive relationship between bridging and Internet usage, and by discussing the potential of LCM for social science research. Copyright © 2014 Elsevier Inc. All rights reserved.
Modelling adversary actions against a nuclear material accounting system
International Nuclear Information System (INIS)
Lim, J.J.; Huebel, J.G.
1979-01-01
A typical nuclear material accounting system employing double-entry bookkeeping is described. A logic diagram is used to model the interactions of the accounting system and the adversary when he attempts to thwart it. Boolean equations are derived from the logic diagram; solution of these equations yields the accounts and records through which the adversary may disguise a SSNM theft and the collusion requirements needed to accomplish this feat. Some technical highlights of the logic diagram are also discussed
Grassmann phase space theory and the Jaynes–Cummings model
International Nuclear Information System (INIS)
Dalton, B.J.; Garraway, B.M.; Jeffers, J.; Barnett, S.M.
2013-01-01
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
BPHZ renormalization in configuration space for the A4-model
Pottel, Steffen
2018-02-01
Recent developments for BPHZ renormalization performed in configuration space are reviewed and applied to the model of a scalar quantum field with quartic self-interaction. An extension of the results regarding the short-distance expansion and the Zimmermann identity is shown for a normal product, which is quadratic in the field operator. The realization of the equation of motion is computed for the interacting field and the relation to parametric differential equations is indicated.
Geodiversity: Exploration of 3D geological model space
Lindsay, M. D.; Jessell, M. W.; Ailleres, L.; Perrouty, S.; de Kemp, E.; Betts, P. G.
2013-05-01
important geometrical characteristics. The configuration of the model space is determined through identifying ‘outlier’ model examples, which potentially represent undiscovered model ‘species’.
A Model of Representational Spaces in Human Cortex.
Guntupalli, J Swaroop; Hanke, Michael; Halchenko, Yaroslav O; Connolly, Andrew C; Ramadge, Peter J; Haxby, James V
2016-06-01
Current models of the functional architecture of human cortex emphasize areas that capture coarse-scale features of cortical topography but provide no account for population responses that encode information in fine-scale patterns of activity. Here, we present a linear model of shared representational spaces in human cortex that captures fine-scale distinctions among population responses with response-tuning basis functions that are common across brains and models cortical patterns of neural responses with individual-specific topographic basis functions. We derive a common model space for the whole cortex using a new algorithm, searchlight hyperalignment, and complex, dynamic stimuli that provide a broad sampling of visual, auditory, and social percepts. The model aligns representations across brains in occipital, temporal, parietal, and prefrontal cortices, as shown by between-subject multivariate pattern classification and intersubject correlation of representational geometry, indicating that structural principles for shared neural representations apply across widely divergent domains of information. The model provides a rigorous account for individual variability of well-known coarse-scale topographies, such as retinotopy and category selectivity, and goes further to account for fine-scale patterns that are multiplexed with coarse-scale topographies and carry finer distinctions. © The Author 2016. Published by Oxford University Press.
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.
Modal Analysis and Model Correlation of the Mir Space Station
Kim, Hyoung M.; Kaouk, Mohamed
2000-01-01
This paper will discuss on-orbit dynamic tests, modal analysis, and model refinement studies performed as part of the Mir Structural Dynamics Experiment (MiSDE). Mir is the Russian permanently manned Space Station whose construction first started in 1986. The MiSDE was sponsored by the NASA International Space Station (ISS) Phase 1 Office and was part of the Shuttle-Mir Risk Mitigation Experiment (RME). One of the main objectives for MiSDE is to demonstrate the feasibility of performing on-orbit modal testing on large space structures to extract modal parameters that will be used to correlate mathematical models. The experiment was performed over a one-year span on the Mir-alone and Mir with a Shuttle docked. A total of 45 test sessions were performed including: Shuttle and Mir thruster firings, Shuttle-Mir and Progress-Mir dockings, crew exercise and pushoffs, and ambient noise during night-to-day and day-to-night orbital transitions. Test data were recorded with a variety of existing and new instrumentation systems that included: the MiSDE Mir Auxiliary Sensor Unit (MASU), the Space Acceleration Measurement System (SAMS), the Russian Mir Structural Dynamic Measurement System (SDMS), the Mir and Shuttle Inertial Measurement Units (IMUs), and the Shuttle payload bay video cameras. Modal analysis was performed on the collected test data to extract modal parameters, i.e. frequencies, damping factors, and mode shapes. A special time-domain modal identification procedure was used on free-decay structural responses. The results from this study show that modal testing and analysis of large space structures is feasible within operational constraints. Model refinements were performed on both the Mir alone and the Shuttle-Mir mated configurations. The design sensitivity approach was used for refinement, which adjusts structural properties in order to match analytical and test modal parameters. To verify the refinement results, the analytical responses calculated using
Effective action and cluster properties of the abelian Higgs model
Energy Technology Data Exchange (ETDEWEB)
Balaban, T; Imbrie, J Z; Jaffe, A
1988-02-01
We continue our program to establish the Higgs mechanism and mass gap for the abelian Higgs model in two and three dimensions. We develop a multiscale cluster expansion for the high frequency modes of the theory, within a framework of iterated renormalization group transformations. The expansions yield decoupling properties needed for a proof of exponential decay of correlations. The result of this analysis is a gauge invariant unit lattice theory with a deep Higgs potential of the shape required to exhibit the Higgs mechanism.
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.
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.
A virtual reality browser for Space Station models
Goldsby, Michael; Pandya, Abhilash; Aldridge, Ann; Maida, James
1993-01-01
The Graphics Analysis Facility at NASA/JSC has created a visualization and learning tool by merging its database of detailed geometric models with a virtual reality system. The system allows an interactive walk-through of models of the Space Station and other structures, providing detailed realistic stereo images. The user can activate audio messages describing the function and connectivity of selected components within his field of view. This paper presents the issues and trade-offs involved in the implementation of the VR system and discusses its suitability for its intended purposes.
Comparison of Meteoroid Flux Models for Near Earth Space
Drolshagen, G.; Liou, J.-C.; Dikarev, V.; Landgraf, M.; Krag, H.; Kuiper, W.
2007-01-01
Over the last decade several new models for the sporadic interplanetary meteoroid flux have been developed. These include the Meteoroid Engineering Model (MEM), the Divine-Staubach model and the Interplanetary Meteoroid Engineering Model (IMEM). They typically cover mass ranges from 10-12 g (or lower) to 1 g and are applicable for model specific sun distance ranges between 0.2 A.U. and 10 A.U. Near 1 A.U. averaged fluxes (over direction and velocities) for all these models are tuned to the well established interplanetary model by Gr?n et. al. However, in many respects these models differ considerably. Examples are the velocity and directional distributions and the assumed meteoroid sources. In this paper flux predictions by the various models to Earth orbiting spacecraft are compared. Main differences are presented and analysed. The persisting differences even for near Earth space can be seen as surprising in view of the numerous ground based (optical, radar) and in-situ (captured IDPs, in-situ detectors and analysis of retrieved hardware) measurements and simulations. Remaining uncertainties and potential additional studies to overcome the existing model discrepancies are discussed.
Heath, Robert L; Lee, Jaesub; Palenchar, Michael J; Lemon, Laura L
2018-02-01
Studies are continuously performed to improve risk communication campaign designs to better prepare residents to act in the safest manner during an emergency. To that end, this article investigates the predictive ability of the protective action decision model (PADM), which links environmental and social cues, predecision processes (attention, exposure, and comprehension), and risk decision perceptions (threat, alternative protective actions, and stakeholder norms) with protective action decision making. This current quasi-longitudinal study of residents (N = 400 for each year) in a high-risk (chemical release) petrochemical manufacturing community investigated whether PADM core risk perceptions predict protective action decision making. Telephone survey data collected at four intervals (1995, 1998, 2002, 2012) reveal that perceptions of protective actions and stakeholder norms, but not of threat, currently predict protective action decision making (intention to shelter in place). Of significance, rather than threat perceptions, perception of Wally Wise Guy (a spokes-character who advocates shelter in place) correlates with perceptions of protective action, stakeholder norms, and protective action decision making. Wally's response-efficacy advice predicts residents' behavioral intentions to shelter in place, thereby offering contextually sensitive support and refinement for PADM. © 2017 Society for Risk Analysis.
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.
Economic analysis of open space box model utilization in spacecraft
Mohammad, Atif F.; Straub, Jeremy
2015-05-01
It is a known fact that the amount of data about space that is stored is getting larger on an everyday basis. However, the utilization of Big Data and related tools to perform ETL (Extract, Transform and Load) applications will soon be pervasive in the space sciences. We have entered in a crucial time where using Big Data can be the difference (for terrestrial applications) between organizations underperforming and outperforming their peers. The same is true for NASA and other space agencies, as well as for individual missions and the highly-competitive process of mission data analysis and publication. In most industries, conventional opponents and new candidates alike will influence data-driven approaches to revolutionize and capture the value of Big Data archives. The Open Space Box Model is poised to take the proverbial "giant leap", as it provides autonomic data processing and communications for spacecraft. We can find economic value generated from such use of data processing in our earthly organizations in every sector, such as healthcare, retail. We also can easily find retailers, performing research on Big Data, by utilizing sensors driven embedded data in products within their stores and warehouses to determine how these products are actually used in the real world.
Action Prediction Allows Hypothesis Testing via Internal Forward Models at 6 Months of Age
Directory of Open Access Journals (Sweden)
Gustaf Gredebäck
2018-03-01
Full Text Available We propose that action prediction provides a cornerstone in a learning process known as internal forward models. According to this suggestion infants’ predictions (looking to the mouth of someone moving a spoon upward will moments later be validated or proven false (spoon was in fact directed toward a bowl, information that is directly perceived as the distance between the predicted and actual goal. Using an individual difference approach we demonstrate that action prediction correlates with the tendency to react with surprise when social interactions are not acted out as expected (action evaluation. This association is demonstrated across tasks and in a large sample (n = 118 at 6 months of age. These results provide the first indication that infants might rely on internal forward models to structure their social world. Additional analysis, consistent with prior work and assumptions from embodied cognition, demonstrates that the latency of infants’ action predictions correlate with the infant’s own manual proficiency.
A logistics model for large space power systems
Koelle, H. H.
Space Power Systems (SPS) have to overcome two hurdles: (1) to find an attractive design, manufacturing and assembly concept and (2) to have available a space transportation system that can provide economical logistic support during the construction and operational phases. An initial system feasibility study, some five years ago, was based on a reference system that used terrestrial resources only and was based partially on electric propulsion systems. The conclusion was: it is feasible but not yet economically competitive with other options. This study is based on terrestrial and extraterrestrial resources and on chemical (LH 2/LOX) propulsion systems. These engines are available from the Space Shuttle production line and require small changes only. Other so-called advanced propulsion systems investigated did not prove economically superior if lunar LOX is available! We assume that a Shuttle derived Heavy Lift Launch Vehicle (HLLV) will become available around the turn of the century and that this will be used to establish a research base on the lunar surface. This lunar base has the potential to grow into a lunar factory producing LOX and construction materials for supporting among other projects also the construction of space power systems in geostationary orbit. A model was developed to simulate the logistics support of such an operation for a 50-year life cycle. After 50 years 111 SPS units with 5 GW each and an availability of 90% will produce 100 × 5 = 500 GW. The model comprises 60 equations and requires 29 assumptions of the parameter involved. 60-state variables calculated with the 60 equations mentioned above are given on an annual basis and as averages for the 50-year life cycle. Recycling of defective parts in geostationary orbit is one of the features of the model. The state-of-the-art with respect to SPS technology is introduced as a variable Mg mass/MW electric power delivered. If the space manufacturing facility, a maintenance and repair facility
Curved-space classical solutions of a massive supermatrix model
International Nuclear Information System (INIS)
Azuma, Takehiro; Bagnoud, Maxime
2003-01-01
We investigate here a supermatrix model with a mass term and a cubic interaction. It is based on the super Lie algebra osp(1 vertical bar 32,R), which could play a role in the construction of the eleven-dimensional M-theory. This model contains a massive version of the IIB matrix model, where some fields have a tachyonic mass term. Therefore, the trivial vacuum of this theory is unstable. However, this model possesses several classical solutions where these fields build noncommutative curved spaces and these solutions are shown to be energetically more favorable than the trivial vacuum. In particular, we describe in details two cases, the SO(3)xSO(3)xSO(3) (three fuzzy 2-spheres) and the SO(9) (fuzzy 8-sphere) classical backgrounds
Rapid State Space Modeling Tool for Rectangular Wing Aeroservoelastic Studies
Suh, Peter M.; Conyers, Howard Jason; Mavris, Dimitri N.
2015-01-01
This report introduces a modeling and simulation tool for aeroservoelastic analysis of rectangular wings with trailing-edge control surfaces. The inputs to the code are planform design parameters such as wing span, aspect ratio, and number of control surfaces. Using this information, the generalized forces are computed using the doublet-lattice method. Using Roger's approximation, a rational function approximation is computed. The output, computed in a few seconds, is a state space aeroservoelastic model which can be used for analysis and control design. The tool is fully parameterized with default information so there is little required interaction with the model developer. All parameters can be easily modified if desired. The focus of this report is on tool presentation, verification, and validation. These processes are carried out in stages throughout the report. The rational function approximation is verified against computed generalized forces for a plate model. A model composed of finite element plates is compared to a modal analysis from commercial software and an independently conducted experimental ground vibration test analysis. Aeroservoelastic analysis is the ultimate goal of this tool, therefore, the flutter speed and frequency for a clamped plate are computed using damping-versus-velocity and frequency-versus-velocity analysis. The computational results are compared to a previously published computational analysis and wind-tunnel results for the same structure. A case study of a generic wing model with a single control surface is presented. Verification of the state space model is presented in comparison to damping-versus-velocity and frequency-versus-velocity analysis, including the analysis of the model in response to a 1-cos gust.
The modeling and solution of course of action generation based on IN-DEA
Wan, Lujun; Li, Wen; Dai, Jiangbin; Huang, Aqian
2017-08-01
The course of action (COA) generation is the course of designing the task planning flow, which is one of the key supporting techniques while the military organization executing aerial operation. Due to the outstanding advantage of influence nets (IN), describing the causal logic between random variable, this proposal will introduce IN into the fast building mechanism of COA model. The COA generation model utilize influence nets is established. The probability propagation method is designed, which is based on influence intensity. An improved differential evolution algorithm (IDEA) is designed to solve the action policy optimized selected model. At last, the simulated result of aerial arrack campaign case show the action policy optimized selected in variety influence constants can improve the capability of cause-effect modeling, and the improved differential evolution algorithm has fine convergent and optimized capability.
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
Modelling the near-Earth space environment using LDEF data
Atkinson, Dale R.; Coombs, Cassandra R.; Crowell, Lawrence B.; Watts, Alan J.
1992-01-01
Near-Earth space is a dynamic environment, that is currently not well understood. In an effort to better characterize the near-Earth space environment, this study compares the results of actual impact crater measurement data and the Space Environment (SPENV) Program developed in-house at POD, to theoretical models established by Kessler (NASA TM-100471, 1987) and Cour-Palais (NASA SP-8013, 1969). With the continuing escalation of debris there will exist a definite hazard to unmanned satellites as well as manned operations. Since the smaller non-trackable debris has the highest impact rate, it is clearly necessary to establish the true debris environment for all particle sizes. Proper comprehension of the near-Earth space environment and its origin will permit improvement in spacecraft design and mission planning, thereby reducing potential disasters and extreme costs. Results of this study directly relate to the survivability of future spacecraft and satellites that are to travel through and/or reside in low Earth orbit (LEO). More specifically, these data are being used to: (1) characterize the effects of the LEO micrometeoroid an debris environment on satellite designs and components; (2) update the current theoretical micrometeoroid and debris models for LEO; (3) help assess the survivability of spacecraft and satellites that must travel through or reside in LEO, and the probability of their collision with already resident debris; and (4) help define and evaluate future debris mitigation and disposal methods. Combined model predictions match relatively well with the LDEF data for impact craters larger than approximately 0.05 cm, diameter; however, for smaller impact craters, the combined predictions diverge and do not reflect the sporadic clouds identified by the Interplanetary Dust Experiment (IDE) aboard LDEF. The divergences cannot currently be explained by the authors or model developers. The mean flux of small craters (approximately 0.05 cm diameter) is
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.
Theories and models on the biological of cells in space
Todd, P.; Klaus, D. M.
1996-01-01
A wide variety of observations on cells in space, admittedly made under constraining and unnatural conditions in may cases, have led to experimental results that were surprising or unexpected. Reproducibility, freedom from artifacts, and plausibility must be considered in all cases, even when results are not surprising. The papers in symposium on 'Theories and Models on the Biology of Cells in Space' are dedicated to the subject of the plausibility of cellular responses to gravity -- inertial accelerations between 0 and 9.8 m/sq s and higher. The mechanical phenomena inside the cell, the gravitactic locomotion of single eukaryotic and prokaryotic cells, and the effects of inertial unloading on cellular physiology are addressed in theoretical and experimental studies.
Action potential conduction between a ventricular cell model and an isolated ventricular cell
Wilders, R.; Kumar, R.; Joyner, R. W.; Jongsma, H. J.; Verheijck, E. E.; Golod, D.; van Ginneken, A. C.; Goolsby, W. N.
1996-01-01
We used the Luo and Rudy (LR) mathematical model of the guinea pig ventricular cell coupled to experimentally recorded guinea pig ventricular cells to investigate the effects of geometrical asymmetry on action potential propagation. The overall correspondence of the LR cell model with the recorded
Liou, Shwu-Ru
2009-01-01
To systematically analyse the Organizational Commitment model and Theory of Reasoned Action and determine concepts that can better explain nurses' intention to leave their job. The Organizational Commitment model and Theory of Reasoned Action have been proposed and applied to understand intention to leave and turnover behaviour, which are major contributors to nursing shortage. However, the appropriateness of applying these two models in nursing was not analysed. Three main criteria of a useful model were used for the analysis: consistency in the use of concepts, testability and predictability. Both theories use concepts consistently. Concepts in the Theory of Reasoned Action are defined broadly whereas they are operationally defined in the Organizational Commitment model. Predictability of the Theory of Reasoned Action is questionable whereas the Organizational Commitment model can be applied to predict intention to leave. A model was proposed based on this analysis. Organizational commitment, intention to leave, work experiences, job characteristics and personal characteristics can be concepts for predicting nurses' intention to leave. Nursing managers may consider nurses' personal characteristics and experiences to increase their organizational commitment and enhance their intention to stay. Empirical studies are needed to test and cross-validate the re-synthesized model for nurses' intention to leave their job.
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…
A dynamic texture based approach to recognition of facial actions and their temporal models
Koelstra, Sander; Pantic, Maja; Patras, Ioannis (Yannis)
2010-01-01
In this work, we propose a dynamic texture-based approach to the recognition of facial Action Units (AUs, atomic facial gestures) and their temporal models (i.e., sequences of temporal segments: neutral, onset, apex, and offset) in near-frontal-view face videos. Two approaches to modeling the
Validation of elastic cross section models for space radiation applications
Energy Technology Data Exchange (ETDEWEB)
Werneth, C.M., E-mail: charles.m.werneth@nasa.gov [NASA Langley Research Center (United States); Xu, X. [National Institute of Aerospace (United States); Norman, R.B. [NASA Langley Research Center (United States); Ford, W.P. [The University of Tennessee (United States); Maung, K.M. [The University of Southern Mississippi (United States)
2017-02-01
The space radiation field is composed of energetic particles that pose both acute and long-term risks for astronauts in low earth orbit and beyond. In order to estimate radiation risk to crew members, the fluence of particles and biological response to the radiation must be known at tissue sites. Given that the spectral fluence at the boundary of the shielding material is characterized, radiation transport algorithms may be used to find the fluence of particles inside the shield and body, and the radio-biological response is estimated from experiments and models. The fidelity of the radiation spectrum inside the shield and body depends on radiation transport algorithms and the accuracy of the nuclear cross sections. In a recent study, self-consistent nuclear models based on multiple scattering theory that include the option to study relativistic kinematics were developed for the prediction of nuclear cross sections for space radiation applications. The aim of the current work is to use uncertainty quantification to ascertain the validity of the models as compared to a nuclear reaction database and to identify components of the models that can be improved in future efforts.
Model based Computerized Ionospheric Tomography in space and time
Tuna, Hakan; Arikan, Orhan; Arikan, Feza
2018-04-01
Reconstruction of the ionospheric electron density distribution in space and time not only provide basis for better understanding the physical nature of the ionosphere, but also provide improvements in various applications including HF communication. Recently developed IONOLAB-CIT technique provides physically admissible 3D model of the ionosphere by using both Slant Total Electron Content (STEC) measurements obtained from a GPS satellite - receiver network and IRI-Plas model. IONOLAB-CIT technique optimizes IRI-Plas model parameters in the region of interest such that the synthetic STEC computations obtained from the IRI-Plas model are in accordance with the actual STEC measurements. In this work, the IONOLAB-CIT technique is extended to provide reconstructions both in space and time. This extension exploits the temporal continuity of the ionosphere to provide more reliable reconstructions with a reduced computational load. The proposed 4D-IONOLAB-CIT technique is validated on real measurement data obtained from TNPGN-Active GPS receiver network in Turkey.
Borgohain, Gargi; Paul, Sandip
2016-03-10
Classical molecular dynamics simulation of GB1 peptide (a 16-residue β-hairpin) in different osmotic environments is studied. Urea is used for denaturation of the peptide, and trimethylamine-N-oxide (TMAO) is used to offset the effect of urea. Protein-urea electrostatic interactions are found to play a major role in protein-denaturation. To emphasize on protein protecting action of TMAO against urea, two different models of TMAO are used, viz., the Kast model and the Osmotic model. We observe that the Osmotic model of TMAO gives the best protection to counteract urea's action when used in ratio 1:2 of urea:TMAO (i.e., reverse ratio). This is because the presence of TMAO makes urea-protein electrostatic interactions more unfavorable. Preferential solvation of TMAO molecules by urea (and water) molecules is also observed, which causes depletion in the number of urea molecules in the vicinity of the protein. The calculations of intraprotein hydrogen bonds between different residues of protein further reveal the breaking of backbone hydrogen bonds of residues 2 and 15 in the presence of urea, and the same is preserved in the presence of TMAO. Free energy landscapes show that the narrowest distribution is obtained for the osmotic TMAO model when used in reverse ratio.
Nonlinear State Space Modeling and System Identification for Electrohydraulic Control
Directory of Open Access Journals (Sweden)
Jun Yan
2013-01-01
Full Text Available The paper deals with nonlinear modeling and identification of an electrohydraulic control system for improving its tracking performance. We build the nonlinear state space model for analyzing the highly nonlinear system and then develop a Hammerstein-Wiener (H-W model which consists of a static input nonlinear block with two-segment polynomial nonlinearities, a linear time-invariant dynamic block, and a static output nonlinear block with single polynomial nonlinearity to describe it. We simplify the H-W model into a linear-in-parameters structure by using the key term separation principle and then use a modified recursive least square method with iterative estimation of internal variables to identify all the unknown parameters simultaneously. It is found that the proposed H-W model approximates the actual system better than the independent Hammerstein, Wiener, and ARX models. The prediction error of the H-W model is about 13%, 54%, and 58% less than the Hammerstein, Wiener, and ARX models, respectively.
The Things You Do: Internal Models of Others' Expected Behaviour Guide Action Observation.
Directory of Open Access Journals (Sweden)
Kimberley C Schenke
Full Text Available 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.
Deferred Action: Theoretical model of process architecture design for emergent business processes
Directory of Open Access Journals (Sweden)
Patel, N.V.
2007-01-01
Full Text Available E-Business modelling and ebusiness systems development assumes fixed company resources, structures, and business processes. Empirical and theoretical evidence suggests that company resources and structures are emergent rather than fixed. Planning business activity in emergent contexts requires flexible ebusiness models based on better management theories and models . This paper builds and proposes a theoretical model of ebusiness systems capable of catering for emergent factors that affect business processes. Drawing on development of theories of the ‘action and design’class the Theory of Deferred Action is invoked as the base theory for the theoretical model. A theoretical model of flexible process architecture is presented by identifying its core components and their relationships, and then illustrated with exemplar flexible process architectures capable of responding to emergent factors. Managerial implications of the model are considered and the model’s generic applicability is discussed.
Haveman, Steven; Bonnema, Gerrit Maarten
2013-01-01
Most formal models are used in detailed design and focus on a single domain. Few effective approaches exist that can effectively tie these lower level models to a high level system model during design space exploration. This complicates the validation of high level system requirements during
Krein Spectral Triples and the Fermionic Action
International Nuclear Information System (INIS)
Dungen, Koen van den
2016-01-01
Motivated by the space of spinors on a Lorentzian manifold, we define Krein spectral triples, which generalise spectral triples from Hilbert spaces to Krein spaces. This Krein space approach allows for an improved formulation of the fermionic action for almost-commutative manifolds. We show by explicit calculation that this action functional recovers the correct Lagrangians for the cases of electrodynamics, the electro-weak theory, and the Standard Model. The description of these examples does not require a real structure, unless one includes Majorana masses, in which case the internal spaces also exhibit a Krein space structure.
Letcher, B. H.; Schueller, P.; Bassar, R.; Coombs, J.; Rosner, A.; Sakrejda, K.; Kanno, Y.; Whiteley, A.; Nislow, K. H.
2013-12-01
For stream fishes, environmental variation is a key driver of individual body growth/movement/survival and, by extension, population dynamics. Identifying how stream fish respond to environmental variation can help clarify mechanisms responsible for population dynamics and can help provide tools to forecast relative resilience of populations across space. Forecasting dynamics across space is challenging, however, because it can be difficult to conduct enough studies with enough intensity to fully characterize broad-scale population response to environmental change. We have adopted a multi-scale approach, using detailed individual-based studies and analyses (integral projection matrix) to determine sensitivities of population growth to environmental variation combined with broad spatial data and analyses (occupancy and abundance models) to estimate patterns of population response across space. Population growth of brook trout was most sensitive to stream flow in the spring and winter, most sensitive to stream temperature in the fall and sensitive to both flow and temperature in the summer. High flow in the spring and winter had negative effects on population growth while high temperature had a negative effect in the fall. Flow had no effect when it was cold, but a positive effect when it was warm in the summer. Combined with occupancy and abundance models, these data give insight into the spatial structure of resilient populations and can help guide prioritization of management actions.
Space shuttle’s liftoff: a didactical model
Borghi, Riccardo; Spinozzi, Turi Maria
2017-07-01
The pedagogical aim of the present paper, thought for an undergraduate audience, is to help students to appreciate how the development of elementary models based on physics first principles is a fundamental and necessary preliminary step for the behaviour of complex real systems to be grasped with minimal amounts of math. In some particularly fortunate cases, such models also show reasonably good results when are compared to reality. The speed behaviour of the Space Shuttle during its first two minutes of flight from liftoff is here analysed from such a didactical point of view. Only the momentum conservation law is employed to develop the model, which is eventually applied to quantitatively interpret the telemetry of the 2011 last launches of Shuttle Discovery and Shuttle Endeavour. To the STS-51-L and STS-107 astronauts, in memoriam.
Vershik, A.
2017-01-01
The paper presents a general duality theory for vector measure spaces taking its origin in the author's papers written in the 1960s. The main result establishes a direct correspondence between the geometry of a measure in a vector space and the properties of the space of measurable linear functionals on this space regarded as closed subspaces of an abstract space of measurable functions. An example of useful new features of this theory is the notion of a free measure and its applications.
HiTEC: a connectionist model of the interaction between perception and action planning.
Haazebroek, Pascal; Raffone, Antonino; Hommel, Bernhard
2017-11-01
Increasing evidence suggests that perception and action planning do not represent separable stages of a unidirectional processing sequence, but rather emerging properties of highly interactive processes. To capture these characteristics of the human cognitive system, we have developed a connectionist model of the interaction between perception and action planning: HiTEC, based on the Theory of Event Coding (Hommel et al. in Behav Brain Sci 24:849-937, 2001). The model is characterized by representations at multiple levels and by shared representations and processes. It complements available models of stimulus-response translation by providing a rationale for (1) how situation-specific meanings of motor actions emerge, (2) how and why some aspects of stimulus-response translation occur automatically and (3) how task demands modulate sensorimotor processing. The model is demonstrated to provide a unitary account and simulation of a number of key findings with multiple experimental paradigms on the interaction between perception and action such as the Simon effect, its inversion (Hommel in Psychol Res 55:270-279, 1993), and action-effect learning.
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.
Operations and support cost modeling of conceptual space vehicles
Ebeling, Charles
1994-01-01
The University of Dayton is pleased to submit this annual report to the National Aeronautics and Space Administration (NASA) Langley Research Center which documents the development of an operations and support (O&S) cost model as part of a larger life cycle cost (LCC) structure. It is intended for use during the conceptual design of new launch vehicles and spacecraft. This research is being conducted under NASA Research Grant NAG-1-1327. This research effort changes the focus from that of the first two years in which a reliability and maintainability model was developed to the initial development of an operations and support life cycle cost model. Cost categories were initially patterned after NASA's three axis work breakdown structure consisting of a configuration axis (vehicle), a function axis, and a cost axis. A revised cost element structure (CES), which is currently under study by NASA, was used to established the basic cost elements used in the model. While the focus of the effort was on operations and maintenance costs and other recurring costs, the computerized model allowed for other cost categories such as RDT&E and production costs to be addressed. Secondary tasks performed concurrent with the development of the costing model included support and upgrades to the reliability and maintainability (R&M) model. The primary result of the current research has been a methodology and a computer implementation of the methodology to provide for timely operations and support cost analysis during the conceptual design activities.
The Einstein action for algebras of matrix valued functions - Toy models
International Nuclear Information System (INIS)
Hajac, P.M.
1995-10-01
Two toy models are considered within the framework of noncommutative differential geometry. In the first one, the Einstein action of the Levi-Civita connection is computed for the algebra of matrix valued functions on a torus. It is shown that, assuming some constraints on the metric, this action splits into a classical-like, a quantum-like and a mixed term. In the second model, an analogue of the Palatini method of variation is applied to obtain critical points of the Einstein action functional for M 4 (R). It is pointed out that a solution to the Palatini variational problem is not necessarily a Levi-Civita connection. In this model, no additional assumptions regarding metrics are made. (author). 14 refs
The Einstein action for algebras of matrix valued functions - Toy models
Energy Technology Data Exchange (ETDEWEB)
Hajac, P M
1995-10-01
Two toy models are considered within the framework of noncommutative differential geometry. In the first one, the Einstein action of the Levi-Civita connection is computed for the algebra of matrix valued functions on a torus. It is shown that, assuming some constraints on the metric, this action splits into a classical-like, a quantum-like and a mixed term. In the second model, an analogue of the Palatini method of variation is applied to obtain critical points of the Einstein action functional for M{sub 4}(R). It is pointed out that a solution to the Palatini variational problem is not necessarily a Levi-Civita connection. In this model, no additional assumptions regarding metrics are made. (author). 14 refs.
Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing
Nance, Donald; Liever, Peter; Nielsen, Tanner
2015-01-01
The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test, conducted at Marshall Space Flight Center. The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.
Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing
Nance, Donald K.; Liever, Peter A.
2015-01-01
The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test (SMAT), conducted at Marshall Space Flight Center (MSFC). The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.
Modeling of action potential generation in NG108-15 cells.
Molnar, Peter; Hickman, James J
2014-01-01
In order to explore the possibility of identifying toxins based on their effect on the shape of action potentials, we created a computer model of the action potential generation in NG108-15 cells (a neuroblastoma/glioma hybrid cell line). To generate the experimental data for model validation, voltage-dependent sodium, potassium and high-threshold calcium currents, as well as action potentials, were recorded from NG108-15 cells with conventional whole-cell patch-clamp methods. Based on the classic Hodgkin-Huxley formalism and the linear thermodynamic description of the rate constants, ion-channel parameters were estimated using an automatic fitting method. Utilizing the established parameters, action potentials were generated using the Hodgkin-Huxley formalism and were fitted to the recorded action potentials. To demonstrate the applicability of the method for toxin detection and discrimination, the effect of tetrodotoxin (a sodium channel blocker) and tefluthrin (a pyrethroid that is a sodium channel opener) were studied. The two toxins affected the shape of the action potentials differently, and their respective effects were identified based on the predicted changes in the fitted parameters.
Dynamics in the Parameter Space of a Neuron Model
Paulo, C. Rech
2012-06-01
Some two-dimensional parameter-space diagrams are numerically obtained by considering the largest Lyapunov exponent for a four-dimensional thirteen-parameter Hindmarsh—Rose neuron model. Several different parameter planes are considered, and it is shown that depending on the combination of parameters, a typical scenario can be preserved: for some choice of two parameters, the parameter plane presents a comb-shaped chaotic region embedded in a large periodic region. It is also shown that there exist regions close to these comb-shaped chaotic regions, separated by the comb teeth, organizing themselves in period-adding bifurcation cascades.
Coset Space Dimensional Reduction approach to the Standard Model
International Nuclear Information System (INIS)
Farakos, K.; Kapetanakis, D.; Koutsoumbas, G.; Zoupanos, G.
1988-01-01
We present a unified theory in ten dimensions based on the gauge group E 8 , which is dimensionally reduced to the Standard Mode SU 3c xSU 2 -LxU 1 , which breaks further spontaneously to SU 3L xU 1em . The model gives similar predictions for sin 2 θ w and proton decay as the minimal SU 5 G.U.T., while a natural choice of the coset space radii predicts light Higgs masses a la Coleman-Weinberg
Documentation of a Model Action Plan to Deter Illicit Nuclear Trafficking
International Nuclear Information System (INIS)
Smith, D; Kristo, M; Niemeyer, S; Dudder, G
2006-01-01
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
Documentation of a model action plan to deter illicit nuclear trafficking
International Nuclear Information System (INIS)
Smith, D.K.; Kristo, M.J.; Niemeyer, S.; Dudder, G.B.
2008-01-01
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. (author)
System resiliency quantification using non-state-space and state-space analytic models
International Nuclear Information System (INIS)
Ghosh, Rahul; Kim, DongSeong; Trivedi, Kishor S.
2013-01-01
Resiliency is becoming an important service attribute for large scale distributed systems and networks. Key problems in resiliency quantification are lack of consensus on the definition of resiliency and systematic approach to quantify system resiliency. In general, resiliency is defined as the ability of (system/person/organization) to recover/defy/resist from any shock, insult, or disturbance [1]. Many researchers interpret resiliency as a synonym for fault-tolerance and reliability/availability. However, effect of failure/repair on systems is already covered by reliability/availability measures and that of on individual jobs is well covered under the umbrella of performability [2] and task completion time analysis [3]. We use Laprie [4] and Simoncini [5]'s definition in which resiliency is the persistence of service delivery that can justifiably be trusted, when facing changes. The changes we are referring to here are beyond the envelope of system configurations already considered during system design, that is, beyond fault tolerance. In this paper, we outline a general approach for system resiliency quantification. Using examples of non-state-space and state-space stochastic models, we analytically–numerically quantify the resiliency of system performance, reliability, availability and performability measures w.r.t. structural and parametric changes
Calculational models of close-spaced thermionic converters
International Nuclear Information System (INIS)
McVey, J.B.
1983-01-01
Two new calculational models have been developed in conjunction with the SAVTEC experimental program. These models have been used to analyze data from experimental close-spaced converters, providing values for spacing, electrode work functions, and converter efficiency. They have also been used to make performance predictions for such converters over a wide range of conditions. Both models are intended for use in the collisionless (Knudsen) regime. They differ from each other in that the simpler one uses a Langmuir-type formulation which only considers electrons emitted from the emitter. This approach is implemented in the LVD (Langmuir Vacuum Diode) computer program, which has the virtue of being both simple and fast. The more complex model also includes both Saha-Langmuir emission of positive cesium ions from the emitter and collector back emission. Computer implementation is by the KMD1 (Knudsen Mode Diode) program. The KMD1 model derives the particle distribution functions from the Vlasov equation. From these the particle densities are found for various interelectrode motive shapes. Substituting the particle densities into Poisson's equation gives a second order differential equation for potential. This equation can be integrated once analytically. The second integration, which gives the interelectrode motive, is performed numerically by the KMD1 program. This is complicated by the fact that the integrand is often singular at one end point of the integration interval. The program performs a transformation on the integrand to make it finite over the entire interval. Once the motive has been computed, the output voltage, current density, power density, and efficiency are found. The program is presently unable to operate when the ion richness ratio β is between about .8 and 1.0, due to the occurrence of oscillatory motives
A continuous time model of the bandwagon effect in collective action
Arieh Gavious; Shlomo Mizrahi
2001-01-01
The paper offers a complex and systematic model of the bandwagon effect in collective action using continuous time equations. The model treats the bandwagon effect as a process influenced by ratio between the mobilization efforts of social activists and the resources invested by the government to counteract this activity. The complex modeling approach makes it possible to identify the conditions for specific types of the bandwagon effect, and determines the scope of that effect. Relying on ce...
Stringy models of modified gravity: space-time defects and structure formation
International Nuclear Information System (INIS)
Mavromatos, Nick E.; Sakellariadou, Mairi; Yusaf, Muhammad Furqaan
2013-01-01
Starting from microscopic models of space-time foam, based on brane universes propagating in bulk space-times populated by D0-brane defects (''D-particles''), we arrive at effective actions used by a low-energy observer on the brane world to describe his/her observations of the Universe. These actions include, apart from the metric tensor field, also scalar (dilaton) and vector fields, the latter describing the interactions of low-energy matter on the brane world with the recoiling point-like space-time defect (D-particle). The vector field is proportional to the recoil velocity of the D-particle and as such it satisfies a certain constraint. The vector breaks locally Lorentz invariance, which however is assumed to be conserved on average in a space-time foam situation, involving the interaction of matter with populations of D-particle defects. In this paper we clarify the role of fluctuations of the vector field on structure formation and galactic growth. In particular we demonstrate that, already at the end of the radiation era, the (constrained) vector field associated with the recoil of the defects provides the seeds for a growing mode in the evolution of the Universe. Such a growing mode survives during the matter dominated era, provided the variance of the D-particle recoil velocities on the brane is larger than a critical value. We note that in this model, as a result of specific properties of D-brane dynamics in the bulk, there is no issue of overclosing the brane Universe for large defect densities. Thus, in these models, the presence of defects may be associated with large-structure formation. Although our string inspired models do have (conventional, from a particle physics point of view) dark matter components, nevertheless it is interesting that the role of ''extra'' dark matter is also provided by the population of massive defects. This is consistent with the weakly interacting character of the D-particle defects, which predominantly interact only
Modeling and Simulation for Multi-Missions Space Exploration Vehicle
Chang, Max
2011-01-01
Asteroids and Near-Earth Objects [NEOs] are of great interest for future space missions. The Multi-Mission Space Exploration Vehicle [MMSEV] is being considered for future Near Earth Object missions and requires detailed planning and study of its Guidance, Navigation, and Control [GNC]. A possible mission of the MMSEV to a NEO would be to navigate the spacecraft to a stationary orbit with respect to the rotating asteroid and proceed to anchor into the surface of the asteroid with robotic arms. The Dynamics and Real-Time Simulation [DARTS] laboratory develops reusable models and simulations for the design and analysis of missions. In this paper, the development of guidance and anchoring models are presented together with their role in achieving mission objectives and relationships to other parts of the simulation. One important aspect of guidance is in developing methods to represent the evolution of kinematic frames related to the tasks to be achieved by the spacecraft and its robot arms. In this paper, we compare various types of mathematical interpolation methods for position and quaternion frames. Subsequent work will be on analyzing the spacecraft guidance system with different movements of the arms. With the analyzed data, the guidance system can be adjusted to minimize the errors in performing precision maneuvers.
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.
Health belief model and reasoned action theory in predicting water saving behaviors in yazd, iran.
Morowatisharifabad, Mohammad Ali; Momayyezi, Mahdieh; Ghaneian, Mohammad Taghi
2012-01-01
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. 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. 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. 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.
A Biologically Inspired Computational Model of Basal Ganglia in Action Selection.
Baston, Chiara; Ursino, Mauro
2015-01-01
The basal ganglia (BG) are a subcortical structure implicated in action selection. The aim of this work is to present a new cognitive neuroscience model of the BG, which aspires to represent a parsimonious balance between simplicity and completeness. The model includes the 3 main pathways operating in the BG circuitry, that is, the direct (Go), indirect (NoGo), and hyperdirect pathways. The main original aspects, compared with previous models, are the use of a two-term Hebb rule to train synapses in the striatum, based exclusively on neuronal activity changes caused by dopamine peaks or dips, and the role of the cholinergic interneurons (affected by dopamine themselves) during learning. Some examples are displayed, concerning a few paradigmatic cases: action selection in basal conditions, action selection in the presence of a strong conflict (where the role of the hyperdirect pathway emerges), synapse changes induced by phasic dopamine, and learning new actions based on a previous history of rewards and punishments. Finally, some simulations show model working in conditions of altered dopamine levels, to illustrate pathological cases (dopamine depletion in parkinsonian subjects or dopamine hypermedication). Due to its parsimonious approach, the model may represent a straightforward tool to analyze BG functionality in behavioral experiments.
A Biologically Inspired Computational Model of Basal Ganglia in Action Selection
Directory of Open Access Journals (Sweden)
Chiara Baston
2015-01-01
Full Text Available The basal ganglia (BG are a subcortical structure implicated in action selection. The aim of this work is to present a new cognitive neuroscience model of the BG, which aspires to represent a parsimonious balance between simplicity and completeness. The model includes the 3 main pathways operating in the BG circuitry, that is, the direct (Go, indirect (NoGo, and hyperdirect pathways. The main original aspects, compared with previous models, are the use of a two-term Hebb rule to train synapses in the striatum, based exclusively on neuronal activity changes caused by dopamine peaks or dips, and the role of the cholinergic interneurons (affected by dopamine themselves during learning. Some examples are displayed, concerning a few paradigmatic cases: action selection in basal conditions, action selection in the presence of a strong conflict (where the role of the hyperdirect pathway emerges, synapse changes induced by phasic dopamine, and learning new actions based on a previous history of rewards and punishments. Finally, some simulations show model working in conditions of altered dopamine levels, to illustrate pathological cases (dopamine depletion in parkinsonian subjects or dopamine hypermedication. Due to its parsimonious approach, the model may represent a straightforward tool to analyze BG functionality in behavioral experiments.
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.
Haveman, Steven P.; Bonnema, G. Maarten
2013-01-01
Most formal models are used in detailed design and focus on a single domain. Few effective approaches exist that can effectively tie these lower level models to a high level system model during design space exploration. This complicates the validation of high level system requirements during detailed design. In this paper, we define requirements for a high level model that is firstly driven by key systems engineering challenges present in industry and secondly connects to several formal and d...
Model of magnetic reconnection in space and astrophysical plasmas
Energy Technology Data Exchange (ETDEWEB)
Boozer, Allen H. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)
2013-03-15
Maxwell's equations imply that exponentially smaller non-ideal effects than commonly assumed can give rapid magnetic reconnection in space and astrophysical plasmas. In an ideal evolution, magnetic field lines act as stretchable strings, which can become ever more entangled but cannot be cut. High entanglement makes the lines exponentially sensitive to small non-ideal changes in the magnetic field. The cause is well known in popular culture as the butterfly effect and in the theory of deterministic dynamical systems as a sensitive dependence on initial conditions, but the importance to magnetic reconnection is not generally recognized. Two-coordinate models are too constrained geometrically for the required entanglement, but otherwise the effect is general and can be studied in simple models. A simple model is introduced, which is periodic in the x and y Cartesian coordinates and bounded by perfectly conducting planes in z. Starting from a constant magnetic field in the z direction, reconnection is driven by a spatially smooth, bounded force. The model is complete and could be used to study the impulsive transfer of energy between the magnetic field and the ions and electrons using a kinetic plasma model.
Model of magnetic reconnection in space and astrophysical plasmas
International Nuclear Information System (INIS)
Boozer, Allen H.
2013-01-01
Maxwell's equations imply that exponentially smaller non-ideal effects than commonly assumed can give rapid magnetic reconnection in space and astrophysical plasmas. In an ideal evolution, magnetic field lines act as stretchable strings, which can become ever more entangled but cannot be cut. High entanglement makes the lines exponentially sensitive to small non-ideal changes in the magnetic field. The cause is well known in popular culture as the butterfly effect and in the theory of deterministic dynamical systems as a sensitive dependence on initial conditions, but the importance to magnetic reconnection is not generally recognized. Two-coordinate models are too constrained geometrically for the required entanglement, but otherwise the effect is general and can be studied in simple models. A simple model is introduced, which is periodic in the x and y Cartesian coordinates and bounded by perfectly conducting planes in z. Starting from a constant magnetic field in the z direction, reconnection is driven by a spatially smooth, bounded force. The model is complete and could be used to study the impulsive transfer of energy between the magnetic field and the ions and electrons using a kinetic plasma model.
Jung, H.; Carruthers, T.; Allison, M. A.; Weathers, D.; Moss, L.; Timmermans, H.
2017-12-01
Pacific Island communities are highly vulnerable to the effects of climate change, specifically accelerating rates of sea level rise, changes to storm intensity and associated rainfall patterns resulting in flooding and shoreline erosion. Nature-based adaptation is being planned not only to reduce the risk from shoreline erosion, but also to support benefits of a healthy ecosystem (e.g., supporting fisheries or coral reefs). In order to assess potential effectiveness of the nature-based actions to dissipate wave energy, two-dimensional X-Beach models were developed to predict the wave attenuation effect of coastal adaptation actions at the pilot sites—the villages of Naselesele and Somosomo on Taveuni island, Fiji. Both sites are experiencing serious shoreline erosion due to sea level rise and storm wave. The water depth (single-beam bathymetry), land elevation (truck-based LiDAR), and vegetation data including stem density and height were collected in both locations in a June 2017 field experiment. Wave height and water velocity were also measured for the model setup and calibration using a series of bottom-mounted instruments deployed in the 0-15 m water depth portions of the study grid. The calibrated model will be used to evaluate a range of possible adaptation actions identified by the community members of Naselesele and Somosomo. Particularly, multiple storm scenario runs with management-relevant shoreline restoration/adaptation options will be implemented to evaluate efficiencies of each adaptation action (e.g., no action, with additional planted trees, with sand mining, with seawalls constructed with natural materials, etc.). These model results will help to better understand how proposed adaption actions may influence future shoreline change and maximize benefits to communities in island nations across the SW Pacific.
Woodbury, Sarah K.
2008-01-01
The introduction of United Space Alliance's Human Engineering Modeling and Performance Laboratory began in early 2007 in an attempt to address the problematic workspace design issues that the Space Shuttle has imposed on technicians performing maintenance and inspection operations. The Space Shuttle was not expected to require the extensive maintenance it undergoes between flights. As a result, extensive, costly resources have been expended on workarounds and modifications to accommodate ground processing personnel. Consideration of basic human factors principles for design of maintenance is essential during the design phase of future space vehicles, facilities, and equipment. Simulation will be needed to test and validate designs before implementation.
Models of Learning Space: Integrating Research on Space, Place and Learning in Higher Education
Ellis, R. A.; Goodyear, P.
2016-01-01
Learning space research is a relatively new field of study that seeks to inform the design, evaluation and management of learning spaces. This paper reviews a dispersed and fragmented literature relevant to understanding connections between university learning spaces and student learning activities. From this review, the paper distils a number of…
Artist-Teachers' In-Action Mental Models While Teaching Visual Arts
Russo-Zimet, Gila
2017-01-01
Studies have examined the assumption that teachers have previous perceptions, beliefs and knowledge about learning (Cochran-Smith & Villegas, 2015). This study presented the In-Action Mental Model of twenty leading artist-teachers while teaching Visual Arts in three Israeli art institutions of higher Education. Data was collected in two…
Mehrdad, GOSHTASBPOUR; Center for Theoretical Physics and Mathematics, AEOI:Department of Physics, Shahid Beheshti University
1991-01-01
Extended D^†+D-DD^† Fujikawa regularization of anomaly and a method of integration of fermions for the chiral Schwinger model are criticized. On the basis of the corrected integration method, a new extended version of D^2 is obtained, resulting in the Jackiw-Rajaraman effective action.
Action and Language Mechanisms in the Brain: Data, Models and Neuroinformatics
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 quench action approach to out-of-equilibrium quantum integrable models
Wouters, B.M.
2015-01-01
In this PhD thesis quantum quenches to 1D quantum integrable models are studied by means of the quench action approach. Using the large-system-size scaling of overlaps between the initial state and Bethe states as basic input, this method gives an exact description in the thermodynamic limit of the
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 ...
The Action of Chain Extenders in Nylon-6, PET, and Model Compounds
Loontjens, T.; Pauwels, K.; Derks, F.; Neilen, M.; Sham, C.K.; Serné, M.
1997-01-01
The action of two complementary chain extenders is studied in model systems as well as in poly(ethylene terephthalate) (PET) and nylon–6. Chain extenders are low molecular weight compounds that can be used to increase the molecular weight of polymers in a short time. The reaction must preferably be
An action-learning model to assist Circuit Teams to support School ...
African Journals Online (AJOL)
We report on the construction of a theoretical model to assist Circuit Teams to support School Management Teams of underperforming high schools towards whole-school development in which these improvement plans play a central role. We followed an action research design, employing qualitative data generation and ...
Morrell, Elizabeth; Sorensen, Janni; Howarth, Joe
2015-01-01
This article describes the evolution of the Charlotte Action Research Project (CHARP), a community-university partnership founded in 2008 at the University of North Carolina at Charlotte, and focuses particularly on the program's unique organizational structure. Research findings of a project evaluation suggest that the CHARP model's unique…
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...
Linking Time and Space Scales in Distributed Hydrological Modelling - a case study for the VIC model
Melsen, Lieke; Teuling, Adriaan; Torfs, Paul; Zappa, Massimiliano; Mizukami, Naoki; Clark, Martyn; Uijlenhoet, Remko
2015-04-01
One of the famous paradoxes of the Greek philosopher Zeno of Elea (~450 BC) is the one with the arrow: If one shoots an arrow, and cuts its motion into such small time steps that at every step the arrow is standing still, the arrow is motionless, because a concatenation of non-moving parts does not create motion. Nowadays, this reasoning can be refuted easily, because we know that motion is a change in space over time, which thus by definition depends on both time and space. If one disregards time by cutting it into infinite small steps, motion is also excluded. This example shows that time and space are linked and therefore hard to evaluate separately. As hydrologists we want to understand and predict the motion of water, which means we have to look both in space and in time. In hydrological models we can account for space by using spatially explicit models. With increasing computational power and increased data availability from e.g. satellites, it has become easier to apply models at a higher spatial resolution. Increasing the resolution of hydrological models is also labelled as one of the 'Grand Challenges' in hydrology by Wood et al. (2011) and Bierkens et al. (2014), who call for global modelling at hyperresolution (~1 km and smaller). A literature survey on 242 peer-viewed articles in which the Variable Infiltration Capacity (VIC) model was used, showed that the spatial resolution at which the model is applied has decreased over the past 17 years: From 0.5 to 2 degrees when the model was just developed, to 1/8 and even 1/32 degree nowadays. On the other hand the literature survey showed that the time step at which the model is calibrated and/or validated remained the same over the last 17 years; mainly daily or monthly. Klemeš (1983) stresses the fact that space and time scales are connected, and therefore downscaling the spatial scale would also imply downscaling of the temporal scale. Is it worth the effort of downscaling your model from 1 degree to 1
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 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 equations
Van Zomeren, M.; Postmes, T.; Spears, R.
An integrative social identity model of collective action (SIMCA) is developed that incorporates 3 socio-psychological perspectives on collective action. Three meta-analyses synthesized a total of 182 effects of perceived injustice, efficacy, and identity on collective action (corresponding to these
van Zomeren, M.; Postmes, T.; Spears, R.
2008-01-01
An integrative social identity model of collective action (SIMCA) is developed that incorporates 3 socio-psychological perspectives on collective action. Three meta-analyses synthesized a total of 182 effects of perceived injustice, efficacy, and identity on collective action (corresponding to these
HYBRID WAYS OF DOING: A MODEL FOR TEACHING PUBLIC SPACE
Directory of Open Access Journals (Sweden)
Gabrielle Bendiner-Viani
2010-07-01
Full Text Available This paper addresses an exploratory practice undertaken by the authors in a co-taught class to hybridize theory, research and practice. This experiment in critical transdisciplinary design education took the form of a “critical studio + practice-based seminar on public space”, two interlinked classes co-taught by landscape architect Elliott Maltby and environmental psychologist Gabrielle Bendiner-Viani at the Parsons, The New School for Design. This design process was grounded in the political and social context of the contested East River waterfront of New York City and valued both intensive study (using a range of social science and design methods and a partnership with a local community organization, engaging with the politics, issues and human needs of a complex site. The paper considers how we encouraged interdisciplinary collaboration and dialogue between teachers as well as between liberal arts and design students and developed strategies to overcome preconceived notions of traditional “studio” and “seminar” work. By exploring the challenges and adjustments made during the semester and the process of teaching this class, this paper addresses how we moved from a model of intertwining theory, research and practice, to a hybrid model of multiple ways of doing, a model particularly apt for teaching public space. Through examples developed for and during our course, the paper suggests practical ways of supporting this transdisciplinary hybrid model.
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.
Improved Nuclear Reactor and Shield Mass Model for Space Applications
Robb, Kevin
2004-01-01
New technologies are being developed to explore the distant reaches of the solar system. Beyond Mars, solar energy is inadequate to power advanced scientific instruments. One technology that can meet the energy requirements is the space nuclear reactor. The nuclear reactor is used as a heat source for which a heat-to-electricity conversion system is needed. Examples of such conversion systems are the Brayton, Rankine, and Stirling cycles. Since launch cost is proportional to the amount of mass to lift, mass is always a concern in designing spacecraft. Estimations of system masses are an important part in determining the feasibility of a design. I worked under Michael Barrett in the Thermal Energy Conversion Branch of the Power & Electric Propulsion Division. An in-house Closed Cycle Engine Program (CCEP) is used for the design and performance analysis of closed-Brayton-cycle energy conversion systems for space applications. This program also calculates the system mass including the heat source. CCEP uses the subroutine RSMASS, which has been updated to RSMASS-D, to estimate the mass of the reactor. RSMASS was developed in 1986 at Sandia National Laboratories to quickly estimate the mass of multi-megawatt nuclear reactors for space applications. In response to an emphasis for lower power reactors, RSMASS-D was developed in 1997 and is based off of the SP-100 liquid metal cooled reactor. The subroutine calculates the mass of reactor components such as the safety systems, instrumentation and control, radiation shield, structure, reflector, and core. The major improvements in RSMASS-D are that it uses higher fidelity calculations, is easier to use, and automatically optimizes the systems mass. RSMASS-D is accurate within 15% of actual data while RSMASS is only accurate within 50%. My goal this summer was to learn FORTRAN 77 programming language and update the CCEP program with the RSMASS-D model.
Topic Modeling of NASA Space System Problem Reports: Research in Practice
Layman, Lucas; Nikora, Allen P.; Meek, Joshua; Menzies, Tim
2016-01-01
Problem reports at NASA are similar to bug reports: they capture defects found during test, post-launch operational anomalies, and document the investigation and corrective action of the issue. These artifacts are a rich source of lessons learned for NASA, but are expensive to analyze since problem reports are comprised primarily of natural language text. We apply topic modeling to a corpus of NASA problem reports to extract trends in testing and operational failures. We collected 16,669 problem reports from six NASA space flight missions and applied Latent Dirichlet Allocation topic modeling to the document corpus. We analyze the most popular topics within and across missions, and how popular topics changed over the lifetime of a mission. We find that hardware material and flight software issues are common during the integration and testing phase, while ground station software and equipment issues are more common during the operations phase. We identify a number of challenges in topic modeling for trend analysis: 1) that the process of selecting the topic modeling parameters lacks definitive guidance, 2) defining semantically-meaningful topic labels requires nontrivial effort and domain expertise, 3) topic models derived from the combined corpus of the six missions were biased toward the larger missions, and 4) topics must be semantically distinct as well as cohesive to be useful. Nonetheless,topic modeling can identify problem themes within missions and across mission lifetimes, providing useful feedback to engineers and project managers.
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.
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.
Modeling of thermal mode of drying special purposes ceramic products in batch action chamber dryers
Lukianov, E. S.; Lozovaya, S. Yu; Lozovoy, N. M.
2018-03-01
The article is devoted to the modeling of batch action chamber dryers in the processing line for producing shaped ceramic products. At the drying stage, for various reasons, most of these products are warped and cracked due to the occurrence of irregular shrinkage deformations due to the action of capillary forces. The primary cause is an untruly organized drying mode due to imperfection of chamber dryers design specifically because of the heat-transfer agent supply method and the possibility of creating a uniform temperature field in the whole volume of the chamber.
Reliability Modeling of Electromechanical System with Meta-Action Chain Methodology
Directory of Open Access Journals (Sweden)
Genbao Zhang
2018-01-01
Full Text Available To establish a more flexible and accurate reliability model, the reliability modeling and solving algorithm based on the meta-action chain thought are used in this thesis. Instead of estimating the reliability of the whole system only in the standard operating mode, this dissertation adopts the structure chain and the operating action chain for the system reliability modeling. The failure information and structure information for each component are integrated into the model to overcome the given factors applied in the traditional modeling. In the industrial application, there may be different operating modes for a multicomponent system. The meta-action chain methodology can estimate the system reliability under different operating modes by modeling the components with varieties of failure sensitivities. This approach has been identified by computing some electromechanical system cases. The results indicate that the process could improve the system reliability estimation. It is an effective tool to solve the reliability estimation problem in the system under various operating modes.
International Nuclear Information System (INIS)
Davis, J. E.; Eddy, M. J.; Sutton, T. M.; Altomari, T. J.
2007-01-01
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. (authors)
Review of the Space Mapping Approach to Engineering Optimization and Modeling
DEFF Research Database (Denmark)
Bakr, M. H.; Bandler, J. W.; Madsen, Kaj
2000-01-01
We review the Space Mapping (SM) concept and its applications in engineering optimization and modeling. The aim of SM is to avoid computationally expensive calculations encountered in simulating an engineering system. The existence of less accurate but fast physically-based models is exploited. S......-based Modeling (SMM). These include Space Derivative Mapping (SDM), Generalized Space Mapping (GSM) and Space Mapping-based Neuromodeling (SMN). Finally, we address open points for research and future development....
Model-based development of a course of action scheduling tool
DEFF Research Database (Denmark)
Kristensen, Lars Michael; Mechlenborg, Peter; Zhang, Lin
2008-01-01
. The scheduling capabilities of COAST are based on state space exploration of the embedded CPN model. Planners interact with COAST using a domain-specific graphical user interface (GUI) that hides the embedded CPN model and analysis algorithms. This means that COAST is based on a rigorous semantical model......, but the use of formal methods is transparent to the users. Trials of operational planning using COAST have been conducted within the Australian Defence Force....
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.
Quantitative Risk Modeling of Fire on the International Space Station
Castillo, Theresa; Haught, Megan
2014-01-01
The International Space Station (ISS) Program has worked to prevent fire events and to mitigate their impacts should they occur. Hardware is designed to reduce sources of ignition, oxygen systems are designed to control leaking, flammable materials are prevented from flying to ISS whenever possible, the crew is trained in fire response, and fire response equipment improvements are sought out and funded. Fire prevention and mitigation are a top ISS Program priority - however, programmatic resources are limited; thus, risk trades are made to ensure an adequate level of safety is maintained onboard the ISS. In support of these risk trades, the ISS Probabilistic Risk Assessment (PRA) team has modeled the likelihood of fire occurring in the ISS pressurized cabin, a phenomenological event that has never before been probabilistically modeled in a microgravity environment. This paper will discuss the genesis of the ISS PRA fire model, its enhancement in collaboration with fire experts, and the results which have informed ISS programmatic decisions and will continue to be used throughout the life of the program.
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.
Scientists as role models in space science outreach
Alexander, D.
The direct participation of scientists significantly enhances the impact of any E/PO effort. This is particularly true when the scientists come from minority or traditionally under-represented groups and, consequently, become role models for a large number of students while presenting positive counter-examples to the usual stereotypes. In this paper I will discuss the impact of scientists as role models through the successful implementation of a set of space physics games and activities, called Solar Week. Targetted at middle-school girls, the key feature of Solar Week is the "Ask a Scientist" section enabling direct interaction between participating students and volunteer scientists. All of the contributing scientists are women, serving as experts in their field and providing role models to whom the students can relate. Solar Week has completed four sessions with a total of some 140 edcuators and 12,000+ students in over 28 states and 9 countries. A major success of the Solar Week program has been the ability of the students to learn more about the scientists as people, through online biographies, and to discuss a variety of topics ranging from science, to careers and common hobbies.
Teaching Ethics in Higher Education Using the Values – Issues – Action (VIA Model
Directory of Open Access Journals (Sweden)
Crystal R Chambers
2016-01-01
Full Text Available Ethics content within higher education graduate programs can help higher education students as emerging leaders become more thoughtful about the decision making process. The purpose of the present manuscript is to explore one vehicle through which current and future higher education leaders can actively contemplate their values and how their values influence their actions when faced with an ethical challenge. The Values – Issue – Action (VIA Model for Ethical Decision Making is a tool for both classroom use and professional reflection through which one can reflect on their values (V and how those values shape how they perceive issues (I, and in turn shape their actions (A. Implications for teaching, learning, and practice are discussed.
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.
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
International Nuclear Information System (INIS)
Ghan, L.S.; Ortiz, M.G.
1991-01-01
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
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 will...
Environmental Disturbance Modeling for Large Inflatable Space Structures
National Research Council Canada - National Science Library
Davis, Donald
2001-01-01
Tightening space budgets and stagnating spacelift capabilities are driving the Air Force and other space agencies to focus on inflatable technology as a reliable, inexpensive means of deploying large structures in orbit...
Observational Model for Precision Astrometry with the Space Interferometry Mission
National Research Council Canada - National Science Library
Turyshev, Slava G; Milman, Mark H
2000-01-01
The Space Interferometry Mission (SIM) is a space-based 10-m baseline Michelson optical interferometer operating in the visible waveband that is designed to achieve astrometric accuracy in the single digits of the microarcsecond domain...
Directory of Open Access Journals (Sweden)
Reny Nadlifatin
2016-11-01
Full Text Available Ecolabel products are one approach towards environmental sustainability. Ecolabel programs have been socialized by governments all over the world to reduce environmental harm caused by the daily life cycles of the products that citizens use. The present study was aimed at measuring citizens’ behavior intention (BI regarding ecolabel product usage. An extended theory of reasoned action (TRA, namely that of pro-environmental reasoned action (PERA, is used as the predictor model. A total of 213 questionnaire data, collected from citizens of Indonesia, was analyzed using structural equation modeling. The analysis results show that the PERA model is able to describe 68% of citizens’ BI regarding ecolabel product usage. The analysis results also reveal that attitude is a key determinant factor. Several practical suggestions based on the results can be used as input for policy makers and company management to consider in their efforts to increase citizens’ BI to use ecolabel products.
DEFF Research Database (Denmark)
Hansen, Bodil Winther; Hatt, Camusa
in interprofessional courses and if the model has a potential as mean of pedagogical development and collaboration. Methods The study is based on action research and is a mixed method study. In 2016 the project will gather data in cooperation with lecturers through qualitative methods and a followup on the baseline...... to further explore the potential of the study activity model as a mean of pedagogical development. The qualitative data will be processed by current hermeneutical and phenomenological methods. Outcomes and implications The outcome of the project should provide deeper insight into facilitating IPE and IPC......Title: Facilitating cooperation in interprofessional education using a study activity model- An action research project . Background Metropolitan University College has over the years developed interprofessional courses for students from 12 different professions, and since 2013 worked...
Optimizing Working Space in Laparoscopy: Studies in a porcine model
J. Vlot (John)
2014-01-01
markdownabstract__Abstract__ Adequate working space is essential for safe and effective laparoscopic surgery. However, the factors that determine working space have not been sufficiently studied. Working space can be very limited, especially in children. A literature review was undertaken to
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.)
International Nuclear Information System (INIS)
Cichy, Krzysztof; Adam Mickiewicz Univ., Poznan; Jansen, Karl; Korcyl, Piotr; Jagiellonian Univ., Krakow
2012-07-01
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 MS 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. (orig.)
d-Lysergic Acid Diethylamide (LSD) as a Model of Psychosis: Mechanism of Action and Pharmacology.
De Gregorio, Danilo; Comai, Stefano; Posa, Luca; Gobbi, Gabriella
2016-11-23
d-Lysergic Acid Diethylamide (LSD) is known for its hallucinogenic properties and psychotic-like symptoms, especially at high doses. It is indeed used as a pharmacological model of psychosis in preclinical research. The goal of this review was to understand the mechanism of action of psychotic-like effects of LSD. We searched Pubmed, Web of Science, Scopus, Google Scholar and articles' reference lists for preclinical studies regarding the mechanism of action involved in the psychotic-like effects induced by LSD. LSD's mechanism of action is pleiotropic, primarily mediated by the serotonergic system in the Dorsal Raphe, binding the 5-HT 2A receptor as a partial agonist and 5-HT 1A as an agonist. LSD also modulates the Ventral Tegmental Area, at higher doses, by stimulating dopamine D₂, Trace Amine Associate receptor 1 (TAAR₁) and 5-HT 2A . More studies clarifying the mechanism of action of the psychotic-like symptoms or psychosis induced by LSD in humans are needed. LSD's effects are mediated by a pleiotropic mechanism involving serotonergic, dopaminergic, and glutamatergic neurotransmission. Thus, the LSD-induced psychosis is a useful model to test the therapeutic efficacy of potential novel antipsychotic drugs, particularly drugs with dual serotonergic and dopaminergic (DA) mechanism or acting on TAAR₁ receptors.
d-Lysergic Acid Diethylamide (LSD as a Model of Psychosis: Mechanism of Action and Pharmacology
Directory of Open Access Journals (Sweden)
Danilo De Gregorio
2016-11-01
Full Text Available d-Lysergic Acid Diethylamide (LSD is known for its hallucinogenic properties and psychotic-like symptoms, especially at high doses. It is indeed used as a pharmacological model of psychosis in preclinical research. The goal of this review was to understand the mechanism of action of psychotic-like effects of LSD. We searched Pubmed, Web of Science, Scopus, Google Scholar and articles’ reference lists for preclinical studies regarding the mechanism of action involved in the psychotic-like effects induced by LSD. LSD’s mechanism of action is pleiotropic, primarily mediated by the serotonergic system in the Dorsal Raphe, binding the 5-HT2A receptor as a partial agonist and 5-HT1A as an agonist. LSD also modulates the Ventral Tegmental Area, at higher doses, by stimulating dopamine D2, Trace Amine Associate receptor 1 (TAAR1 and 5-HT2A. More studies clarifying the mechanism of action of the psychotic-like symptoms or psychosis induced by LSD in humans are needed. LSD’s effects are mediated by a pleiotropic mechanism involving serotonergic, dopaminergic, and glutamatergic neurotransmission. Thus, the LSD-induced psychosis is a useful model to test the therapeutic efficacy of potential novel antipsychotic drugs, particularly drugs with dual serotonergic and dopaminergic (DA mechanism or acting on TAAR1 receptors.
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 %.
Motion Primitives for Action Recognition
DEFF Research Database (Denmark)
Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.
2007-01-01
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......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...... different temporal actions using a probabilistic Edit Distance method. The method is tested on different actions with and without noise and the results show recognition rates of 88.7% and 85.5%, respectively....
Action Recognition using Motion Primitives
DEFF Research Database (Denmark)
Moeslund, Thomas B.; Fihl, Preben; Holte, Michael Boelstoft
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......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...... 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....
A Reparametrization Approach for Dynamic Space-Time Models
Lee, Hyeyoung; Ghosh, Sujit K.
2008-01-01
Researchers in diverse areas such as environmental and health sciences are increasingly working with data collected across space and time. The space-time processes that are generally used in practice are often complicated in the sense that the auto-dependence structure across space and time is non-trivial, often non-separable and non-stationary in space and time. Moreover, the dimension of such data sets across both space and time can be very large leading to computational difficulties due to...
Dynamic Model Averaging in Large Model Spaces Using Dynamic Occam’s Window*
Onorante, Luca; Raftery, Adrian E.
2015-01-01
Bayesian model averaging has become a widely used approach to accounting for uncertainty about the structural form of the model generating the data. When data arrive sequentially and the generating model can change over time, Dynamic Model Averaging (DMA) extends model averaging to deal with this situation. Often in macroeconomics, however, many candidate explanatory variables are available and the number of possible models becomes too large for DMA to be applied in its original form. We propose a new method for this situation which allows us to perform DMA without considering the whole model space, but using a subset of models and dynamically optimizing the choice of models at each point in time. This yields a dynamic form of Occam’s window. We evaluate the method in the context of the problem of nowcasting GDP in the Euro area. We find that its forecasting performance compares well with that of other methods. PMID:26917859
Dynamic Model Averaging in Large Model Spaces Using Dynamic Occam's Window.
Onorante, Luca; Raftery, Adrian E
2016-01-01
Bayesian model averaging has become a widely used approach to accounting for uncertainty about the structural form of the model generating the data. When data arrive sequentially and the generating model can change over time, Dynamic Model Averaging (DMA) extends model averaging to deal with this situation. Often in macroeconomics, however, many candidate explanatory variables are available and the number of possible models becomes too large for DMA to be applied in its original form. We propose a new method for this situation which allows us to perform DMA without considering the whole model space, but using a subset of models and dynamically optimizing the choice of models at each point in time. This yields a dynamic form of Occam's window. We evaluate the method in the context of the problem of nowcasting GDP in the Euro area. We find that its forecasting performance compares well with that of other methods.
Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles
International Nuclear Information System (INIS)
1992-01-01
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
Motivation and justification: a dual-process model of culture in action.
Vaisey, Stephen
2009-05-01
This article presents a new model of culture in action. Although most sociologists who study culture emphasize its role in post hoc sense making, sociologists of religion and social psychologists tend to focus on the role beliefs play in motivation. The dual-process model integrates justificatory and motivational approaches by distinguishing between "discursive" and "practical" modes of culture and cognition. The author uses panel data from the National Study of Youth and Religion to illustrate the model's usefulness. Consistent with its predictions, he finds that though respondents cannot articulate clear principles of moral judgment, their choice from a list of moral-cultural scripts strongly predicts later behavior.
Computer modeling of active experiments in space plasmas
International Nuclear Information System (INIS)
Bollens, R.J.
1993-01-01
The understanding of space plasmas is expanding rapidly. This is, in large part, due to the ambitious efforts of scientists from around the world who are performing large scale active experiments in the space plasma surrounding the earth. One such effort was designated the Active Magnetospheric Particle Tracer Explorers (AMPTE) and consisted of a series of plasma releases that were completed during 1984 and 1985. What makes the AMPTE experiments particularly interesting was the occurrence of a dramatic anomaly that was completely unpredicted. During the AMPTE experiment, three satellites traced the solar-wind flow into the earth's magnetosphere. One satellite, built by West Germany, released a series of barium and lithium canisters that were detonated and subsequently photo-ionized via solar radiation, thereby creating an artificial comet. Another satellite, built by Great Britain and in the vicinity during detonation, carried, as did the first satellite, a comprehensive set of magnetic field, particle and wave instruments. Upon detonation, what was observed by the satellites, as well as by aircraft and ground-based observers, was quite unexpected. The initial deflection of the ion clouds was not in the ambient solar wind's flow direction (rvec V) but rather in the direction transverse to the solar wind and the background magnetic field (rvec V x rvec B). This result was not predicted by any existing theories or simulation models; it is the main subject discussed in this dissertation. A large three dimensional computer simulation was produced to demonstrate that this transverse motion can be explained in terms of a rocket effect. Due to the extreme computer resources utilized in producing this work, the computer methods used to complete the calculation and the visualization techniques used to view the results are also discussed
Learning to Recognize Actions From Limited Training Examples Using a Recurrent Spiking Neural Model
Panda, Priyadarshini; Srinivasa, Narayan
2018-01-01
A fundamental challenge in machine learning today is to build a model that can learn from few examples. Here, we describe a reservoir based spiking neural model for learning to recognize actions with a limited number of labeled videos. First, we propose a novel encoding, inspired by how microsaccades influence visual perception, to extract spike information from raw video data while preserving the temporal correlation across different frames. Using this encoding, we show that the reservoir generalizes its rich dynamical activity toward signature action/movements enabling it to learn from few training examples. We evaluate our approach on the UCF-101 dataset. Our experiments demonstrate that our proposed reservoir achieves 81.3/87% Top-1/Top-5 accuracy, respectively, on the 101-class data while requiring just 8 video examples per class for training. Our results establish a new benchmark for action recognition from limited video examples for spiking neural models while yielding competitive accuracy with respect to state-of-the-art non-spiking neural models. PMID:29551962
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.
Directory of Open Access Journals (Sweden)
Faulkner Guy EJ
2009-12-01
Full Text Available Abstract Background ParticipACTION was a pervasive communication campaign that promoted physical activity in the Canadian population for three decades. According to McGuire's hierarchy-of-effects model (HOEM, this campaign should influence physical activity through intermediate mediators such as beliefs and intention. Also, when such media campaigns occur, knowledge gaps often develop within the population about the messages being conveyed. The purposes of this study were to (a determine the current awareness of ParticipACTION campaigns among Canadians; (b confirm if awareness of the ParticipACTION initiative varied as a function of levels of education and household income; and, (c to examine whether awareness of ParticipACTION was associated with physical activity related beliefs, intentions, and leisure-time physical activity (LTPA as suggested by the HOEM. Specifically, we tested a model including awareness of ParticipACTION (unprompted, prompted, outcome expectations, self-efficacy, intention, and physical activity status. Methods A population-based survey was conducted on 4,650 Canadians over a period of 6 months from August, 2007 to February, 2008 (response rate = 49%. The survey consisted of a set of additional questions on the 2007 Physical Activity Monitor (PAM. Our module on the PAM included questions related to awareness and knowledge of ParticipACTION. Weighted logistic models were constructed to test the knowledge gap hypotheses and to examine whether awareness was associated with physical activity related beliefs (i.e., outcome expectations, self-efficacy, intention, and LTPA. All analyses included those respondents who were 20 years of age and older in 2007/2008 (N = 4424. Results Approximately 8% of Canadians were still aware of ParticipACTION unprompted and 82% were aware when prompted. Both education and income were significant correlates of awareness among Canadians. The odds of people being aware of ParticipACTION were
Spence, John C; Brawley, Lawrence R; Craig, Cora Lynn; Plotnikoff, Ronald C; Tremblay, Mark S; Bauman, Adrian; Faulkner, Guy Ej; Chad, Karen; Clark, Marianne I
2009-12-09
ParticipACTION was a pervasive communication campaign that promoted physical activity in the Canadian population for three decades. According to McGuire's hierarchy-of-effects model (HOEM), this campaign should influence physical activity through intermediate mediators such as beliefs and intention. Also, when such media campaigns occur, knowledge gaps often develop within the population about the messages being conveyed. The purposes of this study were to (a) determine the current awareness of ParticipACTION campaigns among Canadians; (b) confirm if awareness of the ParticipACTION initiative varied as a function of levels of education and household income; and, (c) to examine whether awareness of ParticipACTION was associated with physical activity related beliefs, intentions, and leisure-time physical activity (LTPA) as suggested by the HOEM. Specifically, we tested a model including awareness of ParticipACTION (unprompted, prompted), outcome expectations, self-efficacy, intention, and physical activity status. A population-based survey was conducted on 4,650 Canadians over a period of 6 months from August, 2007 to February, 2008 (response rate = 49%). The survey consisted of a set of additional questions on the 2007 Physical Activity Monitor (PAM). Our module on the PAM included questions related to awareness and knowledge of ParticipACTION. Weighted logistic models were constructed to test the knowledge gap hypotheses and to examine whether awareness was associated with physical activity related beliefs (i.e., outcome expectations, self-efficacy), intention, and LTPA. All analyses included those respondents who were 20 years of age and older in 2007/2008 (N = 4424). Approximately 8% of Canadians were still aware of ParticipACTION unprompted and 82% were aware when prompted. Both education and income were significant correlates of awareness among Canadians. The odds of people being aware of ParticipACTION were greater if they were more educated and reported
Directory of Open Access Journals (Sweden)
González-Bailón, Sandra
2009-12-01
Full Text Available There is interdependence when the actions of an individual influence the decisions (and later actions of other individuals. This paper claims that social networks define the structure of that range of influence and unleash a number of mechanisms that go beyond those captured by rational action theory. Networks give access to the ideas and actions of other individuals, and this exposure determines the activation of thresholds, the timing of actions, and the emergence of contagion processes, informational cascades and epidemics. This paper sustains that rational action theory does not offer the necessary tools to model these processes if it is not inserted in a general theory of networks. This is especially the case in the context opened by new information and communication technologies, where the interdependence of individuals is acquiring greater empirical relevance.
Existe interdependencia cuando las acciones de unos individuos influyen en las decisiones (y posteriores acciones de otros individuos. Este artículo sostiene que las redes sociales definen la estructura de ese espacio de influencia y desatan una serie de mecanismos de los que la teoría de la elección racional no puede dar cuenta. Las redes sociales abren acceso a las ideas y acciones de otros individuos, y esta exposición determina la satisfacción de umbrales, el tempo con en el que se llevan a cabo las acciones y la emergencia de procesos de contagio, cascadas de información y epidemias. Este artículo defiende que la teoría de la elección racional no ofrece las herramientas necesarias para modelizar tales procesos si no se inserta en una teoría general de redes. Éste es especialmente el caso en unos momentos en los que la interdependencia de individuos está adquiriendo, al amparo de las nuevas tecnologías, mayor relevancia empírica.
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…
Spatio-temporal tumour model for analysis and mechanism of action ...
Indian Academy of Sciences (India)
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 ...
Dutta, Sara; Mincholé, Ana; Quinn, T Alexander; Rodriguez, Blanca
2017-10-01
Acute myocardial ischemia is one of the main causes of sudden cardiac death. The mechanisms have been investigated primarily in experimental and computational studies using different animal species, but human studies remain scarce. In this study, we assess the ability of four human ventricular action potential models (ten Tusscher and Panfilov, 2006; Grandi et al., 2010; Carro et al., 2011; O'Hara et al., 2011) to simulate key electrophysiological consequences of acute myocardial ischemia in single cell and tissue simulations. We specifically focus on evaluating the effect of extracellular potassium concentration and activation of the ATP-sensitive inward-rectifying potassium current on action potential duration, post-repolarization refractoriness, and conduction velocity, as the most critical factors in determining reentry vulnerability during ischemia. Our results show that the Grandi and O'Hara models required modifications to reproduce expected ischemic changes, specifically modifying the intracellular potassium concentration in the Grandi model and the sodium current in the O'Hara model. With these modifications, the four human ventricular cell AP models analyzed in this study reproduce the electrophysiological alterations in repolarization, refractoriness, and conduction velocity caused by acute myocardial ischemia. However, quantitative differences are observed between the models and overall, the ten Tusscher and modified O'Hara models show closest agreement to experimental data. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
The modified turning bands (MTB) model for space-time rainfall. I. Model definition and properties
Mellor, Dale
1996-02-01
A new stochastic model of space-time rainfall, the Modified Turning Bands (MTB) model, is proposed which reproduces, in particular, the movements and developments of rainbands, cluster potential regions and raincells, as well as their respective interactions. The ensemble correlation structure is unsuitable for practical estimation of the model parameters because the model is not ergodic in this statistic, and hence it cannot easily be measured from a single real storm. Thus, some general theory on the internal covariance structure of a class of stochastic models is presented, of which the MTB model is an example. It is noted that, for the MTB model, the internal covariance structure may be measured from a single storm, and can thus be used for model identification.
Ultrasonic Enhancement of Antibiotic Action on Escherichia coli Biofilms: an In Vivo Model
Rediske, Andrea M.; Roeder, Beverly L.; Brown, Maren K.; Nelson, Jared L.; Robison, Rachel L.; Draper, David O.; Schaalje, G. Bruce; Robison, Richard A.; Pitt, William G.
1999-01-01
Biofilm infections are a common complication of prosthetic devices in humans. Previous in vitro research has determined that low-frequency ultrasound combined with aminoglycoside antibiotics is an effective method of killing biofilms. We report the development of an in vivo model to determine if ultrasound enhances antibiotic action. Two 24-h-old Escherichia coli (ATCC 10798) biofilms grown on polyethylene disks were implanted subcutaneously on the backs of New Zealand White female rabbits, o...
Belkina, S V; Semkina, M A; Kritskiĭ, R O; Petin, V G
2010-01-01
Data obtained by other authors for mammalian cells treated by sequential action of ionizing radiation and hyperthermia were used to estimate the dependence of synergistic enhancement ratio on the ratio of damages induced by these agents. Experimental results were described and interpreted by means of the mathematical model of synergism in accordance with which the synergism is expected to result from the additional lethal damage arising from the interaction of sublesions induced by both agents.
The Stochastic Early Reaction, Inhibition, and late Action (SERIA model for antisaccades.
Directory of Open Access Journals (Sweden)
Eduardo A Aponte
2017-08-01
Full Text Available The antisaccade task is a classic paradigm used to study the voluntary control of eye movements. It requires participants to suppress a reactive eye movement to a visual target and to concurrently initiate a saccade in the opposite direction. Although several models have been proposed to explain error rates and reaction times in this task, no formal model comparison has yet been performed. Here, we describe a Bayesian modeling approach to the antisaccade task that allows us to formally compare different models on the basis of their evidence. First, we provide a formal likelihood function of actions (pro- and antisaccades and reaction times based on previously published models. Second, we introduce the Stochastic Early Reaction, Inhibition, and late Action model (SERIA, a novel model postulating two different mechanisms that interact in the antisaccade task: an early GO/NO-GO race decision process and a late GO/GO decision process. Third, we apply these models to a data set from an experiment with three mixed blocks of pro- and antisaccade trials. Bayesian model comparison demonstrates that the SERIA model explains the data better than competing models that do not incorporate a late decision process. Moreover, we show that the early decision process postulated by the SERIA model is, to a large extent, insensitive to the cue presented in a single trial. Finally, we use parameter estimates to demonstrate that changes in reaction time and error rate due to the probability of a trial type (pro- or antisaccade are best explained by faster or slower inhibition and the probability of generating late voluntary prosaccades.
Incorporating institutions and collective action into a sociohydrological model of flood resilience
Yu, David J.; Sangwan, Nikhil; Sung, Kyungmin; Chen, Xi; Merwade, Venkatesh
2017-02-01
Stylized sociohydrological models have mainly used social memory aspects such as community awareness or sensitivity to connect hydrologic change and social response. However, social memory alone does not satisfactorily capture the details of how human behavior is translated into collective action for water resources governance. Nor is it the only social mechanism by which the two-way feedbacks of sociohydrology can be operationalized. This study contributes toward bridging of this gap by developing a sociohydrological model of a flood resilience that includes two additional components: (1) institutions for collective action, and (2) connections to an external economic system. Motivated by the case of community-managed flood protection systems (polders) in coastal Bangladesh, we use the model to understand critical general features that affect long-term resilience of human-flood systems. Our findings suggest that occasional adversity can enhance long-term resilience. Allowing some hydrological variability to enter into the polder can increase its adaptive capacity for resilience through the preservation of social norm for collective action. Further, there are potential trade-offs associated with optimization of flood resistance through structural measures. By reducing sensitivity to floods, the system may become more fragile under the double impact of floods and economic change.
Directory of Open Access Journals (Sweden)
Loewe Axel
2015-09-01
Full Text Available Vernakalant is a new antiarrhythmic agent for the treatment of atrial fibrillation. While it has proven to be effective in a large share of patients in clinical studies, its underlying mode of action is not fully understood. In this work, we aim to link experimental data from the subcellular, tissue, and system level using an in-silico approach. A Hill’s equation-based drug model was extended to cover the frequency dependence of sodium channel block. Two model variants were investigated: M1 based on subcellular data and M2 based on tissue level data. 6 action potential (AP markers were evaluated regarding their dose, frequency and substrate dependence. M1 comprising potassium, sodium, and calcium channel block reproduced the reported prolongation of the refractory period. M2 not including the effects on potassium channels reproduced reported AP morphology changes on the other hand. The experimentally observed increase of ERP accompanied by a shortening of APD90 was not reproduced. Thus, explanations for the drug-induced changes are provided while none of the models can explain the effects in their entirety. These results foster the understanding of vernakalant’s cellular mode of action and point out relevant gaps in our current knowledge to be addressed in future in-silico and experimental research on this aspiring antiarrhythmic agent.
DEFF Research Database (Denmark)
Ehnfors, Margareta; Angermo, Lilly Marit; Berring, Lene
2006-01-01
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......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....... 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...
Dynamical modeling of microRNA action on the protein translation process.
Zinovyev, Andrei; Morozova, Nadya; Nonne, Nora; Barillot, Emmanuel; Harel-Bellan, Annick; Gorban, Alexander N
2010-02-24
Protein translation is a multistep process which can be represented as a cascade of biochemical reactions (initiation, ribosome assembly, elongation, etc.), the rate of which can be regulated by small non-coding microRNAs through multiple mechanisms. It remains unclear what mechanisms of microRNA action are the most dominant: moreover, many experimental reports deliver controversial messages on what is the concrete mechanism actually observed in the experiment. Nissan and Parker have recently demonstrated that it might be impossible to distinguish alternative biological hypotheses using the steady state data on the rate of protein synthesis. For their analysis they used two simple kinetic models of protein translation. In contrary to the study by Nissan and Parker, we show that dynamical data allow discriminating some of the mechanisms of microRNA action. We demonstrate this using the same models as developed by Nissan and Parker for the sake of comparison but the methods developed (asymptotology of biochemical networks) can be used for other models. We formulate a hypothesis that the effect of microRNA action is measurable and observable only if it affects the dominant system (generalization of the limiting step notion for complex networks) of the protein translation machinery. The dominant system can vary in different experimental conditions that can partially explain the existing controversy of some of the experimental data. Our analysis of the transient protein translation dynamics shows that it gives enough information to verify or reject a hypothesis about a particular molecular mechanism of microRNA action on protein translation. For multiscale systems only that action of microRNA is distinguishable which affects the parameters of dominant system (critical parameters), or changes the dominant system itself. Dominant systems generalize and further develop the old and very popular idea of limiting step. Algorithms for identifying dominant systems in multiscale
Dynamical modeling of microRNA action on the protein translation process
Directory of Open Access Journals (Sweden)
Barillot Emmanuel
2010-02-01
Full Text Available Abstract Background Protein translation is a multistep process which can be represented as a cascade of biochemical reactions (initiation, ribosome assembly, elongation, etc., the rate of which can be regulated by small non-coding microRNAs through multiple mechanisms. It remains unclear what mechanisms of microRNA action are the most dominant: moreover, many experimental reports deliver controversial messages on what is the concrete mechanism actually observed in the experiment. Nissan and Parker have recently demonstrated that it might be impossible to distinguish alternative biological hypotheses using the steady state data on the rate of protein synthesis. For their analysis they used two simple kinetic models of protein translation. Results In contrary to the study by Nissan and Parker, we show that dynamical data allow discriminating some of the mechanisms of microRNA action. We demonstrate this using the same models as developed by Nissan and Parker for the sake of comparison but the methods developed (asymptotology of biochemical networks can be used for other models. We formulate a hypothesis that the effect of microRNA action is measurable and observable only if it affects the dominant system (generalization of the limiting step notion for complex networks of the protein translation machinery. The dominant system can vary in different experimental conditions that can partially explain the existing controversy of some of the experimental data. Conclusions Our analysis of the transient protein translation dynamics shows that it gives enough information to verify or reject a hypothesis about a particular molecular mechanism of microRNA action on protein translation. For multiscale systems only that action of microRNA is distinguishable which affects the parameters of dominant system (critical parameters, or changes the dominant system itself. Dominant systems generalize and further develop the old and very popular idea of limiting step
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.
Fitting identity in the reasoned action framework: A meta-analysis and model comparison.
Paquin, Ryan S; Keating, David M
2017-01-01
Several competing models have been put forth regarding the role of identity in the reasoned action framework. The standard model proposes that identity is a background variable. Under a typical augmented model, identity is treated as an additional direct predictor of intention and behavior. Alternatively, it has been proposed that identity measures are inadvertent indicators of an underlying intention factor (e.g., a manifest-intention model). In order to test these competing hypotheses, we used data from 73 independent studies (total N = 23,917) to conduct a series of meta-analytic structural equation models. We also tested for moderation effects based on whether there was a match between identity constructs and the target behaviors examined (e.g., if the study examined a "smoker identity" and "smoking behavior," there would be a match; if the study examined a "health conscious identity" and "smoking behavior," there would not be a match). Average effects among primary reasoned action variables were all substantial, rs = .37-.69. Results gave evidence for the manifest-intention model over the other explanations, and a moderation effect by identity-behavior matching.
Optimizing phonon space in the phonon-coupling model
Tselyaev, V.; Lyutorovich, N.; Speth, J.; Reinhard, P.-G.
2017-08-01
We present a new scheme to select the most relevant phonons in the phonon-coupling model, named here the time-blocking approximation (TBA). The new criterion, based on the phonon-nucleon coupling strengths rather than on B (E L ) values, is more selective and thus produces much smaller phonon spaces in the TBA. This is beneficial in two respects: first, it curbs the computational cost, and second, it reduces the danger of double counting in the expansion basis of the TBA. We use here the TBA in a form where the coupling strength is regularized to keep the given Hartree-Fock ground state stable. The scheme is implemented in a random-phase approximation and TBA code based on the Skyrme energy functional. We first explore carefully the cutoff dependence with the new criterion and can work out a natural (optimal) cutoff parameter. Then we use the freshly developed and tested scheme for a survey of giant resonances and low-lying collective states in six doubly magic nuclei looking also at the dependence of the results when varying the Skyrme parametrization.
A model for emergence of space and time
Energy Technology Data Exchange (ETDEWEB)
Ambjørn, J., E-mail: ambjorn@nbi.dk [The Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen Ø (Denmark); Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radbaud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen (Netherlands); Watabiki, Y., E-mail: watabiki@th.phys.titech.ac.jp [Tokyo Institute of Technology, Dept. of Physics, High Energy Theory Group, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan)
2015-10-07
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”)
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”
Retail gentrification. Staged spaces and the gourmet market model
Directory of Open Access Journals (Sweden)
Luz de Lourdes Cordero Gómez del Campo
2017-12-01
Full Text Available Retail gentrification is understood as a process in which commercial activity is transformed to meet the needs of a sector of the population with higher incomes resulting in the displacement of merchants and products, seen from the implementation of the model of the gourmet market. This process, which is seen in the interest of copying the commercial formats of successful cases from gourmet markets such as the San Miguel Market in Madrid or the Borough Market in London, is linked to an offer aimed at satisfying consumption demands produced by a sector of the population that although not being equivalent concepts, different authors identify as cultural omnivores or creative class, coinciding in that these groups have a high cultural and economic capital. In the present work it is discussed how in Mexico City in the absence of the transformation of public markets into gourmet markets and with the inauguration of the Roma Market in 2014, the staging of commercial spaces labeled as gourmet markets has intensified and they are inserted in neighborhoods where they seek to generate development and links with the community, but because of their prices and the characteristics of the products they offer, they are beyond the reach of the local population.
A coarse-grained model for synergistic action of multiple enzymes on cellulose
Directory of Open Access Journals (Sweden)
Asztalos Andrea
2012-08-01
Full Text Available Abstract Background Degradation of cellulose to glucose requires the cooperative action of three classes of enzymes, collectively known as cellulases. Endoglucanases randomly bind to cellulose surfaces and generate new chain ends by hydrolyzing β-1,4-D-glycosidic bonds. Exoglucanases bind to free chain ends and hydrolyze glycosidic bonds in a processive manner releasing cellobiose units. Then, β-glucosidases hydrolyze soluble cellobiose to glucose. Optimal synergistic action of these enzymes is essential for efficient digestion of cellulose. Experiments show that as hydrolysis proceeds and the cellulose substrate becomes more heterogeneous, the overall degradation slows down. As catalysis occurs on the surface of crystalline cellulose, several factors affect the overall hydrolysis. Therefore, spatial models of cellulose degradation must capture effects such as enzyme crowding and surface heterogeneity, which have been shown to lead to a reduction in hydrolysis rates. Results We present a coarse-grained stochastic model for capturing the key events associated with the enzymatic degradation of cellulose at the mesoscopic level. This functional model accounts for the mobility and action of a single cellulase enzyme as well as the synergy of multiple endo- and exo-cellulases on a cellulose surface. The quantitative description of cellulose degradation is calculated on a spatial model by including free and bound states of both endo- and exo-cellulases with explicit reactive surface terms (e.g., hydrogen bond breaking, covalent bond cleavages and corresponding reaction rates. The dynamical evolution of the system is simulated by including physical interactions between cellulases and cellulose. Conclusions Our coarse-grained model reproduces the qualitative behavior of endoglucanases and exoglucanases by accounting for the spatial heterogeneity of the cellulose surface as well as other spatial factors such as enzyme crowding. Importantly, it captures
Tait, Luke; Wedgwood, Kyle; Tsaneva-Atanasova, Krasimira; Brown, Jon T; Goodfellow, Marc
2018-07-14
The entorhinal cortex is a crucial component of our memory and spatial navigation systems and is one of the first areas to be affected in dementias featuring tau pathology, such as Alzheimer's disease and frontotemporal dementia. Electrophysiological recordings from principle cells of medial entorhinal cortex (layer II stellate cells, mEC-SCs) demonstrate a number of key identifying properties including subthreshold oscillations in the theta (4-12 Hz) range and clustered action potential firing. These single cell properties are correlated with network activity such as grid firing and coupling between theta and gamma rhythms, suggesting they are important for spatial memory. As such, experimental models of dementia have revealed disruption of organised dorsoventral gradients in clustered action potential firing. To better understand the mechanisms underpinning these different dynamics, we study a conductance based model of mEC-SCs. We demonstrate that the model, driven by extrinsic noise, can capture quantitative differences in clustered action potential firing patterns recorded from experimental models of tau pathology and healthy animals. The differential equation formulation of our model allows us to perform numerical bifurcation analyses in order to uncover the dynamic mechanisms underlying these patterns. We show that clustered dynamics can be understood as subcritical Hopf/homoclinic bursting in a fast-slow system where the slow sub-system is governed by activation of the persistent sodium current and inactivation of the slow A-type potassium current. In the full system, we demonstrate that clustered firing arises via flip bifurcations as conductance parameters are varied. Our model analyses confirm the experimentally suggested hypothesis that the breakdown of clustered dynamics in disease occurs via increases in AHP conductance. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.
DEFF Research Database (Denmark)
Tan, Qihua; Bathum, L; Christiansen, L
2003-01-01
In this paper, we apply logistic regression models to measure genetic association with human survival for highly polymorphic and pleiotropic genes. By modelling genotype frequency as a function of age, we introduce a logistic regression model with polytomous responses to handle the polymorphic...... situation. Genotype and allele-based parameterization can be used to investigate the modes of gene action and to reduce the number of parameters, so that the power is increased while the amount of multiple testing minimized. A binomial logistic regression model with fractional polynomials is used to capture...... the age-dependent or antagonistic pleiotropic effects. The models are applied to HFE genotype data to assess the effects on human longevity by different alleles and to detect if an age-dependent effect exists. Application has shown that these methods can serve as useful tools in searching for important...
A cosmological model with compact space sections and low mass density
International Nuclear Information System (INIS)
Fagundes, H.V.
1982-01-01
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) [pt
Diffusion with space memory modelled with distributed order space fractional differential equations
Directory of Open Access Journals (Sweden)
M. Caputo
2003-06-01
Full Text Available Distributed order fractional differential equations (Caputo, 1995, 2001; Bagley and Torvik, 2000a,b were fi rst used in the time domain; they are here considered in the space domain and introduced in the constitutive equation of diffusion. The solution of the classic problems are obtained, with closed form formulae. In general, the Green functions act as low pass fi lters in the frequency domain. The major difference with the case when a single space fractional derivative is present in the constitutive equations of diffusion (Caputo and Plastino, 2002 is that the solutions found here are potentially more fl exible to represent more complex media (Caputo, 2001a. The difference between the space memory medium and that with the time memory is that the former is more fl exible to represent local phenomena while the latter is more fl exible to represent variations in space. Concerning the boundary value problem, the difference with the solution of the classic diffusion medium, in the case when a constant boundary pressure is assigned and in the medium the pressure is initially nil, is that one also needs to assign the fi rst order space derivative at the boundary.
Matter fields in curved space-time
International Nuclear Information System (INIS)
Viet, Nguyen Ai; Wali, Kameshwar C.
2000-01-01
We study the geometry of a two-sheeted space-time within the framework of non-commutative geometry. As a prelude to the Standard Model in curved space-time, we present a model of a left- and a right- chiral field living on the two sheeted-space time and construct the action functionals that describe their interactions
On the structure of the space of geometric product-form models
Bayer, Nimrod; Boucherie, Richardus J.
2002-01-01
This article deals with Markovian models defined on a finite-dimensional discrete state space and possess a stationary state distribution of a product-form. We view the space of such models as a mathematical object and explore its structure. We focus on models on an orthant [script Z]+n, which are
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.
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.
Preliminary results from a four-working space, double-acting piston, Stirling engine controls model
Daniele, C. J.; Lorenzo, C. F.
1980-01-01
A four working space, double acting piston, Stirling engine simulation is being developed for controls studies. The development method is to construct two simulations, one for detailed fluid behavior, and a second model with simple fluid behaviour but containing the four working space aspects and engine inertias, validate these models separately, then upgrade the four working space model by incorporating the detailed fluid behaviour model for all four working spaces. The single working space (SWS) model contains the detailed fluid dynamics. It has seven control volumes in which continuity, energy, and pressure loss effects are simulated. Comparison of the SWS model with experimental data shows reasonable agreement in net power versus speed characteristics for various mean pressure levels in the working space. The four working space (FWS) model was built to observe the behaviour of the whole engine. The drive dynamics and vehicle inertia effects are simulated. To reduce calculation time, only three volumes are used in each working space and the gas temperature are fixed (no energy equation). Comparison of the FWS model predicted power with experimental data shows reasonable agreement. Since all four working spaces are simulated, the unique capabilities of the model are exercised to look at working fluid supply transients, short circuit transients, and piston ring leakage effects.
Equivalent circuit modeling of space charge dominated magnetically insulated transmission lines
Energy Technology Data Exchange (ETDEWEB)
Hiraoka, Kazuki; Nakajima, Mitsuo; Horioka, Kazuhiko
1997-12-31
A new equivalent circuit model for space charge dominated MITLs (Magnetically Insulated Transmission Lines) was developed. MITLs under high power operation are dominated with space charge current flowing between anode and cathode. Conventional equivalent circuit model does not account for space charge effects on power flow. The model was modified to discuss the power transportation through the high power MITLs. With this model, it is possible to estimate the effects of space charge current on the power flow efficiency, without using complicated particle code simulations. (author). 3 figs., 3 refs.
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...
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.
Baldassarre, Gianluca; Mannella, Francesco; Fiore, Vincenzo G; Redgrave, Peter; Gurney, Kevin; Mirolli, Marco
2013-05-01
Reinforcement (trial-and-error) learning in animals is driven by a multitude of processes. Most animals have evolved several sophisticated systems of 'extrinsic motivations' (EMs) that guide them to acquire behaviours allowing them to maintain their bodies, defend against threat, and reproduce. Animals have also evolved various systems of 'intrinsic motivations' (IMs) that allow them to acquire actions in the absence of extrinsic rewards. These actions are used later to pursue such rewards when they become available. Intrinsic motivations have been studied in Psychology for many decades and their biological substrates are now being elucidated by neuroscientists. In the last two decades, investigators in computational modelling, robotics and machine learning have proposed various mechanisms that capture certain aspects of IMs. However, we still lack models of IMs that attempt to integrate all key aspects of intrinsically motivated learning and behaviour while taking into account the relevant neurobiological constraints. This paper proposes a bio-constrained system-level model that contributes a major step towards this integration. The model focusses on three processes related to IMs and on the neural mechanisms underlying them: (a) the acquisition of action-outcome associations (internal models of the agent-environment interaction) driven by phasic dopamine signals caused by sudden, unexpected changes in the environment; (b) the transient focussing of visual gaze and actions on salient portions of the environment; (c) the subsequent recall of actions to pursue extrinsic rewards based on goal-directed reactivation of the representations of their outcomes. The tests of the model, including a series of selective lesions, show how the focussing processes lead to a faster learning of action-outcome associations, and how these associations can be recruited for accomplishing goal-directed behaviours. The model, together with the background knowledge reviewed in the paper
Mathematical Model for the Sequential Action of Radiation and Heat on Yeast Cells
International Nuclear Information System (INIS)
Kim, Jin Kyu; Lee, Yun Jong; Kim, Su Hyoun; Nili, Mohammad; Zhurakovskaya, Galina P.; Petin, Vladislav G.
2009-01-01
It is well known that the synergistic interaction of hyperthermia with ionizing radiation and other agents is widely used in hyperthermic oncology. Interaction between two agents may be considered as synergistic or antagonistic when the effect produced is greater or smaller than the sum of the two single responses. It has long be considered that the mechanism of synergistic interaction of hyperthermia and ionizing radiation may be brought about by an inhibition of the repair from sublethal and potentially lethal damage at the cellular level. The inhibition of the recovery process after combined treatments cannot be considered as a reason for the synergy, but rather would be the expected and predicted consequence of the production of irreversible damage. On the basis of it, a simple mathematical model of the synergistic interaction of two agents acting simultaneously has been proposed. However, the model has not been applied to predict the degree of interaction of heat and ionizing radiation after their sequential action. Extension of the model to the sequential treatment of heat and ionizing radiation seems to be of interest for theoretical and practical reasons. Thus, the purposes of the present work is to suggest the simplest mathematical model which would be able to account for the results obtained and currently available experimental information on the sequential action of radiation and heat.
Karim, A.K.M. Rezaul; Proulx, Michael J.; Likova, Lora T.
2016-01-01
Reviewing the relevant literature in visual psychophysics and visual neuroscience we propose a three-stage model of directionality bias in visuospatial functioning. We call this model the ‘Perception-Action-Laterality’ (PAL) hypothesis. We analyzed the research findings for a wide range of visuospatial tasks, showing that there are two major directionality trends: clockwise versus anticlockwise. It appears these preferences are combinatorial, such that a majority of people fall in the first category demonstrating a preference for stimuli/objects arranged from left-to-right rather than from right-to-left, while people in the second category show an opposite trend. These perceptual biases can guide sensorimotor integration and action, creating two corresponding turner groups in the population. In support of PAL, we propose another model explaining the origins of the biases– how the neurogenetic factors and the cultural factors interact in a biased competition framework to determine the direction and extent of biases. This dynamic model can explain not only the two major categories of biases, but also the unbiased, unreliably biased or mildly biased cases in visuosptial functioning. PMID:27350096
Integrated Modeling, Analysis, and Verification for Space Missions, Phase I
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. Phoenix...
Space-Wise approach for airborne gravity data modelling
Sampietro, D.; Capponi, M.; Mansi, A. H.; Gatti, A.; Marchetti, P.; Sansò, F.
2017-05-01
Regional gravity field modelling by means of remove-compute-restore procedure is nowadays widely applied in different contexts: it is the most used technique for regional gravimetric geoid determination, and it is also used in exploration geophysics to predict grids of gravity anomalies (Bouguer, free-air, isostatic, etc.), which are useful to understand and map geological structures in a specific region. Considering this last application, due to the required accuracy and resolution, airborne gravity observations are usually adopted. However, due to the relatively high acquisition velocity, presence of atmospheric turbulence, aircraft vibration, instrumental drift, etc., airborne data are usually contaminated by a very high observation error. For this reason, a proper procedure to filter the raw observations in both the low and high frequencies should be applied to recover valuable information. In this work, a software to filter and grid raw airborne observations is presented: the proposed solution consists in a combination of an along-track Wiener filter and a classical Least Squares Collocation technique. Basically, the proposed procedure is an adaptation to airborne gravimetry of the Space-Wise approach, developed by Politecnico di Milano to process data coming from the ESA satellite mission GOCE. Among the main differences with respect to the satellite application of this approach, there is the fact that, while in processing GOCE data the stochastic characteristics of the observation error can be considered a-priori well known, in airborne gravimetry, due to the complex environment in which the observations are acquired, these characteristics are unknown and should be retrieved from the dataset itself. The presented solution is suited for airborne data analysis in order to be able to quickly filter and grid gravity observations in an easy way. Some innovative theoretical aspects focusing in particular on the theoretical covariance modelling are presented too
Monte Carlo simulations with Symanzik's improved actions in the lattice 0(3) non-linear sigma-model
International Nuclear Information System (INIS)
Berg, B.; Montvay, I.; Meyer, S.
1983-10-01
The scaling properties of the lattice 0(3) non-linear delta-model are studied. The mass-gap, energy-momentum dispersion, correlation functions are measured by numerical Monte Carlo methods. Symanzik's tree-level and 1-loop improved actions are compared to the standard (nearest neigbour) action. (orig.)
Chersi, Fabian; Ferro, Marcello; Pezzulo, Giovanni; Pirrelli, Vito
2011-01-01
Action and language are known to be organized as closely-related brain subsystems. An Italian CNR project implemented a computational neural model where the ability to form chains of goal-directed actions and chains of linguistic units relies on a unified memory architecture obeying the same organizing principles.
International Nuclear Information System (INIS)
Pusztai, B.G.
2011-01-01
In a symplectic reduction framework we construct action-angle systems of canonical coordinates for both the hyperbolic Sutherland and the rational Ruijsenaars-Schneider-van Diejen integrable models associated with the C n root system. The presented dual reduction picture permits us to establish the action-angle duality between these many-particle systems.
Directory of Open Access Journals (Sweden)
Сніжана Сергіївна Чернадчук
2015-05-01
Full Text Available It is studied an aminotransferase activity during injection of thiamin bromide in rat tissues in normal and hypoxic enclosed space. After injection of thiamine bromide we have set reduction of AST and ALT activity, relative to control, except by the brain tissue, where there was an increase of investigated indicators. The decrease of activity of the investigated elements is occurred in animals which before hypoxia were injection of thiamine bromide
Precise Model Analysis for 3-phase High Power Converter using the Harmonic State Space Modeling
DEFF Research Database (Denmark)
Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede
2015-01-01
This paper presents about the generalized multi-frequency modeling and analysis methodology, which can be used in control loop design and stability analysis. In terms of the switching frequency of high power converter, there can be harmonics interruption if the voltage source converter has a low...... switching frequency ratio or multi-sampling frequency. The range of the control bandwidth can include the switching component. Thus, the systems become unstable. This paper applies the Harmonic State Space (HSS) Modeling method in order to find out the transfer function for each harmonics terms...
International Nuclear Information System (INIS)
Mavromatos, N.E.; Miramontes, J.L.
1988-01-01
We discuss generalised functional relations between the β-functions of bosonic σ-models propagating in graviton and dilaton backgrounds and field variations of the associated effective actions based on these backgrounds. We analyse the constraints on the possible form of the proportionality (non-degenerate) tensors, imposed by classical symmetries of the associated point-like action. As an application we derive the second order [O(α')] effective action and we find that it is consistent with a ghost free combination for both fields. Moreover we show explicitly that this action is related to the one computed within the framework of string tree-amplitudes by field redefinitions. (orig.)
Mathematical model of an indirect action fuel flow controller for aircraft jet engines
Tudosie, Alexandru-Nicolae
2017-06-01
The paper deals with a fuel mass flow rate controller with indirect action for aircraft jet engines. The author has identified fuel controller's main parts and its operation mode, then, based on these observations, one has determined motion equations of each main part, which have built system's non-linear mathematical model. In order to realize a better study this model was linearised (using the finite differences method) and then adimensionalized. Based on this new form of the mathematical model, after applying Laplace transformation, the embedded system (controller+engine) was described by the block diagram with transfer functions. Some Simulink-Matlab simulations were performed, concerning system's time behavior for step input, which lead to some useful conclusions and extension possibilities.
Gambling and the Reasoned Action Model: Predicting Past Behavior, Intentions, and Future Behavior.
Dahl, Ethan; Tagler, Michael J; Hohman, Zachary P
2018-03-01
Gambling is a serious concern for society because it is highly addictive and is associated with a myriad of negative outcomes. The current study applied the Reasoned Action Model (RAM) to understand and predict gambling intentions and behavior. Although prior studies have taken a reasoned action approach to understand gambling, no prior study has fully applied the RAM or used the RAM to predict future gambling. Across two studies the RAM was used to predict intentions to gamble, past gambling behavior, and future gambling behavior. In study 1 the model significantly predicted intentions and past behavior in both a college student and Amazon Mechanical Turk sample. In study 2 the model predicted future gambling behavior, measured 2 weeks after initial measurement of the RAM constructs. This study stands as the first to show the utility of the RAM in predicting future gambling behavior. Across both studies, attitudes and perceived normative pressure were the strongest predictors of intentions to gamble. These findings provide increased understanding of gambling and inform the development of gambling interventions based on the RAM.
Study of action of biological aerococcus аutosymbiont on the model of staphylococcal infection
Directory of Open Access Journals (Sweden)
Stepanskyi D.O.
2017-06-01
Full Text Available The paper presents data on the study of the antagonistic effect of aerococcus autosymbionts in experimental models of infections caused by staphylococci. To study the antagonistic action of aerococcus autosymbiont on staphylococcus, a model of chronic staphylococcal infection in white mice and rabbits was used. In staphylococcal experimental infection, aerococcus antagonistic action against staphylococcus was tested by subcutaneous injection on white mice. Aerococci survival under the skin was studied. Aerococcus autosymbionts introduced under the skin to staphylococcus in 5 hours and 3 hours after administration of the latter cause antagonist effect and inhibit the development of infiltrates. Similar results were obtained when introducing aerococcus autosymbionts in the focus of infection in 5 minutes, 5 minutes and 3 hours, 1 and 5 hours after infection. Aerococci introduced after 24 and 48 hours shortened terms of disease manifestations as compared to the control group of mice. The therapeutic effect of aerococcus autosymbionts was tested on the experimental model of burns and wounds infected with staphylococcus. In animals with wounds treated with aerococcus autostrains the number of pathogenic staphylococci was 10 times less than in the control group. According to our observations aerococcus autosymbionts showed no irritant effect when applied on the wound surface, helped its healing, sharply reduced the percentage of staphylococcus inoculation from wound secretions.