WorldWideScience

Sample records for missions general constraints

  1. Mission Implementation Constraints on Planetary Muon Radiography

    Science.gov (United States)

    Jones, Cathleen E.; Kedar, Sharon; Naudet, Charles; Webb, Frank

    2011-01-01

    Cost: Use heritage hardware, especially use a tested landing system to reduce cost (Phoenix or MSL EDL stage). The sky crane technology delivers higher mass to the surface and enables reaching targets at higher elevation, but at a higher mission cost. Rover vs. Stationary Lander: Rover-mounted instrument enables tomography, but the increased weight of the rover reduces the allowable payload weight. Mass is the critical design constraint for an instrument for a planetary mission. Many factors that are minor factors or do not enter into design considerations for terrestrial operation are important for a planetary application. (Landing site, diurnal temperature variation, instrument portability, shock/vibration)

  2. A general treatment of dynamic integrity constraints

    NARCIS (Netherlands)

    de Brock, EO

    This paper introduces a general, set-theoretic model for expressing dynamic integrity constraints, i.e., integrity constraints on the state changes that are allowed in a given state space. In a managerial context, such dynamic integrity constraints can be seen as representations of "real world"

  3. Digital communication constraints in prior space missions

    Science.gov (United States)

    Yassine, Nathan K.

    2004-01-01

    Digital communication is crucial for space endeavors. Jt transmits scientific and command data between earth stations and the spacecraft crew. It facilitates communications between astronauts, and provides live coverage during all phases of the mission. Digital communications provide ground stations and spacecraft crew precise data on the spacecraft position throughout the entire mission. Lessons learned from prior space missions are valuable for our new lunar and Mars missions set by our president s speech. These data will save our agency time and money, and set course our current developing technologies. Limitations on digital communications equipment pertaining mass, volume, data rate, frequency, antenna type and size, modulation, format, and power in the passed space missions are of particular interest. This activity is in support of ongoing communication architectural studies pertaining to robotic and human lunar exploration. The design capabilities and functionalities will depend on the space and power allocated for digital communication equipment. My contribution will be gathering these data, write a report, and present it to Communications Technology Division Staff. Antenna design is very carefully studied for each mission scenario. Currently, Phased array antennas are being developed for the lunar mission. Phased array antennas use little power, and electronically steer a beam instead of DC motors. There are 615 patches in the phased array antenna. These patches have to be modified to have high yield. 50 patches were created for testing. My part is to assist in the characterization of these patch antennas, and determine whether or not certain modifications to quartz micro-strip patch radiators result in a significant yield to warrant proceeding with repairs to the prototype 19 GHz ferroelectric reflect-array antenna. This work requires learning how to calibrate an automatic network, and mounting and testing antennas in coaxial fixtures. The purpose of this

  4. Some general constraints on identical band symmetries

    International Nuclear Information System (INIS)

    Guidry, M.W.; Strayer, M.R.; Wu, C.; Feng, D.H.

    1993-01-01

    We argue on general grounds that nearly identical bands observed for superdeformation and less frequently for normal deformation must be explicable in terms of a symmetry having a microscopic basis. We assume that the unknown symmetry is associated with a Lie algebra generated by terms bilinear in fermion creation and annihilation operators. Observed features of these bands and the general properties of Lie groups are then used to place constraints on acceptable algebras. Additional constraints are placed by assuming that the collective spectrum is associated with a dynamical symmetry, and examining the subgroup structure required by phenomenology. We observe that requisite symmetry cannot be unitary, and that the simplest known group structures consistent with these minimal criteria are associated with the Ginocchio algebras employed in the fermion dynamical symmetry model. However, our arguments are general in nature, and we propose that they imply model-independent constraints on any candidate explanation for identical bands

  5. Generalized Pauli constraints in small atoms

    Science.gov (United States)

    Schilling, Christian; Altunbulak, Murat; Knecht, Stefan; Lopes, Alexandre; Whitfield, James D.; Christandl, Matthias; Gross, David; Reiher, Markus

    2018-05-01

    The natural occupation numbers of fermionic systems are subject to nontrivial constraints, which include and extend the original Pauli principle. A recent mathematical breakthrough has clarified their mathematical structure and has opened up the possibility of a systematic analysis. Early investigations have found evidence that these constraints are exactly saturated in several physically relevant systems, e.g., in a certain electronic state of the beryllium atom. It has been suggested that, in such cases, the constraints, rather than the details of the Hamiltonian, dictate the system's qualitative behavior. Here, we revisit this question with state-of-the-art numerical methods for small atoms. We find that the constraints are, in fact, not exactly saturated, but that they lie much closer to the surface defined by the constraints than the geometry of the problem would suggest. While the results seem incompatible with the statement that the generalized Pauli constraints drive the behavior of these systems, they suggest that the qualitatively correct wave-function expansions can in some systems already be obtained on the basis of a limited number of Slater determinants, which is in line with numerical evidence from quantum chemistry.

  6. Domain general constraints on statistical learning.

    Science.gov (United States)

    Thiessen, Erik D

    2011-01-01

    All theories of language development suggest that learning is constrained. However, theories differ on whether these constraints arise from language-specific processes or have domain-general origins such as the characteristics of human perception and information processing. The current experiments explored constraints on statistical learning of patterns, such as the phonotactic patterns of an infants' native language. Infants in these experiments were presented with a visual analog of a phonotactic learning task used by J. R. Saffran and E. D. Thiessen (2003). Saffran and Thiessen found that infants' phonotactic learning was constrained such that some patterns were learned more easily than other patterns. The current results indicate that infants' learning of visual patterns shows the same constraints as infants' learning of phonotactic patterns. This is consistent with theories suggesting that constraints arise from domain-general sources and, as such, should operate over many kinds of stimuli in addition to linguistic stimuli. © 2011 The Author. Child Development © 2011 Society for Research in Child Development, Inc.

  7. Variational calculus with constraints on general algebroids

    Energy Technology Data Exchange (ETDEWEB)

    Grabowska, Katarzyna [Physics Department, Division of Mathematical Methods in Physics, University of Warsaw, Hoza 69, 00-681 Warszawa (Poland); Grabowski, Janusz [Institute of Mathematics, Polish Academy of Sciences, Sniadeckich 8, PO Box 21, 00-956 Warszawa (Poland)], E-mail: konieczn@fuw.edu.pl, E-mail: jagrab@impan.gov.pl

    2008-05-02

    Variational calculus on a vector bundle E equipped with a structure of a general algebroid is developed, together with the corresponding analogs of Euler-Lagrange equations. Constrained systems are introduced in the variational and geometrical settings. The constrained Euler-Lagrange equations are derived for analogs of holonomic, vakonomic and nonholonomic constraints. This general model covers the majority of first-order Lagrangian systems which are present in the literature and reduces to the standard variational calculus and the Euler-Lagrange equations in classical mechanics for E = TM.

  8. Variational calculus with constraints on general algebroids

    International Nuclear Information System (INIS)

    Grabowska, Katarzyna; Grabowski, Janusz

    2008-01-01

    Variational calculus on a vector bundle E equipped with a structure of a general algebroid is developed, together with the corresponding analogs of Euler-Lagrange equations. Constrained systems are introduced in the variational and geometrical settings. The constrained Euler-Lagrange equations are derived for analogs of holonomic, vakonomic and nonholonomic constraints. This general model covers the majority of first-order Lagrangian systems which are present in the literature and reduces to the standard variational calculus and the Euler-Lagrange equations in classical mechanics for E = TM

  9. Constraints on stress-energy perturbations in general relativity

    International Nuclear Information System (INIS)

    Traschen, J.

    1985-01-01

    Conditions are found for the existence of integral constraints on stress-energy perturbations in general relativity. The integral constraints can be thought of as a general-relativistic generalization of the conservation of energy and momentum of matter perturbations in special relativity. The constraints are stated in terms of a vector field V, and the Robertson-Walker spacetimes are shown to have such constraint vectors. Although in general V is not a Killing vector, in a vacuum spacetime the constraint vectors are precisely the Killing vectors

  10. Generalized Pauli constraints in small atoms

    DEFF Research Database (Denmark)

    Schilling, Christian; Altunbulak, Murat; Knecht, Stefan

    2018-01-01

    investigations have found evidence that these constraints are exactly saturated in several physically relevant systems, e.g., in a certain electronic state of the beryllium atom. It has been suggested that, in such cases, the constraints, rather than the details of the Hamiltonian, dictate the system......'s qualitative behavior. Here, we revisit this question with state-of-the-art numerical methods for small atoms. We find that the constraints are, in fact, not exactly saturated, but that they lie much closer to the surface defined by the constraints than the geometry of the problem would suggest. While...

  11. New constraints for canonical general relativity

    International Nuclear Information System (INIS)

    Reisenberger, M.P.

    1995-01-01

    Ashtekar's canonical theory of classical complex Euclidean GR (no Lorentzian reality conditions) is found to be invariant under the full algebra of infinitesimal 4-diffeomorphisms, but non-invariant under some finite proper 4-diffeos when the densitized dreibein, E a i , is degenerate. The breakdown of 4-diffeo invariance appears to be due to the inability of the Ashtekar Hamiltonian to generate births and deaths of E flux loops (leaving open the possibility that a new 'causality condition' forbidding the birth of flux loops might justify the non-invariance of the theory).A fully 4-diffeo invariant canonical theory in Ashtekar's variables, derived from Plebanski's action, is found to have constraints that are stronger than Ashtekar's for rank E< 2. The corresponding Hamiltonian generates births and deaths of E flux loops.It is argued that this implies a finite amplitude for births and deaths of loops in the physical states of quantum GR in the loop representation, thus modifying this (partly defined) theory substantially.Some of the new constraints are second class, leading to difficulties in quantization in the connection representation. This problem might be overcome in a very nice way by transforming to the classical loop variables, or the 'Faraday line' variables of Newman and Rovelli, and then solving the offending constraints.Note that, though motivated by quantum considerations, the present paper is classical in substance. (orig.)

  12. Missional church and local constraints: A Dutch perspective

    Directory of Open Access Journals (Sweden)

    Rein Brouwer

    2009-09-01

    Full Text Available The missional church concept promises to guide local churches in the direction of a new identity and mission. It is a response to a sense of ecclesiological and congregational urgency that is felt all over the world. In Africa, North America and Europe, churches and local faith communities have been challenged by the changes in the religious state of affairs since the 1960s. Whether we still call it �secularisation� or rephrase it as �differentiated transformation�, the face of religion is changing globally. In many parts of the world, this raises a feeling of crisis that gives way to the redef nition of the mission and purpose of the church. �Missional church�, however, is a precarious concept. Nobody disagrees with the intention but can it be more than an inspiring vision? In order to realise this vision, a multi-layered and multi-dimensional analysis of �culture� is essential. We should move the analysis beyond the philosophical interpretation of relatively abstract and evasive macro-level processes, such as �modernity� and �post-modernity�. The future of the missional church depends on a differentiated and empirical, informed perspective on culture. For this purpose, this article proposes the concept of ecology: A system of diverse populations, including populations of congregations and faith communities, that interacts with these populations and with their specific environments. Preparing a missional congregation for the future should be accompanied with a thorough empirical investigation into the ecology of the congregation. We should be thinking intensively about and looking for vital ecologies.

  13. Parallel Enhancements of the General Mission Analysis Tool, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The General Mission Analysis Tool (GMAT) is a state of the art spacecraft mission design tool under active development at NASA's Goddard Space Flight Center (GSFC)....

  14. General quadratic gauge theory: constraint structure, symmetries and physical functions

    Energy Technology Data Exchange (ETDEWEB)

    Gitman, D M [Institute of Physics, University of Sao Paulo (Brazil); Tyutin, I V [Lebedev Physics Institute, Moscow (Russian Federation)

    2005-06-17

    How can we relate the constraint structure and constraint dynamics of the general gauge theory in the Hamiltonian formulation to specific features of the theory in the Lagrangian formulation, especially relate the constraint structure to the gauge transformation structure of the Lagrangian action? How can we construct the general expression for the gauge charge if the constraint structure in the Hamiltonian formulation is known? Whether we can identify the physical functions defined as commuting with first-class constraints in the Hamiltonian formulation and the physical functions defined as gauge invariant functions in the Lagrangian formulation? The aim of the present paper is to consider the general quadratic gauge theory and to answer the above questions for such a theory in terms of strict assertions. To fulfil such a programme, we demonstrate the existence of the so-called superspecial phase-space variables in terms of which the quadratic Hamiltonian action takes a simple canonical form. On the basis of such a representation, we analyse a functional arbitrariness in the solutions of the equations of motion of the quadratic gauge theory and derive the general structure of symmetries by analysing a symmetry equation. We then use these results to identify the two definitions of physical functions and thus prove the Dirac conjecture.

  15. Constraint and Flight Rule Management for Space Mission Operations

    Science.gov (United States)

    Barreiro, J.; Chachere, J.; Frank, J.; Bertels, C.; Crocker, A.

    2010-01-01

    The exploration of space is one of the most fascinating domains to study from a human factors perspective. Like other complex work domains such as aviation (Pritchett and Kim, 2008), air traffic management (Durso and Manning, 2008), health care (Morrow, North, and Wickens, 2006), homeland security (Cooke and Winner, 2008), and vehicle control (Lee, 2006), space exploration is a large-scale sociotechnical work domain characterized by complexity, dynamism, uncertainty, and risk in real-time operational contexts (Perrow, 1999; Woods et al, 1994). Nearly the entire gamut of human factors issues - for example, human-automation interaction (Sheridan and Parasuraman, 2006), telerobotics, display and control design (Smith, Bennett, and Stone, 2006), usability, anthropometry (Chaffin, 2008), biomechanics (Marras and Radwin, 2006), safety engineering, emergency operations, maintenance human factors, situation awareness (Tenney and Pew, 2006), crew resource management (Salas et al., 2006), methods for cognitive work analysis (Bisantz and Roth, 2008) and the like -- are applicable to astronauts, mission control, operational medicine, Space Shuttle manufacturing and assembly operations, and space suit designers as they are in other work domains (e.g., Bloomberg, 2003; Bos et al, 2006; Brooks and Ince, 1992; Casler and Cook, 1999; Jones, 1994; McCurdy et al, 2006; Neerincx et aI., 2006; Olofinboba and Dorneich, 2005; Patterson, Watts-Perotti and Woods, 1999; Patterson and Woods, 2001; Seagull et ai, 2007; Sierhuis, Clancey and Sims, 2002). The human exploration of space also has unique challenges of particular interest to human factors research and practice. This chapter provides an overview of those issues and reports on some of the latest research results as well as the latest challenges still facing the field.

  16. Habitability constraints/objectives for a Mars manned mission: internal architecture considerations.

    Science.gov (United States)

    Winisdoerffer, F; Soulez-Larivière, C

    1992-01-01

    It is generally accepted that high quality internal environment shall strongly support crew's adaptation and acceptance to situation of long isolation and confinement. Thus, this paper is an attempt to determine to which extent the resulting stress corresponding to the anticipated duration of a trip to Mars (1 and a half years to 2 and a half years) could be decreased when internal architecture of the spacecraft is properly designed. It is assumed that artificial gravity shall be available on board the Mars spacecraft. This will of course have a strong impact on internal architecture as far as a 1-g oriented design will become mandatory, at least in certain inhabited parts of the spacecraft. The review of usual Habitability functions is performed according to the peculiarities of such an extremely long mission. A particular attention is paid to communications issues and the need for privacy. The second step of the paper addresses internal architecture issues through zoning analyses. Common, Service and Personal zones need to be adapted to the constraints associated with the extremely long duration of the mission. Furthermore, due to the nature of the mission itself (relative autonomy, communication problems, monotony) and the type of selected crew (personalities, group structure) the implementation of a "fourth zone", so-called "recreational" zone, seems to be needed. This zoning analysis is then translated into some internal architecture proposals, which are discussed and illustrated. This paper is concluded by a reflection on habitability and recommendations on volumetric requirements. Some ideas to validate proposed habitability items through simulation are also discussed.

  17. Stochastic programming problems with generalized integrated chance constraints

    Czech Academy of Sciences Publication Activity Database

    Branda, Martin

    2012-01-01

    Roč. 61, č. 8 (2012), s. 949-968 ISSN 0233-1934 R&D Projects: GA ČR GAP402/10/1610 Grant - others:SVV(CZ) 261315/2010 Institutional support: RVO:67985556 Keywords : chance constraints * integrated chance constraints * penalty functions * sample approximations * blending problem Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.707, year: 2012 http://library.utia.cas.cz/separaty/2012/E/branda-stochastic programming problems with generalized integrated.pdf

  18. Reconciling Scientific Aspirations and Engineering Constraints for a Lunar Mission via Hyperdimensional Interpolation

    Science.gov (United States)

    Weisbin, Charles R.; Clark, Pamela; Elfes, Alberto; Smith, Jeffrey H.; Mrozinski, Joseph; Adumitroaie, Virgil; Hua, Hook; Shelton, Kacie; Lincoln, William; Silberg, Robert

    2010-01-01

    Virtually every NASA space-exploration mission represents a compromise between the interests of two expert, dedicated, but very different communities: scientists, who want to go quickly to the places that interest them most and spend as much time there as possible conducting sophisticated experiments, and the engineers and designers charged with maximizing the probability that a given mission will be successful and cost-effective. Recent work at NASA's Jet Propulsion Laboratory (JPL) seeks to enhance communication between these two groups, and to help them reconcile their interests, by developing advanced modeling capabilities with which they can analyze the achievement of science goals and objectives against engineering design and operational constraints. The analyses conducted prior to this study have been point-design driven. Each analysis has been of one hypothetical case which addresses the question: Given a set of constraints, how much science can be done? But the constraints imposed by the architecture team-e.g., rover speed, time allowed for extravehicular activity (EVA), number of sites at which science experiments are to be conducted- are all in early development and carry a great deal of uncertainty. Variations can be incorporated into the analysis, and indeed that has been done in sensitivity studies designed to see which constraint variations have the greatest impact on results. But if a very large number of variations can be analyzed all at once, producing a table that includes virtually the entire trade space under consideration, then we have a tool that enables scientists and mission architects to ask the inverse question: For a given desired level of science (or any other objective), what is the range of constraints that would be needed? With this tool, mission architects could determine, for example, what combinations of rover speed, EVA duration, and other constraints produce the desired results. Further, this tool would help them identify which

  19. Constraints on a generalized deceleration parameter from cosmic chronometers

    Science.gov (United States)

    Mamon, Abdulla Al

    2018-04-01

    In this paper, we have proposed a generalized parametrization for the deceleration parameter q in order to study the evolutionary history of the universe. We have shown that the proposed model can reproduce three well known q-parametrized models for some specific values of the model parameter α. We have used the latest compilation of the Hubble parameter measurements obtained from the cosmic chronometer (CC) method (in combination with the local value of the Hubble constant H0) and the Type Ia supernova (SNIa) data to place constraints on the parameters of the model for different values of α. We have found that the resulting constraints on the deceleration parameter and the dark energy equation of state support the ΛCDM model within 1σ confidence level at the present epoch.

  20. Academic general internal medicine: a mission for the future.

    Science.gov (United States)

    Armstrong, Katrina; Keating, Nancy L; Landry, Michael; Crotty, Bradley H; Phillips, Russell S; Selker, Harry P

    2013-06-01

    After five decades of growth that has included advances in medical education and health care delivery, value cohesion, and integration of diversity, we propose an overarching mission for academic general internal medicine to lead excellence, change, and innovation in clinical care, education, and research. General internal medicine aims to achieve health care delivery that is comprehensive, technologically advanced and individualized; instills trust within a culture of respect; is efficient in the use of time, people, and resources; is organized and financed to achieve optimal health outcomes; maximizes equity; and continually learns and adapts. This mission of health care transformation has implications for the clinical, educational, and research activities of divisions of general internal medicine over the next several decades.

  1. Vehicle technology under CO2 constraint: a general equilibrium analysis

    International Nuclear Information System (INIS)

    Schaefer, Andreas; Jacoby, Henry D.

    2006-01-01

    A study is presented of the rates of penetration of different transport technologies under policy constraints on CO 2 emissions. The response of this sector is analyzed within an overall national level of restriction, with a focus on automobiles, light trucks, and heavy freight trucks. Using the US as an example, a linked set of three models is used to carry out the analysis: a multi-sector computable general equilibrium model of the economy, a MARKAL-type model of vehicle and fuel supply technology, and a model simulating the split of personal and freight transport among modes. Results highlight the importance of incremental improvements in conventional internal combustion engine technology, and, in the absence of policies to overcome observed consumer discount rates, the very long time horizons before radical alternatives like the internal combustion engine hybrid drive train vehicle are likely to take substantial market share

  2. Observational constraints on transverse gravity: A generalization of unimodular gravity

    International Nuclear Information System (INIS)

    Lopez-Villarejo, J J

    2010-01-01

    We explore the hypothesis that the set of symmetries enjoyed by the theory that describes gravity is not the full group of diffeomorphisms (Diff(M)), as in General Relativity, but a maximal subgroup of it (TransverseDiff(M)), with its elements having a jacobian equal to unity; at the infinitesimal level, the parameter describing the coordinate change x μ → x μ + ξ μ (x) is transverse, i.e., δ μ ξ μ = 0. Incidentally, this is the smaller symmetry one needs to propagate consistently a graviton, which is a great theoretical motivation for considering these theories. Also, the determinant of the metric, g, behaves as a 'transverse scalar', so that these theories can be seen as a generalization of the better-known unimodular gravity. We present our results on the observational constraints on transverse gravity, in close relation with the claim of equivalence with general scalar-tensor theory. We also comment on the structure of the divergences of the quantum theory to the one-loop order.

  3. Generalized canonical formalism and the S-matrix of theories with constraints of the general type

    International Nuclear Information System (INIS)

    Fradkina, T.Ye.

    1987-01-01

    A canonical quantization method is given for systems with first and second class constraints of arbitrary rank. The effectiveness of the method is demonstrated using sample Yang-Mills and gravitational fields. A correct expression is derived for the S-matrix of theories that are momentum-quadratic within the scope of canonical gauges, including ghost fields. Generalized quantization is performed and the S-matrix is derived in configurational space for theories of relativistic membranes representing a generalization of theories of strings to the case of an extended spatial implementation. It is demonstrated that the theory of membranes in n+l-dimensional space is a system with rank-n constraints

  4. On squaring the primary constraints in a generalized Hamiltonian dynamics

    International Nuclear Information System (INIS)

    Nesterenko, V.V.

    1993-01-01

    Consideration of the model of the relativistic particle with curvature and torsion in the three-dimensional space-time shows that the squaring of the primary constraints entails a wrong result. The complete set of the Hamiltonian constraints arising here corresponds to another model with an action similar but not identical with the initial action. 16 refs

  5. Observational constraints on Hubble parameter in viscous generalized Chaplygin gas

    Science.gov (United States)

    Thakur, P.

    2018-04-01

    Cosmological model with viscous generalized Chaplygin gas (in short, VGCG) is considered here to determine observational constraints on its equation of state parameters (in short, EoS) from background data. These data consists of H(z)-z (OHD) data, Baryonic Acoustic Oscillations peak parameter, CMB shift parameter and SN Ia data (Union 2.1). Best-fit values of the EoS parameters including present Hubble parameter (H0) and their acceptable range at different confidence limits are determined. In this model the permitted range for the present Hubble parameter and the transition redshift (zt) at 1σ confidence limits are H0= 70.24^{+0.34}_{-0.36} and zt=0.76^{+0.07}_{-0.07} respectively. These EoS parameters are then compared with those of other models. Present age of the Universe (t0) have also been determined here. Akaike information criterion and Bayesian information criterion for the model selection have been adopted for comparison with other models. It is noted that VGCG model satisfactorily accommodates the present accelerating phase of the Universe.

  6. Neural network for nonsmooth pseudoconvex optimization with general convex constraints.

    Science.gov (United States)

    Bian, Wei; Ma, Litao; Qin, Sitian; Xue, Xiaoping

    2018-05-01

    In this paper, a one-layer recurrent neural network is proposed for solving a class of nonsmooth, pseudoconvex optimization problems with general convex constraints. Based on the smoothing method, we construct a new regularization function, which does not depend on any information of the feasible region. Thanks to the special structure of the regularization function, we prove the global existence, uniqueness and "slow solution" character of the state of the proposed neural network. Moreover, the state solution of the proposed network is proved to be convergent to the feasible region in finite time and to the optimal solution set of the related optimization problem subsequently. In particular, the convergence of the state to an exact optimal solution is also considered in this paper. Numerical examples with simulation results are given to show the efficiency and good characteristics of the proposed network. In addition, some preliminary theoretical analysis and application of the proposed network for a wider class of dynamic portfolio optimization are included. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. General Constraints on Sampling Wildlife on FIA Plots

    Science.gov (United States)

    Larissa L. Bailey; John R. Sauer; James D. Nichols; Paul H. Geissler

    2005-01-01

    This paper reviews the constraints to sampling wildlife populations at FIA points. Wildlife sampling programs must have well-defined goals and provide information adequate to meet those goals. Investigators should choose a State variable based on information needs and the spatial sampling scale. We discuss estimation-based methods for three State variables: species...

  8. General squark flavour mixing: constraints, phenomenology and benchmarks

    CERN Document Server

    De Causmaecker, Karen; Herrmann, Bjoern; Mahmoudi, Farvah; O'Leary, Ben; Porod, Werner; Sekmen, Sezen; Strobbe, Nadja

    2015-11-19

    We present an extensive study of non-minimal flavour violation in the squark sector in the framework of the Minimal Supersymmetric Standard Model. We investigate the effects of multiple non-vanishing flavour-violating elements in the squark mass matrices by means of a Markov Chain Monte Carlo scanning technique and identify parameter combinations that are favoured by both current data and theoretical constraints. We then detail the resulting distributions of the flavour-conserving and flavour-violating model parameters. Based on this analysis, we propose a set of benchmark scenarios relevant for future studies of non-minimal flavour violation in the Minimal Supersymmetric Standard Model.

  9. Immigration, borrowing constraints and housing market volatility in general equilibrium

    OpenAIRE

    Onshuus, Helene

    2016-01-01

    A loan-to-value borrowing constraint is a significant restriction on household behavior. All policy intervention seeks to steer agents' behavior away from what individual agents would consider optimal in the absence of restrictions. In the wake of the financial crisis in 2007-09 many regulators have turned to macroprudential tools to manage excessive risk-taking on an economy-wide level. In Norway a strict loan-to-value policy was imposed in June 2015, restricting the amount a household can b...

  10. Solar System constraints to general f(R) gravity

    International Nuclear Information System (INIS)

    Chiba, Takeshi; Smith, Tristan L.; Erickcek, Adrienne L.

    2007-01-01

    It has been proposed that cosmic acceleration or inflation can be driven by replacing the Einstein-Hilbert action of general relativity with a function f(R) of the Ricci scalar R. Such f(R) gravity theories have been shown to be equivalent to scalar-tensor theories of gravity that are incompatible with Solar System tests of general relativity, as long as the scalar field propagates over Solar System scales. Specifically, the parameterized post-Newtonian (PPN) parameter in the equivalent scalar-tensor theory is γ=1/2, which is far outside the range allowed by observations. In response to a flurry of papers that questioned the equivalence of f(R) theory to scalar-tensor theories, it was recently shown explicitly, without resorting to the scalar-tensor equivalence, that the vacuum field equations for 1/R gravity around a spherically symmetric mass also yield γ=1/2. Here we generalize this analysis to f(R) gravity and enumerate the conditions that, when satisfied by the function f(R), lead to the prediction that γ=1/2

  11. A Generalized Radiation Model for Human Mobility: Spatial Scale, Searching Direction and Trip Constraint.

    Directory of Open Access Journals (Sweden)

    Chaogui Kang

    Full Text Available We generalized the recently introduced "radiation model", as an analog to the generalization of the classic "gravity model", to consolidate its nature of universality for modeling diverse mobility systems. By imposing the appropriate scaling exponent λ, normalization factor κ and system constraints including searching direction and trip OD constraint, the generalized radiation model accurately captures real human movements in various scenarios and spatial scales, including two different countries and four different cities. Our analytical results also indicated that the generalized radiation model outperformed alternative mobility models in various empirical analyses.

  12. Digital terrain model generalization incorporating scale, semantic and cognitive constraints

    Science.gov (United States)

    Partsinevelos, Panagiotis; Papadogiorgaki, Maria

    2014-05-01

    Cartographic generalization is a well-known process accommodating spatial data compression, visualization and comprehension under various scales. In the last few years, there are several international attempts to construct tangible GIS systems, forming real 3D surfaces using a vast number of mechanical parts along a matrix formation (i.e., bars, pistons, vacuums). Usually, moving bars upon a structured grid push a stretching membrane resulting in a smooth visualization for a given surface. Most of these attempts suffer either in their cost, accuracy, resolution and/or speed. Under this perspective, the present study proposes a surface generalization process that incorporates intrinsic constrains of tangible GIS systems including robotic-motor movement and surface stretching limitations. The main objective is to provide optimized visualizations of 3D digital terrain models with minimum loss of information. That is, to minimize the number of pixels in a raster dataset used to define a DTM, while reserving the surface information. This neighborhood type of pixel relations adheres to the basics of Self Organizing Map (SOM) artificial neural networks, which are often used for information abstraction since they are indicative of intrinsic statistical features contained in the input patterns and provide concise and characteristic representations. Nevertheless, SOM remains more like a black box procedure not capable to cope with possible particularities and semantics of the application at hand. E.g. for coastal monitoring applications, the near - coast areas, surrounding mountains and lakes are more important than other features and generalization should be "biased"-stratified to fulfill this requirement. Moreover, according to the application objectives, we extend the SOM algorithm to incorporate special types of information generalization by differentiating the underlying strategy based on topologic information of the objects included in the application. The final

  13. Generalized Chaplygin gas and cosmic microwave background radiation constraints

    International Nuclear Information System (INIS)

    Bento, M.C.; Bertolami, O.; Sen, A.A.

    2003-01-01

    We study the dependence of the location of the cosmic microwave background radiation peaks on the parameters of the generalized Chaplygin gas model, whose equation of state is given by p=-A/ρ α , where A is a positive constant and 0<α≤1. We find, in particular, that observational data arising from Archeops, BOOMERANG, supernova and high-redshift observations allow constraining significantly the parameter space of the model. Our analysis indicates that the emerging model is clearly distinguishable from the α=1 Chaplygin case and the ΛCDM model

  14. Generalizing Backtrack-Free Search: A Framework for Search-Free Constraint Satisfaction

    Science.gov (United States)

    Jonsson, Ari K.; Frank, Jeremy

    2000-01-01

    Tractable classes of constraint satisfaction problems are of great importance in artificial intelligence. Identifying and taking advantage of such classes can significantly speed up constraint problem solving. In addition, tractable classes are utilized in applications where strict worst-case performance guarantees are required, such as constraint-based plan execution. In this work, we present a formal framework for search-free (backtrack-free) constraint satisfaction. The framework is based on general procedures, rather than specific propagation techniques, and thus generalizes existing techniques in this area. We also relate search-free problem solving to the notion of decision sets and use the result to provide a constructive criterion that is sufficient to guarantee search-free problem solving.

  15. Features in the primordial spectrum: New constraints from WMAP7 and ACT data and prospects for the Planck mission

    International Nuclear Information System (INIS)

    Benetti, Micol; Lattanzi, Massimiliano; Calabrese, Erminia; Melchiorri, Alessandro

    2011-01-01

    We update the constraints on possible features in the primordial inflationary density perturbation spectrum by using the latest data from the WMAP7 and ACT (Atacama Cosmology Telescope) cosmic microwave background experiments. The inclusion of new data significantly improves the constraints with respect to older work, especially to smaller angular scales. While we found no clear statistical evidence in the data for extensions to the simplest, featureless, inflationary model, models with a step provide a significantly better fit than standard featureless power-law spectra. We show that the possibility of a step in the inflationary potential like the one preferred by current data will soon be tested by the forthcoming temperature and polarization data from the Planck satellite mission.

  16. General constraints on the effect of gas flows in the chemical evolution of galaxies

    International Nuclear Information System (INIS)

    Edmunds, M.G.

    1990-01-01

    The basic equations for the chemical evolution of galaxies in which the 'simple' closed box model is modified to allow any form of inflow or outflow are examined. It is found that there are quite general limiting constraints on the effects that such flows can have. Some implications for the actual chemical evolution of galaxies are discussed, and the constraints should also be useful in understanding the behaviour of detailed numerical models of galactic chemical evolution involving gas flows. (author)

  17. Mission reliability of semi-Markov systems under generalized operational time requirements

    International Nuclear Information System (INIS)

    Wu, Xiaoyue; Hillston, Jane

    2015-01-01

    Mission reliability of a system depends on specific criteria for mission success. To evaluate the mission reliability of some mission systems that do not need to work normally for the whole mission time, two types of mission reliability for such systems are studied. The first type corresponds to the mission requirement that the system must remain operational continuously for a minimum time within the given mission time interval, while the second corresponds to the mission requirement that the total operational time of the system within the mission time window must be greater than a given value. Based on Markov renewal properties, matrix integral equations are derived for semi-Markov systems. Numerical algorithms and a simulation procedure are provided for both types of mission reliability. Two examples are used for illustration purposes. One is a one-unit repairable Markov system, and the other is a cold standby semi-Markov system consisting of two components. By the proposed approaches, the mission reliability of systems with time redundancy can be more precisely estimated to avoid possible unnecessary redundancy of system resources. - Highlights: • Two types of mission reliability under generalized requirements are defined. • Equations for both types of reliability are derived for semi-Markov systems. • Numerical methods are given for solving both types of reliability. • Simulation procedure is given for estimating both types of reliability. • Verification of the numerical methods is given by the results of simulation

  18. Supergravity and Yang-Mills theories as generalized topological fields with constraints

    International Nuclear Information System (INIS)

    Ling Yi; Tung Rohsuan; Guo Hanying

    2004-01-01

    We present a general approach to construct a class of generalized topological field theories with constraints by means of generalized differential calculus and its application to connection theory. It turns out that not only the ordinary BF formulations of general relativity and Yang-Mills theories, but also the N=1,2 chiral supergravities can be reformulated as these constrained generalized topological field theories once the free parameters in the Lagrangian are specially chosen. We also show that the Chern-Simons action on the boundary may naturally be induced from the generalized topological action in the bulk, rather than introduced by hand

  19. A Vowel Is a Vowel: Generalizing Newly Learned Phonotactic Constraints to New Contexts

    Science.gov (United States)

    Chambers, Kyle E.; Onishi, Kristine H.; Fisher, Cynthia

    2010-01-01

    Adults can learn novel phonotactic constraints from brief listening experience. We investigated the representations underlying phonotactic learning by testing generalization to syllables containing new vowels. Adults heard consonant-vowel-consonant study syllables in which particular consonants were artificially restricted to the onset or coda…

  20. A note on stability of stationary points in mathematical programs with generalized complementarity constraints

    Czech Academy of Sciences Publication Activity Database

    Červinka, Michal

    2016-01-01

    Roč. 65, č. 5 (2016), s. 1049-1060 ISSN 0233-1934 R&D Projects: GA ČR GAP402/12/1309 Institutional support: RVO:67985556 Keywords : parameter-dependent mathematical programs with generalized equilibrium constraints * M-stationarity * C-stationarity * isolated calmness * Aubin property Subject RIV: BA - General Mathematics Impact factor: 0.943, year: 2016 http://library.utia.cas.cz/separaty/2016/MTR/cervinka-0461163.pdf

  1. Separation and Extension of Cover Inequalities for Conic Quadratic Knapsack Constraints with Generalized Upper Bounds

    DEFF Research Database (Denmark)

    Atamtürk, Alper; Muller, Laurent Flindt; Pisinger, David

    2013-01-01

    Motivated by addressing probabilistic 0-1 programs we study the conic quadratic knapsack polytope with generalized upper bound (GUB) constraints. In particular, we investigate separating and extending GUB cover inequalities. We show that, unlike in the linear case, determining whether a cover can...... be extended with a single variable is NP-hard. We describe and compare a number of exact and heuristic separation and extension algorithms which make use of the structure of the constraints. Computational experiments are performed for comparing the proposed separation and extension algorithms...

  2. Constraint satisfaction adaptive neural network and heuristics combined approaches for generalized job-shop scheduling.

    Science.gov (United States)

    Yang, S; Wang, D

    2000-01-01

    This paper presents a constraint satisfaction adaptive neural network, together with several heuristics, to solve the generalized job-shop scheduling problem, one of NP-complete constraint satisfaction problems. The proposed neural network can be easily constructed and can adaptively adjust its weights of connections and biases of units based on the sequence and resource constraints of the job-shop scheduling problem during its processing. Several heuristics that can be combined with the neural network are also presented. In the combined approaches, the neural network is used to obtain feasible solutions, the heuristic algorithms are used to improve the performance of the neural network and the quality of the obtained solutions. Simulations have shown that the proposed neural network and its combined approaches are efficient with respect to the quality of solutions and the solving speed.

  3. Intra-EVA Space-to-Ground Interactions when Conducting Scientific Fieldwork Under Simulated Mars Mission Constraints

    Science.gov (United States)

    Beaton, Kara H.; Chappell, Steven P.; Abercromby, Andrew F. J.; Lim, Darlene S. S.

    2018-01-01

    The Biologic Analog Science Associated with Lava Terrains (BASALT) project is a four-year program dedicated to iteratively designing, implementing, and evaluating concepts of operations (ConOps) and supporting capabilities to enable and enhance scientific exploration for future human Mars missions. The BASALT project has incorporated three field deployments during which real (non-simulated) biological and geochemical field science have been conducted at two high-fidelity Mars analog locations under simulated Mars mission conditions, including communication delays and data transmission limitations. BASALT's primary Science objective has been to extract basaltic samples for the purpose of investigating how microbial communities and habitability correlate with the physical and geochemical characteristics of chemically altered basalt environments. Field sites include the active East Rift Zone on the Big Island of Hawai'i, reminiscent of early Mars when basaltic volcanism and interaction with water were widespread, and the dormant eastern Snake River Plain in Idaho, similar to present-day Mars where basaltic volcanism is rare and most evidence for volcano-driven hydrothermal activity is relict. BASALT's primary Science Operations objective has been to investigate exploration ConOps and capabilities that facilitate scientific return during human-robotic exploration under Mars mission constraints. Each field deployment has consisted of ten extravehicular activities (EVAs) on the volcanic flows in which crews of two extravehicular and two intravehicular crewmembers conducted the field science while communicating across time delay and under bandwidth constraints with an Earth-based Mission Support Center (MSC) comprised of expert scientists and operators. Communication latencies of 5 and 15 min one-way light time and low (0.512 Mb/s uplink, 1.54 Mb/s downlink) and high (5.0 Mb/s uplink, 10.0 Mb/s downlink) bandwidth conditions were evaluated. EVA crewmembers communicated

  4. Glass Composition Constraint Recommendations for Use in Life-Cycle Mission Modeling

    Energy Technology Data Exchange (ETDEWEB)

    McCloy, John S.; Vienna, John D.

    2010-05-03

    The component concentration limits that most influence the predicted Hanford life-cycle HLW glass volume by HTWOS were re-evaluated. It was assumed that additional research and development work in glass formulation and melter testing would be performed to improve the understanding of component effects on the processability and product quality of these HLW glasses. Recommendations were made to better estimate the potential component concentration limits that could be applied today while technology development is underway to best estimate the volume of HLW glass that will eventually be produced at Hanford. The limits for concentrations of P2O5, Bi2O3, and SO3 were evaluated along with the constraint used to avoid nepheline formation in glass. Recommended concentration limits were made based on the current HLW glass property models being used by HTWOS (Vienna et al. 2009). These revised limits are: 1) The current ND should be augmented by the OB limit of OB ≤ 0.575 so that either the normalized silica (NSi) is less that the 62% limit or the OB is below the 0.575 limit. 2) The mass fraction of P2O5 limit should be revised to allow for up to 4.5 wt%, depending on CaO concentrations. 3) A Bi2O3 concentration limit of 7 wt% should be used. 4) The salt accumulation limit of 0.5 wt% SO3 may be increased to 0.6 wt%. Again, these revised limits do not obviate the need for further testing, but make it possible to more accurately predict the impact of that testing on ultimate HLW glass volumes.

  5. Multistep Hybrid Iterations for Systems of Generalized Equilibria with Constraints of Several Problems

    Directory of Open Access Journals (Sweden)

    Lu-Chuan Ceng

    2014-01-01

    Full Text Available We first introduce and analyze one multistep iterative algorithm by hybrid shrinking projection method for finding a solution of the system of generalized equilibria with constraints of several problems: the generalized mixed equilibrium problem, finitely many variational inclusions, the minimization problem for a convex and continuously Fréchet differentiable functional, and the fixed-point problem of an asymptotically strict pseudocontractive mapping in the intermediate sense in a real Hilbert space. We prove strong convergence theorem for the iterative algorithm under suitable conditions. On the other hand, we also propose another multistep iterative algorithm involving no shrinking projection method and derive its weak convergence under mild assumptions.

  6. The General-Purpose Heat Source Radioisotope Thermoelectric Generator: Power for the Galileo and Ulysses missions

    International Nuclear Information System (INIS)

    Bennett, G.L.; Lombardo, J.J.; Hemler, R.J.; Peterson, J.R.

    1986-01-01

    Electrical power for NASA's Galileo mission to Jupiter and ESA's Ulysses mission to explore the polar regions of the Sun will be provided by General-Purpose Heat Source Radioisotope Thermo-electric Generators (GPHS-RTGs). Building upon the successful RTG technology used in the Voyager program, each GPHS-RTG will provide at least 285 W(e) at beginning-of-mission. The design concept has been proven through extensive tests of an electrically heated Engineering Unit and a nuclear-heated Qualification Unit. Four flight generators have been successfully assembled and tested for use on the Galileo and Ulysses spacecraft. All indications are that the GPHS-RTGs will meet or exceed the power requirement of the missions

  7. Constraints on Generality (COG): A Proposed Addition to All Empirical Papers.

    Science.gov (United States)

    Simons, Daniel J; Shoda, Yuichi; Lindsay, D Stephen

    2017-11-01

    Psychological scientists draw inferences about populations based on samples-of people, situations, and stimuli-from those populations. Yet, few papers identify their target populations, and even fewer justify how or why the tested samples are representative of broader populations. A cumulative science depends on accurately characterizing the generality of findings, but current publishing standards do not require authors to constrain their inferences, leaving readers to assume the broadest possible generalizations. We propose that the discussion section of all primary research articles specify Constraints on Generality (i.e., a "COG" statement) that identify and justify target populations for the reported findings. Explicitly defining the target populations will help other researchers to sample from the same populations when conducting a direct replication, and it could encourage follow-up studies that test the boundary conditions of the original finding. Universal adoption of COG statements would change publishing incentives to favor a more cumulative science.

  8. Sensitivity theory for general non-linear algebraic equations with constraints

    International Nuclear Information System (INIS)

    Oblow, E.M.

    1977-04-01

    Sensitivity theory has been developed to a high state of sophistication for applications involving solutions of the linear Boltzmann equation or approximations to it. The success of this theory in the field of radiation transport has prompted study of possible extensions of the method to more general systems of non-linear equations. Initial work in the U.S. and in Europe on the reactor fuel cycle shows that the sensitivity methodology works equally well for those non-linear problems studied to date. The general non-linear theory for algebraic equations is summarized and applied to a class of problems whose solutions are characterized by constrained extrema. Such equations form the basis of much work on energy systems modelling and the econometrics of power production and distribution. It is valuable to have a sensitivity theory available for these problem areas since it is difficult to repeatedly solve complex non-linear equations to find out the effects of alternative input assumptions or the uncertainties associated with predictions of system behavior. The sensitivity theory for a linear system of algebraic equations with constraints which can be solved using linear programming techniques is discussed. The role of the constraints in simplifying the problem so that sensitivity methodology can be applied is highlighted. The general non-linear method is summarized and applied to a non-linear programming problem in particular. Conclusions are drawn in about the applicability of the method for practical problems

  9. An efficient method for generalized linear multiplicative programming problem with multiplicative constraints.

    Science.gov (United States)

    Zhao, Yingfeng; Liu, Sanyang

    2016-01-01

    We present a practical branch and bound algorithm for globally solving generalized linear multiplicative programming problem with multiplicative constraints. To solve the problem, a relaxation programming problem which is equivalent to a linear programming is proposed by utilizing a new two-phase relaxation technique. In the algorithm, lower and upper bounds are simultaneously obtained by solving some linear relaxation programming problems. Global convergence has been proved and results of some sample examples and a small random experiment show that the proposed algorithm is feasible and efficient.

  10. Role of the pair potential for the saturation of generalized Pauli constraints

    Science.gov (United States)

    Legeza, Örs; Schilling, Christian

    2018-05-01

    The dependence of the (quasi-)saturation of the generalized Pauli constraints on the pair potential is studied for ground states of few-fermion systems. For this, we consider spinless fermions in one dimension which are harmonically confined and interact by pair potentials of the form | xi-xj|s with -1 ≤s ≤5 . We use the density matrix renormalization group approach and large orbital basis to achieve the convergence on more than ten digits of both the variational energy and the natural occupation numbers. Our results confirm that the conflict between energy minimization and fermionic exchange symmetry results in a universal and nontrivial quasisaturation of the generalized Pauli constraints (quasipinning), implying tremendous structural simplifications of the fermionic ground state for all s . Those numerically exact results are complemented by an analytical study based on a self-consistent perturbation theory which we develop for this purpose. The respective results for the weak-coupling regime eventually elucidate the singular behavior found for the specific values s =2 ,4 ,..., resulting in an extremely strong quasipinning.

  11. Domain-specific and domain-general constraints on word and sequence learning.

    Science.gov (United States)

    Archibald, Lisa M D; Joanisse, Marc F

    2013-02-01

    The relative influences of language-related and memory-related constraints on the learning of novel words and sequences were examined by comparing individual differences in performance of children with and without specific deficits in either language or working memory. Children recalled lists of words in a Hebbian learning protocol in which occasional lists repeated, yielding improved recall over the course of the task on the repeated lists. The task involved presentation of pictures of common nouns followed immediately by equivalent presentations of the spoken names. The same participants also completed a paired-associate learning task involving word-picture and nonword-picture pairs. Hebbian learning was observed for all groups. Domain-general working memory constrained immediate recall, whereas language abilities impacted recall in the auditory modality only. In addition, working memory constrained paired-associate learning generally, whereas language abilities disproportionately impacted novel word learning. Overall, all of the learning tasks were highly correlated with domain-general working memory. The learning of nonwords was additionally related to general intelligence, phonological short-term memory, language abilities, and implicit learning. The results suggest that distinct associations between language- and memory-related mechanisms support learning of familiar and unfamiliar phonological forms and sequences.

  12. Power spectra based Planck constraints on compensated isocurvature, and forecasts for LiteBIRD and CORE space missions

    Energy Technology Data Exchange (ETDEWEB)

    Väliviita, Jussi, E-mail: jussi.valiviita@helsinki.fi [University of Helsinki, Department of Physics and Helsinki Institute of Physics, P.O. Box 64, FIN-00014 University of Helsinki (Finland)

    2017-04-01

    Compensated isocurvature perturbations (CIP), where the primordial baryon and cold dark matter density perturbations cancel, do not cause total matter isocurvature perturbation. Consequently, at the linear order in the baryon density contrast Δ, a mixture of CIP and the adiabatic mode leads to the same CMB spectra as the pure adiabatic mode. Only recently, Muñoz et al. showed that at the second order CIP leaves an imprint in the observable CMB by smoothing the power spectra in a similar manner as lensing. This causes a strong degeneracy between the CIP variance Δ{sub rms}{sup 2} ≡ (Δ{sup 2}) and the phenomenological lensing parameter A {sub L}. We study several combinations of the Planck 2015 data and show that the measured lensing potential power spectrum C {sub ℓ}{sup φφ} breaks the degeneracy. Nested sampling of the ΛCDM+Δ{sub rms}{sup 2}(+ A {sub L}) model using the Planck 2015 temperature, polarization, and lensing data gives Δ{sub rms}{sup 2} = (6.9{sup +3.0}{sub −3.1}) × 10{sup −3} at 68% CL. A non-zero value is favoured at 2.3σ (or without the polarization data at 2.8σ). CIP with Δ{sub rms}{sup 2} ≈ 7 × 10{sup −3} improves the bestfit χ{sup 2} by 3.6 compared to the adiabatic ΛCDM model. In contrast, although the temperature data favour A {sub L} ≅ 1.22, allowing A {sub L} ≠ 1 does not improve the joint fit at all, since the lensing data disfavour A {sub L} ≠ 1. Indeed, CIP provides a rare example of a simple model, which is capable of reducing the Planck lensing anomaly significantly and fitting well simultaneously the high (and low) multipole temperature and lensing data, as well as the polarization data. Finally, we derive forecasts for two future satellite missions (LiteBIRD proposal to JAXA/NASA and Exploring Cosmic Origins with CORE proposal to ESA's M5 call) and compare these to simulated Planck data. Due to its coarse angular resolution, LiteBIRD is not able to improve the constraints on Δ{sub rms}{sup 2} or A

  13. Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce

    Directory of Open Access Journals (Sweden)

    Natalya Pya

    2016-02-01

    Full Text Available Background: Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height (dbh can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter (h-d models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods: We develop unconstrained generalized additive models (GAM and shape constrained generalized additive models (SCAM for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results: Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand. The definition of constraints leads only to marginal or minor decline in the model statistics like AIC. An observed structured spatial trend in tree height is modelled via 2-dimensional surface

  14. Generalized stochastic target problems for pricing and partial hedging under loss constraints - Application in optimal book liquidation

    OpenAIRE

    Bouchard , Bruno; Dang , Ngoc Minh

    2013-01-01

    International audience; We consider a singular with state constraints version of the stochastic target problems studied in Soner and Touzi (2002) and more recently Bouchard, Elie and Touzi (2008), among others. This provides a general framework for the pricing of contingent claims under risk constraints. Our extended version perfectly suits to market models with proportional transaction costs and to order book liquidation issues. Our main result is a PDE characterization of the associated pri...

  15. The Lax operator approach for the Virasoro and the W-constraints in the generalized KdV hierarchy

    International Nuclear Information System (INIS)

    Panda, S.; Roy, S.

    1992-08-01

    We show directly in the Lax operator approach how the Virasoro and W-constraints on the τ-function arise in the p-reduced KP hierarchy or Generalized KdV hierarchy. In particular, we consider the KdV and the Boussinesq hierarchy to show that the Virasoro and the W-constraints follow from the string equation by expanding the ''additional symmetry'' operator in terms of the Lax operator. We also mention how this method could be generalized for higher KdV hierarchies. (author). 34 refs

  16. MICROSCOPE Mission: First Constraints on the Violation of the Weak Equivalence Principle by a Light Scalar Dilaton

    Science.gov (United States)

    Bergé, Joel; Brax, Philippe; Métris, Gilles; Pernot-Borràs, Martin; Touboul, Pierre; Uzan, Jean-Philippe

    2018-04-01

    The existence of a light or massive scalar field with a coupling to matter weaker than gravitational strength is a possible source of violation of the weak equivalence principle. We use the first results on the Eötvös parameter by the MICROSCOPE experiment to set new constraints on such scalar fields. For a massive scalar field of mass smaller than 10-12 eV (i.e., range larger than a few 1 05 m ), we improve existing constraints by one order of magnitude to |α |baryon number and to |α |baryon and the lepton numbers. We also consider a model describing the coupling of a generic dilaton to the standard matter fields with five parameters, for a light field: We find that, for masses smaller than 10-12 eV , the constraints on the dilaton coupling parameters are improved by one order of magnitude compared to previous equivalence principle tests.

  17. General constraints on the age and chemical evolution of the Galaxy

    International Nuclear Information System (INIS)

    Meyer, B.S.; Schramm, D.N.

    1986-05-01

    The formalism of Schramm and Wasserburg (1970) for determining the mean age of the elements is extended. Model-independent constraints (constraints that are independent of a specific form for the effective nucleosynthesis rate and Galactic chemical evolution over time) are derived on the first four terms in the expansion giving the mean age of the elements, and from these constraints limits are derived on the total duration of nucleosynthesis. These limits require only input of the Schramm-Wasserburg parameter Δ/sup max/ and of the ratio of the mean time for formation of the elements to the total duration of nucleosynthesis, t/sub nu//T. The former quantity is a function of nuclear input parameters. Limits on the latter are obtained from constraints on the relative rate of nucleosynthesis derived from the 232 Th/ 238 U, 235 U/ 238 U, and shorter-lived chronometric pairs. 65 refs

  18. MICROSCOPE Mission: First Constraints on the Violation of the Weak Equivalence Principle by a Light Scalar Dilaton.

    Science.gov (United States)

    Bergé, Joel; Brax, Philippe; Métris, Gilles; Pernot-Borràs, Martin; Touboul, Pierre; Uzan, Jean-Philippe

    2018-04-06

    The existence of a light or massive scalar field with a coupling to matter weaker than gravitational strength is a possible source of violation of the weak equivalence principle. We use the first results on the Eötvös parameter by the MICROSCOPE experiment to set new constraints on such scalar fields. For a massive scalar field of mass smaller than 10^{-12}  eV (i.e., range larger than a few 10^{5}  m), we improve existing constraints by one order of magnitude to |α|difference between the baryon and the lepton numbers. We also consider a model describing the coupling of a generic dilaton to the standard matter fields with five parameters, for a light field: We find that, for masses smaller than 10^{-12}  eV, the constraints on the dilaton coupling parameters are improved by one order of magnitude compared to previous equivalence principle tests.

  19. The Effects of Life Domains, Constraints, and Motivations on Academic Dishonesty: A Partial Test and Extension of Agnew's General Theory.

    Science.gov (United States)

    Cochran, John K

    2017-08-01

    Recently, Robert Agnew introduced a new general theory of crime and delinquency in which he attempted to corral the vast array of theoretical "causes" of criminal conduct into a more parsimonious statement organized into one of five life domains: self, family, peers, school, and work as well as constraints against crime and motivation for it. These domains are depicted as the source of constraints and motivations and whose effects are, in part, mediated by these constraints and motivations. Based on self-report data on academic dishonesty from a sample of college students, the present study attempts to test this general theory. While several of the life domain variables had significant effects of cheating in the baseline model, all of these effects were fully mediated by constraints and motivations. In the final model, academic dishonesty was observed to be most significantly affected by the perceived severity of formal sanction threats, the number of credit hours enrolled, the frequency of skipping classes, and pressure from friends.

  20. A General Connectionist Model of Attitude Structure and Change: The ACS (Attitudes as Constraint Satisfaction) Model

    Science.gov (United States)

    Monroe, Brian M.; Read, Stephen J.

    2008-01-01

    A localist, parallel constraint satisfaction, artificial neural network model is presented that accounts for a broad collection of attitude and attitude-change phenomena. The network represents the attitude object and cognitions and beliefs related to the attitude, as well as how to integrate a persuasive message into this network. Short-term…

  1. Orbit and geometry constraints on the design and operation of a long-life SIRTF mission. [Shuttle Infrared Telescope Facility

    Science.gov (United States)

    Jackson, R. W.

    1984-01-01

    For a long-life SIRTF mission, the ability of the telescope to observe targets everywhere in the sky is an important requirement. For low-inclination orbits, a telescope aperture shade must be designed for Sun and Earth Limb avoidance angles of 50 deg to 60 deg to prevent unwanted radiation from entering the telescope. The minimum orbit inclination depends on the Earth Limb avoidance angle. About 30 percent of the sky will be prohibited for observations during any day in orbit, with about 100 days in orbit required to observe the entire sky.

  2. Generalized Optimal-State-Constraint Extended Kalman Filter (OSC-EKF)

    Science.gov (United States)

    2017-02-01

    algorithms is demonstrated by achieving reasonable consistency and accuracy on a challenging micro aerial vehicle dataset. simultaneous localization...platforms exist,4 and many others have been constructed with low-cost components. Visual-inertial simultaneous localization and mapping (SLAM) and...epipolar constraints. The OSC-EKF used a window size of 10 frames. The SAM problem was constructed using an inverse -depth feature position param

  3. Evaluation and characterization of General Purpose Heat Source girth welds for the Cassini mission

    International Nuclear Information System (INIS)

    Lynch, C.M.; Moniz, P.F.; Reimus, M.A.H.

    1998-01-01

    General Purpose Heat Sources (GPHSs) are components of Radioisotopic thermoelectric Generators (RTGs) which provide electric power for deep space missions. Each GPHS consists of a 238 Pu oxide ceramic pellet encapsulated in a welded iridium alloy shell which forms a protective barrier against the release of plutonia in the unlikely event of a launch-pad failure or reentry incident. GPHS fueled clad girth weld flaw detection was paramount to ensuring this safety function, and was accomplished using both destructive and non-destructive evaluation techniques. The first girth weld produced from each welding campaign was metallographically examined for flaws such as incomplete weld penetration, cracks, or porosity which would render a GPHS unacceptable for flight applications. After an acceptable example weld was produced, the subsequently welded heat sources were evaluated non-destructively for flaws using ultrasonic immersion testing. Selected heat sources which failed ultrasonic testing would be radiographed, and/or, destructively evaluated to further characterize and document anomalous indications. Metallography was also performed on impacted heat sources to determine the condition of the welds

  4. Transoptr-a second order beam transport design code with automatic internal optimization and general constraints

    International Nuclear Information System (INIS)

    Heighway, E.A.

    1980-07-01

    A second order beam transport design code with parametric optimization is described. The code analyzes the transport of charged particle beams through a user defined magnet system. The magnet system parameters are varied (within user defined limits) until the properties of the transported beam and/or the system transport matrix match those properties requested by the user. The code uses matrix formalism to represent the transport elements and optimization is achieved using the variable metric method. Any constraints that can be expressed algebraically may be included by the user as part of his design. Instruction in the use of the program is given. (auth)

  5. Constraints on the structure of naked singularities in classical general relativity

    International Nuclear Information System (INIS)

    Newman, R.P.A.; Joshi, P.S.

    1988-01-01

    The known examples of naked singularities in general relativity are, in a certain sense, either gravitationally or causally innocuous. A cosmic censorship theorem is formulated and proved to the effect that this behaviour is characteristic of naked singularities in general spacetimes which do not deviate too far from spherical symmetry. copyright 1988 Academic Press, Inc

  6. Image size invariant visual cryptography for general access structures subject to display quality constraints.

    Science.gov (United States)

    Lee, Kai-Hui; Chiu, Pei-Ling

    2013-10-01

    Conventional visual cryptography (VC) suffers from a pixel-expansion problem, or an uncontrollable display quality problem for recovered images, and lacks a general approach to construct visual secret sharing schemes for general access structures. We propose a general and systematic approach to address these issues without sophisticated codebook design. This approach can be used for binary secret images in non-computer-aided decryption environments. To avoid pixel expansion, we design a set of column vectors to encrypt secret pixels rather than using the conventional VC-based approach. We begin by formulating a mathematic model for the VC construction problem to find the column vectors for the optimal VC construction, after which we develop a simulated-annealing-based algorithm to solve the problem. The experimental results show that the display quality of the recovered image is superior to that of previous papers.

  7. Generalized HARQ Protocols with Delayed Channel State Information and Average Latency Constraints

    DEFF Research Database (Denmark)

    Trillingsgaard, Kasper Fløe; Popovski, Petar

    2018-01-01

    In many practical wireless systems, the signal-to-interference-and-noise ratio (SINR) that is applicable to a certain transmission, referred to as channel state information (CSI), can only be learned after the transmission has taken place and is thereby delayed (outdated). In such systems, hybrid...... automatic repeat request (HARQ) protocols are often used to achieve high throughput with low latency. This paper put forth the family of expandable message space (EMS) protocols that generalize the HARQ protocol and allow for rate adaptation based on delayed CSI at the transmitter (CSIT). Assuming a block...

  8. DETECTION OF SOLAR-LIKE OSCILLATIONS, OBSERVATIONAL CONSTRAINTS, AND STELLAR MODELS FOR θ CYG, THE BRIGHTEST STAR OBSERVED BY THE KEPLER MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Guzik, J. A. [Los Alamos National Laboratory, XTD-NTA, MS T-082, Los Alamos, NM 87545 (United States); Houdek, G.; Chaplin, W. J.; Antoci, V.; Bedding, T. R.; Huber, D.; Kjeldsen, H. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Smalley, B. [Astrophysics Group, School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, Staffordshire, ST5 5BG (United Kingdom); Kurtz, D. W. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Gilliland, R. L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Mullally, F.; Rowe, J. F. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Bryson, S. T.; Still, M. D. [NASA Ames Research Center, Bldg. 244, MS-244-30, Moffett Field, CA 94035 (United States); Appourchaux, T. [Institut d’Astrophysique Spatiale, Universitè de Paris Sud–CNRS, Batiment 121, F-91405 ORSAY Cedex (France); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Benomar, O. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Garcia, R. A. [Laboratoire AIM, CEA/DRF—CNRS—Univ. Paris Diderot—IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Latham, D. W. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Metcalfe, T. S. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); and others

    2016-11-01

    θ Cygni is an F3 spectral type magnitude V = 4.48 main-sequence star that was the brightest star observed by the original Kepler spacecraft mission. Short-cadence (58.8 s) photometric data using a custom aperture were first obtained during Quarter 6 (2010 June–September) and subsequently in Quarters 8 and 12–17. We present analyses of solar-like oscillations based on Q6 and Q8 data, identifying angular degree l = 0, 1, and 2 modes with frequencies of 1000–2700 μ Hz, a large frequency separation of 83.9 ± 0.4 μ Hz, and maximum oscillation amplitude at frequency ν {sub max} = 1829 ± 54 μ Hz. We also present analyses of new ground-based spectroscopic observations, which, combined with interferometric angular diameter measurements, give T {sub eff} = 6697 ± 78 K, radius 1.49 ± 0.03 R {sub ⊙}, [Fe/H] = -0.02 ± 0.06 dex, and log g = 4.23 ± 0.03. We calculate stellar models matching these constraints using the Yale Rotating Evolution Code and the Asteroseismic Modeling Portal. The best-fit models have masses of 1.35–1.39 M {sub ⊙} and ages of 1.0–1.6 Gyr. θ Cyg’s T {sub eff} and log g place it cooler than the red edge of the γ Doradus instability region established from pre- Kepler ground-based observations, but just at the red edge derived from pulsation modeling. The pulsation models show γ Dor gravity modes driven by the convective blocking mechanism, with frequencies of 1–3 cycles per day (11 to 33 μ Hz). However, gravity modes were not seen in Kepler data; one signal at 1.776 cycles per day (20.56 μ Hz) may be attributable to a faint, possibly background, binary.

  9. Dark matter annihilations into two light fermions and one gauge boson. General analysis and antiproton constraints

    International Nuclear Information System (INIS)

    Garny, Mathias; Ibarra, Alejandro; Vogl, Stefan

    2011-12-01

    We study in this paper the scenario where the dark matter is constituted by Majo- rana particles which couple to a light Standard Model fermion and an extra scalar via a Yukawa coupling. In this scenario, the annihilation rate into the light fermions with the mediation of the scalar particle is strongly suppressed by the mass of the fermion. Nevertheless, the helicity suppression is lifted by the associated emission of a gauge boson, yielding annihilation rates which could be large enough to allow the indirect detection of the dark matter particles. We perform a general analysis of this scenario, calculating the annihilation cross section of the processes χχ → f anti fV when the dark matter particle is a SU(2) L singlet or doublet, f is a lepton or a quark, and V is a photon, a weak gauge boson or a gluon. We point out that the annihilation rate is particularly enhanced when the dark matter particle is degenerate in mass to the intermediate scalar particle, which is a scenario barely constrained by collider searches of exotic charged or colored particles. Lastly, we derive upper limits on the relevant cross sections from the non-observation of an excess in the cosmic antiproton-to-proton ratio measured by PAMELA. (orig.)

  10. Fast online generalized multiscale finite element method using constraint energy minimization

    Science.gov (United States)

    Chung, Eric T.; Efendiev, Yalchin; Leung, Wing Tat

    2018-02-01

    Local multiscale methods often construct multiscale basis functions in the offline stage without taking into account input parameters, such as source terms, boundary conditions, and so on. These basis functions are then used in the online stage with a specific input parameter to solve the global problem at a reduced computational cost. Recently, online approaches have been introduced, where multiscale basis functions are adaptively constructed in some regions to reduce the error significantly. In multiscale methods, it is desired to have only 1-2 iterations to reduce the error to a desired threshold. Using Generalized Multiscale Finite Element Framework [10], it was shown that by choosing sufficient number of offline basis functions, the error reduction can be made independent of physical parameters, such as scales and contrast. In this paper, our goal is to improve this. Using our recently proposed approach [4] and special online basis construction in oversampled regions, we show that the error reduction can be made sufficiently large by appropriately selecting oversampling regions. Our numerical results show that one can achieve a three order of magnitude error reduction, which is better than our previous methods. We also develop an adaptive algorithm and enrich in selected regions with large residuals. In our adaptive method, we show that the convergence rate can be determined by a user-defined parameter and we confirm this by numerical simulations. The analysis of the method is presented.

  11. Dark matter annihilations into two light fermions and one gauge boson. General analysis and antiproton constraints

    Energy Technology Data Exchange (ETDEWEB)

    Garny, Mathias [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Vogl, Stefan [Technische Univ. Muenchen, Garching (Germany). Physik-Department

    2011-12-15

    We study in this paper the scenario where the dark matter is constituted by Majo- rana particles which couple to a light Standard Model fermion and an extra scalar via a Yukawa coupling. In this scenario, the annihilation rate into the light fermions with the mediation of the scalar particle is strongly suppressed by the mass of the fermion. Nevertheless, the helicity suppression is lifted by the associated emission of a gauge boson, yielding annihilation rates which could be large enough to allow the indirect detection of the dark matter particles. We perform a general analysis of this scenario, calculating the annihilation cross section of the processes {chi}{chi} {yields} f anti fV when the dark matter particle is a SU(2){sub L} singlet or doublet, f is a lepton or a quark, and V is a photon, a weak gauge boson or a gluon. We point out that the annihilation rate is particularly enhanced when the dark matter particle is degenerate in mass to the intermediate scalar particle, which is a scenario barely constrained by collider searches of exotic charged or colored particles. Lastly, we derive upper limits on the relevant cross sections from the non-observation of an excess in the cosmic antiproton-to-proton ratio measured by PAMELA. (orig.)

  12. Fast leaf-fitting with generalized underdose/overdose constraints for real-time MLC tracking

    International Nuclear Information System (INIS)

    Moore, Douglas; Sawant, Amit; Ruan, Dan

    2016-01-01

    Purpose: Real-time multileaf collimator (MLC) tracking is a promising approach to the management of intrafractional tumor motion during thoracic and abdominal radiotherapy. MLC tracking is typically performed in two steps: transforming a planned MLC aperture in response to patient motion and refitting the leaves to the newly generated aperture. One of the challenges of this approach is the inability to faithfully reproduce the desired motion-adapted aperture. This work presents an optimization-based framework with which to solve this leaf-fitting problem in real-time. Methods: This optimization framework is designed to facilitate the determination of leaf positions in real-time while accounting for the trade-off between coverage of the PTV and avoidance of organs at risk (OARs). Derived within this framework, an algorithm is presented that can account for general linear transformations of the planned MLC aperture, particularly 3D translations and in-plane rotations. This algorithm, together with algorithms presented in Sawant et al. [“Management of three-dimensional intrafraction motion through real-time DMLC tracking,” Med. Phys. 35, 2050–2061 (2008)] and Ruan and Keall [Presented at the 2011 IEEE Power Engineering and Automation Conference (PEAM) (2011) (unpublished)], was applied to apertures derived from eight lung intensity modulated radiotherapy plans subjected to six-degree-of-freedom motion traces acquired from lung cancer patients using the kilovoltage intrafraction monitoring system developed at the University of Sydney. A quality-of-fit metric was defined, and each algorithm was evaluated in terms of quality-of-fit and computation time. Results: This algorithm is shown to perform leaf-fittings of apertures, each with 80 leaf pairs, in 0.226 ms on average as compared to 0.082 and 64.2 ms for the algorithms of Sawant et al., Ruan, and Keall, respectively. The algorithm shows approximately 12% improvement in quality-of-fit over the Sawant et al

  13. Fast leaf-fitting with generalized underdose/overdose constraints for real-time MLC tracking

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Douglas, E-mail: douglas.moore@utsouthwestern.edu; Sawant, Amit [Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75390 (United States); Ruan, Dan [Department of Radiation Oncology, University of California, Los Angeles, California 90095 (United States)

    2016-01-15

    Purpose: Real-time multileaf collimator (MLC) tracking is a promising approach to the management of intrafractional tumor motion during thoracic and abdominal radiotherapy. MLC tracking is typically performed in two steps: transforming a planned MLC aperture in response to patient motion and refitting the leaves to the newly generated aperture. One of the challenges of this approach is the inability to faithfully reproduce the desired motion-adapted aperture. This work presents an optimization-based framework with which to solve this leaf-fitting problem in real-time. Methods: This optimization framework is designed to facilitate the determination of leaf positions in real-time while accounting for the trade-off between coverage of the PTV and avoidance of organs at risk (OARs). Derived within this framework, an algorithm is presented that can account for general linear transformations of the planned MLC aperture, particularly 3D translations and in-plane rotations. This algorithm, together with algorithms presented in Sawant et al. [“Management of three-dimensional intrafraction motion through real-time DMLC tracking,” Med. Phys. 35, 2050–2061 (2008)] and Ruan and Keall [Presented at the 2011 IEEE Power Engineering and Automation Conference (PEAM) (2011) (unpublished)], was applied to apertures derived from eight lung intensity modulated radiotherapy plans subjected to six-degree-of-freedom motion traces acquired from lung cancer patients using the kilovoltage intrafraction monitoring system developed at the University of Sydney. A quality-of-fit metric was defined, and each algorithm was evaluated in terms of quality-of-fit and computation time. Results: This algorithm is shown to perform leaf-fittings of apertures, each with 80 leaf pairs, in 0.226 ms on average as compared to 0.082 and 64.2 ms for the algorithms of Sawant et al., Ruan, and Keall, respectively. The algorithm shows approximately 12% improvement in quality-of-fit over the Sawant et al

  14. The general behavior of NLO unintegrated parton distributions based on the single-scale evolution and the angular ordering constraint

    International Nuclear Information System (INIS)

    Hosseinkhani, H.; Modarres, M.

    2011-01-01

    To overcome the complexity of generalized two hard scale (k t ,μ) evolution equation, well known as the Ciafaloni, Catani, Fiorani and Marchesini (CCFM) evolution equations, and calculate the unintegrated parton distribution functions (UPDF), Kimber, Martin and Ryskin (KMR) proposed a procedure based on (i) the inclusion of single-scale (μ) only at the last step of evolution and (ii) the angular ordering constraint (AOC) on the DGLAP terms (the DGLAP collinear approximation), to bring the second scale, k t into the UPDF evolution equations. In this work we intend to use the MSTW2008 (Martin et al.) parton distribution functions (PDF) and try to calculate UPDF for various values of x (the longitudinal fraction of parton momentum), μ (the probe scale) and k t (the parton transverse momentum) to see the general behavior of three-dimensional UPDF at the NLO level up to the LHC working energy scales (μ 2 ). It is shown that there exits some pronounced peaks for the three-dimensional UPDF(f a (x,k t )) with respect to the two variables x and k t at various energies (μ). These peaks get larger and move to larger values of k t , as the energy (μ) is increased. We hope these peaks could be detected in the LHC experiments at CERN and other laboratories in the less exclusive processes.

  15. Structure of the first order reduced density matrix in three electron systems: A generalized Pauli constraints assisted study.

    Science.gov (United States)

    Theophilou, Iris; Lathiotakis, Nektarios N; Helbig, Nicole

    2018-03-21

    We investigate the structure of the one-body reduced density matrix of three electron systems, i.e., doublet and quadruplet spin configurations, corresponding to the smallest interacting system with an open-shell ground state. To this end, we use configuration interaction (CI) expansions of the exact wave function in Slater determinants built from natural orbitals in a finite dimensional Hilbert space. With the exception of maximally polarized systems, the natural orbitals of spin eigenstates are generally spin dependent, i.e., the spatial parts of the up and down natural orbitals form two different sets. A measure to quantify this spin dependence is introduced and it is shown that it varies by several orders of magnitude depending on the system. We also study the ordering issue of the spin-dependent occupation numbers which has practical implications in reduced density matrix functional theory minimization schemes, when generalized Pauli constraints (GPCs) are imposed and in the form of the CI expansion in terms of the natural orbitals. Finally, we discuss the aforementioned CI expansion when there are GPCs that are almost "pinned."

  16. Structure of the first order reduced density matrix in three electron systems: A generalized Pauli constraints assisted study

    Science.gov (United States)

    Theophilou, Iris; Lathiotakis, Nektarios N.; Helbig, Nicole

    2018-03-01

    We investigate the structure of the one-body reduced density matrix of three electron systems, i.e., doublet and quadruplet spin configurations, corresponding to the smallest interacting system with an open-shell ground state. To this end, we use configuration interaction (CI) expansions of the exact wave function in Slater determinants built from natural orbitals in a finite dimensional Hilbert space. With the exception of maximally polarized systems, the natural orbitals of spin eigenstates are generally spin dependent, i.e., the spatial parts of the up and down natural orbitals form two different sets. A measure to quantify this spin dependence is introduced and it is shown that it varies by several orders of magnitude depending on the system. We also study the ordering issue of the spin-dependent occupation numbers which has practical implications in reduced density matrix functional theory minimization schemes, when generalized Pauli constraints (GPCs) are imposed and in the form of the CI expansion in terms of the natural orbitals. Finally, we discuss the aforementioned CI expansion when there are GPCs that are almost "pinned."

  17. PHYSICAL-CONSTRAINT-PRESERVING CENTRAL DISCONTINUOUS GALERKIN METHODS FOR SPECIAL RELATIVISTIC HYDRODYNAMICS WITH A GENERAL EQUATION OF STATE

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kailiang [School of Mathematical Sciences, Peking University, Beijing 100871 (China); Tang, Huazhong, E-mail: wukl@pku.edu.cn, E-mail: hztang@math.pku.edu.cn [HEDPS, CAPT and LMAM, School of Mathematical Sciences, Peking University, Beijing 100871 (China)

    2017-01-01

    The ideal gas equation of state (EOS) with a constant adiabatic index is a poor approximation for most relativistic astrophysical flows, although it is commonly used in relativistic hydrodynamics (RHD). This paper develops high-order accurate, physical-constraints-preserving (PCP), central, discontinuous Galerkin (DG) methods for the one- and two-dimensional special RHD equations with a general EOS. It is built on our theoretical analysis of the admissible states for RHD and the PCP limiting procedure that enforce the admissibility of central DG solutions. The convexity, scaling invariance, orthogonal invariance, and Lax–Friedrichs splitting property of the admissible state set are first proved with the aid of its equivalent form. Then, the high-order central DG methods with the PCP limiting procedure and strong stability-preserving time discretization are proved, to preserve the positivity of the density, pressure, specific internal energy, and the bound of the fluid velocity, maintain high-order accuracy, and be L {sup 1}-stable. The accuracy, robustness, and effectiveness of the proposed methods are demonstrated by several 1D and 2D numerical examples involving large Lorentz factor, strong discontinuities, or low density/pressure, etc.

  18. "Personal mission statement": An analysis of medical students' and general practitioners' reflections on personal beliefs, values and goals in life.

    Science.gov (United States)

    Chew, B H; Lee, P Y; Ismail, I Z

    2014-01-01

    Personal mission in life can determine the motivation, happiness, career advancement and fulfilment in life of the medical students (MSs) along with improvement in professional/clinical performance of the family physicians. This study explored the personal beliefs, values and goals in the lives of MSs and general practitioners (GPs). Fourth-year MSs at the Universiti Putra Malaysia and GPs who participated in a 2-hour session on 'Ethics in Family Medicine' in 2012 were invited. All the participants submitted the post-session written reflections about their personal missions in life. The written reflections were analysed using thematic analysis. A total of 87 MSs and 31 GPs submitted their written reflections. The authors identified 17 categories from the reflections contained by four themes-good vs. smart doctor, professional improvement vs. self-improvement, self-fulfilment and expressed motivation. The most common categories were "to be a good doctor" (97/330) and "professional improvement" (65/330). Many MSs had expressed motivation and wanted to be a smart doctor as compared to the GPs, whereas a larger number of GPs wished to have a fulfilled life and be a good doctor through professional improvement. The difference between the two student groups might indicate different levels of maturity and life experiences. Medical teachers should engage students more effectively in orientating them towards the essential values needed in medical practice.

  19. A Generalized Adsorption Rate Model Based on the Limiting-Component Constraint in Ion-Exchange Chromatographic Separation for Multicomponent Systems

    DEFF Research Database (Denmark)

    such that conventional LDF (linear driving force) type models are extended to inactive zones without loosing their generality. Based on a limiting component constraint, an exchange probability kernel is developed for multi-component systems. The LDF-type model with the kernel is continuous with time and axial direction....... Two tuning parameters such as concentration layer thickness and function change rate at the threshold point are needed for the probability kernels, which are not sensitive to problems considered....

  20. NASA Laboratory Analysis for Manned Exploration Missions

    Science.gov (United States)

    Krihak, Michael K.; Shaw, Tianna E.

    2014-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability Element under the NASA Human Research Program. ELA instrumentation is identified as an essential capability for future exploration missions to diagnose and treat evidence-based medical conditions. However, mission architecture limits the medical equipment, consumables, and procedures that will be available to treat medical conditions during human exploration missions. Allocated resources such as mass, power, volume, and crew time must be used efficiently to optimize the delivery of in-flight medical care. Although commercial instruments can provide the blood and urine based measurements required for exploration missions, these commercial-off-the-shelf devices are prohibitive for deployment in the space environment. The objective of the ELA project is to close the technology gap of current minimally invasive laboratory capabilities and analytical measurements in a manner that the mission architecture constraints impose on exploration missions. Besides micro gravity and radiation tolerances, other principal issues that generally fail to meet NASA requirements include excessive mass, volume, power and consumables, and nominal reagent shelf-life. Though manned exploration missions will not occur for nearly a decade, NASA has already taken strides towards meeting the development of ELA medical diagnostics by developing mission requirements and concepts of operations that are coupled with strategic investments and partnerships towards meeting these challenges. This paper focuses on the remote environment, its challenges, biomedical diagnostics requirements and candidate technologies that may lead to successful blood-urine chemistry and biomolecular measurements in future space exploration missions.

  1. Communication of 5 March 2004 from the Permanent Mission of the Islamic Republic of Iran concerning the report of the Director General contained in GOV/2004/11

    International Nuclear Information System (INIS)

    2004-01-01

    The Secretariat has received a Note Verbale dated 5 March 2004 from the Permanent Mission of the Islamic Republic of Iran attaching 'Comments and Explanatory Notes by the Islamic Republic of Iran on the Report of the IAEA Director General (GOV/2004/11).' As requested in the Note Verbale, the attachment is reproduced herein for the information of Member States

  2. Constraints on a general 3-generation neutrino mass matrix from neutrino data application to the MSSM with R-parity violation

    CERN Document Server

    Abada, A

    2000-01-01

    We consider a general symmetric $(3\\times 3)$ mass matrix for three generations of neutrinos. Imposing the constraints, from the atmospheric neutrino and solar neutrino anomalies as well as from the CHOOZ experiment, on the mass squared differences and on the mixing angles, we identify the ranges of allowed inputs for the 6 matrix elements. We apply our results to Majorana left-handed neutrino masses generated at tree level and through The present experimental results on neutrinos from laboratories, cosmology and astrophysics are implemented to either put bounds on trilinear ($\\lambda_{ijk}, or constrain combinations of products of these couplings.

  3. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca

    2010-01-01

    We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...... results show that constraint differentiation substantially reduces search and considerably improves the performance of OFMC, enabling its application to a wider class of problems....

  4. Figures of merit and constraints from testing general relativity using the latest cosmological data sets including refined COSMOS 3D weak lensing

    International Nuclear Information System (INIS)

    Dossett, Jason N.; Moldenhauer, Jacob; Ishak, Mustapha

    2011-01-01

    We use cosmological constraints from current data sets and a figure of merit approach in order to probe any deviations from general relativity at cosmological scales. The figure of merit approach is used to study and compare the constraining power of various combinations of data sets on the modified gravity (MG) parameters. We use the recently refined HST-COSMOS weak-lensing tomography data, the ISW-galaxy cross correlations from 2MASS and SDSS luminous red galaxy surveys, the matter power spectrum from SDSS-DR7 (MPK), the WMAP7 temperature and polarization spectra, the baryon acoustic oscillations from Two-Degree Field and SDSS-DR7, and the Union2 compilation of type Ia supernovae, in addition to other bounds from Hubble parameter measurements and big bang nucleosynthesis. We use three parametrizations of MG parameters that enter the perturbed field equations. In order to allow for variations of the parameters with the redshift and scale, the first two parametrizations use recently suggested functional forms while the third is based on binning methods. Using the first parametrization, we find that the CMB+ISW+WL combination provides the strongest constraints on the MG parameters followed by CMB+WL or CMB+MPK+ISW. Using the second parametrization or the binning methods, we find that the combination CMB+MPK+ISW consistently provides some of the strongest constraints. This shows that the constraints are parametrization dependent. We find that adding up current data sets does not improve consistently the uncertainties on MG parameters due to tensions between the best-fit MG parameters preferred by different data sets. Furthermore, some functional forms imposed by the parametrizations can lead to an exacerbation of these tensions. Next, unlike some studies that used the CFHTLS lensing data, we do not find any deviation from general relativity using the refined HST-COSMOS data, confirming previous claims in those studies that their result may have been due to some

  5. Entropy maximization under the constraints on the generalized Gini index and its application in modeling income distributions

    Science.gov (United States)

    Khosravi Tanak, A.; Mohtashami Borzadaran, G. R.; Ahmadi, J.

    2015-11-01

    In economics and social sciences, the inequality measures such as Gini index, Pietra index etc., are commonly used to measure the statistical dispersion. There is a generalization of Gini index which includes it as special case. In this paper, we use principle of maximum entropy to approximate the model of income distribution with a given mean and generalized Gini index. Many distributions have been used as descriptive models for the distribution of income. The most widely known of these models are the generalized beta of second kind and its subclass distributions. The obtained maximum entropy distributions are fitted to the US family total money income in 2009, 2011 and 2013 and their relative performances with respect to generalized beta of second kind family are compared.

  6. Using Lava Tube Skylight Thermal Emission Spectra to Determine Lava Composition on Io: Quantitative Constraints for Observations by Future Missions to the Jovian System.

    Science.gov (United States)

    Davies, A. G.

    2008-12-01

    Deriving the composition of Io's dominant lavas (mafic or ultramafic?) is a major objective of the next missions to the jovian system. The best opportunities for making this determination are from observations of thermal emission from skylights, holes in the roof of a lava tube through which incandescent lava radiates, and Io thermal outbursts, where lava fountaining is taking place [1]. Allowing for lava cooling across the skylight, the expected thermal emission spectra from skylights of different sizes have been calculated for laminar and turbulent tube flow and for mafic and ultramafic composition lavas. The difference between the resulting mafic and ultramafic lava spectra has been quantified, as has the instrument sensitivity needed to acquire the necessary data to determine lava eruption temperature, both from Europa orbit and during an Io flyby. A skylight is an excellent target to observe lava that has cooled very little since eruption (California Institute of Technology, under contract to NASA. AGD is supported by a grant from the NASA OPR Program. References: [1] Davies, A. G., 1996, Icarus, 124, 45-61. [2] Keszthelyi, L., et al., 2006, JGS, 163, 253-264. [3] Davies, A. G., 2007, Volcanism on Io, Cambridge University Press. [4] Keszthelyi, L., et al., 2007, Icarus, 192, 491-502. [5] Davies, A. G., et al., 2006, Icarus, 184, 460-477.

  7. Communication of 13 June 2004 from the Permanent Mission of the Islamic Republic of Iran concerning the report of the Director General contained in GOV/2004/34

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-06-16

    The Secretariat has received a Note Verbale dated 13 June 2004 from the Permanent Mission of the Islamic Republic of Iran, transmitting 'Explanatory Comments by the Islamic Republic of Iran on the Report of the IAEA Director General (GOV/2004/34) to the June 2004 Board of Governors'. As requested in the Note Verbale, the attachment is reproduced herein for the information of Member States.

  8. Communication of 13 June 2004 from the Permanent Mission of the Islamic Republic of Iran concerning the report of the Director General contained in GOV/2004/34

    International Nuclear Information System (INIS)

    2004-01-01

    The Secretariat has received a Note Verbale dated 13 June 2004 from the Permanent Mission of the Islamic Republic of Iran, transmitting 'Explanatory Comments by the Islamic Republic of Iran on the Report of the IAEA Director General (GOV/2004/34) to the June 2004 Board of Governors'. As requested in the Note Verbale, the attachment is reproduced herein for the information of Member States

  9. [Survey of general practioners in the management of diabetes in primary health facilities of Casablanca city, Morocco: opportunities and constraints].

    Science.gov (United States)

    Nani, S; Hassoune, S; Chinab, N; Boumdi, Z; Maaroufi, A

    2013-06-01

    Diabetes is a global health problem in full expansion, because of its increasing frequency, it frightening complications and the costs of its medical covering. In this study, we tried to make the current situation of the diabetes management in first-line public structures of the city of Casablanca. The survey of transverse observation to descriptive aiming was conducted using a pre questionnaire tested and selfadministered. It shows that 46.7 % of the questioned general practitioner judged that the quantity and the quality of average therapeutic existing in the center were insufficient to meet the needs for their diabetic patients. The weak socio-economic statute of the patients (78.8% of the cases), the lack of personnel (76.6%), the low educational level of patients (75.2%) and the problem of access to hospital (73.3%) constituted major problems of the correct diabetic medical covering. However, the majority of the doctors (98.1%) estimated to need training on diabetes management. The most required topics requested are: The control of the insulin treatment (97%), the diabetic education (91%) and the follow-up of diabetic (89%). The training of general practitioners particularly motivated and interested in diabetes could be the solution to improve the management of diabetes especially because of the lack of specialists in our country.

  10. General unknown screening procedure for the characterization of human drug metabolites in forensic toxicology: applications and constraints.

    Science.gov (United States)

    Sauvage, François-Ludovic; Picard, Nicolas; Saint-Marcoux, Franck; Gaulier, Jean-Michel; Lachâtre, Gérard; Marquet, Pierre

    2009-09-01

    LC coupled to single (LC-MS) and tandem (LC-MS/MS) mass spectrometry is recognized as the most powerful analytical tools for metabolic studies in drug discovery. In this article, we describe five cases illustrating the utility of screening xenobiotic metabolites in routine analysis of forensic samples using LC-MS/MS. Analyses were performed using a previously published LC-MS/MS general unknown screening (GUS) procedure developed using a hybrid linear IT-tandem mass spectrometer. In each of the cases presented, the presence of metabolites of xenobiotics was suspected after analyzing urine samples. In two cases, the parent drug was also detected and the metabolites were merely useful to confirm drug intake, but in three other cases, metabolite detection was of actual forensic interest. The presented results indicate that: (i) the GUS procedure developed is useful to detect a large variety of drug metabolites, which would have been hardly detected using targeted methods in the context of clinical or forensic toxicology; (ii) metabolite structure can generally be inferred from their "enhanced" product ion scan spectra; and (iii) structure confirmation can be achieved through in vitro metabolic experiments or through the analysis of urine samples from individuals taking the parent drug.

  11. UAV Mission Planning: From Robust to Agile

    NARCIS (Netherlands)

    Evers, L.; Barros, A.I.; Monsuur, H.; Wagelmans, A.

    2015-01-01

    Unmanned Aerial Vehicles (UAVs) are important assets for information gathering in Intelligence Surveillance and Reconnaissance (ISR) missions. Depending on the uncertainty in the planning parameters, the complexity of the mission and its constraints and requirements, different planning methods might

  12. Declarativity and efficiency in providing services of general economic interest. Empirical study regarding the relation between heating costs and budget constraints

    Directory of Open Access Journals (Sweden)

    Dumitru Miron

    2013-06-01

    Full Text Available Defined by each country separately, according to real options, circumstances and traditions, the services of general economic interest have an objective purpose in ensuring protection and security for population. The services of general economic interest involve both public and economic services and show characteristics of both fields, reflecting the capabilities of communities to organize, regulate and provide them. Considering the accessibility to the essential service of general economic interest of providing household heating, as an undeniable condition of consumer protection, an analysis has been made in this field, with reference to the concrete manner of providing these services. The goal of this endeavor was to emphasize the actual conditionalities induced by the budget constraints of households while ensuring the universality of the access to the essential heating service. The empirical study is based on a survey of 55 households in sector 2 of Bucharest that have access to gas heating systems, while they have different revenues and equipments. The processing of the gathered data allowed the procurement of certain indicators that explain how household revenues determine the access to the heating services and how the deficiencies of the insurance system of these services deepen the social polarization and increase the weightings of those living at the limit of subsistence.

  13. Pricing general insurance with constraints

    OpenAIRE

    Emms, P.

    2006-01-01

    Deterministic control theory is used to find the optimal premium strategy for an insurer in order to maximise a given objective. The optimal strategy can be loss-leading depending on the model parameters, which may result in negative premium values. In such circumstances, it is optimal to capture as much of the market as possible before making a profit towards the end of the time horizon. In reality, the amount by which an insurer can lower premiums is constrained by borrowing restrictions an...

  14. Communication dated 6 March 2013 received from the Permanent Mission of the Islamic Republic of Iran to the Agency regarding the Report of the Director General on the Implementation of Safeguards in Iran

    International Nuclear Information System (INIS)

    2013-01-01

    The Secretariat has received a communication dated 6 March 2013 from the Permanent Mission of the Islamic Republic of Iran to the Agency enclosing an explanatory note by the Permanent Mission dated 6 March 2013, on the report of the Director General on ''Implementation of the NPT Safeguards Agreement and relevant provisions of Security Council resolutions in the Islamic Republic of Iran'' contained in GOV/2013/6 (21 February 2013) and three letters from the Resident Representative of Iran addressed to the Director General. The communication and, as requested by the Permanent Mission, the explanatory note and the letters are circulated herewith for information.

  15. Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    Sakuma, Hidenori; Sannino, Francesco

    2010-01-01

    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas......We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self...

  16. Solar constraints

    International Nuclear Information System (INIS)

    Provost, J.

    1984-01-01

    Accurate tests of the theory of stellar structure and evolution are available from the Sun's observations. The solar constraints are reviewed, with a special attention to the recent progress in observing global solar oscillations. Each constraint is sensitive to a given region of the Sun. The present solar models (standard, low Z, mixed) are discussed with respect to neutrino flux, low and high degree five-minute oscillations and low degree internal gravity modes. It appears that actually there do not exist solar models able to fully account for all the observed quantities. (Auth.)

  17. Communication dated 5 March 2014 received from the Permanent Mission of the Islamic Republic of Iran to the Agency regarding the Report of the Director General on the Implementation of Safeguards in Iran

    International Nuclear Information System (INIS)

    2014-01-01

    The Secretariat has received a communication dated 5 March 2014 from the Permanent Mission of the Islamic Republic of Iran to the Agency, enclosing an explanatory note by the Permanent Mission on the report of the Director General on ''Implementation of the NPT Safeguards Agreement and Relevant Provisions of Security Council Resolutions in the Islamic Republic of Iran'' contained in document GOV/2014/10 (20 February 2014). The communication and, as requested by the Permanent Mission, the explanatory note are circulated herewith for information

  18. Communication dated 5 March 2014 received from the Permanent Mission of the Islamic Republic of Iran to the Agency regarding the Report of the Director General on the Implementation of Safeguards in Iran

    International Nuclear Information System (INIS)

    2014-01-01

    The Secretariat has received a communication dated 5 March 2014 from the Permanent Mission of the Islamic Republic of Iran to the Agency, enclosing an explanatory note by the Permanent Mission on the report of the Director General on ''Implementation of the NPT Safeguards Agreement and Relevant Provisions of Security Council Resolutions in the Islamic Republic of Iran'' contained in document GOV/2014/10 (20 February 2014). The communication and, as requested by the Permanent Mission, the explanatory note are circulated herewith for information [es

  19. Communications dated 18 March 2013 received from the Permanent Mission of the Islamic Republic of Iran to the Agency regarding the Report of the Director General on the Implementation of Safeguards in Iran

    International Nuclear Information System (INIS)

    2013-01-01

    The Secretariat has received two communications dated 18 March 2013 from the Permanent Mission of the Islamic Republic of Iran to the Agency enclosing explanatory notes by the Permanent Mission dated September 2012 and November 2012 respectively, on the reports of the Director General on 'Implementation of the NPT Safeguards Agreement and relevant provisions of Security Council resolutions in the Islamic Republic of Iran' contained in GOV/2012/37 (30 August 2012) and GOV/2012/55 (16 November 2012). 2. The communications and, as requested by the Permanent Mission, the explanatory notes are circulated herewith for information.

  20. Gas mission; Mission gaz

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This preliminary report analyses the desirable evolutions of gas transport tariffing and examines some questions relative to the opening of competition on the French gas market. The report is made of two documents: a synthesis of the previous report with some recommendations about the tariffing of gas transport, about the modalities of network access to third parties, and about the dissociation between transport and trade book-keeping activities. The second document is the progress report about the opening of the French gas market. The first part presents the European problem of competition in the gas supply and its consequences on the opening and operation of the French gas market. The second part presents some partial syntheses about each topic of the mission letter of the Ministry of Economics, Finances and Industry: future evolution of network access tariffs, critical analysis of contractual documents for gas transport and delivery, examination of auxiliary services linked with the access to the network (modulation, balancing, conversion), consideration about the processing of network congestions and denied accesses, analysis of the metering dissociation between the integrated activities of gas operators. Some documents are attached in appendixes: the mission letter from July 9, 2001, the detailed analysis of the new temporary tariffs of GdF and CFM, the offer of methane terminals access to third parties, the compatibility of a nodal tariffing with the presence of three transport operators (GdF, CFM and GSO), the contract-type for GdF supply, and the contract-type for GdF connection. (J.S.)

  1. The constraints

    International Nuclear Information System (INIS)

    Jones, P.M.S.

    1987-01-01

    There are considerable incentives for the use of nuclear in preference to other sources for base load electricity generation in most of the developed world. These are economic, strategic, environmental and climatic. However, there are two potential constraints which could hinder the development of nuclear power to its full economic potential. These are public opinion and financial regulations which distort the nuclear economic advantage. The concerns of the anti-nuclear lobby are over safety, (especially following the Chernobyl accident), the management of radioactive waste, the potential effects of large scale exposure of the population to radiation and weapons proliferation. These are discussed. The financial constraint is over two factors, the availability of funds and the perception of cost, both of which are discussed. (U.K.)

  2. General Mission Analysis Tool Project

    Data.gov (United States)

    National Aeronautics and Space Administration — OverviewGMAT is a feature rich system containing high fidelity space system models, optimization and targeting,built in scripting and programming infrastructure, and...

  3. The Impact of Adapting a General Professional Development Framework to the Constraints of In-Service Professional Development on the Next Generation Science Standards in Urban Settings

    Science.gov (United States)

    McGee, Steven; Nutakki, Nivedita

    2017-01-01

    Urban school districts face a dilemma in providing professional development support for teachers in transition to the Next Generation Science Standards (NGSS). Districts need to maximize the quality and amount of professional development within practical funding constraints. In this paper, we discuss preliminary results from a…

  4. Route constraints model based on polychromatic sets

    Science.gov (United States)

    Yin, Xianjun; Cai, Chao; Wang, Houjun; Li, Dongwu

    2018-03-01

    With the development of unmanned aerial vehicle (UAV) technology, the fields of its application are constantly expanding. The mission planning of UAV is especially important, and the planning result directly influences whether the UAV can accomplish the task. In order to make the results of mission planning for unmanned aerial vehicle more realistic, it is necessary to consider not only the physical properties of the aircraft, but also the constraints among the various equipment on the UAV. However, constraints among the equipment of UAV are complex, and the equipment has strong diversity and variability, which makes these constraints difficult to be described. In order to solve the above problem, this paper, referring to the polychromatic sets theory used in the advanced manufacturing field to describe complex systems, presents a mission constraint model of UAV based on polychromatic sets.

  5. [The mission].

    Science.gov (United States)

    Ruiz Moreno, J; Blanch Mon, A

    2000-01-01

    After having made a historical review of the concept of mission statement, of evaluating its importance (See Part I), of describing the bases to create a mission statement from a strategic perspective and of analyzing the advantages of this concept, probably more important as a business policy (See Parts I and II), the authors proceed to analyze the mission statement in health organizations. Due to the fact that a mission statement is lacking in the majority of health organizations, the strategy of health organizations are not exactly favored; as a consequence, neither are its competitive advantage nor the development of its essential competencies. After presenting a series of mission statements corresponding to Anglo-Saxon health organizations, the authors highlight two mission statements corresponding to our social context. The article finishes by suggesting an adequate sequence for developing a mission statement in those health organizations having a strategic sense.

  6. [Myanmar mission].

    Science.gov (United States)

    Alfandari, B; Persichetti, P; Pelissier, P; Martin, D; Baudet, J

    2004-06-01

    The authors report the accomplishment of humanitarian missions in plastic surgery performed by a small team in town practice in Yangon, about their 3 years experience in Myanmar with 300 consultations and 120 surgery cases. They underline the interest of this type of mission and provide us their reflexion about team training, the type of relation with the country where the mission is conducted and the type of right team.

  7. The Ambiguous Role of Constraints in Creativity

    DEFF Research Database (Denmark)

    Biskjær, Michael Mose; Onarheim, Balder; Wiltschnig, Stefan

    2011-01-01

    The relationship between creativity and constraints is often described in the literature either in rather imprecise, general concepts or in relation to very specific domains. Cross-domain and cross-disciplinary takes on how the handling of constraints influences creative activities are rare. In t......-disciplinary research into the ambiguous role of constraints in creativity....

  8. Canada and Missions for Peace

    International Development Research Centre (IDRC) Digital Library (Canada)

    The study focuses primarily on Canada's role in these missions in light of ..... simply because peacekeeping has been the chief form of UN intervention and one in which ... Other factors, such as financial constraints and increasing social problems ..... Luck, superior armaments, the shortage of professional officers among the ...

  9. Analysis of Space Tourism Constraints

    Science.gov (United States)

    Bonnal, Christophe

    2002-01-01

    Space tourism appears today as a new Eldorado in a relatively near future. Private operators are already proposing services for leisure trips in Low Earth Orbit, and some happy few even tested them. But are these exceptional events really marking the dawn of a new space age ? The constraints associated to the space tourism are severe : - the economical balance of space tourism is tricky; development costs of large manned - the technical definition of such large vehicles is challenging, mainly when considering - the physiological aptitude of passengers will have a major impact on the mission - the orbital environment will also lead to mission constraints on aspects such as radiation, However, these constraints never appear as show-stoppers and have to be dealt with pragmatically: - what are the recommendations one can make for future research in the field of space - which typical roadmap shall one consider to develop realistically this new market ? - what are the synergies with the conventional missions and with the existing infrastructure, - how can a phased development start soon ? The paper proposes hints aiming at improving the credibility of Space Tourism and describes the orientations to follow in order to solve the major hurdles found in such an exciting development.

  10. Trajectory optimization for lunar soft landing with complex constraints

    Science.gov (United States)

    Chu, Huiping; Ma, Lin; Wang, Kexin; Shao, Zhijiang; Song, Zhengyu

    2017-11-01

    A unified trajectory optimization framework with initialization strategies is proposed in this paper for lunar soft landing for various missions with specific requirements. Two main missions of interest are Apollo-like Landing from low lunar orbit and Vertical Takeoff Vertical Landing (a promising mobility method) on the lunar surface. The trajectory optimization is characterized by difficulties arising from discontinuous thrust, multi-phase connections, jump of attitude angle, and obstacles avoidance. Here R-function is applied to deal with the discontinuities of thrust, checkpoint constraints are introduced to connect multiple landing phases, attitude angular rate is designed to get rid of radical changes, and safeguards are imposed to avoid collision with obstacles. The resulting dynamic problems are generally with complex constraints. The unified framework based on Gauss Pseudospectral Method (GPM) and Nonlinear Programming (NLP) solver are designed to solve the problems efficiently. Advanced initialization strategies are developed to enhance both the convergence and computation efficiency. Numerical results demonstrate the adaptability of the framework for various landing missions, and the performance of successful solution of difficult dynamic problems.

  11. Liquid Effluents Program mission analysis

    International Nuclear Information System (INIS)

    Lowe, S.S.

    1994-01-01

    Systems engineering is being used to identify work to cleanup the Hanford Site. The systems engineering process transforms an identified mission need into a set of performance parameters and a preferred system configuration. Mission analysis is the first step in the process. Mission analysis supports early decision-making by clearly defining the program objectives, and evaluating the feasibility and risks associated with achieving those objectives. The results of the mission analysis provide a consistent basis for subsequent systems engineering work. A mission analysis was performed earlier for the overall Hanford Site. This work was continued by a ''capstone'' team which developed a top-level functional analysis. Continuing in a top-down manner, systems engineering is now being applied at the program and project levels. A mission analysis was conducted for the Liquid Effluents Program. The results are described herein. This report identifies the initial conditions and acceptable final conditions, defines the programmatic and physical interfaces and sources of constraints, estimates the resources to carry out the mission, and establishes measures of success. The mission analysis reflects current program planning for the Liquid Effluents Program as described in Liquid Effluents FY 1995 Multi-Year Program Plan

  12. Multi-Objective Trajectory Optimization of a Hypersonic Reconnaissance Vehicle with Temperature Constraints

    Science.gov (United States)

    Masternak, Tadeusz J.

    This research determines temperature-constrained optimal trajectories for a scramjet-based hypersonic reconnaissance vehicle by developing an optimal control formulation and solving it using a variable order Gauss-Radau quadrature collocation method with a Non-Linear Programming (NLP) solver. The vehicle is assumed to be an air-breathing reconnaissance aircraft that has specified takeoff/landing locations, airborne refueling constraints, specified no-fly zones, and specified targets for sensor data collections. A three degree of freedom scramjet aircraft model is adapted from previous work and includes flight dynamics, aerodynamics, and thermal constraints. Vehicle control is accomplished by controlling angle of attack, roll angle, and propellant mass flow rate. This model is incorporated into an optimal control formulation that includes constraints on both the vehicle and mission parameters, such as avoidance of no-fly zones and coverage of high-value targets. To solve the optimal control formulation, a MATLAB-based package called General Pseudospectral Optimal Control Software (GPOPS-II) is used, which transcribes continuous time optimal control problems into an NLP problem. In addition, since a mission profile can have varying vehicle dynamics and en-route imposed constraints, the optimal control problem formulation can be broken up into several "phases" with differing dynamics and/or varying initial/final constraints. Optimal trajectories are developed using several different performance costs in the optimal control formulation: minimum time, minimum time with control penalties, and maximum range. The resulting analysis demonstrates that optimal trajectories that meet specified mission parameters and constraints can be quickly determined and used for larger-scale operational and campaign planning and execution.

  13. Constraint-based scheduling

    Science.gov (United States)

    Zweben, Monte

    1993-01-01

    The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

  14. Chance-Constrained Guidance With Non-Convex Constraints

    Science.gov (United States)

    Ono, Masahiro

    2011-01-01

    Missions to small bodies, such as comets or asteroids, require autonomous guidance for descent to these small bodies. Such guidance is made challenging by uncertainty in the position and velocity of the spacecraft, as well as the uncertainty in the gravitational field around the small body. In addition, the requirement to avoid collision with the asteroid represents a non-convex constraint that means finding the optimal guidance trajectory, in general, is intractable. In this innovation, a new approach is proposed for chance-constrained optimal guidance with non-convex constraints. Chance-constrained guidance takes into account uncertainty so that the probability of collision is below a specified threshold. In this approach, a new bounding method has been developed to obtain a set of decomposed chance constraints that is a sufficient condition of the original chance constraint. The decomposition of the chance constraint enables its efficient evaluation, as well as the application of the branch and bound method. Branch and bound enables non-convex problems to be solved efficiently to global optimality. Considering the problem of finite-horizon robust optimal control of dynamic systems under Gaussian-distributed stochastic uncertainty, with state and control constraints, a discrete-time, continuous-state linear dynamics model is assumed. Gaussian-distributed stochastic uncertainty is a more natural model for exogenous disturbances such as wind gusts and turbulence than the previously studied set-bounded models. However, with stochastic uncertainty, it is often impossible to guarantee that state constraints are satisfied, because there is typically a non-zero probability of having a disturbance that is large enough to push the state out of the feasible region. An effective framework to address robustness with stochastic uncertainty is optimization with chance constraints. These require that the probability of violating the state constraints (i.e., the probability of

  15. Machine tongues. X. Constraint languages

    Energy Technology Data Exchange (ETDEWEB)

    Levitt, D.

    Constraint languages and programming environments will help the designer produce a lucid description of a problem domain, and then of particular situations and problems in it. Early versions of these languages were given descriptions of real world domain constraints, like the operation of electrical and mechanical parts. More recently, the author has automated a vocabulary for describing musical jazz phrases, using constraint language as a jazz improviser. General constraint languages will handle all of these domains. Once the model is in place, the system will connect built-in code fragments and algorithms to answer questions about situations; that is, to help solve problems. Bugs will surface not in code, but in designs themselves. 15 references.

  16. Accurate measurement in the field of the earth of the general-relativistic precession of the LAGEOS II pericenter and new constraints on non-newtonian gravity.

    Science.gov (United States)

    Lucchesi, David M; Peron, Roberto

    2010-12-03

    The pericenter shift of a binary system represents a suitable observable to test for possible deviations from the newtonian inverse-square law in favor of new weak interactions between macroscopic objects. We analyzed 13 years of tracking data of the LAGEOS satellites with GEODYN II software but with no models for general relativity. From the fit of LAGEOS II pericenter residuals we have been able to obtain a 99.8% agreement with the predictions of Einstein's theory. This result may be considered as a 99.8% measurement in the field of the Earth of the combination of the γ and β parameters of general relativity, and it may be used to constrain possible deviations from the inverse-square law in favor of new weak interactions parametrized by a Yukawa-like potential with strength α and range λ. We obtained |α| ≲ 1 × 10(-11), a huge improvement at a range of about 1 Earth radius.

  17. General constraints on spin observables; application to p-bar + p → Λ-bar + Λ and to polarized quark distributions

    International Nuclear Information System (INIS)

    Artru, X.; Richard, J.-M.

    2004-01-01

    The density matrix formalism and the positive conditions for general multiple-spin asymmetries are reviewed, taking as an example the case p-bar + p → Λ-bar + Λ in which one, two or three spins are analyzed. Some aspects related to quantum information and entangled states are discussed. Some positivity domains are compared with the experimental data. The case of inclusive reaction is also treated, taking as an example the spin- and transverse momentum-dependent quark distributions [ru

  18. Bomber Deterrence Missions: Criteria To Evaluate Mission Effectiveness

    Science.gov (United States)

    2016-02-16

    international security, the practice of general deterrence usually occurs when nations feel insecure , suspicious or even hostility towards them but...both a deterrence and assurance mission even though it was not planned or advertised as such. Since the intent of this mission was partly perceived

  19. Mars Rover Sample Return aerocapture configuration design and packaging constraints

    Science.gov (United States)

    Lawson, Shelby J.

    1989-01-01

    This paper discusses the aerodynamics requirements, volume and mass constraints that lead to a biconic aeroshell vehicle design that protects the Mars Rover Sample Return (MRSR) mission elements from launch to Mars landing. The aerodynamic requirements for Mars aerocapture and entry and packaging constraints for the MRSR elements result in a symmetric biconic aeroshell that develops a L/D of 1.0 at 27.0 deg angle of attack. A significant problem in the study is obtaining a cg that provides adequate aerodynamic stability and performance within the mission imposed constraints. Packaging methods that relieve the cg problems include forward placement of aeroshell propellant tanks and incorporating aeroshell structure as lander structure. The MRSR missions developed during the pre-phase A study are discussed with dimensional and mass data included. Further study is needed for some missions to minimize MRSR element volume so that launch mass constraints can be met.

  20. Review of Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    S. Fukano, Hidenori; Sannino, Francesco

    2010-01-01

    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas......We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self...

  1. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-12-10

    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  2. “Personal mission statement”: An analysis of medical students’ and general practitioners’ reflections on personal beliefs, values and goals in life

    Directory of Open Access Journals (Sweden)

    Chew Boon How

    2014-08-01

    Full Text Available Personal mission in life can determine motivation, happiness, future career advancement and fulfilment in life of the medical students (MSs along with improvement in professional/ clinical performance of the family physicians.1–5 These personal internal qualities are largely represented by the professional functional knowledge base, which can be influenced by personal awareness (pre-propositional impressions that trigger experiential learning and moral principles.6 Physicians often deal with patients with complex medical and social problems.7 Therefore, a physician’s self-understanding, insight into the nature, limitations of the knowledge and capacity of applying it are crucial in professional practice.8

  3. Hearing of Mr Bernard Bigot, general administrator of the Atomic Energy Commissariat (CEA), on the CEA missions and on Cadarache events

    International Nuclear Information System (INIS)

    2009-01-01

    In this hearing by the Sustainable Development and Land Planning Commission of the French National Assembly, the role and missions of the CEA are presented while evoking its relationship with the State. The CEA representative evokes the various research activities in three main domains: energy, defence, information and health technologies. Then, he discusses the problem of the ageing and dismantling of some installations, notably in the plutonium Technology workshop (ATPu) in Cadarache. He describes this installation, the processes in which it is involved, the safety and security requirements, and comments the problem which occurred in this workshop (plutonium retention in glove boxes). Then he answers several questions asked by the Commission members about the way the CEA handled this incident, and about its severity. Other aspects are addressed like the importance of the nuclear industry and the role the CEA could have in the management of renewable energies at the national level

  4. Searching for genomic constraints

    Energy Technology Data Exchange (ETDEWEB)

    Lio` , P [Cambridge, Univ. (United Kingdom). Genetics Dept.; Ruffo, S [Florence, Univ. (Italy). Fac. di Ingegneria. Dipt. di Energetica ` S. Stecco`

    1998-01-01

    The authors have analyzed general properties of very long DNA sequences belonging to simple and complex organisms, by using different correlation methods. They have distinguished those base compositional rules that concern the entire genome which they call `genomic constraints` from the rules that depend on the `external natural selection` acting on single genes, i. e. protein-centered constraints. They show that G + C content, purine / pyrimidine distributions and biological complexity of the organism are the most important factors which determine base compositional rules and genome complexity. Three main facts are here reported: bacteria with high G + C content have more restrictions on base composition than those with low G + C content; at constant G + C content more complex organisms, ranging from prokaryotes to higher eukaryotes (e.g. human) display an increase of repeats 10-20 nucleotides long, which are also partly responsible for long-range correlations; work selection of length 3 to 10 is stronger in human and in bacteria for two distinct reasons. With respect to previous studies, they have also compared the genomic sequence of the archeon Methanococcus jannaschii with those of bacteria and eukaryotes: it shows sometimes an intermediate statistical behaviour.

  5. Searching for genomic constraints

    International Nuclear Information System (INIS)

    Lio', P.; Ruffo, S.

    1998-01-01

    The authors have analyzed general properties of very long DNA sequences belonging to simple and complex organisms, by using different correlation methods. They have distinguished those base compositional rules that concern the entire genome which they call 'genomic constraints' from the rules that depend on the 'external natural selection' acting on single genes, i. e. protein-centered constraints. They show that G + C content, purine / pyrimidine distributions and biological complexity of the organism are the most important factors which determine base compositional rules and genome complexity. Three main facts are here reported: bacteria with high G + C content have more restrictions on base composition than those with low G + C content; at constant G + C content more complex organisms, ranging from prokaryotes to higher eukaryotes (e.g. human) display an increase of repeats 10-20 nucleotides long, which are also partly responsible for long-range correlations; work selection of length 3 to 10 is stronger in human and in bacteria for two distinct reasons. With respect to previous studies, they have also compared the genomic sequence of the archeon Methanococcus jannaschii with those of bacteria and eukaryotes: it shows sometimes an intermediate statistical behaviour

  6. Linear determining equations for differential constraints

    International Nuclear Information System (INIS)

    Kaptsov, O V

    1998-01-01

    A construction of differential constraints compatible with partial differential equations is considered. Certain linear determining equations with parameters are used to find such differential constraints. They generalize the classical determining equations used in the search for admissible Lie operators. As applications of this approach equations of an ideal incompressible fluid and non-linear heat equations are discussed

  7. Differential constraints and exact solutions of nonlinear diffusion equations

    International Nuclear Information System (INIS)

    Kaptsov, Oleg V; Verevkin, Igor V

    2003-01-01

    The differential constraints are applied to obtain explicit solutions of nonlinear diffusion equations. Certain linear determining equations with parameters are used to find such differential constraints. They generalize the determining equations used in the search for classical Lie symmetries

  8. Using Natural Language to Enhance Mission Effectiveness

    Science.gov (United States)

    Trujillo, Anna C.; Meszaros, Erica

    2016-01-01

    The availability of highly capable, yet relatively cheap, unmanned aerial vehicles (UAVs) is opening up new areas of use for hobbyists and for professional-related activities. The driving function of this research is allowing a non-UAV pilot, an operator, to define and manage a mission. This paper describes the preliminary usability measures of an interface that allows an operator to define the mission using speech to make inputs. An experiment was conducted to begin to enumerate the efficacy and user acceptance of using voice commands to define a multi-UAV mission and to provide high-level vehicle control commands such as "takeoff." The primary independent variable was input type - voice or mouse. The primary dependent variables consisted of the correctness of the mission parameter inputs and the time needed to make all inputs. Other dependent variables included NASA-TLX workload ratings and subjective ratings on a final questionnaire. The experiment required each subject to fill in an online form that contained comparable required information that would be needed for a package dispatcher to deliver packages. For each run, subjects typed in a simple numeric code for the package code. They then defined the initial starting position, the delivery location, and the return location using either pull-down menus or voice input. Voice input was accomplished using CMU Sphinx4-5prealpha for speech recognition. They then inputted the length of the package. These were the option fields. The subject had the system "Calculate Trajectory" and then "Takeoff" once the trajectory was calculated. Later, the subject used "Land" to finish the run. After the voice and mouse input blocked runs, subjects completed a NASA-TLX. At the conclusion of all runs, subjects completed a questionnaire asking them about their experience in inputting the mission parameters, and starting and stopping the mission using mouse and voice input. In general, the usability of voice commands is acceptable

  9. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Valencia, Frank Dan

    Concurrent constraint programming (ccp) is a formalism for concurrency in which agents interact with one another by telling (adding) and asking (reading) information in a shared medium. Temporal ccp extends ccp by allowing agents to be constrained by time conditions. This dissertation studies...... temporal ccp by developing a process calculus called ntcc. The ntcc calculus generalizes the tcc model, the latter being a temporal ccp model for deterministic and synchronouss timed reactive systems. The calculus is built upon few basic ideas but it captures several aspects of timed systems. As tcc, ntcc...... structures, robotic devises, multi-agent systems and music applications. The calculus is provided with a denotational semantics that captures the reactive computations of processes in the presence of arbitrary environments. The denotation is proven to be fully-abstract for a substantial fragment...

  10. Financing Constraints and Entrepreneurship

    OpenAIRE

    William R. Kerr; Ramana Nanda

    2009-01-01

    Financing constraints are one of the biggest concerns impacting potential entrepreneurs around the world. Given the important role that entrepreneurship is believed to play in the process of economic growth, alleviating financing constraints for would-be entrepreneurs is also an important goal for policymakers worldwide. We review two major streams of research examining the relevance of financing constraints for entrepreneurship. We then introduce a framework that provides a unified perspecti...

  11. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia Posso, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...

  12. Prominent Constraints Faced by Government Managers.

    Science.gov (United States)

    1983-06-01

    organizations have varied cultures and missions. 8 There has been little researc -h on the identification of these constraints and the effective...Additionally, in the current environment they4 15 are responsible to set the rate schedule for various services provided to NAVAIR, and to market ...NAVAIR. They are paid on the basis of work to be performed. This allows a better cost accounting system, but results in some marketing behavior by the

  13. Mission analysis for the Martian Moons Explorer (MMX) mission

    Science.gov (United States)

    Campagnola, Stefano; Yam, Chit Hong; Tsuda, Yuichi; Ogawa, Naoko; Kawakatsu, Yasuhiro

    2018-05-01

    Mars Moon eXplorer (MMX) is JAXA's next candidate flagship mission to be launched in the early 2020s. MMX will explore the Martian moons and return a sample from Phobos. This paper presents the mission analysis work, focusing on the transfer legs and comparing several architectures, such as hybrid options with chemical and electric propulsion modules. The selected baseline is a chemical-propulsion Phobos sample return, which is discussed in detail with the launch- and return-window analysis. The trajectories are optimized with the jTOP software, using planetary ephemerides for Mars and the Earth; Earth re-entry constraints are modeled with simple analytical equations. Finally, we introduce an analytical approximation of the three-burn capture strategy used in the Mars system. The approximation can be used together with a Lambert solver to quickly determine the transfer Δ v costs.

  14. Constrained dynamical systems: separation of constraints into first and second classes

    International Nuclear Information System (INIS)

    Chitaya, N.P.; Gogilidze, S.A.; Surovtsev, Yu.S.

    1996-01-01

    In the Dirac approach to the generalized Hamiltonian formalism, dynamical systems with first- and second-class constraints are investigated. The classification and separation of constraints into the first- and second-class ones are presented with the help of passing to an equivalent canonical set of constraints. The general structure of second-class constraints is clarified. 14 refs

  15. Revisiting the simplicity constraints and coherent intertwiners

    International Nuclear Information System (INIS)

    Dupuis, Maite; Livine, Etera R

    2011-01-01

    In the context of loop quantum gravity and spinfoam models, the simplicity constraints are essential in that they allow one to write general relativity as a constrained topological BF theory. In this work, we apply the recently developed U(N) framework for SU(2) intertwiners to the issue of imposing the simplicity constraints to spin network states. More particularly, we focus on solving on individual intertwiners in the 4D Euclidean theory. We review the standard way of solving the simplicity constraints using coherent intertwiners and we explain how these fit within the U(N) framework. Then we show how these constraints can be written as a closed u(N) algebra and we propose a set of U(N) coherent states that solves all the simplicity constraints weakly for an arbitrary Immirzi parameter.

  16. IMPaCT - Integration of Missions, Programs, and Core Technologies

    Science.gov (United States)

    Balacuit, Carlos P.; Cutts, James A.; Peterson, Craig E.; Beauchamp, Patricia M.; Jones, Susan K.; Hang, Winnie N.; Dastur, Shahin D.

    2013-01-01

    IMPaCT enables comprehensive information on current NASA missions, prospective future missions, and the technologies that NASA is investing in, or considering investing in, to be accessed from a common Web-based interface. It allows dependencies to be established between missions and technology, and from this, the benefits of investing in individual technologies can be determined. The software also allows various scenarios for future missions to be explored against resource constraints, and the nominal cost and schedule of each mission to be modified in an effort to fit within a prescribed budget.

  17. Nanosatellite missions - the future

    Science.gov (United States)

    Koudelka, O.; Kuschnig, R.; Wenger, M.; Romano, P.

    2017-09-01

    In the beginning, nanosatellite projects were focused on educational aspects. In the meantime, the technology matured and now allows to test, demonstrate and validate new systems, operational procedures and services in space at low cost and within much shorter timescales than traditional space endeavors. The number of spacecraft developed and launched has been increasing exponentially in the last years. The constellation of BRITE nanosatellites is demonstrating impressively that demanding scientific requirements can be met with small, low-cost satellites. Industry and space agencies are now embracing small satellite technology. Particularly in the USA, companies have been established to provide commercial services based on CubeSats. The approach is in general different from traditional space projects with their strict product/quality assurance and documentation requirements. The paper gives an overview of nanosatellite missions in different areas of application. Based on lessons learnt from the BRITE mission and recent developments at TU Graz (in particular the implementation of the OPS-SAT nanosatellite for ESA), enhanced technical possibilities for a future astronomy mission after BRITE will be discussed. Powerful on-board computers will allow on-board data pre-processing. A state-of-the-art telemetry system with high data rates would facilitate interference-free operations and increase science data return.

  18. Landsat Data Continuity Mission

    Science.gov (United States)

    ,

    2012-01-01

    The Landsat Data Continuity Mission (LDCM) is a partnership formed between the National Aeronautics and Space Administration (NASA) and the U.S. Geological Survey (USGS) to place the next Landsat satellite in orbit in January 2013. The Landsat era that began in 1972 will become a nearly 41-year global land record with the successful launch and operation of the LDCM. The LDCM will continue the acquisition, archiving, and distribution of multispectral imagery affording global, synoptic, and repetitive coverage of the Earth's land surfaces at a scale where natural and human-induced changes can be detected, differentiated, characterized, and monitored over time. The mission objectives of the LDCM are to (1) collect and archive medium resolution (30-meter spatial resolution) multispectral image data affording seasonal coverage of the global landmasses for a period of no less than 5 years; (2) ensure that LDCM data are sufficiently consistent with data from the earlier Landsat missions in terms of acquisition geometry, calibration, coverage characteristics, spectral characteristics, output product quality, and data availability to permit studies of landcover and land-use change over time; and (3) distribute LDCM data products to the general public on a nondiscriminatory basis at no cost to the user.

  19. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  20. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  1. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  2. The Europa Ocean Discovery mission

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, B.C. [Los Alamos National Lab., NM (United States); Chyba, C.F. [Univ. of Arizona, Tucson, AZ (United States); Abshire, J.B. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center] [and others

    1997-06-01

    Since it was first proposed that tidal heating of Europa by Jupiter might lead to liquid water oceans below Europa`s ice cover, there has been speculation over the possible exobiological implications of such an ocean. Liquid water is the essential ingredient for life as it is known, and the existence of a second water ocean in the Solar System would be of paramount importance for seeking the origin and existence of life beyond Earth. The authors present here a Discovery-class mission concept (Europa Ocean Discovery) to determine the existence of a liquid water ocean on Europa and to characterize Europa`s surface structure. The technical goal of the Europa Ocean Discovery mission is to study Europa with an orbiting spacecraft. This goal is challenging but entirely feasible within the Discovery envelope. There are four key challenges: entering Europan orbit, generating power, surviving long enough in the radiation environment to return valuable science, and complete the mission within the Discovery program`s launch vehicle and budget constraints. The authors will present here a viable mission that meets these challenges.

  3. Communication dated 5 September 2005 received from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland to the Agency concerning a letter from the Government of the United Kingdom to the Secretary General of the League of Arab States

    International Nuclear Information System (INIS)

    2005-01-01

    The Secretariat has received a Note Verbale dated 5 September 2005 from the Permanent Mission of the United Kingdom, attaching a letter dated 31 August 2005 from the Minister of State at the Foreign and Commonwealth Office to the Secretary General of the League of Arab States. In the light of the request expressed by the Permanent Mission of the United Kingdom in that Note Verbale, the Note Verbale and the attached letter are hereby circulated for the information of all Member States

  4. Unitarity constraints on trimaximal mixing

    International Nuclear Information System (INIS)

    Kumar, Sanjeev

    2010-01-01

    When the neutrino mass eigenstate ν 2 is trimaximally mixed, the mixing matrix is called trimaximal. The middle column of the trimaximal mixing matrix is identical to tribimaximal mixing and the other two columns are subject to unitarity constraints. This corresponds to a mixing matrix with four independent parameters in the most general case. Apart from the two Majorana phases, the mixing matrix has only one free parameter in the CP conserving limit. Trimaximality results in interesting interplay between mixing angles and CP violation. A notion of maximal CP violation naturally emerges here: CP violation is maximal for maximal 2-3 mixing. Similarly, there is a natural constraint on the deviation from maximal 2-3 mixing which takes its maximal value in the CP conserving limit.

  5. Constraint-based reachability

    Directory of Open Access Journals (Sweden)

    Arnaud Gotlieb

    2013-02-01

    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  6. Data Driven Constraints for the SVM

    DEFF Research Database (Denmark)

    Darkner, Sune; Clemmensen, Line Katrine Harder

    2012-01-01

    We propose a generalized data driven constraint for support vector machines exemplified by classification of paired observations in general and specifically on the human ear canal. This is particularly interesting in dynamic cases such as tissue movement or pathologies developing over time. Assum...

  7. Hamiltonian constraint in polymer parametrized field theory

    International Nuclear Information System (INIS)

    Laddha, Alok; Varadarajan, Madhavan

    2011-01-01

    Recently, a generally covariant reformulation of two-dimensional flat spacetime free scalar field theory known as parametrized field theory was quantized using loop quantum gravity (LQG) type ''polymer'' representations. Physical states were constructed, without intermediate regularization structures, by averaging over the group of gauge transformations generated by the constraints, the constraint algebra being a Lie algebra. We consider classically equivalent combinations of these constraints corresponding to a diffeomorphism and a Hamiltonian constraint, which, as in gravity, define a Dirac algebra. Our treatment of the quantum constraints parallels that of LQG and obtains the following results, expected to be of use in the construction of the quantum dynamics of LQG: (i) the (triangulated) Hamiltonian constraint acts only on vertices, its construction involves some of the same ambiguities as in LQG and its action on diffeomorphism invariant states admits a continuum limit, (ii) if the regulating holonomies are in representations tailored to the edge labels of the state, all previously obtained physical states lie in the kernel of the Hamiltonian constraint, (iii) the commutator of two (density weight 1) Hamiltonian constraints as well as the operator correspondent of their classical Poisson bracket converge to zero in the continuum limit defined by diffeomorphism invariant states, and vanish on the Lewandowski-Marolf habitat, (iv) the rescaled density 2 Hamiltonian constraints and their commutator are ill-defined on the Lewandowski-Marolf habitat despite the well-definedness of the operator correspondent of their classical Poisson bracket there, (v) there is a new habitat which supports a nontrivial representation of the Poisson-Lie algebra of density 2 constraints.

  8. [The Nature and Issues of Drug Addiction Treatment under Constraint].

    Science.gov (United States)

    Quirion, Bastien

    This article is exploring different forms of constraint that are exerted in the field of drug addiction treatment. The objective of this article is to establish benchmarks and to stimulate reflection about the ethical and clinical implications of those constraints in the field of drug addiction treatment. This article is presenting a critical review of different forms of constraint that can be exerted in Canada in regard to the treatment of drug addiction. In the first section of the article, a definition of therapeutic intervention is proposed, that includes the dimension of power, which justifies the importance of considering the coercive aspects of treatment. The second section, which represents the core section of the paper, is devoted to the presentation of different levels of constraint that can be distinguished in regard to drug addicts who are under treatment. Three levels of constraint are exposed: judicial constraint, institutional constraint and relational constraint. The coercive aspect of treatment can then be recognized as a combination of all tree levels of constraint. Judicial constraint refers to any form of constraint in which the court or the judge is imposing or recommending treatment. This particular level of constraint can take different forms, such as therapeutic remands, conditions of a probation order, conditions of a conditional sentence of imprisonment, and coercive treatment such as the ones provided through drug courts. Institutional constraint refers to any form of constraint exerted within any institutional setting, such as correctional facilities and programs offered in community. Correctional facilities being limited by their own specific mission, it might have a major impact on the way the objectives of treatment are defined. Those limitations can then be considered as a form of constraint, in which drug users don't have much space to express their personal needs. Finally, relational constraint refers to any form of constraint in

  9. Life support approaches for Mars missions

    Science.gov (United States)

    Drysdale, A. E.; Ewert, M. K.; Hanford, A. J.

    Life support approaches for Mars missions are evaluated using an equivalent system mass (ESM) approach, in which all significant costs are converted into mass units. The best approach, as defined by the lowest mission ESM, depends on several mission parameters, notably duration, environment and consequent infrastructure costs, and crew size, as well as the characteristics of the technologies which are available. Generally, for the missions under consideration, physicochemical regeneration is most cost effective. However, bioregeneration is likely to be of use for producing salad crops for any mission, for producing staple crops for medium duration missions, and for most food, air and water regeneration for long missions (durations of a decade). Potential applications of in situ resource utilization need to be considered further.

  10. Resources, constraints and capabilities

    NARCIS (Netherlands)

    Dhondt, S.; Oeij, P.R.A.; Schröder, A.

    2018-01-01

    Human and financial resources as well as organisational capabilities are needed to overcome the manifold constraints social innovators are facing. To unlock the potential of social innovation for the whole society new (social) innovation friendly environments and new governance structures

  11. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-01-01

    . The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application

  12. Dynamics and causality constraints

    International Nuclear Information System (INIS)

    Sousa, Manoelito M. de

    2001-04-01

    The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Causality in field theory are kinematical constraints dynamically implemented via solutions of the field equation, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away with deep implications to the nature of physicals interactions. (author)

  13. Vocabulary Constraint on Texts

    Directory of Open Access Journals (Sweden)

    C. Sutarsyah

    2008-01-01

    Full Text Available This case study was carried out in the English Education Department of State University of Malang. The aim of the study was to identify and describe the vocabulary in the reading text and to seek if the text is useful for reading skill development. A descriptive qualitative design was applied to obtain the data. For this purpose, some available computer programs were used to find the description of vocabulary in the texts. It was found that the 20 texts containing 7,945 words are dominated by low frequency words which account for 16.97% of the words in the texts. The high frequency words occurring in the texts were dominated by function words. In the case of word levels, it was found that the texts have very limited number of words from GSL (General Service List of English Words (West, 1953. The proportion of the first 1,000 words of GSL only accounts for 44.6%. The data also show that the texts contain too large proportion of words which are not in the three levels (the first 2,000 and UWL. These words account for 26.44% of the running words in the texts.  It is believed that the constraints are due to the selection of the texts which are made of a series of short-unrelated texts. This kind of text is subject to the accumulation of low frequency words especially those of content words and limited of words from GSL. It could also defeat the development of students' reading skills and vocabulary enrichment.

  14. Momentum constraint relaxation

    International Nuclear Information System (INIS)

    Marronetti, Pedro

    2006-01-01

    Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly

  15. Selection of new constraints

    International Nuclear Information System (INIS)

    Sugier, A.

    2003-01-01

    The selected new constraints should be consistent with the scale of concern i.e. be expressed roughly as fractions or multiples of the average annual background. They should take into account risk considerations and include the values of the currents limits, constraints and other action levels. The recommendation is to select four leading values for the new constraints: 500 mSv ( single event or in a decade) as a maximum value, 0.01 mSv/year as a minimum value; and two intermediate values: 20 mSv/year and 0.3 mSv/year. This new set of dose constraints, representing basic minimum standards of protection for the individuals taking into account the specificity of the exposure situations are thus coherent with the current values which can be found in ICRP Publications. A few warning need however to be noticed: There is no more multi sources limit set by ICRP. The coherence between the proposed value of dose constraint (20 mSv/year) and the current occupational dose limit of 20 mSv/year is valid only if the workers are exposed to one single source. When there is more than one source, it will be necessary to apportion. The value of 1000 mSv lifetimes used for relocation can be expressed into annual dose, which gives approximately 10 mSv/year and is coherent with the proposed dose constraint. (N.C.)

  16. Mission analysis for cross-site transfer

    International Nuclear Information System (INIS)

    Riesenweber, S.D.; Fritz, R.L.; Shipley, L.E.

    1995-11-01

    The Mission Analysis Report describes the requirements and constraints associated with the Transfer Waste Function as necessary to support the Manage Tank Waste, Retrieve Waste, and Process Tank Waste Functions described in WHC-SD-WM-FRD-020, Tank Waste Remediation System (TWRS) Functions and Requirements Document and DOE/RL-92-60, Revision 1, TWRS Functions and Requirements Document, March 1994. It further assesses the ability of the ''initial state'' (or current cross-site transfer system) to meet the requirements and constraints

  17. Improving the Operations of the Earth Observing One Mission via Automated Mission Planning

    Science.gov (United States)

    Chien, Steve A.; Tran, Daniel; Rabideau, Gregg; Schaffer, Steve; Mandl, Daniel; Frye, Stuart

    2010-01-01

    We describe the modeling and reasoning about operations constraints in an automated mission planning system for an earth observing satellite - EO-1. We first discuss the large number of elements that can be naturally represented in an expressive planning and scheduling framework. We then describe a number of constraints that challenge the current state of the art in automated planning systems and discuss how we modeled these constraints as well as discuss tradeoffs in representation versus efficiency. Finally we describe the challenges in efficiently generating operations plans for this mission. These discussions involve lessons learned from an operations model that has been in use since Fall 2004 (called R4) as well as a newer more accurate operations model operational since June 2009 (called R5). We present analysis of the R5 software documenting a significant (greater than 50%) increase in the number of weekly observations scheduled by the EO-1 mission. We also show that the R5 mission planning system produces schedules within 15% of an upper bound on optimal schedules. This operational enhancement has created value of millions of dollars US over the projected remaining lifetime of the EO-1 mission.

  18. Nuclear energy and external constraints

    International Nuclear Information System (INIS)

    Lattes, R.; Thiriet, L.

    1983-01-01

    The structural factors of this crisis probably predominate over factors arising out the economic situation, even if explanations vary in this respect. In this article devoted to nuclear energy, a possible means of Loosering external constraints the current international economic environment is firstly outlined; the context in which the policies of industrialized countries, and therefore that of France, must be developed. An examination of the possible role of energy policies in general and nuclear policies in particular as an instrument of economic policy in providing a partial solution to this crisis, will then enable to quantitatively evaluate the effects of such policies at a national level [fr

  19. Cosmological constraints on Brans-Dicke theory.

    Science.gov (United States)

    Avilez, A; Skordis, C

    2014-07-04

    We report strong cosmological constraints on the Brans-Dicke (BD) theory of gravity using cosmic microwave background data from Planck. We consider two types of models. First, the initial condition of the scalar field is fixed to give the same effective gravitational strength Geff today as the one measured on Earth, GN. In this case, the BD parameter ω is constrained to ω>692 at the 99% confidence level, an order of magnitude improvement over previous constraints. In the second type, the initial condition for the scalar is a free parameter leading to a somewhat stronger constraint of ω>890, while Geff is constrained to 0.981theory and are valid for any Horndeski theory, the most general second-order scalar-tensor theory, which approximates the BD theory on cosmological scales. In this sense, our constraints place strong limits on possible modifications of gravity that might explain cosmic acceleration.

  20. Misconceptions and constraints

    International Nuclear Information System (INIS)

    Whitten, M.; Mahon, R.

    2005-01-01

    In theory, the sterile insect technique (SIT) is applicable to a wide variety of invertebrate pests. However, in practice, the approach has been successfully applied to only a few major pests. Chapters in this volume address possible reasons for this discrepancy, e.g. Klassen, Lance and McInnis, and Robinson and Hendrichs. The shortfall between theory and practice is partly due to the persistence of some common misconceptions, but it is mainly due to one constraint, or a combination of constraints, that are biological, financial, social or political in nature. This chapter's goal is to dispel some major misconceptions, and view the constraints as challenges to overcome, seeing them as opportunities to exploit. Some of the common misconceptions include: (1) released insects retain residual radiation, (2) females must be monogamous, (3) released males must be fully sterile, (4) eradication is the only goal, (5) the SIT is too sophisticated for developing countries, and (6) the SIT is not a component of an area-wide integrated pest management (AW-IPM) strategy. The more obvious constraints are the perceived high costs of the SIT, and the low competitiveness of released sterile males. The perceived high up-front costs of the SIT, their visibility, and the lack of private investment (compared with alternative suppression measures) emerge as serious constraints. Failure to appreciate the true nature of genetic approaches, such as the SIT, may pose a significant constraint to the wider adoption of the SIT and other genetically-based tactics, e.g. transgenic genetically modified organisms (GMOs). Lack of support for the necessary underpinning strategic research also appears to be an important constraint. Hence the case for extensive strategic research in ecology, population dynamics, genetics, and insect behaviour and nutrition is a compelling one. Raising the competitiveness of released sterile males remains the major research objective of the SIT. (author)

  1. OMV mission simulator

    Science.gov (United States)

    Cok, Keith E.

    1989-01-01

    The Orbital Maneuvering Vehicle (OMV) will be remotely piloted during rendezvous, docking, or proximity operations with target spacecraft from a ground control console (GCC). The real-time mission simulator and graphics being used to design a console pilot-machine interface are discussed. A real-time orbital dynamics simulator drives the visual displays. The dynamics simulator includes a J2 oblate earth gravity model and a generalized 1962 rotating atmospheric and drag model. The simulator also provides a variable-length communication delay to represent use of the Tracking and Data Relay Satellite System (TDRSS) and NASA Communications (NASCOM). Input parameter files determine the graphics display. This feature allows rapid prototyping since displays can be easily modified from pilot recommendations. A series of pilot reviews are being held to determine an effective pilot-machine interface. Pilots fly missions with nominal to 3-sigma dispersions in translational or rotational axes. Console dimensions, switch type and layout, hand controllers, and graphic interfaces are evaluated by the pilots and the GCC simulator is modified for subsequent runs. Initial results indicate a pilot preference for analog versus digital displays and for two 3-degree-of-freedom hand controllers.

  2. Artificial intelligence techniques for scheduling Space Shuttle missions

    Science.gov (United States)

    Henke, Andrea L.; Stottler, Richard H.

    1994-01-01

    Planning and scheduling of NASA Space Shuttle missions is a complex, labor-intensive process requiring the expertise of experienced mission planners. We have developed a planning and scheduling system using combinations of artificial intelligence knowledge representations and planning techniques to capture mission planning knowledge and automate the multi-mission planning process. Our integrated object oriented and rule-based approach reduces planning time by orders of magnitude and provides planners with the flexibility to easily modify planning knowledge and constraints without requiring programming expertise.

  3. Planetary protection policy overview and application to future missions

    Science.gov (United States)

    Rummel, John D.

    1989-01-01

    The current status of planetary protection (quarantine) policy within NASA is discussed, together with the issues of planetary protection and back-contamination as related to future missions. The policy adopted by COSPAR in 1984 (and recently reaffirmed by the NASA Administrator) for application to all unmanned missions to other solar system bodies and all manned and unmanned sample return missions is examined. Special attention is given to the implementation of the policy and to the specific quarantine-related constraints on spacecraft involved in solar system exploration that depend on the nature of the mission and the identity of the target body.

  4. Early Mission Maneuver Operations for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

    Science.gov (United States)

    Roberts, Craig; Case, Sara; Reagoso, John; Webster, Cassandra

    2015-01-01

    The Deep Space Climate Observatory mission launched on February 11, 2015, and inserted onto a transfer trajectory toward a Lissajous orbit around the Sun-Earth L1 libration point. This paper presents an overview of the baseline transfer orbit and early mission maneuver operations leading up to the start of nominal science orbit operations. In particular, the analysis and performance of the spacecraft insertion, mid-course correction maneuvers, and the deep-space Lissajous orbit insertion maneuvers are discussed, com-paring the baseline orbit with actual mission results and highlighting mission and operations constraints..

  5. Occupational dose constraint

    International Nuclear Information System (INIS)

    Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria

    2005-01-01

    The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography

  6. Psychological constraints on egalitarianism

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2015-01-01

    processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what......Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...

  7. Planck 2013 Results. XXIV. Constraints on primordial non-Gaussianity

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.

    2013-01-01

    The Planck nominal mission cosmic microwave background (CMB) maps yield unprecedented constraints on primordial non-Gaussianity (NG).Using three optimal bispectrum estimators, separable template-fitting (KSW), binned, and modal, we obtain consistent values for the primordiallocal, equilateral, an...

  8. La géochimie organique des sédiments marins profonds. Mission Orgon 4, 1978 (golfe d'Aden, mer d'Oman. Généralités et résultats obtenus à la mer Organic Geochemistry of Deep Marine Sediments. Organ 4 Mission, 1978 (Gulf of Aden, Sea of Oman. General and Results Obtained At Sea

    Directory of Open Access Journals (Sweden)

    Pelet R.

    2006-11-01

    populations microbiennes a été tenté, par mises en culture sous pression correspondant à la pression de fond, pour essayer de déceler une éventuelle présence de formes barophiles. Four separate articles deal with: 1 general comments on the ORGON 4 mission, 2 the geographic setting and the general geology as well as a description of the tore samples taken, 3 the biochemistry of the waters, and 4 microbiology. Several environments were encountered and investigated, ranging from a lagoon (Ghubbet el Kharab to a deep fault trough (Alula-Fartak trough. Two radials, one in the Arabian Sea and the other in the Gulf of Oman, were used to follow the evolution of their characteristics from coastal zones down to the abyssal plain. The location of core-sampling sites was studied so as to avoid zones with extensive detrital influx (Indus cone. The results given indicate that this goal has certainly been attained and, in particular, that the organic matter in the sediments is massively of autochthonous marine origin (planktonic. An analysis of the waters came up with the same result that had previously been found, i. e. the existence in medium depths (800 to 1800 m of a very pronounced minimum-oxygen-content zone (= 1 ml /I corresponding to sedimentation environments with a clearcut reducing nature and a relatively high organic matter content. More generally, the organic carbon contents of the sediment samples taken during ORGON 4 are the highest of all those measured in the ORGON missions, for both mean and maximum values. This is certainly linked to the exceptional primary productivity of the underlying waters. Microbiological analyses did not find the spectacular phenomena found in ORGON 3, i. e. layers with exceptionally abundant microflora interbedded with sterile layers in the depth of the cores. Nonetheless, there were tendencies to acquire such a nature in some levels. Mention should be made of an attempt to make a more exhaustive investigation of microbial populations by

  9. Intelligent Mission Controller Node

    National Research Council Canada - National Science Library

    Perme, David

    2002-01-01

    The goal of the Intelligent Mission Controller Node (IMCN) project was to improve the process of translating mission taskings between real-world Command, Control, Communications, Computers, and Intelligence (C41...

  10. Critical Robotic Lunar Missions

    Science.gov (United States)

    Plescia, J. B.

    2018-04-01

    Perhaps the most critical missions to understanding lunar history are in situ dating and network missions. These would constrain the volcanic and thermal history and interior structure. These data would better constrain lunar evolution models.

  11. Dukovany ASSET mission preparation

    Energy Technology Data Exchange (ETDEWEB)

    Kouklik, I [NPP Dukovany (Czech Republic)

    1997-12-31

    We are in the final stages of the Dukovany ASSET mission 1996 preparation. I would like to present some of our recent experiences. Maybe they would be helpful to other plants, that host ASSET missions in future.

  12. Dukovany ASSET mission preparation

    International Nuclear Information System (INIS)

    Kouklik, I.

    1996-01-01

    We are in the final stages of the Dukovany ASSET mission 1996 preparation. I would like to present some of our recent experiences. Maybe they would be helpful to other plants, that host ASSET missions in future

  13. The Director-General receives the "150 Years of Romanian Diplomacy" Honorary Award from H.E. Mrs. Maria Ciobanu, Ambassador Extraordinary and Plenipotentiary, Permanent Representative, Permanent Mission of Romania to the United Nations Office and other international organizations in Geneva.

    CERN Multimedia

    Samuel Morier-Genoud

    2012-01-01

    The Director-General receives the "150 Years of Romanian Diplomacy" Honorary Award from H.E. Mrs. Maria Ciobanu, Ambassador Extraordinary and Plenipotentiary, Permanent Representative, Permanent Mission of Romania to the United Nations Office and other international organizations in Geneva.

  14. Constraint qualifications and optimality conditions for optimization problems with cardinality constraints

    Czech Academy of Sciences Publication Activity Database

    Červinka, Michal; Kanzow, Ch.; Schwartz, A.

    2016-01-01

    Roč. 160, č. 1 (2016), s. 353-377 ISSN 0025-5610 R&D Projects: GA ČR GAP402/12/1309; GA ČR GA15-00735S Institutional support: RVO:67985556 Keywords : Cardinality constraints * Constraint qualifications * Optimality conditions * KKT conditions * Strongly stationary points Subject RIV: BA - General Mathematics Impact factor: 2.446, year: 2016 http://library.utia.cas.cz/separaty/2016/MTR/cervinka-0461165.pdf

  15. Evolution of Orion Mission Design for Exploration Mission 1 and 2

    Science.gov (United States)

    Gutkowski, Jeffrey P.; Dawn, Timothy F.; Jedrey, Richard M.

    2016-01-01

    The evolving mission design and concepts of NASA’s next steps have shaped Orion into the spacecraft that it is today. Since the initial inception of Orion, through the Constellation Program, and now in the Exploration Mission frame-work with the Space Launch System (SLS), each mission design concept and pro-gram goal have left Orion with a set of capabilities that can be utilized in many different mission types. Exploration Missions 1 and 2 (EM-1 and EM-2) have now been at the forefront of the mission design focus for the last several years. During that time, different Design Reference Missions (DRMs) were built, analyzed, and modified to solve or mitigate enterprise level design trades to ensure a viable mission from launch to landing. The resulting DRMs for EM-1 and EM-2 were then expanded into multi-year trajectory scans to characterize vehicle performance as affected by variations in Earth-Moon geometry. This provides Orion’s subsystems with stressing reference trajectories to help design their system. Now that Orion has progressed through the Preliminary and Critical Design Reviews (PDR and CDR), there is a general shift in the focus of mission design from aiding the vehicle design to providing mission specific products needed for pre-flight and real time operations. Some of the mission specific products needed include, large quantities of nominal trajectories for multiple monthly launch periods and abort options at any point in the mission for each valid trajectory in the launch window.

  16. Constraint-based scheduling applying constraint programming to scheduling problems

    CERN Document Server

    Baptiste, Philippe; Nuijten, Wim

    2001-01-01

    Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...

  17. Mission operations management

    Science.gov (United States)

    Rocco, David A.

    1994-01-01

    Redefining the approach and philosophy that operations management uses to define, develop, and implement space missions will be a central element in achieving high efficiency mission operations for the future. The goal of a cost effective space operations program cannot be realized if the attitudes and methodologies we currently employ to plan, develop, and manage space missions do not change. A management philosophy that is in synch with the environment in terms of budget, technology, and science objectives must be developed. Changing our basic perception of mission operations will require a shift in the way we view the mission. This requires a transition from current practices of viewing the mission as a unique end product, to a 'mission development concept' built on the visualization of the end-to-end mission. To achieve this change we must define realistic mission success criteria and develop pragmatic approaches to achieve our goals. Custom mission development for all but the largest and most unique programs is not practical in the current budget environment, and we simply do not have the resources to implement all of our planned science programs. We need to shift our management focus to allow us the opportunity make use of methodologies and approaches which are based on common building blocks that can be utilized in the space, ground, and mission unique segments of all missions.

  18. Constraints on Dbar uplifts

    International Nuclear Information System (INIS)

    Alwis, S.P. de

    2016-01-01

    We discuss constraints on KKLT/KKLMMT and LVS scenarios that use anti-branes to get an uplift to a deSitter vacuum, coming from requiring the validity of an effective field theory description of the physics. We find these are not always satisfied or are hard to satisfy.

  19. Ecosystems emerging. 5: Constraints

    Czech Academy of Sciences Publication Activity Database

    Patten, B. C.; Straškraba, Milan; Jorgensen, S. E.

    2011-01-01

    Roč. 222, č. 16 (2011), s. 2945-2972 ISSN 0304-3800 Institutional research plan: CEZ:AV0Z50070508 Keywords : constraint * epistemic * ontic Subject RIV: EH - Ecology, Behaviour Impact factor: 2.326, year: 2011 http://www.sciencedirect.com/science/article/pii/S0304380011002274

  20. Constraints and Ambiguity

    DEFF Research Database (Denmark)

    Dove, Graham; Biskjær, Michael Mose; Lundqvist, Caroline Emilie

    2017-01-01

    groups of students building three models each. We studied groups building with traditional plastic bricks and also using a digital environment. The building tasks students undertake, and our subsequent analysis, are informed by the role constraints and ambiguity play in creative processes. Based...

  1. Computer graphics aid mission operations. [NASA missions

    Science.gov (United States)

    Jeletic, James F.

    1990-01-01

    The application of computer graphics techniques in NASA space missions is reviewed. Telemetric monitoring of the Space Shuttle and its components is discussed, noting the use of computer graphics for real-time visualization problems in the retrieval and repair of the Solar Maximum Mission. The use of the world map display for determining a spacecraft's location above the earth and the problem of verifying the relative position and orientation of spacecraft to celestial bodies are examined. The Flight Dynamics/STS Three-dimensional Monitoring System and the Trajectroy Computations and Orbital Products System world map display are described, emphasizing Space Shuttle applications. Also, consideration is given to the development of monitoring systems such as the Shuttle Payloads Mission Monitoring System and the Attitude Heads-Up Display and the use of the NASA-Goddard Two-dimensional Graphics Monitoring System during Shuttle missions and to support the Hubble Space Telescope.

  2. On relaxing the Mangasarian-Fromovitz constraint qualification

    Czech Academy of Sciences Publication Activity Database

    Kruger, A.Y.; Minchenko, L.; Outrata, Jiří

    2014-01-01

    Roč. 18, č. 1 (2014), s. 171-189 ISSN 1385-1292 R&D Projects: GA ČR GAP402/12/1309 Institutional support: RVO:67985556 Keywords : Nonlinear programming * Regularity conditions * Constraint qualifications * Lagrange multipliers * Mangasarian–Fromovitz constraint qualification * Constant rank constraint qualification Subject RIV: BA - General Mathematics Impact factor: 0.679, year: 2014 http://library.utia.cas.cz/separaty/2014/MTR/outrata-0426110.pdf

  3. Confluence Modulo Equivalence in Constraint Handling Rules

    DEFF Research Database (Denmark)

    Christiansen, Henning; Kirkeby, Maja Hanne

    2015-01-01

    Previous results on confluence for Constraint Handling Rules, CHR, are generalized to take into account user-defined state equivalence relations. This allows a much larger class of programs to enjoy the advantages of confluence, which include various optimization techniques and simplified...

  4. Constraints on low energy Compton scattering amplitudes

    International Nuclear Information System (INIS)

    Raszillier, I.

    1979-04-01

    We derive the constraints and correlations of fairly general type for Compton scattering amplitudes at energies below photoproduction threshold and fixed momentum transfer, following from (an upper bound on) the corresponding differential cross section above photoproduction threshold. The derivation involves the solution of an extremal problem in a certain space of vector - valued analytic functions. (author)

  5. Confluence Modulo Equivalence in Constraint Handling Rules

    DEFF Research Database (Denmark)

    Christiansen, Henning; Kirkeby, Maja Hanne

    2014-01-01

    Previous results on confluence for Constraint Handling Rules, CHR, are generalized to take into account user-defined state equivalence relations. This allows a much larger class of programs to enjoy the ad- vantages of confluence, which include various optimization techniques and simplified...

  6. The Mission Operations Planning Assistant

    Science.gov (United States)

    Schuetzle, James G.

    1987-01-01

    The Mission Operations Planning Assistant (MOPA) is a knowledge-based system developed to support the planning and scheduling of instrument activities on the Upper Atmospheric Research Satellite (UARS). The MOPA system represents and maintains instrument plans at two levels of abstraction in order to keep plans comprehensible to both UARS Principal Investigators and Command Management personnel. The hierarchical representation of plans also allows MOPA to automatically create detailed instrument activity plans from which spacecraft command loads may be generated. The MOPA system was developed on a Symbolics 3640 computer using the ZetaLisp and ART languages. MOPA's features include a textual and graphical interface for plan inspection and modification, recognition of instrument operational constraint violations during the planning process, and consistency maintenance between the different planning levels. This paper describes the current MOPA system.

  7. Faddeev-Jackiw quantization and constraints

    International Nuclear Information System (INIS)

    Barcelos-Neto, J.; Wotzasek, C.

    1992-01-01

    In a recent Letter, Faddeev and Jackiw have shown that the reduction of constrained systems into its canonical, first-order form, can bring some new insight into the research of this field. For sympletic manifolds the geometrical structure, called Dirac or generalized bracket, is obtained directly from the inverse of the nonsingular sympletic two-form matrix. In the cases of nonsympletic manifolds, this two-form is degenerated and cannot be inverted to provide the generalized brackets. This singular behavior of the sympletic matrix is indicative of the presence of constraints that have to be carefully considered to yield to consistent results. One has two possible routes to treat this problem: Dirac has taught us how to implement the constraints into the potential part (Hamiltonian) of the canonical Lagrangian, leading to the well-known Dirac brackets, which are consistent with the constraints and can be mapped into quantum commutators (modulo ordering terms). The second route, suggested by Faddeev and Jackiw, and followed in this paper, is to implement the constraints directly into the canonical part of the first order Lagrangian, using the fact that the consistence condition for the stability of the constrained manifold is linear in the time derivative. This algorithm may lead to an invertible two-form sympletic matrix from where the Dirac brackets are readily obtained. This algorithm is used in this paper to investigate some aspects of the quantization of constrained systems with first- and second-class constraints in the sympletic approach

  8. Applications of nuclear reactor power systems to electric propulsion missions.

    Science.gov (United States)

    Schaupp, R. W.; Sawyer, C. D.

    1971-01-01

    The performance of nuclear electric propulsion systems (NEP) has been evaluated for a wide variety of missions in an attempt to establish the commonality of NEP system requirements. Emphasis was given to those requirements and system characteristics that serve as guidelines for current technology development programs. Various interactions and tradeoffs between NEP system and mission parameters are described. The results show that the most significant factors in selecting NEP system size are launch mode (direct or spiral escape) and, to a weaker extent, launch vehicle capability. Other factors such as mission, payload, and thrust time constraints, have little influence, thus allowing one NEP system to be used for many missions. The results indicated that a 100 kWe NEP would be suitable for most direct escape missions and a 250 kWe NEP system would be suitable for more demanding missions that use the spiral escape mode.

  9. Mission analysis report for single-shell tank leakage mitigation

    International Nuclear Information System (INIS)

    Cruse, J.M.

    1994-01-01

    This document provides an analysis of the leakage mitigation mission applicable to past and potential future leakage from the Hanford Site's 149 single-shell high-level waste tanks. This mission is a part of the overall missions of the Westinghouse Hanford Company Tank Waste Remediation System division to remediate the tank waste in a safe and acceptable manner. Systems engineers principles are being applied to this effort. Mission analysis supports early decision making by clearly defining program objectives. This documents identifies the initial conditions and acceptable final conditions, defines the programmatic and physical interfaces and constraints, estimates the resources to carry out the mission, and establishes measures of success. The results of the mission analysis provide a consistent basis for subsequent systems engineering work

  10. Least Squares Problems with Absolute Quadratic Constraints

    Directory of Open Access Journals (Sweden)

    R. Schöne

    2012-01-01

    Full Text Available This paper analyzes linear least squares problems with absolute quadratic constraints. We develop a generalized theory following Bookstein's conic-fitting and Fitzgibbon's direct ellipse-specific fitting. Under simple preconditions, it can be shown that a minimum always exists and can be determined by a generalized eigenvalue problem. This problem is numerically reduced to an eigenvalue problem by multiplications of Givens' rotations. Finally, four applications of this approach are presented.

  11. Planning for Crew Exercise for Deep Space Mission Scenarios

    Science.gov (United States)

    Moore, E. Cherice; Ryder, Jeff

    2015-01-01

    Exercise which is necessary for maintaining crew health on-orbit and preparing the crew for return to 1G can be challenging to incorporate into spaceflight vehicles. Deep space missions will require further understanding of the physiological response to microgravity, understanding appropriate mitigations, and designing the exercise systems to effectively provide mitigations, and integrating effectively into vehicle design with a focus to support planned mission scenarios. Recognizing and addressing the constraints and challenges can facilitate improved vehicle design and exercise system incorporation.

  12. Graphical constraints: a graphical user interface for constraint problems

    OpenAIRE

    Vieira, Nelson Manuel Marques

    2015-01-01

    A constraint satisfaction problem is a classical artificial intelligence paradigm characterized by a set of variables (each variable with an associated domain of possible values), and a set of constraints that specify relations among subsets of these variables. Solutions are assignments of values to all variables that satisfy all the constraints. Many real world problems may be modelled by means of constraints. The range of problems that can use this representation is very diverse and embrace...

  13. q-Virasoro constraints in matrix models

    Energy Technology Data Exchange (ETDEWEB)

    Nedelin, Anton [Dipartimento di Fisica, Università di Milano-Bicocca and INFN, sezione di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Department of Physics and Astronomy, Uppsala university,Box 516, SE-75120 Uppsala (Sweden); Zabzine, Maxim [Department of Physics and Astronomy, Uppsala university,Box 516, SE-75120 Uppsala (Sweden)

    2017-03-20

    The Virasoro constraints play the important role in the study of matrix models and in understanding of the relation between matrix models and CFTs. Recently the localization calculations in supersymmetric gauge theories produced new families of matrix models and we have very limited knowledge about these matrix models. We concentrate on elliptic generalization of hermitian matrix model which corresponds to calculation of partition function on S{sup 3}×S{sup 1} for vector multiplet. We derive the q-Virasoro constraints for this matrix model. We also observe some interesting algebraic properties of the q-Virasoro algebra.

  14. Constraints on hadronically decaying dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Garny, Mathias [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Tran, David [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Minnesota Univ., Minneapolis, MN (United States). School of Physics and Astronomy

    2012-05-15

    We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic dark matter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the dark matter decays into quark-antiquark pairs at leading order.

  15. Constraints on hadronically decaying dark matter

    International Nuclear Information System (INIS)

    Garny, Mathias; Ibarra, Alejandro; Tran, David; Minnesota Univ., Minneapolis, MN

    2012-05-01

    We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic dark matter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the dark matter decays into quark-antiquark pairs at leading order.

  16. Orthology and paralogy constraints: satisfiability and consistency

    OpenAIRE

    Lafond, Manuel; El-Mabrouk, Nadia

    2014-01-01

    Background A variety of methods based on sequence similarity, reconciliation, synteny or functional characteristics, can be used to infer orthology and paralogy relations between genes of a given gene family   G . But is a given set   C of orthology/paralogy constraints possible, i.e., can they simultaneously co-exist in an evolutionary history for   G ? While previous studies have focused on full sets of constraints, here we consider the general case where   C does not necessarily involve a ...

  17. Distance Constraint Satisfaction Problems

    Science.gov (United States)

    Bodirsky, Manuel; Dalmau, Victor; Martin, Barnaby; Pinsker, Michael

    We study the complexity of constraint satisfaction problems for templates Γ that are first-order definable in ({ Z}; {suc}), the integers with the successor relation. Assuming a widely believed conjecture from finite domain constraint satisfaction (we require the tractability conjecture by Bulatov, Jeavons and Krokhin in the special case of transitive finite templates), we provide a full classification for the case that Γ is locally finite (i.e., the Gaifman graph of Γ has finite degree). We show that one of the following is true: The structure Γ is homomorphically equivalent to a structure with a certain majority polymorphism (which we call modular median) and CSP(Γ) can be solved in polynomial time, or Γ is homomorphically equivalent to a finite transitive structure, or CSP(Γ) is NP-complete.

  18. Superconformal Lagrangian without the need to introduce constraints

    International Nuclear Information System (INIS)

    Pilot, C.H.

    1986-01-01

    A field Lagrangian invariant under all the symmetries of the superconformal group has been constructed without the need to introduce constraints on the curvatures. We have thus generalized the action of Townsend, van Nieuwenhuizen, and Kaku. We maintain that any and all constraints on the curvatures should result as a consequence of spontaneous symmetry breaking and not be a priori enforced. 14 refs

  19. A Constraint Model for Constrained Hidden Markov Models

    DEFF Research Database (Denmark)

    Christiansen, Henning; Have, Christian Theil; Lassen, Ole Torp

    2009-01-01

    A Hidden Markov Model (HMM) is a common statistical model which is widely used for analysis of biological sequence data and other sequential phenomena. In the present paper we extend HMMs with constraints and show how the familiar Viterbi algorithm can be generalized, based on constraint solving ...

  20. 76 FR 58776 - U.S. Aerospace Supplier & Investment Mission

    Science.gov (United States)

    2011-09-22

    .... products to enter Canada duty-free and therefore further contributes to the relatively low-cost, low-risk... 7 8:00-8:30 Mission Welcoming Remarks by Consul General/SCO & Mission Logistics Briefing. 8:30-9:30... mission must complete and submit an application form for consideration by the Department of Commerce. All...

  1. Definition phase of Grand Tour missions/radio science investigations study for outer planets missions

    Science.gov (United States)

    Tyler, G. L.

    1972-01-01

    Scientific instrumentation for satellite communication and radio tracking systems in the outer planet exploration mission is discussed. Mission planning considers observations of planetary and satellite-masses, -atmospheres, -magnetic fields, -surfaces, -gravitational fields, solar wind composition, planetary radio emissions, and tests of general relativity in time delay and ray bending experiments.

  2. Integral constraints on perturbations of Robertson-Walker cosmologies

    International Nuclear Information System (INIS)

    Ellis, G.F.R.; Jaklitsch, M.J.

    1989-01-01

    Integral constraints occur in the case of spherically symmetric inhomogeneities in Robertson-Walker universes, and (according to Traschen) in the case of general perturbations of these models. It is shown that these constraints are the same in the case of spherical symmetry, and they are interpreted as 'fitting conditions', that is, as constraints on the background Robertson-Walker model rather than on the nature of inhomogeneities. These integral constraints significantly affect the interpretation of anisotropies in the cosmic microwave background radiation. 22 refs

  3. Space nuclear tug mission applications

    International Nuclear Information System (INIS)

    Hodge, J.R.; Rauen, L.A.

    1996-01-01

    An initial assessment indicates that the NEBA-1 and NEBA-3 bimodal reactor designs can be integrated into a reusable tug which is capable of supporting many missions including GSO delivery, GSO retrieval, lunar trajectory deliveries, interplanetary deliveries, and a variety of satellite servicing. The tug close-quote s nuclear thermal propulsion provides timely transport and payload delivery, with GSO deliveries on the order of 3 endash 7 days. In general, the tug may provide a number of potential benefits to users. The tug may, for example, extend the life of an existing on-orbit spacecraft, boost spacecraft which were not delivered to their operational orbit, offer increased payload capability, or possibly allow payloads to launch on smaller less expensive launch vehicles. Reusing the tug for 5 or 10 missions requires total reactor burn times of 50 and 100 hours, respectively. Shielding, boom structure, and radiator requirements were identified as key factors in the configuration layout. Economic feasibility is still under evaluation, but preliminary estimates indicate that average flight costs may range from $32 M to $34 M for a 10-mission vehicle and from $39 M to $42 M for a 5-mission vehicle. copyright 1996 American Institute of Physics

  4. The STEREO Mission

    CERN Document Server

    2008-01-01

    The STEREO mission uses twin heliospheric orbiters to track solar disturbances from their initiation to 1 AU. This book documents the mission, its objectives, the spacecraft that execute it and the instruments that provide the measurements, both remote sensing and in situ. This mission promises to unlock many of the mysteries of how the Sun produces what has become to be known as space weather.

  5. VEGA Space Mission

    Science.gov (United States)

    Moroz, V.; Murdin, P.

    2000-11-01

    VEGA (mission) is a combined spacecraft mission to VENUS and COMET HALLEY. It was launched in the USSR at the end of 1984. The mission consisted of two identical spacecraft VEGA 1 and VEGA 2. VEGA is an acronym built from the words `Venus' and `Halley' (`Galley' in Russian spelling). The basic design of the spacecraft was the same as has been used many times to deliver Soviet landers and orbiter...

  6. Efficient Searching with Linear Constraints

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff

    2000-01-01

    We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint. This pr...

  7. Deepening Contractions and Collateral Constraints

    DEFF Research Database (Denmark)

    Jensen, Henrik; Ravn, Søren Hove; Santoro, Emiliano

    and occasionally non-binding credit constraints. Easier credit access increases the likelihood that constraints become slack in the face of expansionary shocks, while contractionary shocks are further amplified due to tighter constraints. As a result, busts gradually become deeper than booms. Based...

  8. Fuzzy Constraint-Based Agent Negotiation

    Institute of Scientific and Technical Information of China (English)

    Menq-Wen Lin; K. Robert Lai; Ting-Jung Yu

    2005-01-01

    Conflicts between two or more parties arise for various reasons and perspectives. Thus, resolution of conflicts frequently relies on some form of negotiation. This paper presents a general problem-solving framework for modeling multi-issue multilateral negotiation using fuzzy constraints. Agent negotiation is formulated as a distributed fuzzy constraint satisfaction problem (DFCSP). Fuzzy constrains are thus used to naturally represent each agent's desires involving imprecision and human conceptualization, particularly when lexical imprecision and subjective matters are concerned. On the other hand, based on fuzzy constraint-based problem-solving, our approach enables an agent not only to systematically relax fuzzy constraints to generate a proposal, but also to employ fuzzy similarity to select the alternative that is subject to its acceptability by the opponents. This task of problem-solving is to reach an agreement that benefits all agents with a high satisfaction degree of fuzzy constraints, and move towards the deal more quickly since their search focuses only on the feasible solution space. An application to multilateral negotiation of a travel planning is provided to demonstrate the usefulness and effectiveness of our framework.

  9. Diffusion Processes Satisfying a Conservation Law Constraint

    Directory of Open Access Journals (Sweden)

    J. Bakosi

    2014-01-01

    Full Text Available We investigate coupled stochastic differential equations governing N nonnegative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires a set of fluctuating variables to be nonnegative and (if appropriately normalized sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the nonnegativity and the unit-sum conservation law constraints are satisfied as the variables evolve in time. We investigate the consequences of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.

  10. The Geospace Dynamics Observatory; a mission of discovery for Geospace

    Science.gov (United States)

    Spann, J. F.; Paxton, L.; Burch, J. L.; Reardon, P.; Habash Krause, L.; Gallagher, D. L.; Hopkins, R.

    2013-12-01

    Geospace Dynamics Observatory (GDO) takes advantage a repurposed optical system to provide new, unique, and cost-effective insights into the dynamics of geospace. New missions investigating the ITM system and the magnetospheric-ionospheric coupling processes have generally been very focused on specific phenomena, generally limited by the resource constraints and mission size. Exploring options for observing these regions with instrumentation that is 'non-traditional' is not often considered. The possibility of using very large optics to image Geospace has recently come to the fore. This talk will address the science that would be enabled by flying an ultraviolet telescope imaging the ITM region with an aperture greater than 2 meters. A brief overview of the use of this asset in a science-driven mission concept called the Geospace Dynamics Observatory (GDO) will be presented. This talk will explore the optical and technical aspects of the GDO mission and the implementation strategy. Additionally, the case will be made that GDO will address a significant portion of the priority mission science articulated in the recent Solar and Space Physics Decadal Survey, and provide unprecedented discovery opportunities. One of the problems common to all of geospace research is that of resolving temporal and spatial ambiguities: are the observed changes due the fact that the location of the observation has changed or have the state variables changed? This is a particularly vexing problem for low-cost missions that may have to rely on in situ measurements or other low spatial resolution techniques such as GPS radio occultation. The exceptional capabilities of the GDO mission include (1) unprecedented improvement in signal to noise for global-scale imaging of Earth's space environment that enables changes in the Earth's space environment to be resolved with orders of magnitude higher temporal and spatial resolution compared to existing data and other approaches, and (2) unrivaled

  11. Three level constraints on conformal field theories and string models

    International Nuclear Information System (INIS)

    Lewellen, D.C.

    1989-05-01

    Simple tree level constraints for conformal field theories which follow from the requirement of crossing symmetry of four-point amplitudes are presented, and their utility for probing general properties of string models is briefly illustrated and discussed. 9 refs

  12. Estimating Crustal Properties Directly from Satellite Tracking Data by Using a Topography-based Constraint

    Science.gov (United States)

    Goossens, S. J.; Sabaka, T. J.; Genova, A.; Mazarico, E. M.; Nicholas, J. B.; Neumann, G. A.; Lemoine, F. G.

    2017-12-01

    The crust of a terrestrial planet is formed by differentiation processes in its early history, followed by magmatic evolution of the planetary surface. It is further modified through impact processes. Knowledge of the crustal structure can thus place constraints on the planet's formation and evolution. In particular, the average bulk density of the crust is a fundamental parameter in geophysical studies, such as the determination of crustal thickness, studies of the mechanisms of topography support, and the planet's thermo-chemical evolution. Yet even with in-situ samples available, the crustal density is difficult to determine unambiguously, as exemplified by the results for the Gravity and Recovery Interior Laboratory (GRAIL) mission, which found an average crustal density for the Moon that was lower than generally assumed. The GRAIL results were possible owing to the combination of its high-resolution gravity and high-resolution topography obtained by the Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO), and high correlations between the two datasets. The crustal density can be determined by its contribution to the gravity field of a planet, but at long wavelengths flexure effects can dominate. On the other hand, short-wavelength gravity anomalies are difficult to measure, and either not determined well enough (other than at the Moon), or their power is suppressed by the standard `Kaula' regularization constraint applied during inversion of the gravity field from satellite tracking data. We introduce a new constraint that has infinite variance in one direction, called xa . For constraint damping factors that go to infinity, it can be shown that the solution x becomes equal to a scale factor times xa. This scale factor is completely determined by the data, and we call our constraint rank-minus-1 (RM1). If we choose xa to be topography-induced gravity, then we can estimate the average bulk crustal density directly from the data

  13. Embedding Temporal Constraints For Coordinated Execution in Habitat Automation

    Science.gov (United States)

    Morris, Paul; Schwabacher, Mark; Dalal, Michael; Fry, Charles

    2013-01-01

    Future NASA plans call for long-duration deep space missions with human crews. Because of light-time delay and other considerations, increased autonomy will be needed. This will necessitate integration of tools in such areas as anomaly detection, diagnosis, planning, and execution. In this paper we investigate an approach that integrates planning and execution by embedding planner-derived temporal constraints in an execution procedure. To avoid the need for propagation, we convert the temporal constraints to dispatchable form. We handle some uncertainty in the durations without it affecting the execution; larger variations may cause activities to be skipped.

  14. Generalized isothermic lattices

    International Nuclear Information System (INIS)

    Doliwa, Adam

    2007-01-01

    We study multi-dimensional quadrilateral lattices satisfying simultaneously two integrable constraints: a quadratic constraint and the projective Moutard constraint. When the lattice is two dimensional and the quadric under consideration is the Moebius sphere one obtains, after the stereographic projection, the discrete isothermic surfaces defined by Bobenko and Pinkall by an algebraic constraint imposed on the (complex) cross-ratio of the circular lattice. We derive the analogous condition for our generalized isothermic lattices using Steiner's projective structure of conics, and we present basic geometric constructions which encode integrability of the lattice. In particular, we introduce the Darboux transformation of the generalized isothermic lattice and we derive the corresponding Bianchi permutability principle. Finally, we study two-dimensional generalized isothermic lattices, in particular geometry of their initial boundary value problem

  15. Mission of Mercy.

    Science.gov (United States)

    Humenik, Mark

    2014-01-01

    Some dentists prefer solo charity work, but there is much to be said for collaboration within the profession in reaching out to those who are dentally underserved. Mission of Mercy (MOM) programs are regularly organized across the country for this purpose. This article describes the structure, reach, and personal satisfaction to be gained from such missions.

  16. IAEA '77: between politics and factual constraints

    International Nuclear Information System (INIS)

    Freytag, A.

    1976-01-01

    The IAEA's organization of its 20th General Conference at Rio de Janeiro clearly underlined the importance of a comprehensive international transfer of nuclear technology. Despite all efforts to keep the Agency out of general political confrontations, the Conference was tinged politically by the PLO and South Africa problems. Besides the next five year program, which was agreed upon in the light of existing factual constraints, the support and control functions of the IAEA and next year's Salzburg Fuel Cycle Conference were other main topics of discussion. The 1977 IAEA budget was approved at a level of 43.5 million, the General Fund at 6.5 million. (orig.) [de

  17. Astrometric tests of General Relativity in the Solar system

    International Nuclear Information System (INIS)

    Gai, M; Vecchiato, A; Riva, A; Lattanzi, M G; Sozzetti, A; Crosta, M T; Busonero, D

    2014-01-01

    Micro-arcsec astronomy is able to verify the predictions of theoretical models of gravitation at a level adequate to constraint relevant parameters and select among different formulations. In particular, this concerns the weak field limit applicable to the Sun neighborhood, where competing models can be expressed in a common framework as the Parametrised Post-Newtonian and Parametrised Post-Post-Newtonian formulations. The mission Gaia is going to provide an unprecedented determination of the γ PPN parameter at the 10 −6 level. Other recently proposed concepts, as GAME, may improve the precision on γ by one or two orders of magnitude and provide constraints on other crucial phenomenological aspects. We review the key concepts of astrometric tests of General Relativity and discuss a possible development scenario

  18. Constraint Embedding Technique for Multibody System Dynamics

    Science.gov (United States)

    Woo, Simon S.; Cheng, Michael K.

    2011-01-01

    Multibody dynamics play a critical role in simulation testbeds for space missions. There has been a considerable interest in the development of efficient computational algorithms for solving the dynamics of multibody systems. Mass matrix factorization and inversion techniques and the O(N) class of forward dynamics algorithms developed using a spatial operator algebra stand out as important breakthrough on this front. Techniques such as these provide the efficient algorithms and methods for the application and implementation of such multibody dynamics models. However, these methods are limited only to tree-topology multibody systems. Closed-chain topology systems require different techniques that are not as efficient or as broad as those for tree-topology systems. The closed-chain forward dynamics approach consists of treating the closed-chain topology as a tree-topology system subject to additional closure constraints. The resulting forward dynamics solution consists of: (a) ignoring the closure constraints and using the O(N) algorithm to solve for the free unconstrained accelerations for the system; (b) using the tree-topology solution to compute a correction force to enforce the closure constraints; and (c) correcting the unconstrained accelerations with correction accelerations resulting from the correction forces. This constraint-embedding technique shows how to use direct embedding to eliminate local closure-loops in the system and effectively convert the system back to a tree-topology system. At this point, standard tree-topology techniques can be brought to bear on the problem. The approach uses a spatial operator algebra approach to formulating the equations of motion. The operators are block-partitioned around the local body subgroups to convert them into aggregate bodies. Mass matrix operator factorization and inversion techniques are applied to the reformulated tree-topology system. Thus in essence, the new technique allows conversion of a system with

  19. Cosmographic Constraints and Cosmic Fluids

    Directory of Open Access Journals (Sweden)

    Salvatore Capozziello

    2013-12-01

    Full Text Available The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations of state evolve as the universe expands, giving rise to the accelerated expansion. We describe in detail the ΛCDM (Λ-Cold Dark Matter and ωCDM models, considering also some specific examples, e.g., Chevallier–Polarsky–Linder, the Chaplygin gas and the Dvali–Gabadadze–Porrati cosmological model. Finally, we consider the cosmological consequences of f(R and f(T gravities and their impact on the framework of cosmography. Keeping these considerations in mind, we point out the model-independent procedure related to cosmography, showing how to match the series of cosmological observables to the free parameters of each model. We critically discuss the role played by cosmography, as a selection criterion to check whether a particular model passes or does not present cosmological constraints. In so doing, we find out cosmological bounds by fitting the luminosity distance expansion of the redshift, z, adopting the recent Union 2.1 dataset of supernovae, combined with the baryonic acoustic oscillation and the cosmic microwave background measurements. We perform cosmographic analyses, imposing different priors on the Hubble rate present value. In addition, we compare our results with recent PLANCK limits, showing that the ΛCDM and ωCDM models seem to be the favorite with respect to other dark energy models. However, we show that cosmographic constraints on f(R and f(T cannot discriminate between extensions of General Relativity and dark energy models, leading to a disadvantageous degeneracy problem.

  20. The Effects of Two Levels of Linguistic Constraint on Echolalia and Generative Language Production in Children with Autism.

    Science.gov (United States)

    Rydell, Patrick J.; Mirenda, Pat

    1991-01-01

    This study of 3 boys (ages 5-6) with autism found that adult high-constraint antecedent utterances elicited more verbal utterances in general, including subjects' echolalia; adult low-constraint utterances elicited more subject high-constraint utterances; and the degree of adult-utterance constraint did not influence the mean lengths of subjects'…

  1. Orbital Express mission operations planning and resource management using ASPEN

    Science.gov (United States)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel

    2008-04-01

    As satellite equipment and mission operations become more costly, the drive to keep working equipment running with less labor-power rises. Demonstrating the feasibility of autonomous satellite servicing was the main goal behind the Orbital Express (OE) mission. Like a tow-truck delivering gas to a car on the road, the "servicing" satellite of OE had to find the "client" from several kilometers away, connect directly to the client, and transfer fluid (or a battery) autonomously, while on earth-orbit. The mission met 100% of its success criteria, and proved that autonomous satellite servicing is now a reality for space operations. Planning the satellite mission operations for OE required the ability to create a plan which could be executed autonomously over variable conditions. As the constraints for execution could change weekly, daily, and even hourly, the tools used create the mission execution plans needed to be flexible and adaptable to many different kinds of changes. At the same time, the hard constraints of the plans needed to be maintained and satisfied. The Automated Scheduling and Planning Environment (ASPEN) tool, developed at the Jet Propulsion Laboratory, was used to create the schedule of events in each daily plan for the two satellites of the OE mission. This paper presents an introduction to the ASPEN tool, an overview of the constraints of the OE domain, the variable conditions that were presented within the mission, and the solution to operations that ASPEN provided. ASPEN has been used in several other domains, including research rovers, Deep Space Network scheduling research, and in flight operations for the NASA's Earth Observing One mission's EO1 satellite. Related work is discussed, as are the future of ASPEN and the future of autonomous satellite servicing.

  2. Coverage-based constraints for IMRT optimization

    Science.gov (United States)

    Mescher, H.; Ulrich, S.; Bangert, M.

    2017-09-01

    Radiation therapy treatment planning requires an incorporation of uncertainties in order to guarantee an adequate irradiation of the tumor volumes. In current clinical practice, uncertainties are accounted for implicitly with an expansion of the target volume according to generic margin recipes. Alternatively, it is possible to account for uncertainties by explicit minimization of objectives that describe worst-case treatment scenarios, the expectation value of the treatment or the coverage probability of the target volumes during treatment planning. In this note we show that approaches relying on objectives to induce a specific coverage of the clinical target volumes are inevitably sensitive to variation of the relative weighting of the objectives. To address this issue, we introduce coverage-based constraints for intensity-modulated radiation therapy (IMRT) treatment planning. Our implementation follows the concept of coverage-optimized planning that considers explicit error scenarios to calculate and optimize patient-specific probabilities q(\\hat{d}, \\hat{v}) of covering a specific target volume fraction \\hat{v} with a certain dose \\hat{d} . Using a constraint-based reformulation of coverage-based objectives we eliminate the trade-off between coverage and competing objectives during treatment planning. In-depth convergence tests including 324 treatment plan optimizations demonstrate the reliability of coverage-based constraints for varying levels of probability, dose and volume. General clinical applicability of coverage-based constraints is demonstrated for two cases. A sensitivity analysis regarding penalty variations within this planing study based on IMRT treatment planning using (1) coverage-based constraints, (2) coverage-based objectives, (3) probabilistic optimization, (4) robust optimization and (5) conventional margins illustrates the potential benefit of coverage-based constraints that do not require tedious adjustment of target volume objectives.

  3. Learning With Mixed Hard/Soft Pointwise Constraints.

    Science.gov (United States)

    Gnecco, Giorgio; Gori, Marco; Melacci, Stefano; Sanguineti, Marcello

    2015-09-01

    A learning paradigm is proposed and investigated, in which the classical framework of learning from examples is enhanced by the introduction of hard pointwise constraints, i.e., constraints imposed on a finite set of examples that cannot be violated. Such constraints arise, e.g., when requiring coherent decisions of classifiers acting on different views of the same pattern. The classical examples of supervised learning, which can be violated at the cost of some penalization (quantified by the choice of a suitable loss function) play the role of soft pointwise constraints. Constrained variational calculus is exploited to derive a representer theorem that provides a description of the functional structure of the optimal solution to the proposed learning paradigm. It is shown that such an optimal solution can be represented in terms of a set of support constraints, which generalize the concept of support vectors and open the doors to a novel learning paradigm, called support constraint machines. The general theory is applied to derive the representation of the optimal solution to the problem of learning from hard linear pointwise constraints combined with soft pointwise constraints induced by supervised examples. In some cases, closed-form optimal solutions are obtained.

  4. Future CMB cosmological constraints in a dark coupled universe

    CERN Document Server

    Martinelli, Matteo; Melchiorri, Alessandro; Mena, Olga

    2010-01-01

    Cosmic Microwave Background satellite missions as the on-going Planck experiment are expected to provide the strongest constraints on a wide set of cosmological parameters. Those constraints, however, could be weakened when the assumption of a cosmological constant as the dark energy component is removed. Here we show that it will indeed be the case when there exists a coupling among the dark energy and the dark matter fluids. In particular, the expected errors on key parameters as the cold dark matter density and the angular diameter distance at decoupling are significantly larger when a dark coupling is introduced. We show that it will be the case also for future satellite missions as EPIC, unless CMB lensing extraction is performed.

  5. Supergravity constraints on monojets

    International Nuclear Information System (INIS)

    Nandi, S.

    1986-01-01

    In the standard model, supplemented by N = 1 minimal supergravity, all the supersymmetric particle masses can be expressed in terms of a few unknown parameters. The resulting mass relations, and the laboratory and the cosmological bounds on these superpartner masses are used to put constraints on the supersymmetric origin of the CERN monojets. The latest MAC data at PEP excludes the scalar quarks, of masses up to 45 GeV, as the origin of these monojets. The cosmological bounds, for a stable photino, excludes the mass range necessary for the light gluino-heavy squark production interpretation. These difficulties can be avoided by going beyond the minimal supergravity theory. Irrespective of the monojets, the importance of the stable γ as the source of the cosmological dark matter is emphasized

  6. EUCLID mission design

    Science.gov (United States)

    Wallner, Oswald; Ergenzinger, Klaus; Tuttle, Sean; Vaillon, L.; Johann, Ulrich

    2017-11-01

    EUCLID, a medium-class mission candidate of ESA's Cosmic Vision 2015-2025 Program, currently in Definition Phase (Phase A/B1), shall map the geometry of the Dark Universe by investigating dark matter distributions, the distance-redshift relationship, and the evolution of cosmic structures. EUCLID consists of a 1.2 m telescope and two scientific instruments for ellipticity and redshift measurements in the visible and nearinfrared wavelength regime. We present a design concept of the EUCLID mission which is fully compliant with the mission requirements. Preliminary concepts of the spacecraft and of the payload including the scientific instruments are discussed.

  7. Advances in Distributed Operations and Mission Activity Planning for Mars Surface Exploration

    Science.gov (United States)

    Fox, Jason M.; Norris, Jeffrey S.; Powell, Mark W.; Rabe, Kenneth J.; Shams, Khawaja

    2006-01-01

    A centralized mission activity planning system for any long-term mission, such as the Mars Exploration Rover Mission (MER), is completely infeasible due to budget and geographic constraints. A distributed operations system is key to addressing these constraints; therefore, future system and software engineers must focus on the problem of how to provide a secure, reliable, and distributed mission activity planning system. We will explain how Maestro, the next generation mission activity planning system, with its heavy emphasis on portability and distributed operations has been able to meet these design challenges. MER has been an excellent proving ground for Maestro's new approach to distributed operations. The backend that has been developed for Maestro could benefit many future missions by reducing the cost of centralized operations system architecture.

  8. Hipparcos: mission accomplished

    Science.gov (United States)

    1993-08-01

    satellite. These catalogues will be of enormous value in astronomers' attempts to understand and describe the properties and evolution of stars, and the dynamical motion of these stars within our Galaxy. In the process, HIPPARCOS has discovered many thousands of new binary star systems, measured the precise light variations of many hundreds of thousands of stars over its operational lifetime, and has provided an accurate and independent validation of the predictions of General Relativity. Scientists working with ESA on the HIPPARCOS programme, were at ESOC on 13-14 July to review the progress of the data processing, and to examine whether any further efforts might allow the satellite to continue operating. "All of us are sorry to see the end of this remarkable satellite" said Dr. Michael Perryman, ESA scientist responsible for HIPPARCOS, "On the other end, we are delighted that it has delivered substantially more than it had been originally designed for. When our final results are published, some very interesting new insights into the nature of our Galaxy, its structure and its evolution, will emerge" he added. A large team of scientists from the various ESA member states are responsible for the analysis and interpretation of the vast amount of data that has been generated by the HIPPARCOS satellite, in what is considered to be the largest single data processing challenge ever undertaken in astronomy. Working with ESA since the time of the mission acceptance in 1980, their immediate work will only end with the publication of the HIPPARCOS and Tycho Star Catalogues later this decade. Only then will an astrophysical exploitation of the results commence. Proposals have already been submitted to ESA to follow up its successful breakthrough into space astrometry with new missions proposed for launch early in the next millennium. Note for Editors : The Hipparcos mission was accepted within the ESA mandatory scientific programme in 1980. With overall management by ESA, the system

  9. On the constraints violation in forward dynamics of multibody systems

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Filipe [University of Minho, Department of Mechanical Engineering (Portugal); Souto, António P. [University of Minho, Department of Textile Engineering (Portugal); Flores, Paulo, E-mail: pflores@dem.uminho.pt [University of Minho, Department of Mechanical Engineering (Portugal)

    2017-04-15

    It is known that the dynamic equations of motion for constrained mechanical multibody systems are frequently formulated using the Newton–Euler’s approach, which is augmented with the acceleration constraint equations. This formulation results in the establishment of a mixed set of partial differential and algebraic equations, which are solved in order to predict the dynamic behavior of general multibody systems. The classical solution of the equations of motion is highly prone to constraints violation because the position and velocity constraint equations are not fulfilled. In this work, a general and comprehensive methodology to eliminate the constraints violation at the position and velocity levels is offered. The basic idea of the described approach is to add corrective terms to the position and velocity vectors with the intent to satisfy the corresponding kinematic constraint equations. These corrective terms are evaluated as a function of the Moore–Penrose generalized inverse of the Jacobian matrix and of the kinematic constraint equations. The described methodology is embedded in the standard method to solve the equations of motion based on the technique of Lagrange multipliers. Finally, the effectiveness of the described methodology is demonstrated through the dynamic modeling and simulation of different planar and spatial multibody systems. The outcomes in terms of constraints violation at the position and velocity levels, conservation of the total energy and computational efficiency are analyzed and compared with those obtained with the standard Lagrange multipliers method, the Baumgarte stabilization method, the augmented Lagrangian formulation, the index-1 augmented Lagrangian, and the coordinate partitioning method.

  10. Social Constraints on Animate Vision

    National Research Council Canada - National Science Library

    Breazeal, Cynthia; Edsinger, Aaron; Fitzpatrick, Paul; Scassellati, Brian

    2000-01-01

    .... In humanoid robotic systems, or in any animate vision system that interacts with people, social dynamics provide additional levels of constraint and provide additional opportunities for processing economy...

  11. PLA Missions Beyond Taiwan

    National Research Council Canada - National Science Library

    Miller, Marc

    2008-01-01

    KEY INSIGHTS: *The PLA is being assigned and training for an increasing variety of missions, including nontraditional battlefields such as outer space and cyber space, as well as nontraditional functions...

  12. Near-Optimal Fingerprinting with Constraints

    Directory of Open Access Journals (Sweden)

    Gulyás Gábor György

    2016-10-01

    Full Text Available Several recent studies have demonstrated that people show large behavioural uniqueness. This has serious privacy implications as most individuals become increasingly re-identifiable in large datasets or can be tracked, while they are browsing the web, using only a couple of their attributes, called as their fingerprints. Often, the success of these attacks depends on explicit constraints on the number of attributes learnable about individuals, i.e., the size of their fingerprints. These constraints can be budget as well as technical constraints imposed by the data holder. For instance, Apple restricts the number of applications that can be called by another application on iOS in order to mitigate the potential privacy threats of leaking the list of installed applications on a device. In this work, we address the problem of identifying the attributes (e.g., smartphone applications that can serve as a fingerprint of users given constraints on the size of the fingerprint. We give the best fingerprinting algorithms in general, and evaluate their effectiveness on several real-world datasets. Our results show that current privacy guards limiting the number of attributes that can be queried about individuals is insufficient to mitigate their potential privacy risks in many practical cases.

  13. Modifier constraint in alkali borophosphate glasses using topological constraint theory

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zeng, Huidan, E-mail: hdzeng@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Jiang, Qi [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao, Donghui [Unifrax Corporation, Niagara Falls, NY 14305 (United States); Chen, Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Wang, Zhaofeng; Sun, Luyi [Department of Chemical & Biomolecular Engineering and Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States); Chen, Jianding [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-12-01

    In recent years, composition-dependent properties of glasses have been successfully predicted using the topological constraint theory. The constraints of the glass network are derived from two main parts: network formers and network modifiers. The constraints of the network formers can be calculated on the basis of the topological structure of the glass. However, the latter cannot be accurately calculated in this way, because of the existing of ionic bonds. In this paper, the constraints of the modifier ions in phosphate glasses were thoroughly investigated using the topological constraint theory. The results show that the constraints of the modifier ions are gradually increased with the addition of alkali oxides. Furthermore, an improved topological constraint theory for borophosphate glasses is proposed by taking the composition-dependent constraints of the network modifiers into consideration. The proposed theory is subsequently evaluated by analyzing the composition dependence of the glass transition temperature in alkali borophosphate glasses. This method is supposed to be extended to other similar glass systems containing alkali ions.

  14. Human exploration mission studies

    Science.gov (United States)

    Cataldo, Robert L.

    1989-01-01

    The Office of Exploration has established a process whereby all NASA field centers and other NASA Headquarters offices participate in the formulation and analysis of a wide range of mission strategies. These strategies were manifested into specific scenarios or candidate case studies. The case studies provided a systematic approach into analyzing each mission element. First, each case study must address several major themes and rationale including: national pride and international prestige, advancement of scientific knowledge, a catalyst for technology, economic benefits, space enterprise, international cooperation, and education and excellence. Second, the set of candidate case studies are formulated to encompass the technology requirement limits in the life sciences, launch capabilities, space transfer, automation, and robotics in space operations, power, and propulsion. The first set of reference case studies identify three major strategies: human expeditions, science outposts, and evolutionary expansion. During the past year, four case studies were examined to explore these strategies. The expeditionary missions include the Human Expedition to Phobos and Human Expedition to Mars case studies. The Lunar Observatory and Lunar Outpost to Early Mars Evolution case studies examined the later two strategies. This set of case studies established the framework to perform detailed mission analysis and system engineering to define a host of concepts and requirements for various space systems and advanced technologies. The details of each mission are described and, specifically, the results affecting the advanced technologies required to accomplish each mission scenario are presented.

  15. Missions to Venus

    Science.gov (United States)

    Titov, D. V.; Baines, K. H.; Basilevsky, A. T.; Chassefiere, E.; Chin, G.; Crisp, D.; Esposito, L. W.; Lebreton, J.-P.; Lellouch, E.; Moroz, V. I.; Nagy, A. F.; Owen, T. C.; Oyama, K.-I.; Russell, C. T.; Taylor, F. W.; Young, R. E.

    2002-10-01

    Venus has always been a fascinating objective for planetary studies. At the beginning of the space era Venus became one of the first targets for spacecraft missions. Our neighbour in the solar system and, in size, the twin sister of Earth, Venus was expected to be very similar to our planet. However, the first phase of Venus spacecraft exploration in 1962-1992 by the family of Soviet Venera and Vega spacecraft and US Mariner, Pioneer Venus, and Magellan missions discovered an entirely different, exotic world hidden behind a curtain of dense clouds. These studies gave us a basic knowledge of the conditions on the planet, but generated many more questions concerning the atmospheric composition, chemistry, structure, dynamics, surface-atmosphere interactions, atmospheric and geological evolution, and the plasma environment. Despite all of this exploration by more than 20 spacecraft, the "morning star" still remains a mysterious world. But for more than a decade Venus has been a "forgotten" planet with no new missions featuring in the plans of the world space agencies. Now we are witnessing the revival of interest in this planet: the Venus Orbiter mission is approved in Japan, Venus Express - a European orbiter mission - has successfully passed the selection procedure in ESA, and several Venus Discovery proposals are knocking at the doors of NASA. The paper presents an exciting story of Venus spacecraft exploration, summarizes open scientific problems, and builds a bridge to the future missions.

  16. Automatic Verification of Timing Constraints for Safety Critical Space Systems

    Science.gov (United States)

    Fernandez, Javier; Parra, Pablo; Sanchez Prieto, Sebastian; Polo, Oscar; Bernat, Guillem

    2015-09-01

    In this paper is presented an automatic process of verification. We focus in the verification of scheduling analysis parameter. This proposal is part of process based on Model Driven Engineering to automate a Verification and Validation process of the software on board of satellites. This process is implemented in a software control unit of the energy particle detector which is payload of Solar Orbiter mission. From the design model is generated a scheduling analysis model and its verification model. The verification as defined as constraints in way of Finite Timed Automatas. When the system is deployed on target the verification evidence is extracted as instrumented points. The constraints are fed with the evidence, if any of the constraints is not satisfied for the on target evidence the scheduling analysis is not valid.

  17. Seismological Constraints on Geodynamics

    Science.gov (United States)

    Lomnitz, C.

    2004-12-01

    Earth is an open thermodynamic system radiating heat energy into space. A transition from geostatic earth models such as PREM to geodynamical models is needed. We discuss possible thermodynamic constraints on the variables that govern the distribution of forces and flows in the deep Earth. In this paper we assume that the temperature distribution is time-invariant, so that all flows vanish at steady state except for the heat flow Jq per unit area (Kuiken, 1994). Superscript 0 will refer to the steady state while x denotes the excited state of the system. We may write σ 0=(J{q}0ṡX{q}0)/T where Xq is the conjugate force corresponding to Jq, and σ is the rate of entropy production per unit volume. Consider now what happens after the occurrence of an earthquake at time t=0 and location (0,0,0). The earthquake introduces a stress drop Δ P(x,y,z) at all points of the system. Response flows are directed along the gradients toward the epicentral area, and the entropy production will increase with time as (Prigogine, 1947) σ x(t)=σ 0+α {1}/(t+β )+α {2}/(t+β )2+etc A seismological constraint on the parameters may be obtained from Omori's empirical relation N(t)=p/(t+q) where N(t) is the number of aftershocks at time t following the main shock. It may be assumed that p/q\\sim\\alpha_{1}/\\beta times a constant. Another useful constraint is the Mexican-hat geometry of the seismic transient as obtained e.g. from InSAR radar interferometry. For strike-slip events such as Landers the distribution of \\DeltaP is quadrantal, and an oval-shaped seismicity gap develops about the epicenter. A weak outer triggering maxiμm is found at a distance of about 17 fault lengths. Such patterns may be extracted from earthquake catalogs by statistical analysis (Lomnitz, 1996). Finally, the energy of the perturbation must be at least equal to the recovery energy. The total energy expended in an aftershock sequence can be found approximately by integrating the local contribution over

  18. A comparison of Heuristic method and Llewellyn’s rules for identification of redundant constraints

    Science.gov (United States)

    Estiningsih, Y.; Farikhin; Tjahjana, R. H.

    2018-03-01

    Important techniques in linear programming is modelling and solving practical optimization. Redundant constraints are consider for their effects on general linear programming problems. Identification and reduce redundant constraints are for avoidance of all the calculations associated when solving an associated linear programming problems. Many researchers have been proposed for identification redundant constraints. This paper a compararison of Heuristic method and Llewellyn’s rules for identification of redundant constraints.

  19. Performance deterioration modeling and optimal preventive maintenance strategy under scheduled servicing subject to mission time

    Directory of Open Access Journals (Sweden)

    Li Dawei

    2014-08-01

    Full Text Available Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintenance strategy. In order to model the maintenance effect of servicing, this study analyzes the deterioration characteristics of system under scheduled servicing. And then the deterioration model is established from the failure mechanism by compound Poisson process. On the basis of the system damage value and failure mechanism, the failure rate refresh factor is proposed to describe the maintenance effect of servicing. A maintenance strategy is developed which combines the benefits of scheduled servicing and preventive maintenance. Then the optimization model is given to determine the optimal servicing period and preventive maintenance time, with an objective to minimize the system expected life-cycle cost per unit time and a constraint on system survival probability for the duration of mission time. Subject to mission time, it can control the ability of accomplishing the mission at any time so as to ensure the high dependability. An example of water pump rotor relating to scheduled servicing is introduced to illustrate the failure rate refresh factor and the proposed maintenance strategy. Compared with traditional methods, the numerical results show that the failure rate refresh factor can describe the maintenance effect of servicing more intuitively and objectively. It also demonstrates that this maintenance strategy can prolong the lifetime, reduce the total lifetime maintenance cost and guarantee the dependability of system.

  20. The HAMMER: High altitude multiple mission environmental researcher

    Science.gov (United States)

    Hayashi, Darren; Zylla, Cara; Amaro, Ernesto; Colin, Phil; Klause, Thomas; Lopez, Bernardo; Williamson, Danna

    1991-01-01

    At the equator, the ozone layer ranges from 65,000 to 130,000+ feet which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission which ranges from Chile to the South Pole and back to Chile, a total range of 6000 n. mi. at 100,000 feet with a 2500 lb. payload. The second mission is also a polar mission with a decreased altitude of 70,000 feet and an increased payload of 4000 lb. For the third mission, the aircraft will take-off at NASA Ames, cruise at 100,000 feet carrying a 2500 lb. payload, and land in Puerto Montt, Chile. The final mission requires the aircraft to take-off at NASA Ames, cruise at 100,000 feet with a 1000 lb. payload, make an excursion to 120,000 feet, and land at Howard AFB, Panama. All three missions require that a subsonic Mach number is maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations were determined to be the most suitable for meeting the above requirements. The performance of each configuration is analyzed to investigate the feasibility of the project requirements. In the event that a requirement can not be obtained within the given constraints, recommendations for proposal modifications are given.

  1. Mean-Reverting Portfolio With Budget Constraint

    Science.gov (United States)

    Zhao, Ziping; Palomar, Daniel P.

    2018-05-01

    This paper considers the mean-reverting portfolio design problem arising from statistical arbitrage in the financial markets. We first propose a general problem formulation aimed at finding a portfolio of underlying component assets by optimizing a mean-reversion criterion characterizing the mean-reversion strength, taking into consideration the variance of the portfolio and an investment budget constraint. Then several specific problems are considered based on the general formulation, and efficient algorithms are proposed. Numerical results on both synthetic and market data show that our proposed mean-reverting portfolio design methods can generate consistent profits and outperform the traditional design methods and the benchmark methods in the literature.

  2. MMPM - Mars MetNet Precursor Mission

    Science.gov (United States)

    Harri, A.-M.; Schmidt, W.; Pichkhadze, K.; Linkin, V.; Vazquez, L.; Uspensky, M.; Polkko, J.; Genzer, M.; Lipatov, A.; Guerrero, H.; Alexashkin, S.; Haukka, H.; Savijarvi, H.; Kauhanen, J.

    2008-09-01

    MetNet Mars Mission will provide a crucial support for the safety of large landing missions in general and manned Mars missions in particular. Accurate knowledge of atmospheric conditions and weather data is essential to guarantee safe landings of the forthcoming Mars mission elements. The MetNet Mars Mission is exactly this type of tool that is needed both for the Martian atmospheric science as well as for the mission safety issues.

  3. Observational constraints on interstellar chemistry

    International Nuclear Information System (INIS)

    Winnewisser, G.

    1984-01-01

    The author points out presently existing observational constraints in the detection of interstellar molecular species and the limits they may cast on our knowledge of interstellar chemistry. The constraints which arise from the molecular side are summarised and some technical difficulties encountered in detecting new species are discussed. Some implications for our understanding of molecular formation processes are considered. (Auth.)

  4. Market segmentation using perceived constraints

    Science.gov (United States)

    Jinhee Jun; Gerard Kyle; Andrew Mowen

    2008-01-01

    We examined the practical utility of segmenting potential visitors to Cleveland Metroparks using their constraint profiles. Our analysis identified three segments based on their scores on the dimensions of constraints: Other priorities--visitors who scored the highest on 'other priorities' dimension; Highly Constrained--visitors who scored relatively high on...

  5. Fixed Costs and Hours Constraints

    Science.gov (United States)

    Johnson, William R.

    2011-01-01

    Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…

  6. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjær, Michael Mose

    2013-01-01

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due to n...

  7. Constraint Programming for Context Comprehension

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    A close similarity is demonstrated between context comprehension, such as discourse analysis, and constraint programming. The constraint store takes the role of a growing knowledge base learned throughout the discourse, and a suitable con- straint solver does the job of incorporating new pieces...

  8. Pairwise Constraint-Guided Sparse Learning for Feature Selection.

    Science.gov (United States)

    Liu, Mingxia; Zhang, Daoqiang

    2016-01-01

    Feature selection aims to identify the most informative features for a compact and accurate data representation. As typical supervised feature selection methods, Lasso and its variants using L1-norm-based regularization terms have received much attention in recent studies, most of which use class labels as supervised information. Besides class labels, there are other types of supervised information, e.g., pairwise constraints that specify whether a pair of data samples belong to the same class (must-link constraint) or different classes (cannot-link constraint). However, most of existing L1-norm-based sparse learning methods do not take advantage of the pairwise constraints that provide us weak and more general supervised information. For addressing that problem, we propose a pairwise constraint-guided sparse (CGS) learning method for feature selection, where the must-link and the cannot-link constraints are used as discriminative regularization terms that directly concentrate on the local discriminative structure of data. Furthermore, we develop two variants of CGS, including: 1) semi-supervised CGS that utilizes labeled data, pairwise constraints, and unlabeled data and 2) ensemble CGS that uses the ensemble of pairwise constraint sets. We conduct a series of experiments on a number of data sets from University of California-Irvine machine learning repository, a gene expression data set, two real-world neuroimaging-based classification tasks, and two large-scale attribute classification tasks. Experimental results demonstrate the efficacy of our proposed methods, compared with several established feature selection methods.

  9. Mission operations technology

    Science.gov (United States)

    Varsi, Giulio

    In the last decade, the operation of a spacecraft after launch has emerged as a major component of the total cost of the mission. This trend is sustained by the increasing complexity, flexibility, and data gathering capability of the space assets and by their greater reliability and consequent longevity. The trend can, however, be moderated by the progressive transfer of selected functions from the ground to the spacecraft and by application, on the ground, of new technology. Advances in ground operations derive from the introduction in the mission operations environment of advanced microprocessor-based workstations in the class of a few million instructions per second and from the selective application of artificial intelligence technology. In the last few years a number of these applications have been developed, tested in operational settings and successfully demonstrated to users. Some are now being integrated in mission operations facilities. An analysis of mission operations indicates that the key areas are: concurrent control of multiple missions; automated/interactive production of command sequences of high integrity at low cost; automated monitoring of spacecraft health and automated aides for fault diagnosis; automated allocation of resources; automated processing of science data; and high-fidelity, high-speed spacecraft simulation. Examples of major advances in selected areas are described.

  10. Algorithms and ordering heuristics for distributed constraint satisfaction problems

    CERN Document Server

    Wahbi , Mohamed

    2013-01-01

    DisCSP (Distributed Constraint Satisfaction Problem) is a general framework for solving distributed problems arising in Distributed Artificial Intelligence.A wide variety of problems in artificial intelligence are solved using the constraint satisfaction problem paradigm. However, there are several applications in multi-agent coordination that are of a distributed nature. In this type of application, the knowledge about the problem, that is, variables and constraints, may be logically or geographically distributed among physical distributed agents. This distribution is mainly due to p

  11. Exact penalty results for mathematical programs with vanishing constraints

    Czech Academy of Sciences Publication Activity Database

    Hoheisel, T.; Kanzow, Ch.; Outrata, Jiří

    2010-01-01

    Roč. 72, č. 5 (2010), s. 2514-2526 ISSN 0362-546X R&D Projects: GA AV ČR IAA100750802 Institutional research plan: CEZ:AV0Z10750506 Keywords : Mathematical programs with vanishing constraints * Mathematical programs with equilibrium constraints * Exact penalization * Calmness * Subdifferential calculus * Limiting normal cone Subject RIV: BA - General Mathematics Impact factor: 1.279, year: 2010 http://library.utia.cas.cz/separaty/2010/MTR/outrata-exact penalty results for mathematical programs with vanishing constraints.pdf

  12. The poloidal OHM's law and a profile constraint in tokamaks

    International Nuclear Information System (INIS)

    Segre, S.E.; Zanza, V.

    1991-01-01

    Explicit use of the poloidal Ohm's law, together with the radial plasma velocity (obtained from the distribution of plasma sources), leads to a very general constraint on the possible radial profiles of plasma density and temperature. The constraint does not require any ad hoc assumption; it can place severe restrictions on the allowed profiles and is independent of energy and particle transport; also, it may be the underlying principle of profile consistency. The constraint is discussed in the framework of neoclassical theory, using results from the Frascati tokamak. (author). 23 refs, 7 figs

  13. About some types of constraints in problems of routing

    Science.gov (United States)

    Petunin, A. A.; Polishuk, E. G.; Chentsov, A. G.; Chentsov, P. A.; Ukolov, S. S.

    2016-12-01

    Many routing problems arising in different applications can be interpreted as a discrete optimization problem with additional constraints. The latter include generalized travelling salesman problem (GTSP), to which task of tool routing for CNC thermal cutting machines is sometimes reduced. Technological requirements bound to thermal fields distribution during cutting process are of great importance when developing algorithms for this task solution. These requirements give rise to some specific constraints for GTSP. This paper provides a mathematical formulation for the problem of thermal fields calculating during metal sheet thermal cutting. Corresponding algorithm with its programmatic implementation is considered. The mathematical model allowing taking such constraints into account considering other routing problems is discussed either.

  14. Linear Temporal Logic-based Mission Planning

    Directory of Open Access Journals (Sweden)

    Anil Kumar

    2016-06-01

    Full Text Available In this paper, we describe the Linear Temporal Logic-based reactive motion planning. We address the problem of motion planning for mobile robots, wherein the goal specification of planning is given in complex environments. The desired task specification may consist of complex behaviors of the robot, including specifications for environment constraints, need of task optimality, obstacle avoidance, rescue specifications, surveillance specifications, safety specifications, etc. We use Linear Temporal Logic to give a representation for such complex task specification and constraints. The specifications are used by a verification engine to judge the feasibility and suitability of plans. The planner gives a motion strategy as output. Finally a controller is used to generate the desired trajectory to achieve such a goal. The approach is tested using simulations on the LTLMoP mission planning tool, operating over the Robot Operating System. Simulation results generated using high level planners and low level controllers work simultaneously for mission planning and controlling the physical behavior of the robot.

  15. Microbial diversity arising from thermodynamic constraints

    Science.gov (United States)

    Großkopf, Tobias; Soyer, Orkun S

    2016-01-01

    The microbial world displays an immense taxonomic diversity. This diversity is manifested also in a multitude of metabolic pathways that can utilise different substrates and produce different products. Here, we propose that these observations directly link to thermodynamic constraints that inherently arise from the metabolic basis of microbial growth. We show that thermodynamic constraints can enable coexistence of microbes that utilise the same substrate but produce different end products. We find that this thermodynamics-driven emergence of diversity is most relevant for metabolic conversions with low free energy as seen for example under anaerobic conditions, where population dynamics is governed by thermodynamic effects rather than kinetic factors such as substrate uptake rates. These findings provide a general understanding of the microbial diversity based on the first principles of thermodynamics. As such they provide a thermodynamics-based framework for explaining the observed microbial diversity in different natural and synthetic environments. PMID:27035705

  16. Microbial diversity arising from thermodynamic constraints.

    Science.gov (United States)

    Großkopf, Tobias; Soyer, Orkun S

    2016-11-01

    The microbial world displays an immense taxonomic diversity. This diversity is manifested also in a multitude of metabolic pathways that can utilise different substrates and produce different products. Here, we propose that these observations directly link to thermodynamic constraints that inherently arise from the metabolic basis of microbial growth. We show that thermodynamic constraints can enable coexistence of microbes that utilise the same substrate but produce different end products. We find that this thermodynamics-driven emergence of diversity is most relevant for metabolic conversions with low free energy as seen for example under anaerobic conditions, where population dynamics is governed by thermodynamic effects rather than kinetic factors such as substrate uptake rates. These findings provide a general understanding of the microbial diversity based on the first principles of thermodynamics. As such they provide a thermodynamics-based framework for explaining the observed microbial diversity in different natural and synthetic environments.

  17. Neutrino mass constraints on β decay

    International Nuclear Information System (INIS)

    Ito, Takeyasu M.; Prezeau, Gary

    2005-01-01

    Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-standard-model interactions that can generate loop corrections to the neutrino mass, we derive constraints on some non-standard-model d→ue - ν interactions. When cast into limits on n→pe - ν coupling constants, our results yield constraints on scalar and tensor weak interactions improved by more than an order of magnitude over the current experimental limits. When combined with the existing limits, our results yield vertical bar C S /C V vertical bar or approx. 5x10 -3 , vertical bar C S ' /C V vertical bar or approx. 5x10 -3 , vertical bar C T /C A vertical bar -2 , and vertical bar C T ' /C A vertical bar -2

  18. It Takes a Village. Collaborative Outer Planet Missions

    Science.gov (United States)

    Rymer, A. M.; Turtle, E. P.; Hofstadter, M. D.; Simon, A. A.; Hospodarsky, G. B.

    2017-01-01

    A mission to one or both of our local Ice Giants (Uranus and Neptune) emerged as a high priority in the most recent Planetary Science Decadal Survey and was also specifically mentioned supportively in the Heliophysics Decadal Survey. In 2016, NASA convened a science definition team to study ice giant mission concepts in more detail. Uranus and Neptune represent the last remaining planetary type in our Solar System to have a dedicated orbiting mission. The case for a Uranus mission has been made eloquently in the Decadal Surveys. Here we summarize some of the major drivers that lead to enthusiastic support for an Ice Giant mission in general, and use the example of a Uranus Mission concept to illustrate opportunities such a mission might provide for cross-division collaboration and cost-sharing.

  19. Mission to the comets

    International Nuclear Information System (INIS)

    Hughes, D.

    1980-01-01

    The plans of space agencies in the United States and Europe for an exploratory comet mission including a one year rendezvous with comet Temple-2 and a fast fly-by of comet Halley are discussed. The mission provides an opportunity to make comparative measurements on the two different types of comets and also satisfies the three major scientific objectives of cometary missions namely: (1) To determine the chemical nature and the physical structure of cometary nuclei, and the changes that occur with time and orbital position. (2) To study the chemical and physical nature of the atmospheres and ionospheres of comets, the processes that occur in them, and their development with time and orbital position. (3) To determine the nature of the tails of comets and the processes by which they are formed, and to characterise the interaction of comets with solar wind. (UK)

  20. Country programming mission. Namibia

    International Nuclear Information System (INIS)

    1991-01-01

    In response to a request from the Government of Namibia conveyed in a letter dated 29 November 1990 IAEA provided a multi-disciplinary Programming Mission which visited Namibia from 15 - 19 July 1991. The terms of reference of the Mission were: 1. To assess the possibilities and benefits of nuclear energy applications in Namibia's development; 2. To advise on the infrastructure required for nuclear energy projects; 3. To assist in the formulation of project proposals which could be submitted for Agency assistance. This report is based on the findings of the Mission and falls into 3 sections with 8 appendices. The first section is a country profile providing background information, the second section deals with sectorial needs and institutional review of the sectors of agriculture including animal production, life sciences (nuclear medicine and radiotherapy) and radiation protection. The third section includes possible future technical co-operation activities

  1. MIV Project: Mission scenario

    DEFF Research Database (Denmark)

    Ravazzotti, Mariolina T.; Jørgensen, John Leif; Thuesen, Gøsta

    1997-01-01

    Under the ESA contract #11453/95/NL/JG(SC), aiming at assessing the feasibility of Rendez-vous and docking of unmanned spacecrafts, a msiision scenario was defined. This report describes the secquence of manouvres and task allocations for such missions.......Under the ESA contract #11453/95/NL/JG(SC), aiming at assessing the feasibility of Rendez-vous and docking of unmanned spacecrafts, a msiision scenario was defined. This report describes the secquence of manouvres and task allocations for such missions....

  2. Mars Stratigraphy Mission

    Science.gov (United States)

    Budney, C. J.; Miller, S. L.; Cutts, J. A.

    2000-01-01

    The Mars Stratigraphy Mission lands a rover on the surface of Mars which descends down a cliff in Valles Marineris to study the stratigraphy. The rover carries a unique complement of instruments to analyze and age-date materials encountered during descent past 2 km of strata. The science objective for the Mars Stratigraphy Mission is to identify the geologic history of the layered deposits in the Valles Marineris region of Mars. This includes constraining the time interval for formation of these deposits by measuring the ages of various layers and determining the origin of the deposits (volcanic or sedimentary) by measuring their composition and imaging their morphology.

  3. The OICETS mission

    Science.gov (United States)

    Jono, Takashi; Arai, Katsuyoshi

    2017-11-01

    The Optical Inter-orbit Communications Engineering Test Satellite (OICETS) was successfully launched on 23th August 2005 and thrown into a circular orbit at the altitude of 610 km. The main mission is to demonstrate the free-space inter satellite laser communications with the cooperation of the Advanced Relay and Technology Mission (ARTEMIS) geostationary satellite developed by the European Space Agency. This paper presents the overview of the OICETS and laser terminal, a history of international cooperation between Japan Aerospace Exploration Agency (JAXA) and ESA and typical results of the inter-orbit laser communication experiment carried out with ARTEMIS.

  4. An Efficient Energy Constraint Based UAV Path Planning for Search and Coverage

    OpenAIRE

    Gramajo, German; Shankar, Praveen

    2017-01-01

    A path planning strategy for a search and coverage mission for a small UAV that maximizes the area covered based on stored energy and maneuverability constraints is presented. The proposed formulation has a high level of autonomy, without requiring an exact choice of optimization parameters, and is appropriate for real-time implementation. The computed trajectory maximizes spatial coverage while closely satisfying terminal constraints on the position of the vehicle and minimizing the time of ...

  5. Hydrostatic equilibrium of stars without electroneutrality constraint

    Science.gov (United States)

    Krivoruchenko, M. I.; Nadyozhin, D. K.; Yudin, A. V.

    2018-04-01

    The general solution of hydrostatic equilibrium equations for a two-component fluid of ions and electrons without a local electroneutrality constraint is found in the framework of Newtonian gravity theory. In agreement with the Poincaré theorem on analyticity and in the context of Dyson's argument, the general solution is demonstrated to possess a fixed (essential) singularity in the gravitational constant G at G =0 . The regular component of the general solution can be determined by perturbation theory in G starting from a locally neutral solution. The nonperturbative component obtained using the method of Wentzel, Kramers and Brillouin is exponentially small in the inner layers of the star and grows rapidly in the outward direction. Near the surface of the star, both components are comparable in magnitude, and their nonlinear interplay determines the properties of an electro- or ionosphere. The stellar charge varies within the limits of -0.1 to 150 C per solar mass. The properties of electro- and ionospheres are exponentially sensitive to variations of the fluid densities in the central regions of the star. The general solutions of two exactly solvable stellar models without a local electroneutrality constraint are also presented.

  6. Exploration Mission Benefits From Logistics Reduction Technologies

    Science.gov (United States)

    Broyan, James Lee, Jr.; Schlesinger, Thilini; Ewert, Michael K.

    2016-01-01

    Technologies that reduce logistical mass, volume, and the crew time dedicated to logistics management become more important as exploration missions extend further from the Earth. Even modest reductions in logical mass can have a significant impact because it also reduces the packing burden. NASA's Advanced Exploration Systems' Logistics Reduction Project is developing technologies that can directly reduce the mass and volume of crew clothing and metabolic waste collection. Also, cargo bags have been developed that can be reconfigured for crew outfitting and trash processing technologies to increase habitable volume and improve protection against solar storm events are under development. Additionally, Mars class missions are sufficiently distant that even logistics management without resupply can be problematic due to the communication time delay with Earth. Although exploration vehicles are launched with all consumables and logistics in a defined configuration, the configuration continually changes as the mission progresses. Traditionally significant ground and crew time has been required to understand the evolving configuration and locate misplaced items. For key mission events and unplanned contingencies, the crew will not be able to rely on the ground for logistics localization assistance. NASA has been developing a radio frequency identification autonomous logistics management system to reduce crew time for general inventory and enable greater crew self-response to unplanned events when a wide range of items may need to be located in a very short time period. This paper provides a status of the technologies being developed and there mission benefits for exploration missions.

  7. A Lean, Fast Mars Round-trip Mission Architecture: Using Current Technologies for a Human Mission in the 2030s

    Science.gov (United States)

    Bailey, Lora; Folta, David; Barbee, Brent W.; Vaughn, Frank; Kirchman, Frank; Englander, Jacob; Campbell, Bruce; Thronson, Harley; Lin, Tzu Yu

    2013-01-01

    We present a lean fast-transfer architecture concept for a first human mission to Mars that utilizes current technologies and two pivotal parameters: an end-to-end Mars mission duration of approximately one year, and a deep space habitat of approximately 50 metric tons. These parameters were formulated by a 2012 deep space habitat study conducted at the NASA Johnson Space Center (JSC) that focused on a subset of recognized high- engineering-risk factors that may otherwise limit space travel to destinations such as Mars or near-Earth asteroid (NEA)s. With these constraints, we model and promote Mars mission opportunities in the 2030s enabled by a combination of on-orbit staging, mission element pre-positioning, and unique round-trip trajectories identified by state-of-the-art astrodynamics algorithms.

  8. Cosmic microwave background constraints on the tensor-to-scalar ratio

    International Nuclear Information System (INIS)

    Lau King; Tang Jia-Yu; Chu Ming-Chung

    2014-01-01

    One of the main goals of modern cosmic microwave background (CMB) missions is to measure the tensor-to-scalar ratio r accurately to constrain inflation models. Due to ignorance about the reionization history X e (z), this analysis is usually done by assuming an instantaneous reionization X e (z) which, however, can bias the best-fit value of r. Moreover, due to the strong mixing of B-mode and E-mode polarizations in cut-sky measurements, multiplying the sky coverage fraction f sky by the full-sky likelihood would not give satisfactory results. In this work, we forecast constraints on r for the Planck mission taking into account the general reionization scenario and cut-sky effects. Our results show that by applying an N-point interpolation analysis to the reionization history, the bias induced by the assumption of instantaneous reionization is removed and the value of r is constrained within 5% error level, if the true value of r is greater than about 0.1

  9. Robust UAV Mission Planning

    NARCIS (Netherlands)

    Evers, L.; Dollevoet, T.; Barros, A.I.; Monsuur, H.

    2014-01-01

    Unmanned Aerial Vehicles (UAVs) can provide significant contributions to information gathering in military missions. UAVs can be used to capture both full motion video and still imagery of specific target locations within the area of interest. In order to improve the effectiveness of a

  10. Robust UAV mission planning

    NARCIS (Netherlands)

    Evers, L.; Dollevoet, T.; Barros, A.I.; Monsuur, H.

    2011-01-01

    Unmanned Areal Vehicles (UAVs) can provide significant contributions to information gathering in military missions. UAVs can be used to capture both full motion video and still imagery of specific target locations within the area of interest. In order to improve the effectiveness of a reconnaissance

  11. Robust UAV Mission Planning

    NARCIS (Netherlands)

    Evers, L.; Dollevoet, T; Barros, A.I.; Monsuur, H.

    2011-01-01

    Unmanned Aerial Vehicles (UAVs) can provide significant contributions to information gathering in military missions. UAVs can be used to capture both full motion video and still imagery of specific target locations within the area of interest. In order to improve the effectiveness of a

  12. Robust UAV Mission Planning

    NARCIS (Netherlands)

    L. Evers (Lanah); T.A.B. Dollevoet (Twan); A.I. Barros (Ana); H. Monsuur (Herman)

    2011-01-01

    textabstractUnmanned Areal Vehicles (UAVs) can provide significant contributions to information gathering in military missions. UAVs can be used to capture both full motion video and still imagery of specific target locations within the area of interest. In order to improve the effectiveness of a

  13. The Lobster Mission

    Science.gov (United States)

    Barthelmy, Scott

    2011-01-01

    I will give an overview of the Goddard Lobster mission: the science goals, the two instruments, the overall instruments designs, with particular attention to the wide-field x-ray instrument (WFI) using the lobster-eye-like micro-channel optics.

  14. Towards A Shared Mission

    DEFF Research Database (Denmark)

    Staunstrup, Jørgen; Orth Gaarn-Larsen, Carsten

    A mission shared by stakeholders, management and employees is a prerequisite for an engaging dialog about the many and substantial changes and challenges currently facing universities. Too often this essen-tial dialog reveals mistrust and misunderstandings about the role and outcome of the univer......A mission shared by stakeholders, management and employees is a prerequisite for an engaging dialog about the many and substantial changes and challenges currently facing universities. Too often this essen-tial dialog reveals mistrust and misunderstandings about the role and outcome...... on a shared mission aiming at value creation (in the broadest interpretation). One important aspect of choosing value as the cornerstone of the mission of universities is to stress that the outcome is measured by external stakeholders and by their standards. Most of the paper is devoted to discussing value...... it possible to lead through processes that engage and excite while creating transparency and accountability. The paper will be illustrated with examples from Denmark and the Helios initiative taken by the Danish Academy of Technical Sciences (ATV) under the headline “The value creating university – courage...

  15. Titan Orbiter Aerorover Mission

    Science.gov (United States)

    Sittler Jr., E. C.; Acuna, M.; Burchell, M. J.; Coates, A.; Farrell, W.; Flasar, M.; Goldstein, B. E.; Gorevan, S.; Hartle, R. E.; Johnson, W. T. K.

    2001-01-01

    We propose a combined Titan orbiter and Titan Aerorover mission with an emphasis on both in situ and remote sensing measurements of Titan's surface, atmosphere, ionosphere, and magnetospheric interaction. The biological aspect of the Titan environment will be emphasized by the mission (i.e., search for organic materials which may include simple organics to 'amono' analogues of amino acids and possibly more complex, lightening detection and infrared, ultraviolet, and charged particle interactions with Titan's surface and atmosphere). An international mission is assumed to control costs. NASA will provide the orbiter, launch vehicle, DSN coverage and operations, while international partners will provide the Aerorover and up to 30% of the cost for the scientific instruments through collaborative efforts. To further reduce costs we propose a single PI for orbiter science instruments and a single PI for Aerorover science instruments. This approach will provide single command/data and power interface between spacecraft and orbiter instruments that will have redundant central DPU and power converter for their instruments. A similar approach could be used for the Aerorover. The mission profile will be constructed to minimize conflicts between Aerorover science, orbiter radar science, orbiter radio science, orbiter imaging science, and orbiter fields and particles (FP) science. Additional information is contained in the original extended abstract.

  16. The LISA Pathfinder Mission

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    LISA Pathfinder (LPF), the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology validation mission for future spaceborne gravitational wave detectors, such as the proposed eLISA mission. LISA Pathfinder, and its scientific payload - the LISA Technology Package - will test, in flight, the critical technologies required for low frequency gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. LISA Pathfinder is due to be launched in mid-2015, with first results on the performance of the system being available 6 months thereafter.The paper introduces the LISA Pathfinder mission, followed by an explanation of the physical principles of measurement concept and associated hardware. We then provide a detailed discussion of the LISA Technology Package, including both the inertial sensor and interferometric readout. As we approach the launch of the LISA Pathfinder, the focus of the development is shifting towards the science operations and data analysis - this is described in the final section of the paper (paper)

  17. The Gaia mission

    NARCIS (Netherlands)

    Collaboration, Gaia; Prusti, T.; de Bruijne, J. H. J.; Brown, A. G. A.; Vallenari, A.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; Mignard, F.; Milligan, D. J.; Panem, C.; Poinsignon, V.; Pourbaix, D.; Randich, S.; Sarri, G.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Valette, V.; van Leeuwen, F.; Walton, N. A.; Aerts, C.; Arenou, F.; Cropper, M.; Drimmel, R.; Høg, E.; Katz, D.; Lattanzi, M. G.; O'Mullane, W.; Grebel, E. K.; Holland, A. D.; Huc, C.; Passot, X.; Bramante, L.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Hernández, J.; Jean-Antoine-Piccolo, A.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Ordóñez-Blanco, D.; Panuzzo, P.; Portell, J.; Richards, P. J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Torra, J.; Els, S. G.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Lock, T.; Mercier, E.; Altmann, M.; Andrae, R.; Astraatmadja, T. L.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Cowell, S.; Creevey, O.; Cuypers, J.; Davidson, M.; De Ridder, J.; de Torres, A.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Frémat, Y.; García-Torres, M.; Gosset, E.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hauser, M.; Hestroffer, D.; Hodgkin, S. T.; Huckle, H. E.; Hutton, A.; Jasniewicz, G.; Jordan, S.; Kontizas, M.; Korn, A. J.; Lanzafame, A. C.; Manteiga, M.; Moitinho, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Robin, A. C.; Sarro, L. M.; Siopis, C.; Smith, M.; Smith, K. W.; Sozzetti, A.; Thuillot, W.; van Reeven, W.; Viala, Y.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aguado, J. J.; Allan, P. M.; Allasia, W.; Altavilla, G.; Álvarez, M. A.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Antón, S.; Arcay, B.; Atzei, A.; Ayache, L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Barache, C.; Barata, C.; Barbier, A.; Barblan, F.; Baroni, M.; Barrado y Navascués, D.; Barros, M.; Barstow, M. A.; Becciani, U.; Bellazzini, M.; Bellei, G.; Bello García, A.; Belokurov, V.; Bendjoya, P.; Berihuete, A.; Bianchi, L.; Bienaymé, O.; Billebaud, F.; Blagorodnova, N.; Blanco-Cuaresma, S.; Boch, T.; Bombrun, A.; Borrachero, R.; Bouquillon, S.; Bourda, G.; Bouy, H.; Bragaglia, A.; Breddels, M. A.; Brouillet, N.; Brüsemeister, T.; Bucciarelli, B.; Budnik, F.; Burgess, P.; Burgon, R.; Burlacu, A.; Busonero, D.; Buzzi, R.; Caffau, E.; Cambras, J.; Campbell, H.; Cancelliere, R.; Cantat-Gaudin, T.; Carlucci, T.; Carrasco, J. M.; Castellani, M.; Charlot, P.; Charnas, J.; Charvet, P.; Chassat, F.; Chiavassa, A.; Clotet, M.; Cocozza, G.; Collins, R. S.; Collins, P.; Costigan, G.; Crifo, F.; Cross, N. J. G.; Crosta, M.; Crowley, C.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; De Cat, P.; de Felice, F.; de Laverny, P.; De Luise, F.; De March, R.; de Martino, D.; de Souza, R.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; di Marco, F.; Di Matteo, P.; Diakite, S.; Distefano, E.; Dolding, C.; Dos Anjos, S.; Drazinos, P.; Durán, J.; Dzigan, Y.; Ecale, E.; Edvardsson, B.; Enke, H.; Erdmann, M.; Escolar, D.; Espina, M.; Evans, N. W.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Faye, F.; Federici, L.; Fedorets, G.; Fernández-Hernández, J.; Fernique, P.; Fienga, A.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fouesneau, M.; Fraile, E.; Fraser, M.; Fuchs, J.; Furnell, R.; Gai, M.; Galleti, S.; Galluccio, L.; Garabato, D.; García-Sedano, F.; Garé, P.; Garofalo, A.; Garralda, N.; Gavras, P.; Gerssen, J.; Geyer, R.; Gilmore, G.; Girona, S.; Giuffrida, G.; Gomes, M.; González-Marcos, A.; González-Núñez, J.; González-Vidal, J. J.; Granvik, M.; Guerrier, A.; Guillout, P.; Guiraud, J.; Gúrpide, A.; Gutiérrez-Sánchez, R.; Guy, L. P.; Haigron, R.; Hatzidimitriou, D.; Haywood, M.; Heiter, U.; Helmi, A.; Hobbs, D.; Hofmann, W.; Holl, B.; Holland, G.; Hunt, J. A. S.; Hypki, A.; Icardi, V.; Irwin, M.; Jevardat de Fombelle, G.; Jofré, P.; Jonker, P. G.; Jorissen, A.; Julbe, F.; Karampelas, A.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Koubsky, P.; Kowalczyk, A.; Krone-Martins, A.; Kudryashova, M.; Kull, I.; Bachchan, R. K.; Lacoste-Seris, F.; Lanza, A. F.; Lavigne, J. -B; Le Poncin-Lafitte, C.; Lebreton, Y.; Lebzelter, T.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lemaitre, V.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; Löffler, W.; López, M.; Lopez-Lozano, A.; Lorenz, D.; Loureiro, T.; MacDonald, I.; Magalhães Fernandes, T.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marie, J.; Marinoni, S.; Marrese, P. M.; Marschalkó, G.; Marshall, D. J.; Martín-Fleitas, J. M.; Martino, M.; Mary, N.; Matijevič, G.; Mazeh, T.; McMillan, P. J.; Messina, S.; Mestre, A.; Michalik, D.; Millar, N. R.; Miranda, B. M. H.; Molina, D.; Molinaro, R.; Molinaro, M.; Molnár, L.; Moniez, M.; Montegriffo, P.; Monteiro, D.; Mor, R.; Mora, A.; Morbidelli, R.; Morel, T.; Morgenthaler, S.; Morley, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Narbonne, J.; Nelemans, G.; Nicastro, L.; Noval, L.; Ordénovic, C.; Ordieres-Meré, J.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Parsons, P.; Paulsen, T.; Pecoraro, M.; Pedrosa, R.; Pentikäinen, H.; Pereira, J.; Pichon, B.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poujoulet, E.; Prša, A.; Pulone, L.; Ragaini, S.; Rago, S.; Rambaux, N.; Ramos-Lerate, M.; Ranalli, P.; Rauw, G.; Read, A.; Regibo, S.; Renk, F.; Reylé, C.; Ribeiro, R. A.; Rimoldini, L.; Ripepi, V.; Riva, A.; Rixon, G.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Rudolph, A.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sarasso, M.; Savietto, H.; Schnorhk, A.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Segransan, D.; Serpell, E.; Shih, I. -C; Smareglia, R.; Smart, R. L.; Smith, C.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Süveges, M.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Tingley, B.; Trager, S. C.; Turon, C.; Ulla, A.; Utrilla, E.; Valentini, G.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Varadi, M.; Vecchiato, A.; Veljanoski, J.; Via, T.; Vicente, D.; Vogt, S.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Weingrill, K.; Werner, D.; Wevers, T.; Whitehead, G.; Wyrzykowski, Ł.; Yoldas, A.; Žerjal, M.; Zucker, S.; Zurbach, C.; Zwitter, T.; Alecu, A.; Allen, M.; Allende Prieto, C.; Amorim, A.; Anglada-Escudé, G.; Arsenijevic, V.; Azaz, S.; Balm, P.; Beck, M.; Bernstein, H. -H; Bigot, L.; Bijaoui, A.; Blasco, C.; Bonfigli, M.; Bono, G.; Boudreault, S.; Bressan, A.; Brown, S.; Brunet, P. -M; Bunclark, P.; Buonanno, R.; Butkevich, A. G.; Carret, C.; Carrion, C.; Chemin, L.; Chéreau, F.; Corcione, L.; Darmigny, E.; de Boer, K. S.; de Teodoro, P.; de Zeeuw, P. T.; Delle Luche, C.; Domingues, C. D.; Dubath, P.; Fodor, F.; Frézouls, B.; Fries, A.; Fustes, D.; Fyfe, D.; Gallardo, E.; Gallegos, J.; Gardiol, D.; Gebran, M.; Gomboc, A.; Gómez, A.; Grux, E.; Gueguen, A.; Heyrovsky, A.; Hoar, J.; Iannicola, G.; Isasi Parache, Y.; Janotto, A. -M; Joliet, E.; Jonckheere, A.; Keil, R.; Kim, D. -W; Klagyivik, P.; Klar, J.; Knude, J.; Kochukhov, O.; Kolka, I.; Kos, J.; Kutka, A.; Lainey, V.; LeBouquin, D.; Liu, C.; Loreggia, D.; Makarov, V. V.; Marseille, M. G.; Martayan, C.; Martinez-Rubi, O.; Massart, B.; Meynadier, F.; Mignot, S.; Munari, U.; Nguyen, A. -T; Nordlander, T.; Ocvirk, P.; O'Flaherty, K. S.; Olias Sanz, A.; Ortiz, P.; Osorio, J.; Oszkiewicz, D.; Ouzounis, A.; Palmer, M.; Park, P.; Pasquato, E.; Peltzer, C.; Peralta, J.; Péturaud, F.; Pieniluoma, T.; Pigozzi, E.; Poels, J.; Prat, G.; Prod'homme, T.; Raison, F.; Rebordao, J. M.; Risquez, D.; Rocca-Volmerange, B.; Rosen, S.; Ruiz-Fuertes, M. I.; Russo, F.; Sembay, S.; Serraller Vizcaino, I.; Short, A.; Siebert, A.; Silva, H.; Sinachopoulos, D.; Slezak, E.; Soffel, M.; Sosnowska, D.; Straižys, V.; ter Linden, M.; Terrell, D.; Theil, S.; Tiede, C.; Troisi, L.; Tsalmantza, P.; Tur, D.; Vaccari, M.; Vachier, F.; Valles, P.; Van Hamme, W.; Veltz, L.; Virtanen, J.; Wallut, J. -M; Wichmann, R.; Wilkinson, M. I.; Ziaeepour, H.; Zschocke, S.

    2016-01-01

    Gaia is a cornerstone mission in the science programme of the EuropeanSpace Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by

  18. The Mothership Mission Architecture

    Science.gov (United States)

    Ernst, S. M.; DiCorcia, J. D.; Bonin, G.; Gump, D.; Lewis, J. S.; Foulds, C.; Faber, D.

    2015-12-01

    The Mothership is considered to be a dedicated deep space carrier spacecraft. It is currently being developed by Deep Space Industries (DSI) as a mission concept that enables a broad participation in the scientific exploration of small bodies - the Mothership mission architecture. A Mothership shall deliver third-party nano-sats, experiments and instruments to Near Earth Asteroids (NEOs), comets or moons. The Mothership service includes delivery of nano-sats, communication to Earth and visuals of the asteroid surface and surrounding area. The Mothership is designed to carry about 10 nano-sats, based upon a variation of the Cubesat standard, with some flexibility on the specific geometry. The Deep Space Nano-Sat reference design is a 14.5 cm cube, which accommodates the same volume as a traditional 3U CubeSat. To reduce cost, Mothership is designed as a secondary payload aboard launches to GTO. DSI is offering slots for nano-sats to individual customers. This enables organizations with relatively low operating budgets to closely examine an asteroid with highly specialized sensors of their own choosing and carry out experiments in the proximity of or on the surface of an asteroid, while the nano-sats can be built or commissioned by a variety of smaller institutions, companies, or agencies. While the overall Mothership mission will have a financial volume somewhere between a European Space Agencies' (ESA) S- and M-class mission for instance, it can be funded through a number of small and individual funding sources and programs, hence avoiding the processes associated with traditional space exploration missions. DSI has been able to identify a significant interest in the planetary science and nano-satellite communities.

  19. The Double Star mission

    Directory of Open Access Journals (Sweden)

    Liu

    2005-11-01

    Full Text Available The Double Star Programme (DSP was first proposed by China in March, 1997 at the Fragrant Hill Workshop on Space Science, Beijing, organized by the Chinese Academy of Science. It is the first mission in collaboration between China and ESA. The mission is made of two spacecraft to investigate the magnetospheric global processes and their response to the interplanetary disturbances in conjunction with the Cluster mission. The first spacecraft, TC-1 (Tan Ce means "Explorer", was launched on 29 December 2003, and the second one, TC-2, on 25 July 2004 on board two Chinese Long March 2C rockets. TC-1 was injected in an equatorial orbit of 570x79000 km altitude with a 28° inclination and TC-2 in a polar orbit of 560x38000 km altitude. The orbits have been designed to complement the Cluster mission by maximizing the time when both Cluster and Double Star are in the same scientific regions. The two missions allow simultaneous observations of the Earth magnetosphere from six points in space. To facilitate the comparison of data, half of the Double Star payload is made of spare or duplicates of the Cluster instruments; the other half is made of Chinese instruments. The science operations are coordinated by the Chinese DSP Scientific Operations Centre (DSOC in Beijing and the European Payload Operations Service (EPOS at RAL, UK. The spacecraft and ground segment operations are performed by the DSP Operations and Management Centre (DOMC and DSOC in China, using three ground station, in Beijing, Shanghai and Villafranca.

  20. TDEM for Martian in situ resource prospecting missions

    Directory of Open Access Journals (Sweden)

    G. Tacconi

    2003-06-01

    Full Text Available This paper presents a TDEM (Time Domain Electromagnetic Methods application, addressed to the search for water on Mars. In this context, the opportunities for a TDEM system as payload in a future mission are investigated for different in situ exploration scenarios. The TDEM sounding capability is evaluated with respect to the expected Martian environment, and some considerations are made about the many unknown variables (above all the background EM noise and the subsoil composition altogether with the limited resources availability (mission constraints in mass, time and power and the way they could represent an obstacle for operations and measurements.

  1. Fluid convection, constraint and causation

    Science.gov (United States)

    Bishop, Robert C.

    2012-01-01

    Complexity—nonlinear dynamics for my purposes in this essay—is rich with metaphysical and epistemological implications but is receiving sustained philosophical analysis only recently. I will explore some of the subtleties of causation and constraint in Rayleigh–Bénard convection as an example of a complex phenomenon, and extract some lessons for further philosophical reflection on top-down constraint and causation particularly with respect to causal foundationalism. PMID:23386955

  2. Current constraints on the cosmic growth history

    International Nuclear Information System (INIS)

    Bean, Rachel; Tangmatitham, Matipon

    2010-01-01

    We present constraints on the cosmic growth history with recent cosmological data, allowing for deviations from ΛCDM as might arise if cosmic acceleration is due to modifications to general relativity or inhomogeneous dark energy. We combine measures of the cosmic expansion history, from Type 1a supernovae, baryon acoustic oscillations, and the cosmic microwave background (CMB), with constraints on the growth of structure from recent galaxy, CMB, and weak lensing surveys along with integated Sachs Wolfe-galaxy cross correlations. Deviations from ΛCDM are parameterized by phenomenological modifications to the Poisson equation and the relationship between the two Newtonian potentials. We find modifications that are present at the time the CMB is formed are tightly constrained through their impact on the well-measured CMB acoustic peaks. By contrast, constraints on late-time modifications to the growth history, as might arise if modifications are related to the onset of cosmic acceleration, are far weaker, but remain consistent with ΛCDM at the 95% confidence level. For these late-time modifications we find that differences in the evolution on large and small scales could provide an interesting signature by which to search for modified growth histories with future wide angular coverage, large scale structure surveys.

  3. Constraints on grand unified superstring theories

    International Nuclear Information System (INIS)

    Ellis, J.; Lopez, J.L.; Nanopoulos, D.V.; Houston Advanced Research Center

    1990-01-01

    We evaluate some constraints on the construction of grand unified superstring theories (GUSTs) using higher level Kac-Moody algebras on the world-sheet. In the most general formulation of the heterotic string in four dimensions, an analysis of the basic GUST model-building constraints, including a realistic hidden gauge group, reveals that there are no E 6 models and any SO(10) models can only exist at level-5. Also, any such SU(5) models can exist only for levels 4≤k≤19. These SO(10) and SU(5) models risk having many large, massless, phenomenologically troublesome representations. We also show that with a suitable hidden sector gauge group, it is possible to avoid free light fractionally charged particles, which are endemic to string derived models. We list all such groups and their representations for the flipped SU(5)xU(1) model. We conclude that a sufficiently binding hidden sector gauge group becomes a basic model-building constraint. (orig.)

  4. Constraint theory, singular lagrangians and multitemporal dynamics

    International Nuclear Information System (INIS)

    Lusanna, L.

    1988-01-01

    Singular Lagrangians and constraint theory permeate theoretical physics, as shown by the relevance of gauge theories, string models and general relativity. Their study used finite---dimensional models as a guide to develop the theory, but their main use was in classical field theory, due to the necessity of understanding their quantization. The covariant quantization of singular Lagrangians led to the BRST approach and to the theory of the effective action. On the other hand their phase---space formulation, culminated with the BFV approach for first class, second class and reducible constraints. It, in turn, gave new insights in the theory of singular Lagrangians and constraints and in their cohomological aspects. However the Hamiltonian approach to field theory is highly nontrivial, is open to criticism due to its problems with locality, geometry and manifest covariance and its canonical quantization has still to be developed, because there is no proof of the renormalizability of the Schroedinger representation of field theory. This paper discusses how, notwithstanding these developments, there is still a big amount of ambiguity at every level of the theory

  5. Orthology and paralogy constraints: satisfiability and consistency.

    Science.gov (United States)

    Lafond, Manuel; El-Mabrouk, Nadia

    2014-01-01

    A variety of methods based on sequence similarity, reconciliation, synteny or functional characteristics, can be used to infer orthology and paralogy relations between genes of a given gene family  G. But is a given set  C of orthology/paralogy constraints possible, i.e., can they simultaneously co-exist in an evolutionary history for  G? While previous studies have focused on full sets of constraints, here we consider the general case where  C does not necessarily involve a constraint for each pair of genes. The problem is subdivided in two parts: (1) Is  C satisfiable, i.e. can we find an event-labeled gene tree G inducing  C? (2) Is there such a G which is consistent, i.e., such that all displayed triplet phylogenies are included in a species tree? Previous results on the Graph sandwich problem can be used to answer to (1), and we provide polynomial-time algorithms for satisfiability and consistency with a given species tree. We also describe a new polynomial-time algorithm for the case of consistency with an unknown species tree and full knowledge of pairwise orthology/paralogy relationships, as well as a branch-and-bound algorithm in the case when unknown relations are present. We show that our algorithms can be used in combination with ProteinOrtho, a sequence similarity-based orthology detection tool, to extract a set of robust orthology/paralogy relationships.

  6. The Simbol-X Mission

    International Nuclear Information System (INIS)

    Ferrando, P.; Goldwurm, A.; Laurent, P.; Lebrun, F.; Arnaud, M.; Briel, U.; Cavazzuti, E.; Giommi, P.; Piermaria, M.; Cledassou, R.; Counil, J. L.; Lamarle, O.; Fiore, F.; Malaguti, G.; Mereghetti, S.; Micela, G.; Pareschi, G.; Tagliaferri, G.; Roques, J. P.; Santangelo, A.

    2009-01-01

    The elucidation of key questions in astrophysics, in particular those related to black hole physics and census, and to particle acceleration mechanisms, necessitates to develop new observational capabilities in the hard X-ray domain with performances several orders of magnitude better than presently available. Relying on two spacecrafts in a formation flying configuration, Simbol-X will provide the world-wide astrophysics community with a single optics long focal length telescope. This observatory will have unrivaled performances in the hard X-ray domain, up to ∼80 keV, as well as very good characteristics in the soft X-ray domain, down to ∼0.5 keV. The Simbol-X mission has successfully passed a phase A study, jointly conducted by CNES and ASI, with the participation of German laboratories. It is now entering phase B studies with the participation of new international partners, for a launch in 2015. We give in this paper a general overview of the mission, as consolidated at the start of phase B.

  7. The Simbol-X Mission

    Science.gov (United States)

    Ferrando, P.; Arnaud, M.; Briel, U.; Cavazzuti, E.; Clédassou, R.; Counil, J. L.; Fiore, F.; Giommi, P.; Goldwurm, A.; Lamarle, O.; Laurent, P.; Lebrun, F.; Malaguti, G.; Mereghetti, S.; Micela, G.; Pareschi, G.; Piermaria, M.; Roques, J. P.; Santangelo, A.; Tagliaferri, G.

    2009-05-01

    The elucidation of key questions in astrophysics, in particular those related to black hole physics and census, and to particle acceleration mechanisms, necessitates to develop new observational capabilities in the hard X-ray domain with performances several orders of magnitude better than presently available. Relying on two spacecrafts in a formation flying configuration, Simbol-X will provide the world-wide astrophysics community with a single optics long focal length telescope. This observatory will have unrivaled performances in the hard X-ray domain, up to ~80 keV, as well as very good characteristics in the soft X-ray domain, down to ~0.5 keV. The Simbol-X mission has successfully passed a phase A study, jointly conducted by CNES and ASI, with the participation of German laboratories. It is now entering phase B studies with the participation of new international partners, for a launch in 2015. We give in this paper a general overview of the mission, as consolidated at the start of phase B.

  8. Temperature control of the Mariner class spacecraft - A seven mission summary.

    Science.gov (United States)

    Dumas, L. N.

    1973-01-01

    Mariner spacecraft have completed five missions of scientific investigation of the planets. Two additional missions are planned. A description of the thermal design of these seven spacecraft is given herein. The factors which have influenced the thermal design include the mission requirements and constraints, the flight environment, certain programmatic considerations and the experience gained as each mission is completed. These factors are reviewed and the impact of each on thermal design and developmental techniques is assessed. It is concluded that the flight success of these spacecraft indicates that adequate temperature control has been obtained, but that improvements in design data, hardware performance and analytical techniques are needed.

  9. Categorical database generalization in GIS

    NARCIS (Netherlands)

    Liu, Y.

    2002-01-01

    Key words: Categorical database, categorical database generalization, Formal data structure, constraints, transformation unit, classification hierarchy, aggregation hierarchy, semantic similarity, data model,

  10. Constraints on the braneworld from compact stars

    Energy Technology Data Exchange (ETDEWEB)

    Felipe, R.G. [Instituto Politecnico de Lisboa, ISEL, Instituto Superior de Engenharia de Lisboa, Lisboa (Portugal); Instituto Superior Tecnico, Universidade de Lisboa, Departamento de Fisica, Centro de Fisica Teorica de Particulas, CFTP, Lisboa (Portugal); Paret, D.M. [Universidad de la Habana, Departamento de Fisica General, Facultad de Fisica, La Habana (Cuba); Martinez, A.P. [Instituto de Cibernetica, Matematica y Fisica (ICIMAF), La Habana (Cuba); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico, Distrito Federal (Mexico)

    2016-06-15

    According to the braneworld idea, ordinary matter is confined on a three-dimensional space (brane) that is embedded in a higher-dimensional space-time where gravity propagates. In this work, after reviewing the limits coming from general relativity, finiteness of pressure and causality on the brane, we derive observational constraints on the braneworld parameters from the existence of stable compact stars. The analysis is carried out by solving numerically the brane-modified Tolman-Oppenheimer-Volkoff equations, using different representative equations of state to describe matter in the star interior. The cases of normal dense matter, pure quark matter and hybrid matter are considered. (orig.)

  11. Soft Budget Constraints in Professional Football

    DEFF Research Database (Denmark)

    Storm, Rasmus K.; Nielsen, Klaus

    2012-01-01

    European professional football clubs go out of business even though they operate chronically on the edge of financial collapse? The paper argues that the paradox can be explained by the fact that professional football clubs operate within soft budget constraints in a way which is similar to the role...... of large companies in socialist economies – a phenomenon which was first identified by the Hungarian Economist János Kornai. More generally, it is argued that our understanding of the peculiar economics of professional team sports can be enhanced significantly by applying the soft budget constrain concept...

  12. Total-variation regularization with bound constraints

    International Nuclear Information System (INIS)

    Chartrand, Rick; Wohlberg, Brendt

    2009-01-01

    We present a new algorithm for bound-constrained total-variation (TV) regularization that in comparison with its predecessors is simple, fast, and flexible. We use a splitting approach to decouple TV minimization from enforcing the constraints. Consequently, existing TV solvers can be employed with minimal alteration. This also makes the approach straightforward to generalize to any situation where TV can be applied. We consider deblurring of images with Gaussian or salt-and-pepper noise, as well as Abel inversion of radiographs with Poisson noise. We incorporate previous iterative reweighting algorithms to solve the TV portion.

  13. B plant mission analysis report

    International Nuclear Information System (INIS)

    Lund, D.P.

    1995-01-01

    This report further develops the mission for B Plant originally defined in WHC-EP-0722, ''System Engineering Functions and Requirements for the Hanford Cleanup Mission: First Issue.'' The B Plant mission analysis will be the basis for a functional analysis that breaks down the B Plant mission statement into the necessary activities to accomplish the mission. These activities are the product of the functional analysis and will then be used in subsequent steps of the systems engineering process, such as identifying requirements and allocating those requirements to B Plant functions. The information in this mission analysis and the functional and requirements analysis are a part of the B Plant technical baseline

  14. Mars MetNet Mission Status

    Science.gov (United States)

    Harri, Ari-Matti; Aleksashkin, Sergei; Arruego, Ignacio; Schmidt, Walter; Genzer, Maria; Vazquez, Luis; Haukka, Harri

    2015-04-01

    descent phase starting shortly after separation from the spacecraft. MetNet Mission payload instruments are specially designed to operate in very low power conditions. MNL flexible solar panels provides a total of approximately 0.7-0.8 W of electric power during the daylight time. As the provided power output is insufficient to operate all instruments simultaneously they are activated sequentially according to a specially designed cyclogram table which adapts itself to the different environmental constraints. 3. Mission Status Full Qualification Model (QM) of the MetNet landing unit with the Precursor Mission payload is currently under functional tests. In near future the QM unit will be exposed to environmental tests with qualification levels including vibrations, thermal balance, thermal cycling and mechanical impact shock. One complete flight unit of the entry, descent and landing systems (EDLS) has been manufactured and tested with acceptance levels. Another flight-like EDLS has been exposed to most of the qualification tests, and hence it may be used for flight after refurbishments. Accordingly two flight-capable EDLS systems exist. The eventual goal is to create a network of atmospheric observational posts around the Martian surface. Even if the MetNet mission is focused on the atmospheric science, the mission payload will also include additional kinds of geophysical instrumentation. The next step in the MetNet Precursor Mission to demonstrate the technical robustness and scientific capabilities of the MetNet type of landing vehicle. Definition of the Precursor Mission and discussions on launch opportunities are currently under way. The baseline program development funding exists for the next five years. Flight unit manufacture of the payload bay takes about 18 months, and it will be commenced after the Precursor Mission has been defined. References [1] http://metnet.fmi.fi

  15. Galileo and Ulysses missions safety analysis and launch readiness status

    International Nuclear Information System (INIS)

    Cork, M.J.; Turi, J.A.

    1989-01-01

    The Galileo spacecraft will explore the Jupiter system and Ulysses will fly by Jupiter en route to a polar orbit of the sun. Both spacecraft are powered by general purpose heat source radioisotope thermoelectric generators (RTGs). As a result of the Challenger accident and subsequent mission reprogramming, the Galileo and Ulysses missions' safety analysis had to be repeated. In addition to presenting an overview of the safety analysis status for the missions, this paper presents a brief review of the missions' objectives and design approaches, RTG design characteristics and development history, and a description of the safety analysis process. (author)

  16. Review on abort trajectory for manned lunar landing mission

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Abort trajectory is a passage that ensures the astronauts to return safely to the earth when an emergency occurs. Firstly,the essential elements of mission abort are analyzed entirely based on summarizing the existing studies. Then,abort trajectory requirement and rational selection for different flight phases of typical manned lunar mission are discussed specifically. Considering a trade-off between the two primary constrains of an abort,the return time of flight and energy requirement,a general optimizing method for mission abort is proposed. Finally,some suggestions are given for China’s future manned lunar landing mission.

  17. Mission Analysis, Operations, and Navigation Toolkit Environment (Monte) Version 040

    Science.gov (United States)

    Sunseri, Richard F.; Wu, Hsi-Cheng; Evans, Scott E.; Evans, James R.; Drain, Theodore R.; Guevara, Michelle M.

    2012-01-01

    Monte is a software set designed for use in mission design and spacecraft navigation operations. The system can process measurement data, design optimal trajectories and maneuvers, and do orbit determination, all in one application. For the first time, a single software set can be used for mission design and navigation operations. This eliminates problems due to different models and fidelities used in legacy mission design and navigation software. The unique features of Monte 040 include a blowdown thruster model for GRAIL (Gravity Recovery and Interior Laboratory) with associated pressure models, as well as an updated, optimalsearch capability (COSMIC) that facilitated mission design for ARTEMIS. Existing legacy software lacked the capabilities necessary for these two missions. There is also a mean orbital element propagator and an osculating to mean element converter that allows long-term orbital stability analysis for the first time in compiled code. The optimized trajectory search tool COSMIC allows users to place constraints and controls on their searches without any restrictions. Constraints may be user-defined and depend on trajectory information either forward or backwards in time. In addition, a long-term orbit stability analysis tool (morbiter) existed previously as a set of scripts on top of Monte. Monte is becoming the primary tool for navigation operations, a core competency at JPL. The mission design capabilities in Monte are becoming mature enough for use in project proposals as well as post-phase A mission design. Monte has three distinct advantages over existing software. First, it is being developed in a modern paradigm: object- oriented C++ and Python. Second, the software has been developed as a toolkit, which allows users to customize their own applications and allows the development team to implement requirements quickly, efficiently, and with minimal bugs. Finally, the software is managed in accordance with the CMMI (Capability Maturity Model

  18. Spacelab 3 mission

    Science.gov (United States)

    Dalton, Bonnie P.

    1990-01-01

    Spacelab-3 (SL-3) was the first microgravity mission of extended duration involving crew interaction with animal experiments. This interaction involved sharing the Spacelab environmental system, changing animal food, and changing animal waste trays by the crew. Extensive microbial testing was conducted on the animal specimens and crew and on their ground and flight facilities during all phases of the mission to determine the potential for cross contamination. Macroparticulate sampling was attempted but was unsuccessful due to the unforseen particulate contamination occurring during the flight. Particulate debris of varying size (250 micron to several inches) and composition was recovered post flight from the Spacelab floor, end cones, overhead areas, avionics fan filter, cabin fan filters, tunnel adaptor, and from the crew module. These data are discussed along with solutions, which were implemented, for particulate and microbial containment for future flight facilities.

  19. The THEMIS Mission

    CERN Document Server

    Burch, J. L

    2009-01-01

    The THEMIS mission aims to determine the trigger and large-scale evolution of substorms by employing five identical micro-satellites which line up along the Earth's magnetotail to track the motion of particles, plasma, and waves from one point to another and for the first time, resolve space-time ambiguities in key regions of the magnetosphere on a global scale. The primary goal of THEMIS is to elucidate which magnetotail process is responsible for substorm onset at the region where substorm auroras map: (i) local disruption of the plasma sheet current (current disruption) or (ii) the interaction of the current sheet with the rapid influx of plasma emanating from reconnection. The probes also traverse the radiation belts and the dayside magnetosphere, allowing THEMIS to address additional baseline objectives. This volume describes the mission, the instrumentation, and the data derived from them.

  20. Future applications of artificial intelligence to Mission Control Centers

    Science.gov (United States)

    Friedland, Peter

    1991-01-01

    Future applications of artificial intelligence to Mission Control Centers are presented in the form of the viewgraphs. The following subject areas are covered: basic objectives of the NASA-wide AI program; inhouse research program; constraint-based scheduling; learning and performance improvement for scheduling; GEMPLAN multi-agent planner; planning, scheduling, and control; Bayesian learning; efficient learning algorithms; ICARUS (an integrated architecture for learning); design knowledge acquisition and retention; computer-integrated documentation; and some speculation on future applications.

  1. Cyber Network Mission Dependencies

    Science.gov (United States)

    2015-09-18

    leak paths”) and determine if firewalls and router access control lists are violating network policy. Visualization tools are provided to help analysts...with which a supply agent may not be familiar. In this environment, errors in requisition are easy to make, and they are costly : an incomplete cyber...establishing an email network and recommend a firewall and additional laptops. YMAL would also match mission details like the deployment location with

  2. A Somalia mission experience.

    Science.gov (United States)

    Mahomed, Zeyn; Moolla, Muhammad; Motara, Feroza; Laher, Abdullah

    2012-06-28

    Reports about The Horn of Africa Famine Crisis in 2011 flooded our news bulletins and newspapers. Yet the nations of the world failed to respond and alleviate the unfolding disaster. In August 2011, the Gift of the Givers Foundation mobilised what was to become the largest humanitarian mission ever conducted by an African organisation. Almost a year later, the effort continues, changing the face of disaster medicine as we know it.

  3. The money mission matrix

    OpenAIRE

    Cuperus, Mirthe

    2017-01-01

    Social entrepreneurship is popular in current academics and other media. This thesis adds to this literature by discovering what the drivers are for sustainable social entrepreneurship. Several stakeholders were identified, creating profiles of the key players in social entrepreneurship. These stakeholders uncovered key factors that represent the drivers for sustainable social entrepreneurship. Key factors were then aligned along the two dimensions: Money and Mission. This crea...

  4. Asteroid Kinetic Impactor Missions

    Science.gov (United States)

    Chesley, Steven

    2015-08-01

    Asteroid impact missions can be carried out as a relatively low-cost add-ons to most asteroid rendezvous missions and such impact experiments have tremendous potential, both scientifically and in the arena of planetary defense.The science returns from an impactor demonstration begin with the documentation of the global effects of the impact, such as changes in orbit and rotation state, the creation and dissipation of an ejecta plume and debris disk, and morphological changes across the body due to the transmission of seismic waves, which might induce landslides and toppling of boulders, etc. At a local level, an inspection of the impact crater and ejecta blanket reveals critical material strength information, as well as spectral differences between the surface and subsurface material.From the planetary defense perspective, an impact demonstration will prove humankind’s capacity to alter the orbit of a potentially threatening asteroid. This technological leap comes in two parts. First, terminal guidance systems that can deliver an impactor with small errors relative to the ~100-200 meter size of a likely impactor have yet to be demonstrated in a deep space environment. Second, the response of an asteroid to such an impact is only understood theoretically due to the potentially significant dependence on the momentum carried by escaping ejecta, which would tend to enhance the deflection by tens of percent and perhaps as much as a factor of a few. A lack of validated understanding of momentum enhancement is a significant obstacle in properly sizing a real-world impactor deflection mission.This presentation will describe the drivers for asteroid impact demonstrations and cover the range of such concepts, starting with ESA’s pioneering Don Quijote mission concept and leading to a brief description of concepts under study at the present time, including the OSIRIS-REx/ISIS, BASiX/KIX and AIM/DART (AIDA) concepts.

  5. The Gaia mission

    OpenAIRE

    Prusti, T.; de Bruijne, J. H. J.; Brown, A. G. A.; Vallenari, A.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.

    2016-01-01

    Gaia is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia wa...

  6. Iterative Schemes for Convex Minimization Problems with Constraints

    Directory of Open Access Journals (Sweden)

    Lu-Chuan Ceng

    2014-01-01

    Full Text Available We first introduce and analyze one implicit iterative algorithm for finding a solution of the minimization problem for a convex and continuously Fréchet differentiable functional, with constraints of several problems: the generalized mixed equilibrium problem, the system of generalized equilibrium problems, and finitely many variational inclusions in a real Hilbert space. We prove strong convergence theorem for the iterative algorithm under suitable conditions. On the other hand, we also propose another implicit iterative algorithm for finding a fixed point of infinitely many nonexpansive mappings with the same constraints, and derive its strong convergence under mild assumptions.

  7. Dawn Mission Update

    Science.gov (United States)

    Sykes, M. V.; Russell, C. T.; Coradini, A.; Christensen, U.; de Sanctis, M. C.; Feldman, W. C.; Jaumann, R.; Keller, U.; Konopliv, A. S.; McCord, T. B.; McFadden, L. A.; McSween, H. Y.; Mottola, S.; Neukum, G.; Pieters, C. M.; Prettyman, T. H.; Raymond, C. A.; Smith, D. E.; Williams, B. G.; Wise, J.; Zuber, M. T.

    2004-11-01

    Dawn, the ninth Discovery mission, will be the first spacecraft to rendezvous with two solar system bodies, the main belt asteroids Vesta and Ceres. This is made possible by utilizing ion propulsion to reach its targets and to maneuver into (and depart) orbits about these bodies. Vesta and Ceres are two terrestrial protoplanets that have survived since the earliest epoch of the solar system and will provide important insights into planet building processes and their evolution under very different circumstances, with and without water. Dawn carries a double framing camera, a visible and infrared mapping spectrometer, and a gamma ray and neutron detector. At Vesta our studies will include the volcanic emplacement of basalts, its differentiation, the possible exposure of its interior near the south pole. At Ceres our studies will include the role of water in its evolution, hydration processes on its surface, and the possible existence of a subsurface ocean. The mission has passed its critical design review and is scheduled to be launched in June 2006 with arrival at Vesta in 2011 and Ceres in 2015. Operation strategies will be presented. Groundbased observations of Vesta, Ceres, and Vesta family members over broad wavelengths, periods and phases will play an important role in detailed mission planning.

  8. The Spartan 1 mission

    Science.gov (United States)

    Cruddace, Raymond G.; Fritz, G. G.; Shrewsberry, D. J.; Brandenstein, D. J.; Creighton, D. C.; Gutschewski, G.; Lucid, S. W.; Nagel, J. M.; Fabian, J. M.; Zimmerman, D.

    1989-01-01

    The first Spartan mission is documented. The Spartan program, an outgrowth of a joint Naval Research Laboratory (NRL)/National Aeronautics and Space Administration (NASA)-Goddard Space Flight Center (GSFC) development effort, was instituted by NASA for launching autonomous, recoverable payloads from the space shuttle. These payloads have a precise pointing system and are intended to support a wide range of space-science observations and experiments. The first Spartan, carrying an NRL X-ray astronomy instrument, was launched by the orbiter Discovery (STS51G) on June 20, 1985 and recovered successfully 45 h later, on June 22. During this period, Spartan 1 conducted a preprogrammed series of observations of two X-ray sources: the Perseus cluster of galaxies and the center of our galaxy. The mission was successful from both on engineering and a scientific viewpoint. Only one problem was encountered, the attitude control system (ACS) shut down earlier than planned because of high attitude control system gas consumption. A preplanned emergency mode then placed Spartan 1 into a stable, safe condition and allowed a safe recovery. The events are described of the mission and presents X-ray maps of the two observed sources, which were produced from the flight data.

  9. SPICE for ESA Planetary Missions

    Science.gov (United States)

    Costa, M.

    2018-04-01

    The ESA SPICE Service leads the SPICE operations for ESA missions and is responsible for the generation of the SPICE Kernel Dataset for ESA missions. This contribution will describe the status of these datasets and outline the future developments.

  10. Mission Critical Occupation (MCO) Charts

    Data.gov (United States)

    Office of Personnel Management — Agencies report resource data and targets for government-wide mission critical occupations and agency specific mission critical and/or high risk occupations. These...

  11. Developmental constraints on behavioural flexibility.

    Science.gov (United States)

    Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

  12. Data assimilation with inequality constraints

    Science.gov (United States)

    Thacker, W. C.

    If values of variables in a numerical model are limited to specified ranges, these restrictions should be enforced when data are assimilated. The simplest option is to assimilate without regard for constraints and then to correct any violations without worrying about additional corrections implied by correlated errors. This paper addresses the incorporation of inequality constraints into the standard variational framework of optimal interpolation with emphasis on our limited knowledge of the underlying probability distributions. Simple examples involving only two or three variables are used to illustrate graphically how active constraints can be treated as error-free data when background errors obey a truncated multi-normal distribution. Using Lagrange multipliers, the formalism is expanded to encompass the active constraints. Two algorithms are presented, both relying on a solution ignoring the inequality constraints to discover violations to be enforced. While explicitly enforcing a subset can, via correlations, correct the others, pragmatism based on our poor knowledge of the underlying probability distributions suggests the expedient of enforcing them all explicitly to avoid the computationally expensive task of determining the minimum active set. If additional violations are encountered with these solutions, the process can be repeated. Simple examples are used to illustrate the algorithms and to examine the nature of the corrections implied by correlated errors.

  13. NASA Extreme Environment Mission Operations: Science Operations Development for Human Exploration

    Science.gov (United States)

    Bell, Mary S.

    2014-01-01

    The purpose of NASA Extreme Environment Mission Operations (NEEMO) mission 16 in 2012 was to evaluate and compare the performance of a defined series of representative near-Earth asteroid (NEA) extravehicular activity (EVA) tasks under different conditions and combinations of work systems, constraints, and assumptions considered for future human NEA exploration missions. NEEMO 16 followed NASA's 2011 Desert Research and Technology Studies (D-RATS), the primary focus of which was understanding the implications of communication latency, crew size, and work system combinations with respect to scientific data quality, data management, crew workload, and crew/mission control interactions. The 1-g environment precluded meaningful evaluation of NEA EVA translation, worksite stabilization, sampling, or instrument deployment techniques. Thus, NEEMO missions were designed to provide an opportunity to perform a preliminary evaluation of these important factors for each of the conditions being considered. NEEMO 15 also took place in 2011 and provided a first look at many of the factors, but the mission was cut short due to a hurricane threat before all objectives were completed. ARES Directorate (KX) personnel consulted with JSC engineers to ensure that high-fidelity planetary science protocols were incorporated into NEEMO mission architectures. ARES has been collaborating with NEEMO mission planners since NEEMO 9 in 2006, successively building upon previous developments to refine science operations concepts within engineering constraints; it is expected to continue the collaboration as NASA's human exploration mission plans evolve.

  14. Nuclear risk analysis of the Ulysses mission

    International Nuclear Information System (INIS)

    Bartram, B.W.; Vaughan, F.R.; Englehart, D.R.W.

    1991-01-01

    The use of a radioisotope thermoelectric generator fueled with plutonium-238 dioxide on the Space Shuttle-launched Ulysses mission implies some level of risk due to potential accidents. This paper describes the method used to quantify risks in the Ulysses mission Final Safety Analysis Report prepared for the U.S. Department of Energy. The starting point for the analysis described herein is following input of source term probability distributions from the General Electric Company. A Monte Carlo technique is used to develop probability distributions of radiological consequences for a range of accident scenarios thoughout the mission. Factors affecting radiological consequences are identified, the probability distribution of the effect of each factor determined, and the functional relationship among all the factors established. The probability distributions of all the factor effects are then combined using a Monte Carlo technique. The results of the analysis are presented in terms of complementary cumulative distribution functions (CCDF) by mission sub-phase, phase, and the overall mission. The CCDFs show the total probability that consequences (calculated health effects) would be equal to or greater than a given value

  15. Recent observational constraints on generalized Chaplygin gas in ...

    Indian Academy of Sciences (India)

    2017-02-10

    Feb 10, 2017 ... on the EoS parameters. Best-fit values of the EoS parameters H0, As and α (As and α are defined in the energy ... This late acceleration cannot be realized in the frame- ... today). The other choices are: (i) a light homogeneous.

  16. A maintenance optimization model for mission-oriented systems based on Wiener degradation

    International Nuclear Information System (INIS)

    Guo, Chiming; Wang, Wenbin; Guo, Bo; Si, Xiaosheng

    2013-01-01

    Over the past few decades, condition-based maintenance (CBM) has attracted many researchers because of its effectiveness and practical significance. This paper deals with mission-oriented systems subject to gradual degradation modeled by a Wiener stochastic process within the context of CBM. For a mission-oriented system, the mission usually has constraints on availability/reliability, the opportunity for maintenance actions, and the monitoring type (continuous or discrete). Furthermore, in practice, a mission-oriented system may undertake some preventive maintenance (PM) and after such PM, the system may return to an intermediate state between an as-good-as new state and an as-bad-as old state, i.e., the PM is not perfect and only partially restores the system. However, very few CBM models integrated these mission constraints together with an imperfect nature of the PM into the course of optimizing the PM policy. This paper develops a model to optimize the PM policy in terms of the maintenance related cost jointly considering the mission constraints and the imperfect PM nature. A numerical example is presented to demonstrate the proposed model. The comparison with the simulated results and the sensitivity analysis show the usefulness of the optimization model for mission-oriented system maintenance presented in this paper.

  17. A note on the CFT origin of the strong constraint of DFT

    International Nuclear Information System (INIS)

    Betz, André; Blumenhagen, Ralph; Lüst, Dieter; Rennecke, Felix

    2014-01-01

    In double field theory, motivated by its field theoretic consistency, the level matching condition is generalized to the so-called strong constraint. In this note, it is investigated what the two-dimensional conformal field theory origin of this constraint is. Initially treating the left- and right-movers as independent, we compute the torus partition function as well as a generalized Virasoro-Shapiro amplitude. In non-compact directions the strong constraint arises from the factorization of the Virasoro-Shapiro amplitude over physical states as determined by the modular invariant partition function. From the same argument, along internal toroidal directions, no analogous constraint arises

  18. La géochimie organique des sédiments marins profonds. Mission orgon 3, 1976 (Mauritanie, Sénégal, Iles du Cap-Vert. Généralités et résultats obtenus à la mer. Organic Geochemistry of Deep Marine Sediments. Orgon 3 Mission, 1976 (Mauritania,Senegal,Cape Verde Islands. General and Results Obtained At Sea

    Directory of Open Access Journals (Sweden)

    Pelet R.

    2006-11-01

    écédentes missions ORLON. A la pauvreté générale en bactéries des sédiments étudiés, jointe à la disparition totale de ces bactéries très rapidement dans la profondeur des carottes, se superpose ici, dans des niveaux profonds différents suivant les carottes, une microflore très abondante et active (non sporulée. L'importance géologique de cette découverte ne saurait être sous-estimée. Seven separate articles will be published on the ORLON 3 mission.The first will deal with general aspects, the second with the general geological setting and the other five with the results obtained at sea in the fields of interpreting echosounder profiles, describing tore samples, observing parriculote organic motter, examining entrapped gas and investigating microbiology. Echosounder profiles describe the topography of the sea bed which appears to be slashed by canyons. They also detect sedimentary sliding which appears as a normal process of sediment deposition in the region being investigated. The im.nediate description of core samples in particular revealed turbidite levels with bioclastic elements subsisting under the lysocline, thus confirming the preceding considerations among others. An examination of the figured elements in the organic matter suggests the importance of eolian detrital influx, which is something new. An analysis of the entrappeci gas gives rise ta clearcut opposition between the northern region (radial of Nouadhibou and the southern region (a region of coastal rivers and the Kayar canyon. In the latter region, the gas contains almost nothing other thon methane as a hydrocarbon. The amounts of methane in the gas are irregularly distributed and show no correlation either with the organic carbon contents or with the microbial richness of the levels. In the north the methane is slightly less predominant (ethane represents a few hundredths of methane, and the upper homo-logous series have merely traces. Although there is no correlation witb the microbial richness

  19. Lunar Global Heat Flow: Predictions and Constraints

    Science.gov (United States)

    Siegler, M.; Williams, J. P.; Paige, D. A.; Feng, J.

    2017-12-01

    The global thermal state of the Moon provides fundamental information on its bulk composition and interior evolution. The Moon is known to have a highly asymmetric surface composition [e.g. Lawrence et al., 2003] and crustal thickness [Wieczorek et al.,2012], which is suspected to result from interior asymmetries [Wieczorek and Phillips, 2000; Laneuville et al., 2013]. This is likely to cause a highly asymmetric surface heat flux, both past and present. Our understanding the thermal evolution and composition of the bulk moon therefore requires a global picture of the present lunar thermal state, well beyond our two-point Apollo era measurement. As on the on the Earth, heat flow measurements need to be taken in carefully selected locations to truly characterize the state of the planet's interior. Future surface heat flux and seismic observations will be affected by the presence of interior temperature and crustal radiogenic anomalies, so placement of such instruments is critically important for understanding the lunar interior. The unfortunate coincidence that Apollo geophysical measurements lie areas within or directly abutting the highly radiogenic, anomalously thin-crusted Procellarum region highlights the importance of location for in situ geophysical study [e.g. Siegler and Smrekar, 2014]. Here we present the results of new models of global lunar geothermal heat flux. We synthesize data from several recent missions to constrain lunar crustal composition, thickness and density to provide global predictions of the surface heat flux of the Moon. We also discuss implications from new surface heat flux constraints from the LRO Diviner Lunar Radiometer Experiment and Chang'E 2 Microwave Radiometer. We will identify areas with the highest uncertainty to provide insight on the placement of future landed geophysical missions, such as the proposed Lunar Geophysical Network, to better aim our future exploration of the Moon.

  20. Water Cycle Missions for the Next Decade

    Science.gov (United States)

    Houser, P. R.

    2013-12-01

    The global water cycle describes the circulation of water as a vital and dynamic substance in its liquid, solid, and vapor phases as it moves through the atmosphere, oceans and land. Life in its many forms exists because of water, and modern civilization depends on learning how to live within the constraints imposed by the availability of water. The scientific challenge posed by the need to observe the global water cycle is to integrate in situ and space-borne observations to quantify the key water-cycle state variables and fluxes. The vision to address that challenge is a series of Earth observation missions that will measure the states, stocks, flows, and residence times of water on regional to global scales followed by a series of coordinated missions that will address the processes, on a global scale, that underlie variability and changes in water in all its three phases. The accompanying societal challenge is to foster the improved use of water data and information as a basis for enlightened management of water resources, to protect life and property from effects of extremes in the water cycle. A major change in thinking about water science that goes beyond its physics to include its role in ecosystems and society is also required. Better water-cycle observations, especially on the continental and global scales, will be essential. Water-cycle predictions need to be readily available globally to reduce loss of life and property caused by water-related natural hazards. Building on the 2007 Earth Science Decadal Survey, NASA's Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space , and the 2012 Chapman Conference on Remote Sensing of the Terrestrial Water Cycle, a workshop was held in April 2013 to gather wisdom and determine how to prepare for the next generation of water cycle missions in support of the second Earth Science Decadal Survey. This talk will present the outcomes of the workshop including the intersection between

  1. Constraint programming and decision making

    CERN Document Server

    Kreinovich, Vladik

    2014-01-01

    In many application areas, it is necessary to make effective decisions under constraints. Several area-specific techniques are known for such decision problems; however, because these techniques are area-specific, it is not easy to apply each technique to other applications areas. Cross-fertilization between different application areas is one of the main objectives of the annual International Workshops on Constraint Programming and Decision Making. Those workshops, held in the US (El Paso, Texas), in Europe (Lyon, France), and in Asia (Novosibirsk, Russia), from 2008 to 2012, have attracted researchers and practitioners from all over the world. This volume presents extended versions of selected papers from those workshops. These papers deal with all stages of decision making under constraints: (1) formulating the problem of multi-criteria decision making in precise terms, (2) determining when the corresponding decision problem is algorithmically solvable; (3) finding the corresponding algorithms, and making...

  2. Planck 2015 results: XVII. Constraints on primordial non-Gaussianity

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Arnaud, M.

    2016-01-01

    The Planck full mission cosmic microwave background (CMB) temperature and E-mode polarization maps are analysed to obtain constraints on primordial non-Gaussianity (NG). Using three classes of optimal bispectrum estimators – separable template-fitting (KSW), binned, and modal – we obtain consiste...

  3. Planck 2015 results: XX. Constraints on inflation

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Arnaud, M.

    2016-01-01

    data are consistent with adiabatic primordial perturbations, and the estimated values for the parameters of the base Λ cold dark matter (ΛCDM) model are not significantly altered when more general initial conditions are admitted. In correlated mixed adiabatic and isocurvature models, the 95% CL upper...... are consistent with the Planck 2013 analysis based on the nominal mission data and further constrain slow-roll single-field inflationary models, as expected from the increased precision of Planck data using the full set of observations....

  4. Adaptive laser link reconfiguration using constraint propagation

    Science.gov (United States)

    Crone, M. S.; Julich, P. M.; Cook, L. M.

    1993-01-01

    This paper describes Harris AI research performed on the Adaptive Link Reconfiguration (ALR) study for Rome Lab, and focuses on the application of constraint propagation to the problem of link reconfiguration for the proposed space based Strategic Defense System (SDS) Brilliant Pebbles (BP) communications system. According to the concept of operations at the time of the study, laser communications will exist between BP's and to ground entry points. Long-term links typical of RF transmission will not exist. This study addressed an initial implementation of BP's based on the Global Protection Against Limited Strikes (GPALS) SDI mission. The number of satellites and rings studied was representative of this problem. An orbital dynamics program was used to generate line-of-site data for the modeled architecture. This was input into a discrete event simulation implemented in the Harris developed COnstraint Propagation Expert System (COPES) Shell, developed initially on the Rome Lab BM/C3 study. Using a model of the network and several heuristics, the COPES shell was used to develop the Heuristic Adaptive Link Ordering (HALO) Algorithm to rank and order potential laser links according to probability of communication. A reduced set of links based on this ranking would then be used by a routing algorithm to select the next hop. This paper includes an overview of Constraint Propagation as an Artificial Intelligence technique and its embodiment in the COPES shell. It describes the design and implementation of both the simulation of the GPALS BP network and the HALO algorithm in COPES. This is described using a 59 Data Flow Diagram, State Transition Diagrams, and Structured English PDL. It describes a laser communications model and the heuristics involved in rank-ordering the potential communication links. The generation of simulation data is described along with its interface via COPES to the Harris developed View Net graphical tool for visual analysis of communications

  5. Path following control of planar snake robots using virtual holonomic constraints: theory and experiments.

    Science.gov (United States)

    Rezapour, Ehsan; Pettersen, Kristin Y; Liljebäck, Pål; Gravdahl, Jan T; Kelasidi, Eleni

    This paper considers path following control of planar snake robots using virtual holonomic constraints. In order to present a model-based path following control design for the snake robot, we first derive the Euler-Lagrange equations of motion of the system. Subsequently, we define geometric relations among the generalized coordinates of the system, using the method of virtual holonomic constraints. These appropriately defined constraints shape the geometry of a constraint manifold for the system, which is a submanifold of the configuration space of the robot. Furthermore, we show that the constraint manifold can be made invariant by a suitable choice of feedback. In particular, we analytically design a smooth feedback control law to exponentially stabilize the constraint manifold. We show that enforcing the appropriately defined virtual holonomic constraints for the configuration variables implies that the robot converges to and follows a desired geometric path. Numerical simulations and experimental results are presented to validate the theoretical approach.

  6. Planetary protection issues linked to human missions to Mars

    Science.gov (United States)

    Debus, A.

    According to United Nations Treaties and handled presently by the Committee of Space Research COSPAR the exploration of the Solar System has to comply with planetary protection requirements The goal of planetary protection is to protect celestial bodies from terrestrial contamination and also to protect the Earth environment from an eventual biocontamination carried by return samples or by space systems returning to the Earth Mars is presently one of the main target at exobiology point of view and a lot of missions are operating on travel or scheduled for its exploration Some of them include payload dedicated to the search of life or traces of life and one of the goals of these missions is also to prepare sample return missions with the ultimate objective to walk on Mars Robotic missions to Mars have to comply with planetary protection specifications well known presently and planetary protection programs are implemented with a very good reliability taking into account an experience of 40 years now For sample return missions a set of stringent requirements have been approved by the COSPAR and technical challenges have now to be won in order to preserve Earth biosphere from an eventual contamination risk Sending astronauts on Mars will gather all these constraints added with the human dimension of the mission The fact that the astronauts are huge contamination sources for Mars and that they are also potential carrier of a contamination risk back to Earth add also ethical considerations to be considered For the preparation of a such

  7. Mission to Planet Earth

    Science.gov (United States)

    Tilford, Shelby G.; Asrar, Ghassem; Backlund, Peter W.

    1994-01-01

    Mission to Planet Earth (MTPE) is NASA's concept for an international science program to produce the understanding needed to predict changes in the Earth's environment. NASA and its interagency and international partners will place satellites carrying advanced sensors in strategic Earth orbits to gather multidisciplinary data. A sophisticated data system will process and archive an unprecedented amount of information about the Earth and how it works as a system. Increased understanding of the Earth system is a basic human responsibility, a prerequisite to informed management of the planet's resources and to the preservation of the global environment.

  8. The ARTEMIS mission

    CERN Document Server

    Angelopoulos, Vassilis

    2014-01-01

    The ARTEMIS mission was initiated by skillfully moving the two outermost Earth-orbiting THEMIS spacecraft into lunar orbit to conduct unprecedented dual spacecraft observations of the lunar environment. ARTEMIS stands for Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun. Indeed, this volume discusses initial findings related to the Moon’s magnetic and plasma environments and the electrical conductivity of the lunar interior. This work is aimed at researchers and graduate students in both heliophysics and planetary physics. Originally published in Space Science Reviews, Vol. 165/1-4, 2011.

  9. The solar probe mission

    International Nuclear Information System (INIS)

    Feldman, W.C.; Anderson, J.; Bohlin, J.D.; Burlaga, L.F.; Farquhar, R.; Gloeckler, G.; Goldstein, B.E.; Harvey, J.W.; Holzer, T.E.; Jones, W.V.; Kellogg, P.J.; Krimigis, S.M.; Kundu, M.R.; Lazarus, A.J.; Mellott, M.M.; Parker, E.N.; Rosner, R.; Rottman, G.J.; Slavin, J.A.; Suess, S.T.; Tsurutani, B.T.; Woo, R.T.; Zwickl, R.D.

    1990-01-01

    The Solar Probe will deliver a 133.5 kg science payload into a 4 R s perihelion solar polar orbit (with the first perihelion passage in 2004) to explore in situ one of the last frontiers in the solar system---the solar corona. This mission is both affordable and technologically feasible. Using a payload of 12 (predominantly particles and fields) scientific experiments, it will be possible to answer many long-standing, fundamental problems concerning the structure and dynamics of the outer solar atmosphere, including the acceleration, storage, and transport of energetic particles near the Sun and in the inner ( s ) heliosphere

  10. Mission to Planet Earth

    International Nuclear Information System (INIS)

    Wilson, G.S.; Backlund, P.W.

    1992-01-01

    Mission to Planet Earth (MTPE) is NASA's concept for an international science program to produce the understanding needed to predict changes in the earth's environment. NASA and its interagency and international partners will place satellites carrying advanced sensors in strategic earth orbits to gather multidisciplinary data. A sophisticated data system will process and archive an unprecedented amount of information about the earth and how it works as a system. Increased understanding of the earth system is a basic human responsibility, a prerequisite to informed management of the planet's resources and to the preservation of the global environment. 8 refs

  11. Open source IPSEC software in manned and unmanned space missions

    Science.gov (United States)

    Edwards, Jacob

    Network security is a major topic of research because cyber attackers pose a threat to national security. Securing ground-space communications for NASA missions is important because attackers could endanger mission success and human lives. This thesis describes how an open source IPsec software package was used to create a secure and reliable channel for ground-space communications. A cost efficient, reproducible hardware testbed was also created to simulate ground-space communications. The testbed enables simulation of low-bandwidth and high latency communications links to experiment how the open source IPsec software reacts to these network constraints. Test cases were built that allowed for validation of the testbed and the open source IPsec software. The test cases also simulate using an IPsec connection from mission control ground routers to points of interest in outer space. Tested open source IPsec software did not meet all the requirements. Software changes were suggested to meet requirements.

  12. Comet rendezvous mission design using Solar Electric Propulsion

    Science.gov (United States)

    Sackett, L. L.; Hastrup, R. C.; Yen, C.-W. L.; Wood, L. J.

    1979-01-01

    A dual comet (Halley Flyby/Tempel 2 Rendezvous) mission, which is planned to be the first to use the Solar Electric Propulsion System (SEPS), is to be launched in 1985. The purpose of this paper is to describe how the mission design attempts to maximize science return while working within spacecraft and other constraints. Science requirements and desires are outlined and specific instruments are considered. Emphasis is on the strategy for operations in the vicinity of Tempel 2, for which a representative profile is described. The mission is planned to extend about one year past initial rendezvous. Because of the large uncertainty in the comet environment the Tempel 2 operations strategy must be highly adaptive.

  13. An Efficient Energy Constraint Based UAV Path Planning for Search and Coverage

    Directory of Open Access Journals (Sweden)

    German Gramajo

    2017-01-01

    Full Text Available A path planning strategy for a search and coverage mission for a small UAV that maximizes the area covered based on stored energy and maneuverability constraints is presented. The proposed formulation has a high level of autonomy, without requiring an exact choice of optimization parameters, and is appropriate for real-time implementation. The computed trajectory maximizes spatial coverage while closely satisfying terminal constraints on the position of the vehicle and minimizing the time of flight. Comparisons of this formulation to a path planning algorithm based on those with time constraint show equivalent coverage performance but improvement in prediction of overall mission duration and accuracy of the terminal position of the vehicle.

  14. Trajectory Design to Mitigate Risk on the Transiting Exoplanet Survey Satellite (TESS) Mission

    Science.gov (United States)

    Dichmann, Donald

    2016-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will employ a highly eccentric Earth orbit, in 2:1 lunar resonance, reached with a lunar flyby preceded by 3.5 phasing loops. The TESS mission has limited propellant and several orbit constraints. Based on analysis and simulation, we have designed the phasing loops to reduce delta-V and to mitigate risk due to maneuver execution errors. We have automated the trajectory design process and use distributed processing to generate and to optimize nominal trajectories, check constraint satisfaction, and finally model the effects of maneuver errors to identify trajectories that best meet the mission requirements.

  15. Computing group cardinality constraint solutions for logistic regression problems.

    Science.gov (United States)

    Zhang, Yong; Kwon, Dongjin; Pohl, Kilian M

    2017-01-01

    We derive an algorithm to directly solve logistic regression based on cardinality constraint, group sparsity and use it to classify intra-subject MRI sequences (e.g. cine MRIs) of healthy from diseased subjects. Group cardinality constraint models are often applied to medical images in order to avoid overfitting of the classifier to the training data. Solutions within these models are generally determined by relaxing the cardinality constraint to a weighted feature selection scheme. However, these solutions relate to the original sparse problem only under specific assumptions, which generally do not hold for medical image applications. In addition, inferring clinical meaning from features weighted by a classifier is an ongoing topic of discussion. Avoiding weighing features, we propose to directly solve the group cardinality constraint logistic regression problem by generalizing the Penalty Decomposition method. To do so, we assume that an intra-subject series of images represents repeated samples of the same disease patterns. We model this assumption by combining series of measurements created by a feature across time into a single group. Our algorithm then derives a solution within that model by decoupling the minimization of the logistic regression function from enforcing the group sparsity constraint. The minimum to the smooth and convex logistic regression problem is determined via gradient descent while we derive a closed form solution for finding a sparse approximation of that minimum. We apply our method to cine MRI of 38 healthy controls and 44 adult patients that received reconstructive surgery of Tetralogy of Fallot (TOF) during infancy. Our method correctly identifies regions impacted by TOF and generally obtains statistically significant higher classification accuracy than alternative solutions to this model, i.e., ones relaxing group cardinality constraints. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. STS-61 mission director's post-mission report

    Science.gov (United States)

    Newman, Ronald L.

    1995-01-01

    To ensure the success of the complex Hubble Space Telescope servicing mission, STS-61, NASA established a number of independent review groups to assess management, design, planning, and preparation for the mission. One of the resulting recommendations for mission success was that an overall Mission Director be appointed to coordinate management activities of the Space Shuttle and Hubble programs and to consolidate results of the team reviews and expedite responses to recommendations. This report presents pre-mission events important to the experience base of mission management, with related Mission Director's recommendations following the event(s) to which they apply. All Mission Director's recommendations are presented collectively in an appendix. Other appendixes contain recommendations from the various review groups, including Payload Officers, the JSC Extravehicular Activity (EVA) Section, JSC EVA Management Office, JSC Crew and Thermal Systems Division, and the STS-61 crew itself. This report also lists mission events in chronological order and includes as an appendix a post-mission summary by the lead Payload Deployment and Retrieval System Officer. Recommendations range from those pertaining to specific component use or operating techniques to those for improved management, review, planning, and safety procedures.

  17. Computational needs survey of NASA automation and robotics missions. Volume 2: Appendixes

    Science.gov (United States)

    Davis, Gloria J.

    1991-01-01

    NASA's operational use of advanced processor technology in space systems lags behind its commercial development by more than eight years. One of the factors contributing to this is the fact that mission computing requirements are frequency unknown, unstated, misrepresented, or simply not available in a timely manner. NASA must provide clear common requirements to make better use of available technology, to cut development lead time on deployable architectures, and to increase the utilization of new technology. Here, NASA, industry and academic communities are provided with a preliminary set of advanced mission computational processing requirements of automation and robotics (A and R) systems. The results were obtained in an assessment of the computational needs of current projects throughout NASA. The high percent of responses indicated a general need for enhanced computational capabilities beyond the currently available 80386 and 68020 processor technology. Because of the need for faster processors and more memory, 90 percent of the polled automation projects have reduced or will reduce the scope of their implemented capabilities. The requirements are presented with respect to their targeted environment, identifying the applications required, system performance levels necessary to support them, and the degree to which they are met with typical programmatic constraints. Here, appendixes are provided.

  18. Computational needs survey of NASA automation and robotics missions. Volume 1: Survey and results

    Science.gov (United States)

    Davis, Gloria J.

    1991-01-01

    NASA's operational use of advanced processor technology in space systems lags behind its commercial development by more than eight years. One of the factors contributing to this is that mission computing requirements are frequently unknown, unstated, misrepresented, or simply not available in a timely manner. NASA must provide clear common requirements to make better use of available technology, to cut development lead time on deployable architectures, and to increase the utilization of new technology. A preliminary set of advanced mission computational processing requirements of automation and robotics (A&R) systems are provided for use by NASA, industry, and academic communities. These results were obtained in an assessment of the computational needs of current projects throughout NASA. The high percent of responses indicated a general need for enhanced computational capabilities beyond the currently available 80386 and 68020 processor technology. Because of the need for faster processors and more memory, 90 percent of the polled automation projects have reduced or will reduce the scope of their implementation capabilities. The requirements are presented with respect to their targeted environment, identifying the applications required, system performance levels necessary to support them, and the degree to which they are met with typical programmatic constraints. Volume one includes the survey and results. Volume two contains the appendixes.

  19. Planning for Crew Exercise for Future Deep Space Mission Scenarios

    Science.gov (United States)

    Moore, Cherice; Ryder, Jeff

    2015-01-01

    Providing the necessary exercise capability to protect crew health for deep space missions will bring new sets of engineering and research challenges. Exercise has been found to be a necessary mitigation for maintaining crew health on-orbit and preparing the crew for return to earth's gravity. Health and exercise data from Apollo, Space Lab, Shuttle, and International Space Station missions have provided insight into crew deconditioning and the types of activities that can minimize the impacts of microgravity on the physiological systems. The hardware systems required to implement exercise can be challenging to incorporate into spaceflight vehicles. Exercise system design requires encompassing the hardware required to provide mission specific anthropometrical movement ranges, desired loads, and frequencies of desired movements as well as the supporting control and monitoring systems, crew and vehicle interfaces, and vibration isolation and stabilization subsystems. The number of crew and operational constraints also contribute to defining the what exercise systems will be needed. All of these features require flight vehicle mass and volume integrated with multiple vehicle systems. The International Space Station exercise hardware requires over 1,800 kg of equipment and over 24 m3 of volume for hardware and crew operational space. Improvements towards providing equivalent or better capabilities with a smaller vehicle impact will facilitate future deep space missions. Deep space missions will require more understanding of the physiological responses to microgravity, understanding appropriate mitigations, designing the exercise systems to provide needed mitigations, and integrating effectively into vehicle design with a focus to support planned mission scenarios. Recognizing and addressing the constraints and challenges can facilitate improved vehicle design and exercise system incorporation.

  20. Constraint elimination in dynamical systems

    Science.gov (United States)

    Singh, R. P.; Likins, P. W.

    1989-01-01

    Large space structures (LSSs) and other dynamical systems of current interest are often extremely complex assemblies of rigid and flexible bodies subjected to kinematical constraints. A formulation is presented for the governing equations of constrained multibody systems via the application of singular value decomposition (SVD). The resulting equations of motion are shown to be of minimum dimension.

  1. Constraint Programming versus Mathematical Programming

    DEFF Research Database (Denmark)

    Hansen, Jesper

    2003-01-01

    Constraint Logic Programming (CLP) is a relatively new technique from the 80's with origins in Computer Science and Artificial Intelligence. Lately, much research have been focused on ways of using CLP within the paradigm of Operations Research (OR) and vice versa. The purpose of this paper...

  2. Sterile neutrino constraints from cosmology

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, Georg G.

    2012-01-01

    The presence of light particles beyond the standard model's three neutrino species can profoundly impact the physics of decoupling and primordial nucleosynthesis. I review the observational signatures of extra light species, present constraints from recent data, and discuss the implications of po...... of possible sterile neutrinos with O(eV)-masses for cosmology....

  3. Intertemporal consumption and credit constraints

    DEFF Research Database (Denmark)

    Leth-Petersen, Søren

    2010-01-01

    There is continuing controversy over the importance of credit constraints. This paper investigates whether total household expenditure and debt is affected by an exogenous increase in access to credit provided by a credit market reform that enabled Danish house owners to use housing equity...

  4. Financial Constraints: Explaining Your Position.

    Science.gov (United States)

    Cargill, Jennifer

    1988-01-01

    Discusses the importance of educating library patrons about the library's finances and the impact of budget constraints and the escalating cost of serials on materials acquisition. Steps that can be taken in educating patrons by interpreting and publicizing financial information are suggested. (MES)

  5. Planck 2015. XX. Constraints on inflation

    CERN Document Server

    Ade, P.A.R.; Arnaud, M.; Arroja, F.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Ballardini, M.; Banday, A.J.; Barreiro, R.B.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit, A.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R.C.; Calabrese, E.; Cardoso, J.F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.R.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Contreras, D.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Desert, F.X.; Diego, J.M.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Ensslin, T.A.; Eriksen, H.K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Frejsel, A.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Gauthier, C.; Giard, M.; Giraud-Heraud, Y.; Gjerlow, E.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hamann, J.; Handley, W.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huang, Z.; Huffenberger, K.M.; Hurier, G.; Jaffe, A.H.; Jaffe, T.R.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kim, J.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lahteenmaki, A.; Lamarre, J.M.; Lasenby, A.; Lattanzi, M.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Lewis, A.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Ma, Y.Z.; Macias-Perez, J.F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; McGehee, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschenes, M.A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munchmeyer, M.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Pandolfi, S.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T.J.; Peiris, H.V.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G.W.; Prezeau, G.; Prunet, S.; Puget, J.L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rowan-Robinson, M.; Rubino-Martin, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Shiraishi, M.; Spencer, L.D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Trombetti, T.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L.A.; Wandelt, B.D.; Wehus, I.K.; White, M.; Yvon, D.; Zacchei, A.; Zibin, J.P.; Zonca, A.

    2016-09-20

    We present the implications for cosmic inflation of the Planck measurements of the cosmic microwave background (CMB) anisotropies in both temperature and polarization based on the full Planck survey. The Planck full mission temperature data and a first release of polarization data on large angular scales measure the spectral index of curvature perturbations to be $n_\\mathrm{s} = 0.968 \\pm 0.006$ and tightly constrain its scale dependence to $d n_s/d \\ln k =-0.003 \\pm 0.007$ when combined with the Planck lensing likelihood. When the high-$\\ell$ polarization data is included, the results are consistent and uncertainties are reduced. The upper bound on the tensor-to-scalar ratio is $r_{0.002} < 0.11$ (95% CL), consistent with the B-mode polarization constraint $r< 0.12$ (95% CL) obtained from a joint BICEP2/Keck Array and Planck analysis. These results imply that $V(\\phi) \\propto \\phi^2$ and natural inflation are now disfavoured compared to models predicting a smaller tensor-to-scalar ratio, such as $R^2$ ...

  6. Solar maximum mission

    International Nuclear Information System (INIS)

    Ryan, J.

    1981-01-01

    By understanding the sun, astrophysicists hope to expand this knowledge to understanding other stars. To study the sun, NASA launched a satellite on February 14, 1980. The project is named the Solar Maximum Mission (SMM). The satellite conducted detailed observations of the sun in collaboration with other satellites and ground-based optical and radio observations until its failure 10 months into the mission. The main objective of the SMM was to investigate one aspect of solar activity: solar flares. A brief description of the flare mechanism is given. The SMM satellite was valuable in providing information on where and how a solar flare occurs. A sequence of photographs of a solar flare taken from SMM satellite shows how a solar flare develops in a particular layer of the solar atmosphere. Two flares especially suitable for detailed observations by a joint effort occurred on April 30 and May 21 of 1980. These flares and observations of the flares are discussed. Also discussed are significant discoveries made by individual experiments

  7. The Euclid mission design

    Science.gov (United States)

    Racca, Giuseppe D.; Laureijs, René; Stagnaro, Luca; Salvignol, Jean-Christophe; Lorenzo Alvarez, José; Saavedra Criado, Gonzalo; Gaspar Venancio, Luis; Short, Alex; Strada, Paolo; Bönke, Tobias; Colombo, Cyril; Calvi, Adriano; Maiorano, Elena; Piersanti, Osvaldo; Prezelus, Sylvain; Rosato, Pierluigi; Pinel, Jacques; Rozemeijer, Hans; Lesna, Valentina; Musi, Paolo; Sias, Marco; Anselmi, Alberto; Cazaubiel, Vincent; Vaillon, Ludovic; Mellier, Yannick; Amiaux, Jérôme; Berthé, Michel; Sauvage, Marc; Azzollini, Ruyman; Cropper, Mark; Pottinger, Sabrina; Jahnke, Knud; Ealet, Anne; Maciaszek, Thierry; Pasian, Fabio; Zacchei, Andrea; Scaramella, Roberto; Hoar, John; Kohley, Ralf; Vavrek, Roland; Rudolph, Andreas; Schmidt, Micha

    2016-07-01

    Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the nature of dark energy, dark matter and gravity by observing the geometry of the Universe and on the formation of structures over cosmological timescales. Euclid will use two probes of the signature of dark matter and energy: Weak gravitational Lensing, which requires the measurement of the shape and photometric redshifts of distant galaxies, and Galaxy Clustering, based on the measurement of the 3-dimensional distribution of galaxies through their spectroscopic redshifts. The mission is scheduled for launch in 2020 and is designed for 6 years of nominal survey operations. The Euclid Spacecraft is composed of a Service Module and a Payload Module. The Service Module comprises all the conventional spacecraft subsystems, the instruments warm electronics units, the sun shield and the solar arrays. In particular the Service Module provides the extremely challenging pointing accuracy required by the scientific objectives. The Payload Module consists of a 1.2 m three-mirror Korsch type telescope and of two instruments, the visible imager and the near-infrared spectro-photometer, both covering a large common field-of-view enabling to survey more than 35% of the entire sky. All sensor data are downlinked using K-band transmission and processed by a dedicated ground segment for science data processing. The Euclid data and catalogues will be made available to the public at the ESA Science Data Centre.

  8. EU Universities’ Mission Statements

    Directory of Open Access Journals (Sweden)

    Liudmila Arcimaviciene

    2015-04-01

    Full Text Available In the last 10 years, a highly productive space of metaphor analysis has been established in the discourse studies of media, politics, business, and education. In the theoretical framework of Conceptual Metaphor Theory and Critical Discourse Analysis, the restored metaphorical patterns are especially valued for their implied ideological value as realized both conceptually and linguistically. By using the analytical framework of Critical Metaphor Analysis and procedurally employing Pragglejaz Group’s Metaphor Identification Procedure, this study aims at analyzing the implied value of the evoked metaphors in the mission statements of the first 20 European Universities, according to the Webometrics ranking. In this article, it is proposed that Universities’ mission statements are based on the positive evaluation of the COMMERCE metaphor, which does not fully correlate with the ideological framework of sustainability education but is rather oriented toward consumerism in both education and society. Despite this overall trend, there are some traceable features of the conceptualization reflecting the sustainability approach to higher education, as related to freedom of speech, tolerance, and environmental concerns. Nonetheless, these are suppressed by the metaphoric usages evoking traditional dogmas of the conservative ideology grounded in the concepts of the transactional approach to relationship, competitiveness for superiority, the importance of self-interest and strength, and quantifiable quality.

  9. STS-78 Mission Insignia

    Science.gov (United States)

    1996-01-01

    The STS-78 patch links past with present to tell the story of its mission and science through a design imbued with the strength and vitality of the 2-dimensional art of North America's northwest coast Indians. Central to the design is the space Shuttle whose bold lines and curves evoke the Indian image for the eagle, a native American symbol of power and prestige as well as the national symbol of the United States. The wings of the Shuttle suggest the wings of the eagle whose feathers, indicative of peace and friendship in Indian tradition, are captured by the U forms, a characteristic feature of Northwest coast Indian art. The nose of the Shuttle is the strong downward curve of the eagle's beak, and the Shuttle's forward windows, the eagle's eyes, represented through the tapered S forms again typical of this Indian art form. The basic black and red atoms orbiting the mission number recall the original NASA emblem while beneath, utilizing Indian ovoid forms, the major mission scientific experiment package LMS (Life and Materials Sciences) housed in the Shuttle's cargo bay is depicted in a manner reminiscent of totem-pole art. This image of a bird poised for flight, so common to Indian art, is counterpointed by an equally familiar Tsimshian Indian symbol, a pulsating sun with long hyperbolic rays, the symbol of life. Within each of these rays are now encased crystals, the products of this mission's 3 major, high-temperature materials processing furnaces. And as the sky in Indian lore is a lovely open country, home of the Sun Chief and accessible to travelers through a hole in the western horizon, so too, space is a vast and beckoning landscape for explorers launched beyond the horizon. Beneath the Tsimshian sun, the colors of the earth limb are appropriately enclosed by a red border representing life to the Northwest coast Indians. The Indian colors of red, navy blue, white, and black pervade the STS-78 path. To the right of the Shuttle-eagle, the constellation

  10. Density Control of Multi-Agent Systems with Safety Constraints: A Markov Chain Approach

    Science.gov (United States)

    Demirer, Nazli

    The control of systems with autonomous mobile agents has been a point of interest recently, with many applications like surveillance, coverage, searching over an area with probabilistic target locations or exploring an area. In all of these applications, the main goal of the swarm is to distribute itself over an operational space to achieve mission objectives specified by the density of swarm. This research focuses on the problem of controlling the distribution of multi-agent systems considering a hierarchical control structure where the whole swarm coordination is achieved at the high-level and individual vehicle/agent control is managed at the low-level. High-level coordination algorithms uses macroscopic models that describes the collective behavior of the whole swarm and specify the agent motion commands, whose execution will lead to the desired swarm behavior. The low-level control laws execute the motion to follow these commands at the agent level. The main objective of this research is to develop high-level decision control policies and algorithms to achieve physically realizable commanding of the agents by imposing mission constraints on the distribution. We also make some connections with decentralized low-level motion control. This dissertation proposes a Markov chain based method to control the density distribution of the whole system where the implementation can be achieved in a decentralized manner with no communication between agents since establishing communication with large number of agents is highly challenging. The ultimate goal is to guide the overall density distribution of the system to a prescribed steady-state desired distribution while satisfying desired transition and safety constraints. Here, the desired distribution is determined based on the mission requirements, for example in the application of area search, the desired distribution should match closely with the probabilistic target locations. The proposed method is applicable for both

  11. Causal vs. analytic constraints on anomalous quartic gauge couplings

    International Nuclear Information System (INIS)

    Vecchi, L.

    2007-01-01

    We derive one loop constraints on the anomalous quartic gauge couplings using a general non-forward dispersion relation for the elastic scattering amplitude of two longitudinally polarized vector bosons. We show that for exactly chiral theories more stringent bounds can be obtained by the assumption that the underlying theory satisfies the causality principle of Special Relativity

  12. Causal vs. Analytic constraints on anomalous quartic gauge couplings

    OpenAIRE

    Vecchi, Luca

    2007-01-01

    We derive one loop constraints on the anomalous quartic gauge couplings using a general non-forward dispersion relation for the elastic scattering amplitude of two longitudinally polarized vector bosons. We compare this result with another one derived by the assumption that the underlying theory satisfies the causality principle of Special Relativity and show that this latter is more constraining.

  13. Bond constraint theory and the quest for the glass computer

    Indian Academy of Sciences (India)

    The tool that leads to this deeper understanding is the bond constraint theory. We explain how this theory leads to an explanation of switching and of the behavior and properties of amorphous materials in general. Finally, the prospects for developing. GST-related materials into non-volatile memory media that could be the ...

  14. Mission Analysis and Orbit Control of Interferometric Wheel Formation Flying

    Science.gov (United States)

    Fourcade, J.

    Flying satellite in formation requires maintaining the specific relative geometry of the spacecraft with high precision. This requirement raises new problem of orbit control. This paper presents the results of the mission analysis of a low Earth observation system, the interferometric wheel, patented by CNES. This wheel is made up of three receiving spacecraft, which follow an emitting Earth observation radar satellite. The first part of this paper presents trades off which were performed to choose orbital elements of the formation flying which fulfils all constraints. The second part presents orbit positioning strategies including reconfiguration of the wheel to change its size. The last part describes the station keeping of the formation. Two kinds of constraints are imposed by the interferometric system : a constraint on the distance between the wheel and the radar satellite, and constraints on the distance between the wheel satellites. The first constraint is fulfilled with a classical chemical station keeping strategy. The second one is fulfilled using pure passive actuators. Due to the high stability of the relative eccentricity of the formation, only the relative semi major axis had to be controlled. Differential drag due to differential attitude motion was used to control relative altitude. An autonomous orbit controller was developed and tested. The final accuracy is a relative station keeping better than few meters for a wheel size of one kilometer.

  15. Effect of Financial Constraint and Financial Incentive on Supply Efficient of Providing Public Goods in Public-Private-Partnership Mode: General Equilibrium Analysis Based on Incomplete Contracting Theory%融资激励和融资约束对PPP模式下公共产品提供效率的影响——基于不完全契约理论的一般均衡分析

    Institute of Scientific and Technical Information of China (English)

    蔡东方; 孔淑红

    2017-01-01

    This paper compares the effects of financial constraint and financial incentive in public-private-partnership(PPP) mode on the supply efficient of public goods and social welfare,and analyzes the efficiency loss under financial constraints by constructing a general equilibrium model based on the incomplete contracting theory.The result shows as follows:depending on the professionalization,financial incentives from private sectors could improve the productivity of public goods,but financial constraints eliminate the benefit of professionalization,which results in the loss of social welfare.Finally,it suggests that the government should break the financial constraints and institutional discrimination,and improve financial market,and introduce specialized private sectors into the various industries of public goods in fair and competitive market environment.%通过构建不完全契约理论下的一般均衡模型,对比分析了PPP模式中的融资约束和融资激励对公共产品提供效率和社会福利的影响,并探讨了融资约束条件下的效率损失.结果显示:私人融资的专业性可以提高公共产品合意程度,但是私人部门的融资约束会抵消其专业性带来的好处,导致社会福利损失.最后针对民营企业参与PPP项目对政府提出建议:必须打破融资约束和制度歧视,完善和规范金融市场,在公平、竞争的市场环境下引入专业机构参与公共产品提供的各个领域.

  16. SOLON: An autonomous vehicle mission planner

    Science.gov (United States)

    Dudziak, M. J.

    1987-01-01

    The State-Operator Logic Machine (SOLON) Planner provides an architecture for effective real-time planning and replanning for an autonomous vehicle. The highlights of the system, which distinguish it from other AI-based planners that have been designed previously, are its hybrid application of state-driven control architecture and the use of both schematic representations and logic programming for the management of its knowledge base. SOLON is designed to provide multiple levels of planning for a single autonomous vehicle which is supplied with a skeletal, partially-specified mission plan at the outset of the vehicle's operations. This mission plan consists of a set of objectives, each of which will be decomposable by the planner into tasks. These tasks are themselves comparatively complex sets of actions which are executable by a conventional real-time control system which does not perform planning but which is capable of making adjustments or modifications to the provided tasks according to constraints and tolerances provided by the Planner. The current implementation of the SOLON is in the form of a real-time simulation of the Planner module of an Intelligent Vehicle Controller (IVC) on-board an autonomous underwater vehicle (AUV). The simulation is embedded within a larger simulator environment known as ICDS (Intelligent Controller Development System) operating on a Symbolics 3645/75 computer.

  17. Interactive Dynamic Mission Scheduling for ASCA

    Science.gov (United States)

    Antunes, A.; Nagase, F.; Isobe, T.

    The Japanese X-ray astronomy satellite ASCA (Advanced Satellite for Cosmology and Astrophysics) mission requires scheduling for each 6-month observation phase, further broken down into weekly schedules at a few minutes resolution. Two tools, SPIKE and NEEDLE, written in Lisp and C, use artificial intelligence (AI) techniques combined with a graphic user interface for fast creation and alteration of mission schedules. These programs consider viewing and satellite attitude constraints as well as observer-requested criteria and present an optimized set of solutions for review by the planner. Six-month schedules at 1 day resolution are created for an oversubscribed set of targets by the SPIKE software, originally written for HST and presently being adapted for EUVE, XTE and AXAF. The NEEDLE code creates weekly schedules at 1 min resolution using in-house orbital routines and creates output for processing by the command generation software. Schedule creation on both the long- and short-term scale is rapid, less than 1 day for long-term, and one hour for short-term.

  18. IMP - INTEGRATED MISSION PROGRAM

    Science.gov (United States)

    Dauro, V. A.

    1994-01-01

    IMP is a simulation language that is used to model missions around the Earth, Moon, Mars, or other planets. It has been used to model missions for the Saturn Program, Apollo Program, Space Transportation System, Space Exploration Initiative, and Space Station Freedom. IMP allows a user to control the mission being simulated through a large event/maneuver menu. Up to three spacecraft may be used: a main, a target and an observer. The simulation may begin at liftoff, suborbital, or orbital. IMP incorporates a Fehlberg seventh order, thirteen evaluation Runge-Kutta integrator with error and step-size control to numerically integrate the equations of motion. The user may choose oblate or spherical gravity for the central body (Earth, Mars, Moon or other) while a spherical model is used for the gravity of an additional perturbing body. Sun gravity and pressure and Moon gravity effects are user-selectable. Earth/Mars atmospheric effects can be included. The optimum thrust guidance parameters are calculated automatically. Events/maneuvers may involve many velocity changes, and these velocity changes may be impulsive or of finite duration. Aerobraking to orbit is also an option. Other simulation options include line-of-sight communication guidelines, a choice of propulsion systems, a soft landing on the Earth or Mars, and rendezvous with a target vehicle. The input/output is in metric units, with the exception of thrust and weight which are in English units. Input is read from the user's input file to minimize real-time keyboard input. Output includes vehicle state, orbital and guide parameters, event and total velocity changes, and propellant usage. The main output is to the user defined print file, but during execution, part of the input/output is also displayed on the screen. An included FORTRAN program, TEKPLOT, will display plots on the VDT as well as generating a graphic file suitable for output on most laser printers. The code is double precision. IMP is written in

  19. Moon manned missions radiation safety analysis

    Science.gov (United States)

    Tripathi, R. K.; Wilson, J. W.; de Anlelis, G.; Badavi, F. F.

    An analysis is performed on the radiation environment found on the surface of the Moon, and applied to different possible lunar base mission scenarios. An optimization technique has been used to obtain mission scenarios minimizing the astronaut radiation exposure and at the same time controlling the effect of shielding, in terms of mass addition and material choice, as a mission cost driver. The optimization process has been realized through minimization of mass along all phases of a mission scenario, in terms of time frame (dates, transfer time length and trajectory, radiation environment), equipment (vehicles, in terms of shape, volume, onboard material choice, size and structure), location (if in space, on the surface, inside or outside a certain habitats), crew characteristics (number, gender, age, tasks) and performance required (spacecraft and habitat volumes), radiation exposure annual and career limit constraint (from NCRP 132), and implementation of the ALARA principle (shelter from the occurrence of Solar Particle Events). On the lunar surface the most important contribution to radiation exposure is given by background Galactic Cosmic Rays (GCR) particles, mostly protons, alpha particles, and some heavy ions, and by locally induced particles, mostly neutrons, created by the interaction between GCR and surface material and emerging from below the surface due to backscattering processes. In this environment manned habitats are to host future crews involved in the construction and/or in the utilization of moon based infrastructure. Three different kinds of lunar missions are considered in the analysis, Moon Base Construction Phase, during which astronauts are on the surface just to build an outpost for future resident crews, Moon Base Outpost Phase, during which astronaut crews are resident but continuing exploration and installation activities, and Moon Base Routine Phase, with long-term shifting resident crews. In each scenario various kinds of habitats

  20. The Long, Bumpy Road to a Mars Aeronomy Mission (Invited)

    Science.gov (United States)

    Grebowsky, J. M.; Luhmann, J. G.; Bougher, S. W.; Jakosky, B. M.

    2013-12-01

    With the advent of the space age, early focus was put into characterizing the Earth's upper atmosphere with aeronomy missions. These missions were designed to study the upper atmosphere region of a planet where the ionosphere is produced with particular attention given to the composition, properties and motion of atmosphere constituents. In particular a very successful US series of Atmosphere Explorer aeronomy spacecraft (1963-1977) was implemented. This upper atmosphere region is the envelope that all energy from the sun must penetrate and is recognized as an inseparable part of a planet's entire atmosphere. Venus was the next planet to have its upper atmosphere/ionosphere deeply probed via the Pioneer Venus Orbiter (1978-1986) that carried a complement of instruments similar to some flown on the Atmosphere Explorers. The planet which humans have long set their imagination on, Mars, has yet to be subjected to the same detailed upper atmosphere perusal until now, with MAVEN. Not that attempts have been wanting. More than 30 spacecraft launches to Mars were attempted, but half were not successful and those that attained orbit came far short of attaining the same level of knowledge of the Martian upper atmosphere. Other countries had planned Mars aeronomy missions that didn't bear fruit - e.g. Mars-96 and Nozomi and the US did studies for two missions, Mars Aeronomy Orbiter and MUADEE, that never were implemented. This is about to change. NASA's Scout Program singled out two aeronomy missions in its final competition and the selected mission, MAVEN, will fly with the needed sophistication of instruments to finally probe and understand the top of Mars' atmosphere. Was this late selection of a NASA aeronomy mission to Mars a philosophy change in US priorities or was it an accident of planning and budget constraints? Was it driven by the developing knowledge that Mars really had an early atmosphere environment conducive to life and that an aeronomy mission is indeed

  1. New Space at Airbus Defence & Space to facilitate science missions

    Science.gov (United States)

    Boithias, Helene; Benchetrit, Thierry

    2016-10-01

    In addition to Airbus legacy activities, where Airbus satellites usually enable challenging science missions such as Venus Express, Mars Express, Rosetta with an historic landing on a comet, Bepi Colombo mission to Mercury and JUICE to orbit around Jupiter moon Ganymede, Swarm studying the Earth magnetic field, Goce to measure the Earth gravitational field and Cryosat to monitor the Earth polar ice, Airbus is now developing a new approach to facilitate next generation missions.After more than 25 years of collaboration with the scientists on space missions, Airbus has demonstrated its capacity to implement highly demanding missions implying a deep understanding of the science mission requirements and their intrinsic constraints such as- a very fierce competition between the scientific communities,- the pursuit of high maturity for the science instrument in order to be selected,- the very strict institutional budget limiting the number of operational missions.As a matter of fact, the combination of these constraints may lead to the cancellation of valuable missions.Based on that and inspired by the New Space trend, Airbus is developing an highly accessible concept called HYPE.The objective of HYPE is to make access to Space much more simple, affordable and efficient.With a standardized approach, the scientist books only the capacities he needs among the resources available on-board, as the HYPE satellites can host a large range of payloads from 1kg up to 60kg.At prices significantly more affordable than those of comparable dedicated satellite, HYPE is by far a very cost-efficient way of bringing science missions to life.After the launch, the scientist enjoys a plug-and-play access to two-way communications with his instrument through a secure high-speed portal available online 24/7.Everything else is taken care of by Airbus: launch services and the associated risk, reliable power supply, setting up and operating the communication channels, respect of space law

  2. Cost-Effective Icy Bodies Exploration using Small Satellite Missions

    Science.gov (United States)

    Jonsson, Jonas; Mauro, David; Stupl, Jan; Nayak, Michael; Aziz, Jonathan; Cohen, Aaron; Colaprete, Anthony; Dono-Perez, Andres; Frost, Chad; Klamm, Benjamin; hide

    2015-01-01

    It has long been known that Saturn's moon Enceladus is expelling water-rich plumes into space, providing passing spacecraft with a window into what is hidden underneath its frozen crust. Recent discoveries indicate that similar events could also occur on other bodies in the solar system, such as Jupiter's moon Europa and the dwarf planet Ceres in the asteroid belt. These plumes provide a possible giant leap forward in the search for organics and assessing habitability beyond Earth, stepping stones toward the long-term goal of finding extraterrestrial life. The United States Congress recently requested mission designs to Europa, to fit within a cost cap of $1B, much less than previous mission designs' estimates. Here, innovative cost-effective small spacecraft designs for the deep-space exploration of these icy worlds, using new and emerging enabling technologies, and how to explore the outer solar system on a budget below the cost horizon of a flagship mission, are investigated. Science requirements, instruments selection, rendezvous trajectories, and spacecraft designs are some topics detailed. The mission concepts revolve around a comparably small-sized and low-cost Plume Chaser spacecraft, instrumented to characterize the vapor constituents encountered on its trajectory. In the event that a plume is not encountered, an ejecta plume can be artificially created by a companion spacecraft, the Plume Maker, on the target body at a location timed with the passage of the Plume Chaser spacecraft. Especially in the case of Ceres, such a mission could be a great complimentary mission to Dawn, as well as a possible future Europa Clipper mission. The comparably small volume of the spacecraft enables a launch to GTO as a secondary payload, providing multiple launch opportunities per year. Plume Maker's design is nearly identical to the Plume Chaser, and fits within the constraints for a secondary payload launch. The cost-effectiveness of small spacecraft missions enables the

  3. The Waste Negotiator's mission

    International Nuclear Information System (INIS)

    Bataille, Christian

    1993-01-01

    The mission of the Waste Negotiator is to seek out sites for deep underground laboratories to study their potential for disposal of high level radioactive waste. Although appointed by the government, he acts independently. In 1990, faced by severe public criticism at the way that the waste disposal was being handled, and under increasing pressure to find an acceptable solution, the government stopped the work being carried out by ANDRA (Agence nationale pour la gestion des dechets radioactifs) and initiated a full review of the issues involved. At the same time, parliament also started its own extensive investigation to find a way forward. These efforts finally led to the provision of a detailed framework for the management of long lived radioactive waste, including the construction of two laboratories to investigate possible repository sites. The Waste Negotiator was appointed to carry out a full consultative process in the communities which are considering accepting an underground laboratory. (Author)

  4. Creativity from Constraints in Engineering Design

    DEFF Research Database (Denmark)

    Onarheim, Balder

    2012-01-01

    This paper investigates the role of constraints in limiting and enhancing creativity in engineering design. Based on a review of literature relating constraints to creativity, the paper presents a longitudinal participatory study from Coloplast A/S, a major international producer of disposable...... and ownership of formal constraints played a crucial role in defining their influence on creativity – along with the tacit constraints held by the designers. The designers were found to be highly constraint focused, and four main creative strategies for constraint manipulation were observed: blackboxing...

  5. STS-40 Mission Insignia

    Science.gov (United States)

    1990-01-01

    The STS-40 patch makes a contemporary statement focusing on human beings living and working in space. Against a background of the universe, seven silver stars, interspersed about the orbital path of Columbia, represent the seven crew members. The orbiter's flight path forms a double-helix, designed to represent the DNA molecule common to all living creatures. In the words of a crew spokesman, ...(the helix) affirms the ceaseless expansion of human life and American involvement in space while simultaneously emphasizing the medical and biological studies to which this flight is dedicated. Above Columbia, the phrase Spacelab Life Sciences 1 defines both the Shuttle mission and its payload. Leonardo Da Vinci's Vitruvian man, silhouetted against the blue darkness of the heavens, is in the upper center portion of the patch. With one foot on Earth and arms extended to touch Shuttle's orbit, the crew feels, he serves as a powerful embodiment of the extension of human inquiry from the boundaries of Earth to the limitless laboratory of space. Sturdily poised amid the stars, he serves to link scentists on Earth to the scientists in space asserting the harmony of efforts which produce meaningful scientific spaceflight missions. A brilliant red and yellow Earth limb (center) links Earth to space as it radiates from a native American symbol for the sun. At the frontier of space, the traditional symbol for the sun vividly links America's past to America's future, the crew states. Beneath the orbiting Shuttle, darkness of night rests peacefully over the United States. Drawn by artist Sean Collins, the STS 40 Space Shuttle patch was designed by the crewmembers for the flight.

  6. NASA CYGNSS Mission Overview

    Science.gov (United States)

    Ruf, C. S.; Balasubramaniam, R.; Gleason, S.; McKague, D. S.; O'Brien, A.

    2017-12-01

    The CYGNSS constellation of eight satellites was successfully launched on 15 December 2016 into a low inclination (tropical) Earth orbit. Each satellite carries a four-channel bi-static radar receiver that measures GPS signals scattered by the ocean, from which ocean surface roughness, near surface wind speed, and air-sea latent heat flux are estimated. The measurements are unique in several respects, most notably in their ability to penetrate through all levels of precipitation, made possible by the low frequency at which GPS operates, and in the frequent sampling of tropical cyclone intensification and of the diurnal cycle of winds, made possible by the large number of satellites. Engineering commissioning of the constellation was successfully completed in March 2017 and the mission is currently in the early phase of science operations. Level 2 science data products have been developed for near surface (10 m referenced) ocean wind speed, ocean surface roughness (mean square slope) and latent heat flux. Level 3 gridded versions of the L2 products have also been developed. A set of Level 4 products have also been developed specifically for direct tropical cyclone overpasses. These include the storm intensity (peak sustained winds) and size (radius of maximum winds), its extent (34, 50 and 64 knot wind radii), and its integrated kinetic energy. Assimilation of CYGNSS L2 wind speed data into the HWRF hurricane weather prediction model has also been developed. An overview and the current status of the mission will be presented, together with highlights of early on-orbit performance and scientific results.

  7. 6 January 2011 - Extraordinary and plenipotentiary Ambassador M. Kovačič, Permanent Representative of the Republic of Slovenia to the United Nations Office and other international Organisations at Geneva (and Permanent Mission Staff)signing the guest book with CERN Director-General R. Heuer; in the ATLAS visitor centre, ATLAS underground area and LHC tunnel with Collaboration Spokesperson F. Gianotti and Adviser T. Kurtyka.

    CERN Multimedia

    Jean-Claude Gadmer

    2011-01-01

    6 January 2011 - Extraordinary and plenipotentiary Ambassador M. Kovačič, Permanent Representative of the Republic of Slovenia to the United Nations Office and other international Organisations at Geneva (and Permanent Mission Staff)signing the guest book with CERN Director-General R. Heuer; in the ATLAS visitor centre, ATLAS underground area and LHC tunnel with Collaboration Spokesperson F. Gianotti and Adviser T. Kurtyka.

  8. IAEA Remediation Mission Issues Final Report

    International Nuclear Information System (INIS)

    2011-01-01

    Full text: A team of international experts today completed their assessment of the strategy and plans being considered by the Japanese authorities to remediate the areas off-site TEPCO's Fukushima Daiichi Nuclear Power Plant (NPP). Their Final Report, delivered to the Japanese authorities, is available here. ''A lot of good work, done at all levels, is on-going in Japan in the area of environmental remediation,'' said Juan Carlos Lentijo, Team Leader and General Director for Radiation Protection at Spain's nuclear regulatory authority. In the report, Japan is encouraged to continue its remediation efforts, taking into account the advice provided by the Mission. ''In the early phases of the Fukushima Daiichi accident, a very cautious approach was adopted by the Japanese authorities in terms of dealing with the handling of residue materials. It is considered right to do so,'' Lentijo said. ''However, at this point in time, we see that there is room to take a more balanced approach, focussing on the real priority areas, classifying residue materials and adopting appropriate remediation measures on the basis of the results of safety assessments for each specific situation.'' The IAEA stands ready to support Japan as it continues its efforts to remediate the environment in the area off-site the Fukushima Daiichi NPP. The IAEA sent the mission to Japan from 7 to 15 October 2011 following a request from the country's government. The mission, comprising 12 international and IAEA experts from several countries, visited numerous locations in the Fukushima Prefecture and conducted meetings in Tokyo and Fukushima with Japanese officials from several ministries and institutions. A Preliminary Summary Report was issued on 14 October. Background The accident at the Fukushima Daiichi NPP has led to elevated levels of radiation over large areas. The Government of Japan has been formulating a strategy and plans to implement countermeasures to remediate these areas. The IAEA

  9. The Messenger Mission to Mercury

    CERN Document Server

    Domingue, D. L

    2007-01-01

    NASA’s MESSENGER mission, launched on 3 August, 2004 is the seventh mission in the Discovery series. MESSENGER encounters the planet Mercury four times, culminating with an insertion into orbit on 18 March 2011. It carries a comprehensive package of geophysical, geological, geochemical, and space environment experiments to complete the complex investigations of this solar-system end member, which begun with Mariner 10. The articles in this book, written by the experts in each area of the MESSENGER mission, describe the mission, spacecraft, scientific objectives, and payload. The book is of interest to all potential users of the data returned by the MESSENGER mission, to those studying the nature of the planet Mercury, and by all those interested in the design and implementation of planetary exploration missions.

  10. Movement constraints on interpersonal coordination and communication.

    Science.gov (United States)

    Tolston, Michael T; Shockley, Kevin; Riley, Michael A; Richardson, Michael J

    2014-10-01

    The present study investigated how constraining movement affects interpersonal coordination and joint cognitive performance. Pairs of participants worked cooperatively to solve picture-puzzle tasks in which they conversed to identify differences between pictures in 3 degree-of-constraint conditions: both participants were free to move their hands (free-free; FF); both participants' hands were restrained (restrained-restrained; RR); and the hands of 1 participant were free while the hands of the other participant were restrained (free-restrained; FR). Eye tracking data were collected, and movement was measured at the waist, hand, and head. Data were analyzed using Cross-Recurrence Quantification Analysis (CRQ). Postural sway coordination, gaze coordination, and task performance were predicted to be highest in FF, followed by RR, and then by FR. Results showed the asymmetric FR condition generally exhibited lesser degrees of coordination than the symmetric Conditions FF and RR, and that the patterning of coordination in the symmetric conditions varied across the measured body segments. These results demonstrate that movement restraints affect not only interpersonal postural coordination, but also joint attention. Additionally, significant positive relationships were found between task performance and total amount of anterior-posterior movement measured at the head, hand and waist; number of utterances; and number of differences pairs found in the puzzles. These findings indicate a relationship between movement and task performance consistent with the hypotheses that both interpersonal coordination and cognitive performance are sensitive to local action constraints.

  11. Heat exchanger networks design with constraints

    International Nuclear Information System (INIS)

    Amidpur, M.; Zoghi, A.; Nasiri, N.

    2000-01-01

    So far there have been two approaches to the problem of heat recovery system design where stream matching constraints exist. The first approach involves mathematical techniques for solving the combinational problem taking due recognition of the constraints. These methodologies are now efficient, still suffer from the problem of taking a significant amount of control and direction away from the designer. The second approach based upon so called pinch technology and involves the use of adaptation of standard problem table algorithm. Unfortunately, the proposed methodologies are not very easy to understand, therefore they fail to provide the insight and generally associated with these approaches. Here, a new pinch based methodology is presented. In this method, we modified the traditional numerical targeting procedure-problem table algorithm which is stream cascade table. Unconstrained groups are established by using of artificial intelligence method such that they have minimum utility consumption among different alternatives. Each group is an individual network, therefore, traditional optimization, used in pinch technology, should be employed. By transferring energy between groups heat recovery can be maximized, then each group designs individually and finally networks combine together. One of the advantages of using this method is simple targeting and easy networks-design. Besides the approach has the potential using of new network design methods such as dual temperature approach, flexible pinch design, pseudo pinch design. It is hoped that this methodology provides insight easy network design

  12. Model-independent cosmological constraints from growth and expansion

    Science.gov (United States)

    L'Huillier, Benjamin; Shafieloo, Arman; Kim, Hyungjin

    2018-05-01

    Reconstructing the expansion history of the Universe from Type Ia supernovae data, we fit the growth rate measurements and put model-independent constraints on some key cosmological parameters, namely, Ωm, γ, and σ8. The constraints are consistent with those from the concordance model within the framework of general relativity, but the current quality of the data is not sufficient to rule out modified gravity models. Adding the condition that dark energy density should be positive at all redshifts, independently of its equation of state, further constrains the parameters and interestingly supports the concordance model.

  13. Constraint Logic Programming for Resolution of Relative Time Expressions

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    Translating time expression into absolute time points or durations is a challenge for natural languages processing such as text mining and text understanding in general. We present a constraint logic language CLP(Time) tailored to text usages concerned with time and calendar. It provides a simple...... and flexible formalism to express relationships between different time expressions in a text, thereby giving a recipe for resolving them into absolute time. A constraint solver is developed which, as opposed to some earlier approaches, is independent of the order in which temporal information is introduced...

  14. A compendium of chameleon constraints

    International Nuclear Information System (INIS)

    Burrage, Clare; Sakstein, Jeremy

    2016-01-01

    The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f ( R ) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.

  15. A compendium of chameleon constraints

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, Clare [School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Sakstein, Jeremy, E-mail: clare.burrage@nottingham.ac.uk, E-mail: jeremy.sakstein@port.ac.uk [Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, 209 S. 33rd St., Philadelphia, PA 19104 (United States)

    2016-11-01

    The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f ( R ) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.

  16. Self-Imposed Creativity Constraints

    DEFF Research Database (Denmark)

    Biskjaer, Michael Mose

    2013-01-01

    Abstract This dissertation epitomizes three years of research guided by the research question: how can we conceptualize creative self-binding as a resource in art and design processes? Concretely, the dissertation seeks to offer insight into the puzzling observation that highly skilled creative...... practitioners sometimes freely and intentionally impose rigid rules, peculiar principles, and other kinds of creative obstructions on themselves as a means to spur momentum in the process and reach a distinctly original outcome. To investigate this the dissertation is composed of four papers (Part II) framed...... of analysis. Informed by the insight that constraints both enable and restrain creative agency, the dissertation’s main contention is that creative self- binding may profitably be conceptualized as the exercise of self-imposed creativity constraints. Thus, the dissertation marks an analytical move from vague...

  17. New constraints on variations of the fine structure constant from CMB anisotropies

    International Nuclear Information System (INIS)

    Menegoni, Eloisa; Melchiorri, Alessandro; Galli, Silvia; Bartlett, James G.; Martins, C. J. A. P.

    2009-01-01

    We demonstrate that recent measurements of cosmic microwave background temperature and polarization anisotropy made by the ACBAR, QUAD, and BICEP experiments substantially improve the cosmological constraints on possible variations of the fine structure constant in the early universe. This data, combined with the five year observations from the WMAP mission, yield the constraint α/α 0 =0.987±0.012 at 68% C.L. The inclusion of the new Hubble Space Telescope constraints on the Hubble constant further increases the accuracy to α/α 0 =1.001±0.007 at 68% C.L., bringing possible deviations from the current value below the 1% level and improving previous constraints by a factor of ∼3.

  18. Introducing geometric constraint expressions into robot constrained motion specification and control

    NARCIS (Netherlands)

    Borghesan, G.; Scioni, E.; Kheddar, A.; Bruyninckx, H.P.J.

    2016-01-01

    The problem of robotic task definition and execution was pioneered by Mason, who defined setpoint constraints where the position, velocity, and/or forces are expressed in one particular task frame for a 6-DOF robot. Later extensions generalized this approach to constraints in 1) multiple frames; 2)

  19. Macroscopic constraints on string unification

    International Nuclear Information System (INIS)

    Taylor, T.R.

    1989-03-01

    The comparison of sting theory with experiment requires a huge extrapolation from the microscopic distances, of order of the Planck length, up to the macroscopic laboratory distances. The quantum effects give rise to large corrections to the macroscopic predictions of sting unification. I discus the model-independent constraints on the gravitational sector of string theory due to the inevitable existence of universal Fradkin-Tseytlin dilatons. 9 refs

  20. Financial Constraints and Franchising Decisions

    OpenAIRE

    Kai-Uwe Kuhn; Francine Lafontaine; Ying Fan

    2013-01-01

    We study how the financial constraints of agents affect the behavior of principals in the context of franchising. We develop an empirical model of franchising starting with a principal-agent framework that emphasizes the role of franchisees' collateral from an incentive perspective. We estimate the determinants of chains' entry (into franchising) and growth decisions using data on franchised chains and data on local macroeconomic conditions. In particular, we use collateralizable housing weal...

  1. Lunar Exploration Missions Since 2006

    Science.gov (United States)

    Lawrence, S. J. (Editor); Gaddis, L. R.; Joy, K. H.; Petro, N. E.

    2017-01-01

    The announcement of the Vision for Space Exploration in 2004 sparked a resurgence in lunar missions worldwide. Since the publication of the first "New Views of the Moon" volume, as of 2017 there have been 11 science-focused missions to the Moon. Each of these missions explored different aspects of the Moon's geology, environment, and resource potential. The results from this flotilla of missions have revolutionized lunar science, and resulted in a profoundly new emerging understanding of the Moon. The New Views of the Moon II initiative itself, which is designed to engage the large and vibrant lunar science community to integrate the results of these missions into new consensus viewpoints, is a direct outcome of this impressive array of missions. The "Lunar Exploration Missions Since 2006" chapter will "set the stage" for the rest of the volume, introducing the planetary community at large to the diverse array of missions that have explored the Moon in the last decade. Content: This chapter will encompass the following missions: Kaguya; ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun); Chang’e-1; Chandrayaan-1; Moon Impact Probe; Lunar Reconnaissance Orbiter (LRO); Lunar Crater Observation Sensing Satellite (LCROSS); Chang’e-2; Gravity Recovery and Interior Laboratory (GRAIL); Lunar Atmosphere and Dust Environment Explorer (LADEE); Chang’e-3.

  2. IRIS Mission Operations Director's Colloquium

    Science.gov (United States)

    Carvalho, Robert; Mazmanian, Edward A.

    2014-01-01

    Pursuing the Mysteries of the Sun: The Interface Region Imaging Spectrograph (IRIS) Mission. Flight controllers from the IRIS mission will present their individual experiences on IRIS from development through the first year of flight. This will begin with a discussion of the unique nature of IRISs mission and science, and how it fits into NASA's fleet of solar observatories. Next will be a discussion of the critical roles Ames contributed in the mission including spacecraft and flight software development, ground system development, and training for launch. This will be followed by experiences from launch, early operations, ongoing operations, and unusual operations experiences. The presentation will close with IRIS science imagery and questions.

  3. Generally covariant gauge theories

    International Nuclear Information System (INIS)

    Capovilla, R.

    1992-01-01

    A new class of generally covariant gauge theories in four space-time dimensions is investigated. The field variables are taken to be a Lie algebra valued connection 1-form and a scalar density. Modulo an important degeneracy, complex [euclidean] vacuum general relativity corresponds to a special case in this class. A canonical analysis of the generally covariant gauge theories with the same gauge group as general relativity shows that they describe two degrees of freedom per space point, qualifying therefore as a new set of neighbors of general relativity. The modification of the algebra of the constraints with respect to the general relativity case is computed; this is used in addressing the question of how general relativity stands out from its neighbors. (orig.)

  4. Infrared Constraint on Ultraviolet Theories

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Yuhsin [Cornell Univ., Ithaca, NY (United States)

    2012-08-01

    While our current paradigm of particle physics, the Standard Model (SM), has been extremely successful at explaining experiments, it is theoretically incomplete and must be embedded into a larger framework. In this thesis, we review the main motivations for theories beyond the SM (BSM) and the ways such theories can be constrained using low energy physics. The hierarchy problem, neutrino mass and the existence of dark matter (DM) are the main reasons why the SM is incomplete . Two of the most plausible theories that may solve the hierarchy problem are the Randall-Sundrum (RS) models and supersymmetry (SUSY). RS models usually suffer from strong flavor constraints, while SUSY models produce extra degrees of freedom that need to be hidden from current experiments. To show the importance of infrared (IR) physics constraints, we discuss the flavor bounds on the anarchic RS model in both the lepton and quark sectors. For SUSY models, we discuss the difficulties in obtaining a phenomenologically allowed gaugino mass, its relation to R-symmetry breaking, and how to build a model that avoids this problem. For the neutrino mass problem, we discuss the idea of generating small neutrino masses using compositeness. By requiring successful leptogenesis and the existence of warm dark matter (WDM), we can set various constraints on the hidden composite sector. Finally, to give an example of model independent bounds from collider experiments, we show how to constrain the DM–SM particle interactions using collider results with an effective coupling description.

  5. Isocurvature constraints on portal couplings

    Energy Technology Data Exchange (ETDEWEB)

    Kainulainen, Kimmo; Nurmi, Sami; Vaskonen, Ville [Department of Physics, University of Jyväskylä, P.O.Box 35 (YFL), FI-40014 University of Jyväskylä (Finland); Tenkanen, Tommi; Tuominen, Kimmo, E-mail: kimmo.kainulainen@jyu.fi, E-mail: sami.t.nurmi@jyu.fi, E-mail: tommi.tenkanen@helsinki.fi, E-mail: kimmo.i.tuominen@helsinki.fi, E-mail: ville.vaskonen@jyu.fi [Department of Physics, University of Helsinki P.O. Box 64, FI-00014, Helsinki (Finland)

    2016-06-01

    We consider portal models which are ultraweakly coupled with the Standard Model, and confront them with observational constraints on dark matter abundance and isocurvature perturbations. We assume the hidden sector to contain a real singlet scalar s and a sterile neutrino ψ coupled to s via a pseudoscalar Yukawa term. During inflation, a primordial condensate consisting of the singlet scalar s is generated, and its contribution to the isocurvature perturbations is imprinted onto the dark matter abundance. We compute the total dark matter abundance including the contributions from condensate decay and nonthermal production from the Standard Model sector. We then use the Planck limit on isocurvature perturbations to derive a novel constraint connecting dark matter mass and the singlet self coupling with the scale of inflation: m {sub DM}/GeV ∼< 0.2λ{sub s}{sup 3/8} ( H {sub *}/10{sup 11} GeV){sup −3/2}. This constraint is relevant in most portal models ultraweakly coupled with the Standard Model and containing light singlet scalar fields.

  6. A Strategic Approach to Medical Care for Exploration Missions

    Science.gov (United States)

    Canga, Michael A.; Shah, Ronak V.; Mindock, Jennifer A.; Antonsen, Erik L.

    2016-01-01

    Exploration missions will present significant new challenges to crew health, including effects of variable gravity environments, limited communication with Earth-based personnel for diagnosis and consultation for medical events, limited resupply, and limited ability for crew return. Providing health care capabilities for exploration class missions will require system trades be performed to identify a minimum set of requirements and crosscutting capabilities, which can be used in design of exploration medical systems. Medical data, information, and knowledge collected during current space missions must be catalogued and put in formats that facilitate querying and analysis. These data are used to inform the medical research and development program through analysis of risk trade studies between medical care capabilities and system constraints such as mass, power, volume, and training. Medical capability as a quantifiable variable is proposed as a surrogate risk metric and explored for trade space analysis that can improve communication between the medical and engineering approaches to mission design. The resulting medical system design approach selected will inform NASA mission architecture, vehicle, and subsystem design for the next generation of spacecraft.

  7. Design and evaluation of an integrated Quiet, Clean General Aviation Turbofan (QCGAT) engine and aircraft propulsion system

    Science.gov (United States)

    German, J.; Fogel, P.; Wilson, C.

    1980-01-01

    The design was based on the LTS-101 engine family for the core engine. A high bypass fan design (BPR=9.4) was incorporated to provide reduced fuel consumption for the design mission. All acoustic and pollutant emissions goals were achieved. A discussion of the preliminary design of a business jet suitable for the developed propulsion system is included. It is concluded that large engine technology can be successfully applied to small turbofans, and noise or pollutant levels need not be constraints for the design of future small general aviation turbofan engines.

  8. Relaxations of semiring constraint satisfaction problems

    CSIR Research Space (South Africa)

    Leenen, L

    2007-03-01

    Full Text Available The Semiring Constraint Satisfaction Problem (SCSP) framework is a popular approach for the representation of partial constraint satisfaction problems. In this framework preferences can be associated with tuples of values of the variable domains...

  9. Generalized Superconductivity. Generalized Levitation

    International Nuclear Information System (INIS)

    Ciobanu, B.; Agop, M.

    2004-01-01

    In the recent papers, the gravitational superconductivity is described. We introduce the concept of generalized superconductivity observing that any nongeodesic motion and, in particular, the motion in an electromagnetic field, can be transformed in a geodesic motion by a suitable choice of the connection. In the present paper, the gravitoelectromagnetic London equations have been obtained from the generalized Helmholtz vortex theorem using the generalized local equivalence principle. In this context, the gravitoelectromagnetic Meissner effect and, implicitly, the gravitoelectromagnetic levitation are given. (authors)

  10. On Dirac's conjecture for Hamiltonian systems with first and second class constraints

    International Nuclear Information System (INIS)

    Cabo, A.; Louis Martinez, D.

    1989-07-01

    It is shown for a wide class of systems in the framework of the Total Hamiltonian Procedure that all the first class constraints generate canonical transformations connecting physically equivalent states. It occurs whenever the constraints arising in the Dirac algorithm are effective when considered in the functional form as they appear in the consistency conditions. The property of hereditary separation between first and second class constraints also follows from the above condition. General Poisson bracket relations among constraints in the representation used here are also obtained. The sources of anomalies in the hereditary property reported in the literature are identified. (author). 15 refs

  11. On Dirac's conjecture for Hamiltonian systems with first- and second-class constraints

    International Nuclear Information System (INIS)

    Cabo, A.; Louis-Martinez, D.

    1990-01-01

    It is shown for a wide class of systems in the framework of the total Hamiltonian procedure that all first-class constraints generate canonical transformations connecting physically equivalent states. It occurs whenever the constraints arising in the Dirac algorithm are effective when considered in the functional form as they appear in the consistency conditions. The property of hereditary separation between first- and second-class constraints also follows from the above condition. General Poisson-brackets relations among constraints in the representation used here are also obtained. The sources of anomalies in the hereditary property reported in the literature are identified

  12. Simulation of Mission Phases

    Science.gov (United States)

    Carlstrom, Nicholas Mercury

    2016-01-01

    This position with the Simulation and Graphics Branch (ER7) at Johnson Space Center (JSC) provided an introduction to vehicle hardware, mission planning, and simulation design. ER7 supports engineering analysis and flight crew training by providing high-fidelity, real-time graphical simulations in the Systems Engineering Simulator (SES) lab. The primary project assigned by NASA mentor and SES lab manager, Meghan Daley, was to develop a graphical simulation of the rendezvous, proximity operations, and docking (RPOD) phases of flight. The simulation is to include a generic crew/cargo transportation vehicle and a target object in low-Earth orbit (LEO). Various capsule, winged, and lifting body vehicles as well as historical RPOD methods were evaluated during the project analysis phase. JSC core mission to support the International Space Station (ISS), Commercial Crew Program (CCP), and Human Space Flight (HSF) influenced the project specifications. The simulation is characterized as a 30 meter +V Bar and/or -R Bar approach to the target object's docking station. The ISS was selected as the target object and the international Low Impact Docking System (iLIDS) was selected as the docking mechanism. The location of the target object's docking station corresponds with the RPOD methods identified. The simulation design focuses on Guidance, Navigation, and Control (GNC) system architecture models with station keeping and telemetry data processing capabilities. The optical and inertial sensors, reaction control system thrusters, and the docking mechanism selected were based on CCP vehicle manufacturer's current and proposed technologies. A significant amount of independent study and tutorial completion was required for this project. Multiple primary source materials were accessed using the NASA Technical Report Server (NTRS) and reference textbooks were borrowed from the JSC Main Library and International Space Station Library. The Trick Simulation Environment and User

  13. Business analysis: The commercial mission of the International Asteroid Mission

    Science.gov (United States)

    The mission of the International Asteroid Mission (IAM) is providing asteroidal resources to support activities in space. The short term goal is to initiate IAM by mining a near-Earth, hydrous carbonaceous chondrite asteroid to service the nearer-term market of providing cryogenic rocket fuel in low lunar orbit (LLO). The IAM will develop and contract for the building of the transportation vehicles and equipment necessary for this undertaking. The long-term goal is to expand operations by exploiting asteroids in other manners, as these options become commercially viable. The primary business issues are what revenue can be generated from the baseline mission, how much will the mission cost, and how funding for this mission can be raised. These issues are addressed.

  14. The Impact of Mission Duration on a Mars Orbital Mission

    Science.gov (United States)

    Arney, Dale; Earle, Kevin; Cirillo, Bill; Jones, Christopher; Klovstad, Jordan; Grande, Melanie; Stromgren, Chel

    2017-01-01

    Performance alone is insufficient to assess the total impact of changing mission parameters on a space mission concept, architecture, or campaign; the benefit, cost, and risk must also be understood. This paper examines the impact to benefit, cost, and risk of changing the total mission duration of a human Mars orbital mission. The changes in the sizing of the crew habitat, including consumables and spares, was assessed as a function of duration, including trades of different life support strategies; this was used to assess the impact on transportation system requirements. The impact to benefit is minimal, while the impact on cost is dominated by the increases in transportation costs to achieve shorter total durations. The risk is expected to be reduced by decreasing total mission duration; however, large uncertainty exists around the magnitude of that reduction.

  15. Constraints on the evolution of phenotypic plasticity

    DEFF Research Database (Denmark)

    Murren, Courtney J; Auld, Josh R.; Callahan, Hilary S

    2015-01-01

    Phenotypic plasticity is ubiquitous and generally regarded as a key mechanism for enabling organisms to survive in the face of environmental change. Because no organism is infinitely or ideally plastic, theory suggests that there must be limits (for example, the lack of ability to produce...... an optimal trait) to the evolution of phenotypic plasticity, or that plasticity may have inherent significant costs. Yet numerous experimental studies have not detected widespread costs. Explicitly differentiating plasticity costs from phenotype costs, we re-evaluate fundamental questions of the limits...... to the evolution of plasticity and of generalists vs specialists. We advocate for the view that relaxed selection and variable selection intensities are likely more important constraints to the evolution of plasticity than the costs of plasticity. Some forms of plasticity, such as learning, may be inherently...

  16. Astrophysical constraints on Planck scale dissipative phenomena.

    Science.gov (United States)

    Liberati, Stefano; Maccione, Luca

    2014-04-18

    The emergence of a classical spacetime from any quantum gravity model is still a subtle and only partially understood issue. If indeed spacetime is arising as some sort of large scale condensate of more fundamental objects, then it is natural to expect that matter, being a collective excitation of the spacetime constituents, will present modified kinematics at sufficiently high energies. We consider here the phenomenology of the dissipative effects necessarily arising in such a picture. Adopting dissipative hydrodynamics as a general framework for the description of the energy exchange between collective excitations and the spacetime fundamental degrees of freedom, we discuss how rates of energy loss for elementary particles can be derived from dispersion relations and used to provide strong constraints on the base of current astrophysical observations of high-energy particles.

  17. Lot Sizing Based on Stochastic Demand and Service Level Constraint

    Directory of Open Access Journals (Sweden)

    hajar shirneshan

    2012-06-01

    Full Text Available Considering its application, stochastic lot sizing is a significant subject in production planning. Also the concept of service level is more applicable than shortage cost from managers' viewpoint. In this paper, the stochastic multi period multi item capacitated lot sizing problem has been investigated considering service level constraint. First, the single item model has been developed considering service level and with no capacity constraint and then, it has been solved using dynamic programming algorithm and the optimal solution has been derived. Then the model has been generalized to multi item problem with capacity constraint. The stochastic multi period multi item capacitated lot sizing problem is NP-Hard, hence the model could not be solved by exact optimization approaches. Therefore, simulated annealing method has been applied for solving the problem. Finally, in order to evaluate the efficiency of the model, low level criterion has been used .

  18. Comments on the nilpotent constraint of the goldstino superfield

    CERN Document Server

    Ghilencea, D M

    2016-01-01

    Superfield constraints were often used in the past, in particular to describe the Akulov-Volkov action of the goldstino by a superfield formulation with $L=(\\Phi^\\dagger \\Phi)_D + [(f\\Phi)_F + h.c.]$ endowed with the nilpotent constraint $\\Phi^2=0$ for the goldstino superfield ($\\Phi$). Inspired by this, such constraint is often used to define the goldstino superfield even in the presence of additional superfields, for example in models of "nilpotent inflation". In this review we show that the nilpotent property is not valid in general, under the assumption of a microscopic (ultraviolet) description of the theory with linear supermultiplets. Sometimes only weaker versions of the nilpotent relation are true such as $\\Phi^3=0$ or $\\Phi^4=0$ ($\\Phi^2\

  19. Transmission and capacity pricing and constraints

    International Nuclear Information System (INIS)

    Fusco, M.

    1999-01-01

    A series of overhead viewgraphs accompanied this presentation which discussed the following issues regarding the North American electric power industry: (1) capacity pricing transmission constraints, (2) nature of transmission constraints, (3) consequences of transmission constraints, and (4) prices as market evidence. Some solutions suggested for pricing constraints included the development of contingent contracts, back-up power in supply regions, and new line capacity construction. 8 tabs., 20 figs

  20. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine

    2013-01-01

    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  1. Collaboration support system for "Phobos-Soil" space mission.

    Science.gov (United States)

    Nazarov, V.; Nazirov, R.; Zakharov, A.

    2009-04-01

    Rapid development of communication facilities leads growth of interactions done via electronic means. However we can see some paradox in this segment in last times: Extending of communication facilities increases collaboration chaos. And it is very sensitive for space missions in general and scientific space mission particularly because effective decision of this task provides successful realization of the missions and promises increasing the ratio of functional characteristic and cost of mission at all. Resolving of this problem may be found by using respective modern technologies and methods which widely used in different branches and not in the space researches only. Such approaches as Social Networking, Web 2.0 and Enterprise 2.0 look most prospective in this context. The primary goal of the "Phobos-Soil" mission is an investigation of the Phobos which is the Martian moon and particularly its regolith, internal structure, peculiarities of the orbital and proper motion, as well as a number of different scientific measurements and experiments for investigation of the Martian environment. A lot of investigators involved in the mission. Effective collaboration system is key facility for information support of the mission therefore. Further to main goal: communication between users of the system, modern approaches allows using such capabilities as self-organizing community, user generated content, centralized and federative control of the system. Also it may have one unique possibility - knowledge management which is very important for space mission realization. Therefore collaboration support system for "Phobos-Soil" mission designed on the base of multilayer model which includes such levels as Communications, Announcement and Information, Data sharing and Knowledge management. The collaboration support system for "Phobos-Soil" mission will be used as prototype for prospective Russian scientific space missions and the presentation describes its architecture

  2. Learning and Parallelization Boost Constraint Search

    Science.gov (United States)

    Yun, Xi

    2013-01-01

    Constraint satisfaction problems are a powerful way to abstract and represent academic and real-world problems from both artificial intelligence and operations research. A constraint satisfaction problem is typically addressed by a sequential constraint solver running on a single processor. Rather than construct a new, parallel solver, this work…

  3. Planned Environmental Microbiology Aspects of Future Lunar and Mars Missions

    Science.gov (United States)

    Ott, C. Mark; Castro, Victoria A.; Pierson, Duane L.

    2006-01-01

    With the establishment of the Constellation Program, NASA has initiated efforts designed similar to the Apollo Program to return to the moon and subsequently travel to Mars. Early lunar sorties will take 4 crewmembers to the moon for 4 to 7 days. Later missions will increase in duration up to 6 months as a lunar habitat is constructed. These missions and vehicle designs are the forerunners of further missions destined for human exploration of Mars. Throughout the planning and design process, lessons learned from the International Space Station (ISS) and past programs will be implemented toward future exploration goals. The standards and requirements for these missions will vary depending on life support systems, mission duration, crew activities, and payloads. From a microbiological perspective, preventative measures will remain the primary techniques to mitigate microbial risk. Thus, most of the effort will focus on stringent preflight monitoring requirements and engineering controls designed into the vehicle, such as HEPA air filters. Due to volume constraints in the CEV, in-flight monitoring will be limited for short-duration missions to the measurement of biocide concentration for water potability. Once long-duration habitation begins on the lunar surface, a more extensive environmental monitoring plan will be initiated. However, limited in-flight volume constraints and the inability to return samples to Earth will increase the need for crew capabilities in determining the nature of contamination problems and method of remediation. In addition, limited shelf life of current monitoring hardware consumables and limited capabilities to dispose of biohazardous trash will drive flight hardware toward non-culture based methodologies, such as hardware that rapidly distinguishes biotic versus abiotic surface contamination. As missions progress to Mars, environmental systems will depend heavily on regeneration of air and water and biological waste remediation and

  4. The AGILE Mission

    CERN Document Server

    Tavani, M.; Argan, A.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P.W.; Chen, A.W.; Cocco, V.; Costa, E.; D'Ammando, F.; Del Monte, E.; De Paris, G.; Di Cocco, G.; Di Persio, G.; Donnarumma, I.; Evangelista, Y.; Feroci, M.; Ferrari, A.; Fiorini, M.; Fornari, F.; Fuschino, F.; Froysland, T.; Frutti, M.; Galli, M.; Gianotti, F.; Giuliani, A.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Liello, F.; Lipari, P.; Longo, F.; Mattaini, E.; Marisaldi, M.; Mastropietro, M.; Mauri, A.; Mauri, F.; Mereghetti, S.; Morelli, E.; Morselli, A.; Pacciani, L.; Pellizzoni, A.; Perotti, F.; Piano, G.; Picozza, P.; Pontoni, C.; Porrovecchio, G.; Prest, M.; Pucella, G.; Rapisarda, M.; Rappoldi, A.; Rossi, E.; Rubini, A.; Soffitta, P.; Traci, A.; Trifoglio, M.; Trois, A.; Vallazza, E.; Vercellone, S.; Vittorini, V.; Zambra, A.; Zanello, D.; Pittori, C.; Preger, B.; Santolamazza, P.; Verrecchia, F.; Giommi, P.; Colafrancesco, S.; Antonelli, A.; Cutini, S.; Gasparrini, D.; Stellato, S.; Fanari, G.; Primavera, R.; Tamburelli, F.; Viola, F.; Guarrera, G.; Salotti, L.; D'Amico, F.; Marchetti, E.; Crisconio, M.; Sabatini, P.; Annoni, G.; Alia, S.; Longoni, A.; Sanquerin, R.; Battilana, M.; Concari, P.; Dessimone, E.; Grossi, R.; Parise, A.; Monzani, F.; Artina, E.; Pavesi, R.; Marseguerra, G.; Nicolini, L.; Scandelli, L.; Soli, L.; Vettorello, V.; Zardetto, E.; Bonati, A.; Maltecca, L.; D'Alba, E.; Patane, M.; Babini, G.; Onorati, F.; Acquaroli, L.; Angelucci, M.; Morelli, B.; Agostara, C.; Cerone, M.; Michetti, A.; Tempesta, P.; D'Eramo, S.; Rocca, F.; Giannini, F.; Borghi, G.; Garavelli, B.; Conte, M.; Balasini, M.; Ferrario, I.; Vanotti, M.; Collavo, E.; Giacomazzo, M.

    2008-01-01

    AGILE is an Italian Space Agency mission dedicated to the observation of the gamma-ray Universe. The AGILE very innovative instrumentation combines for the first time a gamma-ray imager (sensitive in the energy range 30 MeV - 50 GeV), a hard X-ray imager (sensitive in the range 18-60 keV) together with a Calorimeter (sensitive in the range 300 keV - 100 MeV) and an anticoincidence system. AGILE was successfully launched on April 23, 2007 from the Indian base of Sriharikota and was inserted in an equatorial orbit with a very low particle background. AGILE provides crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, pulsars, unidentified gamma-ray sources, Galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. An optimal angular resolution (reaching 0.1-0.2 degrees in gamma-rays, 1-2 arcminutes in hard X-rays) and very large fields of view (2.5 sr and 1 sr, respectively) are obtained by the use of Silicon detectors integrated in a very compa...

  5. STS-68 Mission Insignia

    Science.gov (United States)

    1994-01-01

    This STS-68 patch was designed by artist Sean Collins. Exploration of Earth from space is the focus of the design of the insignia, the second flight of the Space Radar Laboratory (SRL-2). SRL-2 was part of NASA's Mission to Planet Earth (MTPE) project. The world's land masses and oceans dominate the center field, with the Space Shuttle Endeavour circling the globe. The SRL-2 letters span the width and breadth of planet Earth, symbolizing worldwide coverage of the two prime experiments of STS-68: The Shuttle Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) instruments; and the Measurement of Air Pollution from Satellites (MAPS) sensor. The red, blue, and black colors of the insignia represent the three operating wavelengths of SIR-C/X-SAR, and the gold band surrounding the globe symbolizes the atmospheric envelope examined by MAPS. The flags of international partners Germany and Italy are shown opposite Endeavour. The relationship of the Orbiter to Earth highlights the usefulness of human space flights in understanding Earth's environment, and the monitoring of its changing surface and atmosphere. In the words of the crew members, the soaring Orbiter also typifies the excellence of the NASA team in exploring our own world, using the tools which the Space Program developed to explore the other planets in the solar system.

  6. Draft Mission Plan Amendment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-09-01

    The Department of Energy`s Office Civilian Radioactive Waste Management has prepared this document to report plans for the Civilian Radioactive Waste Management Program, whose mission is to manage and dispose of the nation`s spent fuel and high-level radioactive waste in a manner that protects the health and safety of the public and of workers and the quality of the environment. The Congress established this program through the Nuclear Waste Policy Act of 1982. Specifically, the Congress directed us to isolate these wastes in geologic repositories constructed in suitable rock formations deep beneath the surface of the earth. In the Nuclear Waste Policy Amendments Act of 1987, the Congress mandated that only one repository was to be developed at present and that only the Yucca Mountain candidate site in Nevada was to be characterized at this time. The Amendments Act also authorized the construction of a facility for monitored retrievable storage (MRS) and established the Office of the Nuclear Waste Negotiator and the Nuclear Waste Technical Review Board. After a reassessment in 1989, the Secretary of Energy restructured the program, focusing the repository effort scientific evaluations of the Yucca Mountain candidate site, deciding to proceed with the development of an MRS facility, and strengthening the management of the program. 48 refs., 32 figs.

  7. NASA's interstellar probe mission

    International Nuclear Information System (INIS)

    Liewer, P.C.; Ayon, J.A.; Wallace, R.A.; Mewaldt, R.A.

    2000-01-01

    NASA's Interstellar Probe will be the first spacecraft designed to explore the nearby interstellar medium and its interaction with our solar system. As envisioned by NASA's Interstellar Probe Science and Technology Definition Team, the spacecraft will be propelled by a solar sail to reach >200 AU in 15 years. Interstellar Probe will investigate how the Sun interacts with its environment and will directly measure the properties and composition of the dust, neutrals and plasma of the local interstellar material which surrounds the solar system. In the mission concept developed in the spring of 1999, a 400-m diameter solar sail accelerates the spacecraft to ∼15 AU/year, roughly 5 times the speed of Voyager 1 and 2. The sail is used to first bring the spacecraft to ∼0.25 AU to increase the radiation pressure before heading out in the interstellar upwind direction. After jettisoning the sail at ∼5 AU, the spacecraft coasts to 200-400 AU, exploring the Kuiper Belt, the boundaries of the heliosphere, and the nearby interstellar medium

  8. Draft Mission Plan Amendment

    International Nuclear Information System (INIS)

    1991-09-01

    The Department of Energy's Office Civilian Radioactive Waste Management has prepared this document to report plans for the Civilian Radioactive Waste Management Program, whose mission is to manage and dispose of the nation's spent fuel and high-level radioactive waste in a manner that protects the health and safety of the public and of workers and the quality of the environment. The Congress established this program through the Nuclear Waste Policy Act of 1982. Specifically, the Congress directed us to isolate these wastes in geologic repositories constructed in suitable rock formations deep beneath the surface of the earth. In the Nuclear Waste Policy Amendments Act of 1987, the Congress mandated that only one repository was to be developed at present and that only the Yucca Mountain candidate site in Nevada was to be characterized at this time. The Amendments Act also authorized the construction of a facility for monitored retrievable storage (MRS) and established the Office of the Nuclear Waste Negotiator and the Nuclear Waste Technical Review Board. After a reassessment in 1989, the Secretary of Energy restructured the program, focusing the repository effort scientific evaluations of the Yucca Mountain candidate site, deciding to proceed with the development of an MRS facility, and strengthening the management of the program. 48 refs., 32 figs

  9. Autonomous Mission Design in Extreme Orbit Environments

    Science.gov (United States)

    Surovik, David Allen

    An algorithm for autonomous online mission design at asteroids, comets, and small moons is developed to meet the novel challenges of their complex non-Keplerian orbit environments, which render traditional methods inapplicable. The core concept of abstract reachability analysis, in which a set of impulsive maneuvering options is mapped onto a space of high-level mission outcomes, is applied to enable goal-oriented decision-making with robustness to uncertainty. These nuanced analyses are efficiently computed by utilizing a heuristic-based adaptive sampling scheme that either maximizes an objective function for autonomous planning or resolves details of interest for preliminary analysis and general study. Illustrative examples reveal the chaotic nature of small body systems through the structure of various families of reachable orbits, such as those that facilitate close-range observation of targeted surface locations or achieve soft impact upon them. In order to fulfill extensive sets of observation tasks, the single-maneuver design method is implemented in a receding-horizon framework such that a complete mission is constructed on-the-fly one piece at a time. Long-term performance and convergence are assured by augmenting the objective function with a prospect heuristic, which approximates the likelihood that a reachable end-state will benefit the subsequent planning horizon. When state and model uncertainty produce larger trajectory deviations than were anticipated, the next control horizon is advanced to allow for corrective action -- a low-frequency form of feedback control. Through Monte Carlo analysis, the planning algorithm is ultimately demonstrated to produce mission profiles that vary drastically in their physical paths but nonetheless consistently complete all goals, suggesting a high degree of flexibility. It is further shown that the objective function can be tuned to preferentially minimize fuel cost or mission duration, as well as to optimize

  10. STS-51J Mission Insignia

    Science.gov (United States)

    1985-01-01

    The 51-J mission insignia, designed by Atlantis's first crew, pays tribute to the Statue of Liberty and the ideas it symbolizes. The historical gateway figure bears additional significance for Astronauts Karol J. Bobko, mission commander; and Ronald J. Grabe, pilot, both New Your Natives.

  11. Comparison of technologies for deorbiting spacecraft from low-earth-orbit at end of mission

    Science.gov (United States)

    Sánchez-Arriaga, G.; Sanmartín, J. R.; Lorenzini, E. C.

    2017-09-01

    An analytical comparison of four technologies for deorbiting spacecraft from Low-Earth-Orbit at end of mission is presented. Basic formulas based on simple physical models of key figures of merit for each device are found. Active devices - rockets and electrical thrusters - and passive technologies - drag augmentation devices and electrodynamic tethers - are considered. A basic figure of merit is the deorbit device-to-spacecraft mass ratio, which is, in general, a function of environmental variables, technology development parameters and deorbit time. For typical state-of-the-art values, equal deorbit time, middle inclination and initial altitude of 850 km, the analysis indicates that tethers are about one and two orders of magnitude lighter than active technologies and drag augmentation devices, respectively; a tether needs a few percent mass-ratio for a deorbit time of a couple of weeks. For high inclination, the performance drop of the tether system is moderate: mass ratio and deorbit time increase by factors of 2 and 4, respectively. Besides collision risk with other spacecraft and system mass considerations, such as main driving factors for deorbit space technologies, the analysis addresses other important constraints, like deorbit time, system scalability, manoeuver capability, reliability, simplicity, attitude control requirement, and re-entry and multi-mission capability (deorbit and re-boost) issues. The requirements and constraints are used to make a critical assessment of the four technologies as functions of spacecraft mass and initial orbit (altitude and inclination). Emphasis is placed on electrodynamic tethers, including the latest advances attained in the FP7/Space project BETs. The superiority of tape tethers as compared to round and multi-line tethers in terms of deorbit mission performance is highlighted, as well as the importance of an optimal geometry selection, i.e. tape length, width, and thickness, as function of spacecraft mass and initial

  12. Command and Control of Joint Air Operations through Mission Command

    Science.gov (United States)

    2016-06-01

    and outlines the C2 architecture systems, processes, and philosophy of com- mand required to enable mission command effectively. Mission Command...General Dempsey highlights the fact that “trust is the moral sinew that binds the distributed Joint Force 2020 together” and observes that “unless...con- fident about how their subordinates will make decisions and adapt to the dynamic battlespace environment. Processes, Systems, and Philosophy of

  13. Flight demonstration of formation flying capabilities for future missions (NEAT Pathfinder)

    DEFF Research Database (Denmark)

    Delpech, M.; Malbet, F.; Karlsson, T.

    2015-01-01

    given the numerous constraints from propellant usage to star tracker blinding. The paper presents the experiment objectives in relation with the NEAT/microNEAT mission concept, describes its main design features along with the guidance and control algorithms evolutions and discusses the results in terms...

  14. Optimizing mission critical data dissemination in massive IoT networks

    KAUST Repository

    Farooq, Muhammad Junaid; Elsawy, Hesham; Zhu, Quanyan; Alouini, Mohamed-Slim

    2017-01-01

    Mission critical data dissemination in massive Internet of things (IoT) networks imposes constraints on the message transfer delay between devices. Due to low power and communication range of IoT devices, data is foreseen to be relayed over multiple

  15. 77 FR 60966 - Executive-Led Trade Mission to South Africa and Zambia

    Science.gov (United States)

    2012-10-05

    ... Africa and Zambia AGENCY: International Trade Administration, Department of Commerce. ACTION: Notice...- Led Trade Mission to South Africa and Zambia scheduled for November 26- 30, 2012, to revise the dates... and scheduling constraints permit), interested U.S. agriculture, mining, transportation, water, energy...

  16. Mission-directed path planning for planetary rover exploration

    Science.gov (United States)

    Tompkins, Paul

    2005-07-01

    Robotic rovers uniquely benefit planetary exploration---they enable regional exploration with the precision of in-situ measurements, a combination impossible from an orbiting spacecraft or fixed lander. Mission planning for planetary rover exploration currently utilizes sophisticated software for activity planning and scheduling, but simplified path planning and execution approaches tailored for localized operations to individual targets. This approach is insufficient for the investigation of multiple, regionally distributed targets in a single command cycle. Path planning tailored for this task must consider the impact of large scale terrain on power, speed and regional access; the effect of route timing on resource availability; the limitations of finite resource capacity and other operational constraints on vehicle range and timing; and the mutual influence between traverses and upstream and downstream stationary activities. Encapsulating this reasoning in an efficient autonomous planner would allow a rover to continue operating rationally despite significant deviations from an initial plan. This research presents mission-directed path planning that enables an autonomous, strategic reasoning capability for robotic explorers. Planning operates in a space of position, time and energy. Unlike previous hierarchical approaches, it treats these dimensions simultaneously to enable globally-optimal solutions. The approach calls on a near incremental search algorithm designed for planning and re-planning under global constraints, in spaces of higher than two dimensions. Solutions under this method specify routes that avoid terrain obstacles, optimize the collection and use of rechargable energy, satisfy local and global mission constraints, and account for the time and energy of interleaved mission activities. Furthermore, the approach efficiently re-plans in response to updates in vehicle state and world models, and is well suited to online operation aboard a robot

  17. The LUVOIR Decadal Mission Concept

    Science.gov (United States)

    Arney, G. N.; Crooke, J.; Domagal-Goldman, S. D.; Fischer, D.; Peterson, B.; Schmidt, B. E.; Stdt, T. L. T.

    2017-12-01

    The Large UV-Optical-Infrared (LUVOIR) Surveyor is one of four mission concepts being studied by NASA in preparation for the 2020 Astrophysics Decadal Survey. LUVOIR is a general-purpose space-based observatory with a large aperture in the 8-16 m range and a total bandpass spanning from the far-UV to the near-infrared. This observatory will enable revolutionary new studies in many areas of astronomy, including planetary science within and beyond our Solar System. Because LUVOIR is being considered for the next decadal survey, it must be capable of advancing our understanding of astronomical targets, including exoplanets, far beyond what will be achieved by the next two decades of observations from other space- or ground-based facilities. This means that the mission must move past planet detection, which is happening now with Kepler and ground-based measurements and will continue with TESS (Transiting Exoplanet Survey Satellite) and WFIRST (Wide Field Infrared Survey Telescope). It must also move beyond the chemical characterization of gas giants, which has begun with observations from Spitzer, Hubble, and ground-based telescopes and will greatly advances with the upcoming JWST (James Webb Space Telescope) and WFIRST coronagraph. Therefore, one of LUVOIR's main science objectives will be to directly image rocky Earth-sized planets in the habitable zones of other stars, measure their spectra, analyze the chemistry of their atmospheres, and obtain information about their surfaces. Such observations will allow us to evaluate these worlds' habitability and potential for life. We will review the specific observational strategies needed for astrobiological assessments of exoplanetary environments, including the wavelength range and spectral resolution required for these habitability analyses and biosignature searches. Further, we will discuss how the observational requirements to make measurements of "Earthlike" worlds will allow high-quality observations of a wide

  18. GRACE Status at Mission End

    Science.gov (United States)

    Tapley, B. D.; Flechtner, F. M.; Watkins, M. M.; Bettadpur, S. V.

    2017-12-01

    The twin satellites of the Gravity Recovery and Climate Experiment (GRACE) were launched on March 17, 2002 and have operated for nearly 16 years. The mission objectives are to observe the spatial and temporal variations of the Earth's mass through its effects on the gravity field at the GRACE satellite altitude. The mass changes observed are related to both the changes within the solid earth and the change within and between the Erath system components. A significant cause of the time varying mass is water motion and the GRACE mission has provided a continuous decade long measurement sequence which characterizes the seasonal cycle of mass transport between the oceans, land, cryosphere and atmosphere; its inter-annual variability; and the climate driven secular, or long period, mass transport signals. The fifth reanalysis on the mission data set, the RL05 data, were released in mid-2013. With the planned launch of GRACE Follow-On in early 2018, plans are underway for a reanalysis that will be consistent with the GRACE FO processing standards. The mission is entering the final phases of its operation life with mission end expected to occur in early 2018. The current mission operations strategy emphasizes extending the mission lifetime to obtain an overlap with the GRACE FO. This presentation will review the mission status and the projections for mission lifetime, describe the current operations philosophy and its impact on the science data, discuss the issues related to achieving the GRACE and GRACE FO connection and discuss issues related to science data products during this phase of the mission period.

  19. Monte Carlo Analysis as a Trajectory Design Driver for the TESS Mission

    Science.gov (United States)

    Nickel, Craig; Lebois, Ryan; Lutz, Stephen; Dichmann, Donald; Parker, Joel

    2016-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will be injected into a highly eccentric Earth orbit and fly 3.5 phasing loops followed by a lunar flyby to enter a mission orbit with lunar 2:1 resonance. Through the phasing loops and mission orbit, the trajectory is significantly affected by lunar and solar gravity. We have developed a trajectory design to achieve the mission orbit and meet mission constraints, including eclipse avoidance and a 30-year geostationary orbit avoidance requirement. A parallelized Monte Carlo simulation was performed to validate the trajectory after injecting common perturbations, including launch dispersions, orbit determination errors, and maneuver execution errors. The Monte Carlo analysis helped identify mission risks and is used in the trajectory selection process.

  20. Monte Carlo Analysis as a Trajectory Design Driver for the Transiting Exoplanet Survey Satellite (TESS) Mission

    Science.gov (United States)

    Nickel, Craig; Parker, Joel; Dichmann, Don; Lebois, Ryan; Lutz, Stephen

    2016-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will be injected into a highly eccentric Earth orbit and fly 3.5 phasing loops followed by a lunar flyby to enter a mission orbit with lunar 2:1 resonance. Through the phasing loops and mission orbit, the trajectory is significantly affected by lunar and solar gravity. We have developed a trajectory design to achieve the mission orbit and meet mission constraints, including eclipse avoidance and a 30-year geostationary orbit avoidance requirement. A parallelized Monte Carlo simulation was performed to validate the trajectory after injecting common perturbations, including launch dispersions, orbit determination errors, and maneuver execution errors. The Monte Carlo analysis helped identify mission risks and is used in the trajectory selection process.

  1. Constraint Specialisation in Horn Clause Verification

    DEFF Research Database (Denmark)

    Kafle, Bishoksan; Gallagher, John Patrick

    2015-01-01

    We present a method for specialising the constraints in constrained Horn clauses with respect to a goal. We use abstract interpretation to compute a model of a query-answer transformation of a given set of clauses and a goal. The effect is to propagate the constraints from the goal top......-down and propagate answer constraints bottom-up. Our approach does not unfold the clauses at all; we use the constraints from the model to compute a specialised version of each clause in the program. The approach is independent of the abstract domain and the constraints theory underlying the clauses. Experimental...

  2. Constraint specialisation in Horn clause verification

    DEFF Research Database (Denmark)

    Kafle, Bishoksan; Gallagher, John Patrick

    2017-01-01

    We present a method for specialising the constraints in constrained Horn clauses with respect to a goal. We use abstract interpretation to compute a model of a query–answer transformed version of a given set of clauses and a goal. The constraints from the model are then used to compute...... a specialised version of each clause. The effect is to propagate the constraints from the goal top-down and propagate answer constraints bottom-up. The specialisation procedure can be repeated to yield further specialisation. The approach is independent of the abstract domain and the constraint theory...

  3. The Magnetospheric Multiscale Mission

    Science.gov (United States)

    Burch, James

    Magnetospheric Multiscale (MMS), a NASA four-spacecraft mission scheduled for launch in November 2014, will investigate magnetic reconnection in the boundary regions of the Earth’s magnetosphere, particularly along its dayside boundary with the solar wind and the neutral sheet in the magnetic tail. Among the important questions about reconnection that will be addressed are the following: Under what conditions can magnetic-field energy be converted to plasma energy by the annihilation of magnetic field through reconnection? How does reconnection vary with time, and what factors influence its temporal behavior? What microscale processes are responsible for reconnection? What determines the rate of reconnection? In order to accomplish its goals the MMS spacecraft must probe both those regions in which the magnetic fields are very nearly antiparallel and regions where a significant guide field exists. From previous missions we know the approximate speeds with which reconnection layers move through space to be from tens to hundreds of km/s. For electron skin depths of 5 to 10 km, the full 3D electron population (10 eV to above 20 keV) has to be sampled at rates greater than 10/s. The MMS Fast-Plasma Instrument (FPI) will sample electrons at greater than 30/s. Because the ion skin depth is larger, FPI will make full ion measurements at rates of greater than 6/s. 3D E-field measurements will be made by MMS once every ms. MMS will use an Active Spacecraft Potential Control device (ASPOC), which emits indium ions to neutralize the photoelectron current and keep the spacecraft from charging to more than +4 V. Because ion dynamics in Hall reconnection depend sensitively on ion mass, MMS includes a new-generation Hot Plasma Composition Analyzer (HPCA) that corrects problems with high proton fluxes that have prevented accurate ion-composition measurements near the dayside magnetospheric boundary. Finally, Energetic Particle Detector (EPD) measurements of electrons and

  4. The SCOPE Mission

    International Nuclear Information System (INIS)

    Fujimoto, M.; Tsuda, Y.; Saito, Y.; Shinohara, I.; Takashima, T.; Matsuoka, A.; Kojima, H.; Kasaba, Y.

    2009-01-01

    In order to reach the new horizon of the space physics research, the Plasma Universe, via in-situ measurements in the Earth's magnetosphere, SCOPE will perform formation flying observations combined with high-time resolution electron measurements. The simultaneous multi-scale observations by SCOPE of various plasma dynamical phenomena will enable data-based study of the key space plasma processes from the cross-scale coupling point of view. Key physical processes to be studied are magnetic reconnection under various boundary conditions, shocks in space plasma, collisionless plasma mixing at the boundaries, and physics of current sheets embedded in complex magnetic geometries. The SCOPE formation is made up of 5 spacecraft and is put into the equatorial orbit with the apogee at 30 Re (Re: earth radius). One of the spacecraft is a large mother ship which is equipped with a full suite of particle detectors including ultra-high time resolution electron detector. Among other 4 small spacecraft, one remains near (∼10 km) the mother ship and the spacecraft-pair will focus on the electron-scale physics. Others at the distance of 100∼3000 km(electron∼ion spatial scales) from the mother ship will monitor plasma dynamics surrounding the mother-daughter pair. There is lively on-going discussion on Japan-Europe international collaboration (ESA's Cross-Scale), which would certainly make better the coverage over the scales of interest and thus make the success of the mission, i.e., clarifying the multi-scale nature of the Plasma Universe, to be attained at an even higher level.

  5. 15 CFR 921.1 - Mission, goals and general provisions.

    Science.gov (United States)

    2010-01-01

    ... or state authority (e.g., threatened/endangered species or significant historical or cultural.../unintentional species composition changes—introduced and exotic species). In those areas proposed or designated..., draft management plan preparation and conduct of basic characterization studies. Acquisition and...

  6. General general game AI

    OpenAIRE

    Togelius, Julian; Yannakakis, Georgios N.; 2016 IEEE Conference on Computational Intelligence and Games (CIG)

    2016-01-01

    Arguably the grand goal of artificial intelligence research is to produce machines with general intelligence: the capacity to solve multiple problems, not just one. Artificial intelligence (AI) has investigated the general intelligence capacity of machines within the domain of games more than any other domain given the ideal properties of games for that purpose: controlled yet interesting and computationally hard problems. This line of research, however, has so far focuse...

  7. Accessing Information on the Mars Exploration Rovers Mission

    Science.gov (United States)

    Walton, J. D.; Schreiner, J. A.

    2005-12-01

    In January 2004, the Mars Exploration Rovers (MER) mission successfully deployed two robotic geologists - Spirit and Opportunity - to opposite sides of the red planet. Onboard each rover is an array of cameras and scientific instruments that send data back to Earth, where ground-based systems process and store the information. During the height of the mission, a team of about 250 scientists and engineers worked around the clock to analyze the collected data, determine a strategy and activities for the next day and then carefully compose the command sequences that would instruct the rovers in how to perform their tasks. The scientists and engineers had to work closely together to balance the science objectives with the engineering constraints so that the mission achieved its goals safely and quickly. To accomplish this coordinated effort, they adhered to a tightly orchestrated schedule of meetings and processes. To keep on time, it was critical that all team members were aware of what was happening, knew how much time they had to complete their tasks, and could easily access the information they need to do their jobs. Computer scientists and software engineers at NASA Ames Research Center worked closely with the mission managers at the Jet Propulsion Laboratory (JPL) to create applications that support the mission. One such application, the Collaborative Information Portal (CIP), helps mission personnel perform their daily tasks, whether they work inside mission control or the science areas at JPL, or in their homes, schools, or offices. With a three-tiered, service-oriented architecture (SOA) - client, middleware, and data repository - built using Java and commercial software, CIP provides secure access to mission schedules and to data and images transmitted from the Mars rovers. This services-based approach proved highly effective for building distributed, flexible applications, and is forming the basis for the design of future mission software systems. Almost two

  8. An Analog Rover Exploration Mission for Education and Outreach

    Science.gov (United States)

    Moores, John; Campbell, Charissa L.; Smith, Christina L.; Cooper, Brittney A.

    2017-10-01

    This abstract describes an analog rover exploration mission designed as an outreach program for high school and undergraduate students. This program is used to teach them about basic mission control operations, how to manage a rover as if it were on another planetary body, and employing the rover remotely to complete mission objectives. One iteration of this program has been completed and another is underway. In both trials, participants were shown the different operation processes involved in a real-life mission. Modifications were made to these processes to decrease complexity and better simulate a mission control environment in a short time period (three 20-minute-long mission “days”). In the first run of the program, participants selected a landing site, what instruments would be on the rover - subject to cost, size, and weight limitations - and were randomly assigned one of six different mission operations roles, each with specific responsibilities. For example, a Science Planner/Integrator (SPI) would plan science activities whilst a Rover Engineer (RE) would keep on top of rover constraints. Planning consisted of a series of four meetings to develop and verify the current plan, pre-plan the next day's activities and uplink the activities to the “rover” (a human colleague). Participants were required to attend certain meetings depending upon their assigned role. To conclude the mission, students viewed the site to understand any differences between remote viewing and reality in relation to the rover. Another mission is currently in progress with revisions from the earlier run to improve the experience. This includes broader roles and meetings and pre-selecting the landing site and rover. The new roles are: Mission Lead, Rover Engineer and Science Planner. The SPI role was previously popular so most of the students were placed in this category. The meetings were reduced to three but extended in length. We are also planning to integrate this program

  9. Real-Time Attitude Control Algorithm for Fast Tumbling Objects under Torque Constraint

    Science.gov (United States)

    Tsuda, Yuichi; Nakasuka, Shinichi

    This paper describes a new control algorithm for achieving any arbitrary attitude and angular velocity states of a rigid body, even fast and complicated tumbling rotations, under some practical constraints. This technique is expected to be applied for the attitude motion synchronization to capture a non-cooperative, tumbling object in such missions as removal of debris from orbit, servicing broken-down satellites for repairing or inspection, rescue of manned vehicles, etc. For this objective, we have introduced a novel control algorithm called Free Motion Path Method (FMPM) in the previous paper, which was formulated as an open-loop controller. The next step of this consecutive work is to derive a closed-loop FMPM controller, and as the preliminary step toward the objective, this paper attempts to derive a conservative state variables representation of a rigid body dynamics. 6-Dimensional conservative state variables are introduced in place of general angular velocity-attitude angle representation, and how to convert between both representations are shown in this paper.

  10. Multiple spacecraft configuration designs for coordinated flight missions

    Science.gov (United States)

    Fumenti, Federico; Theil, Stephan

    2018-06-01

    Coordinated flight allows the replacement of a single monolithic spacecraft with multiple smaller ones, based on the principle of distributed systems. According to the mission objectives and to ensure a safe relative motion, constraints on the relative distances need to be satisfied. Initially, differential perturbations are limited by proper orbit design. Then, the induced differential drifts can be properly handled through corrective maneuvers. In this work, several designs are surveyed, defining the initial configuration of a group of spacecraft while counteracting the differential perturbations. For each of the investigated designs, focus is placed upon the number of deployable spacecraft and on the possibility to ensure safe relative motion through station keeping of the initial configuration, with particular attention to the required Δ V budget and the constraints violations.

  11. Developmental constraint of insect audition

    Directory of Open Access Journals (Sweden)

    Strauß Johannes

    2006-12-01

    Full Text Available Abstract Background Insect ears contain very different numbers of sensory cells, from only one sensory cell in some moths to thousands of sensory cells, e.g. in cicadas. These differences still await functional explanation and especially the large numbers in cicadas remain puzzling. Insects of the different orders have distinct developmental sequences for the generation of auditory organs. These sensory cells might have different functions depending on the developmental stages. Here we propose that constraints arising during development are also important for the design of insect ears and might influence cell numbers of the adults. Presentation of the hypothesis We propose that the functional requirements of the subadult stages determine the adult complement of sensory units in the auditory system of cicadas. The hypothetical larval sensory organ should function as a vibration receiver, representing a functional caenogenesis. Testing the hypothesis Experiments at different levels have to be designed to test the hypothesis. Firstly, the neuroanatomy of the larval sense organ should be analyzed to detail. Secondly, the function should be unraveled neurophysiologically and behaviorally. Thirdly, the persistence of the sensory cells and the rebuilding of the sensory organ to the adult should be investigated. Implications of the hypothesis Usually, the evolution of insect ears is viewed with respect to physiological and neuronal mechanisms of sound perception. This view should be extended to the development of sense organs. Functional requirements during postembryonic development may act as constraints for the evolution of adult organs, as exemplified with the auditory system of cicadas.

  12. Executive Summary - Our mission

    International Nuclear Information System (INIS)

    2005-01-01

    On September 1 st 2003, the Henryk Niewodniczanski Institute of Nuclear Physics in Cracow joined the Polish Academy of Sciences. The Polish Academy of Sciences (PAN), founded in 1952, is a state-sponsored scientific institution acting through an elected corporation of leading scholars, their research organizations and through numerous scientific establishments. PAN is a major national scientific advisory body acting via its scientific committees which represent all disciplines of science. There are currently 79 PAN research establishments (institutes and research centers, research stations, botanical gardens and other research units) and a number of auxiliary scientific units (such as archives, libraries, museums, and PAN stations abroad). Our Institute is currently one of the largest research institutions of the Polish Academy of Sciences. The research activity of the Academy is financed mainly from the State budget via the Ministry of Scientific Research and Information Technology. The mission of the Institute of Nuclear Physics, IFJ is stated in its Charter. According to Paragraphs 5, 6, and 7 of the 2004 Charter, the Institute's duty is to carry out research activities in the following areas:1. High energy and elementary particle physics (including astrophysics), 2. Nuclear physics and physics of mechanisms of nuclear interaction, 3. Condensed matter physics, 4. Interdisciplinary research, and in particular: in radiation and environmental biology, environmental physics, medical physics, dosimetry, nuclear geophysics, radiochemistry and material engineering. The main tasks of the Institute are: 1. To perform research in the above disciplines, 2. To promote the development of scientists and of specialists qualified to carry out research in these disciplines, 3. To organize a Post-Doctoral Study Course, 4. To permit, through agreements with national and foreign research institutions, external scholars to train and gain academic qualifications in the Institute

  13. The Ulysses mission: An introduction

    International Nuclear Information System (INIS)

    Marsden, R.G.

    1996-01-01

    On 30 September 1995, Ulysses completed its initial, highly successful, survey of the polar regions of the heliosphere in both southern and northern hemispheres, thereby fulfilling its prime mission. The results obtained to date are leading to a revision of many earlier ideas concerning the solar wind and the heliosphere. Now embarking on the second phase of the mission, Ulysses will continue along its out-of-ecliptic flight path for another complete orbit of the Sun. In contrast to the high-latitude phase of the prime mission, which occurred near solar minimum, the next polar passes (in 2000 and 2001) will take place when the Sun is at its most active

  14. Cosmological constraints on exotic injection of electromagnetic energy

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Vivian; Serpico, Pasquale D. [LAPTh, Université Savoie Mont Blanc and CNRS, 9 Chemin de Bellevue BP 110 Annecy-le-Vieux F-74941 Annecy Cedex (France); Lesgourgues, Julien, E-mail: Vivian.Poulin@lapth.cnrs.fr, E-mail: Pasquale.Serpico@lapth.cnrs.fr, E-mail: Julien.Lesgourgues@physik.rwth-aachen.de [Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University, D-52056 Aachen (Germany)

    2017-03-01

    We compute cosmic microwave background (CMB) anisotropy constraints on exotic forms of energy injection in electromagnetic (e.m.) channels over a large range of timescales. We show that these constraints are very powerful around or just after recombination, although CMB keeps some sensitivity e.g. to decaying species with lifetimes as long as 10{sup 25} s. These bounds are complementary to CMB spectral distortions and primordial nucleosynthesis ones, which dominate at earlier timescales, as we also review here. For the first time, we describe the effects of the e.m. energy injection on the CMB power spectra as a function of the injection epoch , using the lifetime of a decaying particle as proxy. We also identify a suitable on-the-spot approximation, that can be used to derive accurate constraints, and describe its differences with the most up-to-date treatment. Our results are of interest not only for early universe relics constituting (a fraction of) the dark matter, but also for other exotic injection of e.m. radiation. For illustration, we apply our formalism to: i) Primordial black holes of mass 10{sup 13.5} g ∼< M ∼< 10{sup 16.8} g, showing that the constraints are comparable to the ones obtained from gamma-ray background studies and even dominate below ∼ 10{sup 14} g. ii) To a peculiar mass-mixing range in the sterile neutrino parameter space, complementary to other astrophysical and laboratory probes. iii) Finally, we provide a first estimate of the room for improvement left for forthcoming 21 cm experiments, comparing it with the reach of proposed CMB spectral distortion (PiXiE) and CMB angular power spectrum (CORE) missions. We show that the best and most realistic opportunity to look for this signal (or to improve over current constraints) in the 21 cm probe is to focus on the Cosmic Dawn epoch, 15 ∼< z ∼< 30, where the qualitatively unambiguous signature of a spectrum in emission can be expected for models that evade all current constraints.

  15. Peer-to-Peer Planning for Space Mission Control

    Science.gov (United States)

    Barreiro, Javier; Jones, Grailing, Jr.; Schaffer, Steve

    2009-01-01

    Planning and scheduling for space operations entails the development of applications that embed intimate domain knowledge of distinct areas of mission control, while allowing for significant collaboration among them. The separation is useful because of differences in the planning problem, solution methods, and frequencies of replanning that arise in the different disciplines. For example, planning the activities of human spaceflight crews requires some reasoning about all spacecraft resources at timescales of minutes or seconds, and is subject to considerable volatility. Detailed power planning requires managing the complex interplay of power consumption and production, involves very different classes of constraints and preferences, but once plans are generated they are relatively stable.

  16. Mission Operations Planning with Preferences: An Empirical Study

    Science.gov (United States)

    Bresina, John L.; Khatib, Lina; McGann, Conor

    2006-01-01

    This paper presents an empirical study of some nonexhaustive approaches to optimizing preferences within the context of constraint-based, mixed-initiative planning for mission operations. This work is motivated by the experience of deploying and operating the MAPGEN (Mixed-initiative Activity Plan GENerator) system for the Mars Exploration Rover Mission. Responsiveness to the user is one of the important requirements for MAPGEN, hence, the additional computation time needed to optimize preferences must be kept within reasonabble bounds. This was the primary motivation for studying non-exhaustive optimization approaches. The specific goals of rhe empirical study are to assess the impact on solution quality of two greedy heuristics used in MAPGEN and to assess the improvement gained by applying a linear programming optimization technique to the final solution.

  17. Propulsive maneuver design for the Mars Exploration Rover mission

    Science.gov (United States)

    Potts, Christopher L.; Kangas, Julie A.; Raofi, Behzad

    2006-01-01

    Starting from approximately 150 candidate Martian landing sites, two distinct sites have been selected for further investigation by sophisticated rovers. The two rovers, named 'Spirit' and 'Opportunity', begin the surface mission respectively to Gusec Crater and Meridiani Planum in January 2004. the rovers are essentially robotic geologists, sent on a mission to research for evidence in the rocks and soil pertaining to the historical presence of water and the ability to possibly sustain life. Before this scientific search can commence, precise trajectory targeting and control is necessary to achieve the entry requirements for the selected landing sites within the constraints of the flight system. The maneuver design challenge is to meet or exceed these requirements while maintaining the necessary design flexibility to accommodate additional project concerns. Opportunities to improve performance and reduce risk based on trajectory control characteristics are also evaluated.

  18. Thermomechanical constraints and constitutive formulations in thermoelasticity

    Directory of Open Access Journals (Sweden)

    Baek S.

    2003-01-01

    Full Text Available We investigate three classes of constraints in a thermoelastic body: (i a deformation-temperature constraint, (ii a deformation-entropy constraint, and (iii a deformation-energy constraint. These constraints are obtained as limits of unconstrained thermoelastic materials and we show that constraints (ii and (iii are equivalent. By using a limiting procedure, we show that for the constraint (i, the entropy plays the role of a Lagrange multiplier while for (ii and (iii, the absolute temperature plays the role of Lagrange multiplier. We further demonstrate that the governing equations for materials subject to constraint (i are identical to those of an unconstrained material whose internal energy is an affine function of the entropy, while those for materials subject to constraints (ii and (iii are identical to those of an unstrained material whose Helmholtz potential is affine in the absolute temperature. Finally, we model the thermoelastic response of a peroxide-cured vulcanizate of natural rubber and show that imposing the constraint in which the volume change depends only on the internal energy leads to very good predictions (compared to experimental results of the stress and temperature response under isothermal and isentropic conditions.

  19. Sum rules and constraints on passive systems

    International Nuclear Information System (INIS)

    Bernland, A; Gustafsson, M; Luger, A

    2011-01-01

    A passive system is one that cannot produce energy, a property that naturally poses constraints on the system. A system in convolution form is fully described by its transfer function, and the class of Herglotz functions, holomorphic functions mapping the open upper half-plane to the closed upper half-plane, is closely related to the transfer functions of passive systems. Following a well-known representation theorem, Herglotz functions can be represented by means of positive measures on the real line. This fact is exploited in this paper in order to rigorously prove a set of integral identities for Herglotz functions that relate weighted integrals of the function to its asymptotic expansions at the origin and infinity. The integral identities are the core of a general approach introduced here to derive sum rules and physical limitations on various passive physical systems. Although similar approaches have previously been applied to a wide range of specific applications, this paper is the first to deliver a general procedure together with the necessary proofs. This procedure is described thoroughly and exemplified with examples from electromagnetic theory.

  20. Testing multiple coordination constraints with a novel bimanual visuomotor task.

    Directory of Open Access Journals (Sweden)

    Helene M Sisti

    Full Text Available The acquisition of a new bimanual skill depends on several motor coordination constraints. To date, coordination constraints have often been tested relatively independently of one another, particularly with respect to isofrequency and multifrequency rhythms. Here, we used a new paradigm to test the interaction of multiple coordination constraints. Coordination constraints that were tested included temporal complexity, directionality, muscle grouping, and hand dominance. Twenty-two healthy young adults performed a bimanual dial rotation task that required left and right hand coordination to track a moving target on a computer monitor. Two groups were compared, either with or without four days of practice with augmented visual feedback. Four directional patterns were tested such that both hands moved either rightward (clockwise, leftward (counterclockwise, inward or outward relative to each other. Seven frequency ratios (3∶1, 2∶1, 3∶2, 1∶1, 2∶3. 1∶2, 1∶3 between the left and right hand were introduced. As expected, isofrequency patterns (1∶1 were performed more successfully than multifrequency patterns (non 1∶1. In addition, performance was more accurate when participants were required to move faster with the dominant right hand (1∶3, 1∶2 and 2∶3 than with the non-dominant left hand (3∶1, 2∶1, 3∶2. Interestingly, performance deteriorated as the relative angular velocity between the two hands increased, regardless of whether the required frequency ratio was an integer or non-integer. This contrasted with previous finger tapping research where the integer ratios generally led to less error than the non-integer ratios. We suggest that this is due to the different movement topologies that are required of each paradigm. Overall, we found that this visuomotor task was useful for testing the interaction of multiple coordination constraints as well as the release from these constraints with practice in the presence of

  1. Orion Optical Navigation Progress Toward Exploration: Mission 1

    Science.gov (United States)

    Holt, Greg N.; D'Souza, Christopher N.; Saley, David

    2018-01-01

    Optical navigation of human spacecraft was proposed on Gemini and implemented successfully on Apollo as a means of autonomously operating the vehicle in the event of lost communication with controllers on Earth. It shares a history with the "method of lunar distances" that was used in the 18th century and gained some notoriety after its use by Captain James Cook during his 1768 Pacific voyage of the HMS Endeavor. The Orion emergency return system utilizing optical navigation has matured in design over the last several years, and is currently undergoing the final implementation and test phase in preparation for Exploration Mission 1 (EM-1) in 2019. The software development is being worked as a Government Furnished Equipment (GFE) project delivered as an application within the Core Flight Software of the Orion camera controller module. The mathematical formulation behind the initial ellipse fit in the image processing is detailed in Christian. The non-linear least squares refinement then follows the technique of Mortari as an estimation process of the planetary limb using the sigmoid function. The Orion optical navigation system uses a body fixed camera, a decision that was driven by mass and mechanism constraints. The general concept of operations involves a 2-hour pass once every 24 hours, with passes specifically placed before all maneuvers to supply accurate navigation information to guidance and targeting. The pass lengths are limited by thermal constraints on the vehicle since the OpNav attitude generally deviates from the thermally stable tail-to-sun attitude maintained during the rest of the orbit coast phase. Calibration is scheduled prior to every pass due to the unknown nature of thermal effects on the lens distortion and the mounting platform deformations between the camera and star trackers. The calibration technique is described in detail by Christian, et al. and simultaneously estimates the Brown-Conrady coefficients and the Star Tracker

  2. Planet Detection: The Kepler Mission

    Science.gov (United States)

    Jenkins, Jon M.; Smith, Jeffrey C.; Tenenbaum, Peter; Twicken, Joseph D.; Van Cleve, Jeffrey

    2012-03-01

    , only ˜0.5% will exhibit transits. By observing such a large number of stars, Kepler is guaranteed to produce a robust null result in the unhappy event that no Earth-size planets are detected in or near the habitable zone. Such a result would indicate that worlds like ours are extremely rare in the Milky Way galaxy and perhaps the cosmos, and that we might be solitary sojourners in the quest to answer the age-old question: "Are we alone?" Kepler is an audacious mission that places rigorous demands on the science pipeline used to process the ever-accumulating, large amount of data and to identify and characterize the minute planetary signatures hiding in the data haystack. Kepler observes over 160,000 stars simultaneously over a field of view (FOV) of 115 square degrees with a focal plane consisting of 42 charge-coupled devices‡ (CCDs), each of which images 2.75 square degrees of sky onto 2200×1024 pixels. The photometer, which contains the CCD array, reads out each CCD every 6.54 s [10,11] and co-adds the images for 29.4 min, called a long cadence (LC) interval. Due to storage and bandwidth constraints, only the pixels of interest, those that contain images of target stars, are saved onboard the solid-state recorder (SSR), which can store 66+ days of data. An average of 32 pixels per star is allowed for up to 170,000 stellar target definitions. In addition, a total of 512 targets are sampled at 58.85-s short cadence (SC) intervals, permitting further characterization of the planet-star systems for the brighter stars with a Kepler magnitude,* Kp, brighter than 12 (Kp machine learning and data mining. First, Section 17.2 gives a brief overview of the SOC science processing pipeline. This includes a special subsection detailing the adaptive, wavelet-based transit detector in the transiting planet search (TPS) pipeline component that performs the automated search through each of the hundreds of thousands of light curves for transit signatures of Earth-size planets

  3. International partnership in lunar missions

    Indian Academy of Sciences (India)

    related to space science and Moon missions are being addressed in this conference. .... flight. The studies in India suggest that an 'aerobic' space transportation vehicle can indeed have a ... space from Earth at very, very low cost first before.

  4. Telepresence for Deep Space Missions

    Data.gov (United States)

    National Aeronautics and Space Administration — Incorporating telepresence technologies into deep space mission operations can give the crew and ground personnel the impression that they are in a location at time...

  5. Mission Level Autonomy for USSV

    Science.gov (United States)

    Huntsberger, Terry; Stirb, Robert C.; Brizzolara, Robert

    2011-01-01

    On-water demonstration of a wide range of mission-proven, advanced technologies at TRL 5+ that provide a total integrated, modular approach to effectively address the majority of the key needs for full mission-level autonomous, cross-platform control of USV s. Wide baseline stereo system mounted on the ONR USSV was shown to be an effective sensing modality for tracking of dynamic contacts as a first step to automated retrieval operations. CASPER onboard planner/replanner successfully demonstrated realtime, on-water resource-based analysis for mission-level goal achievement and on-the-fly opportunistic replanning. Full mixed mode autonomy was demonstrated on-water with a seamless transition between operator over-ride and return to current mission plan. Autonomous cooperative operations for fixed asset protection and High Value Unit escort using 2 USVs (AMN1 & 14m RHIB) were demonstrated during Trident Warrior 2010 in JUN 2010

  6. Green Propellant Infusion Mission Program

    Data.gov (United States)

    National Aeronautics and Space Administration — The mission is architected as a collaboration of NASA, Industry, and Air Force partners with the objective to advance the technology for propulsion components using...

  7. Lidar instruments for ESA Earth observation missions

    Science.gov (United States)

    Hélière, Arnaud; Armandillo, Errico; Durand, Yannig; Culoma, Alain; Meynart, Roland

    2017-11-01

    The idea of deploying a lidar system on an Earthorbiting satellite stems from the need for continuously providing profiles of our atmospheric structure with high accuracy and resolution and global coverage. Interest in this information for climatology, meteorology and the atmospheric sciences in general is huge. Areas of application range from the determination of global warming and greenhouse effects, to monitoring the transport and accumulation of pollutants in the different atmospheric regions (such as the recent fires in Southeast Asia), to the assessment of the largely unknown microphysical properties and the structural dynamics of the atmosphere itself. Spaceborne lidar systems have been the subject of extensive investigations by the European Space Agency since mid 1970's, resulting in mission and instrument concepts, such as ATLID, the cloud backscatter lidar payload of the EarthCARE mission, ALADIN, the Doppler wind lidar of the Atmospheric Dynamics Mission (ADM) and more recently a water vapour Differential Absorption Lidar considered for the WALES mission. These studies have shown the basic scientific and technical feasibility of spaceborne lidars, but they have also demonstrated their complexity from the instrument viewpoint. As a result, the Agency undertook technology development in order to strengthen the instrument maturity. This is the case for ATLID, which benefited from a decade of technology development and supporting studies and is now studied in the frame of the EarthCARE mission. ALADIN, a Direct Detection Doppler Wind Lidar operating in the Ultra -Violet, will be the 1st European lidar to fly in 2007 as payload of the Earth Explorer Core Mission ADM. WALES currently studied at the level of a phase A, is based upon a lidar operating at 4 wavelengths in near infrared and aims to profile the water vapour in the lower part of the atmosphere with high accuracy and low bias. Lastly, the European Space Agency is extending the lidar instrument field

  8. Constraint algebra in Smolin's G →0 limit of 4D Euclidean gravity

    Science.gov (United States)

    Varadarajan, Madhavan

    2018-05-01

    Smolin's generally covariant GNewton→0 limit of 4d Euclidean gravity is a useful toy model for the study of the constraint algebra in loop quantum gravity (LQG). In particular, the commutator between its Hamiltonian constraints has a metric dependent structure function. While a prior LQG-like construction of nontrivial anomaly free constraint commutators for the model exists, that work suffers from two defects. First, Smolin's remarks on the inability of the quantum dynamics to generate propagation effects apply. Second, the construction only yields the action of a single Hamiltonian constraint together with the action of its commutator through a continuum limit of corresponding discrete approximants; the continuum limit of a product of two or more constraints does not exist. Here, we incorporate changes in the quantum dynamics through structural modifications in the choice of discrete approximants to the quantum Hamiltonian constraint. The new structure is motivated by that responsible for propagation in an LQG-like quantization of paramatrized field theory and significantly alters the space of physical states. We study the off shell constraint algebra of the model in the context of these structural changes and show that the continuum limit action of multiple products of Hamiltonian constraints is (a) supported on an appropriate domain of states, (b) yields anomaly free commutators between pairs of Hamiltonian constraints, and (c) is diffeomorphism covariant. Many of our considerations seem robust enough to be applied to the setting of 4d Euclidean gravity.

  9. Institutional constraints on alternative water for energy: a guidebook for regional assessments

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    Basic information is presented about the legal, political, and social constraints faced by energy developers in the acquisition of water from underground, irrigation return flow, municipal waste, and saline sources. It is a guide to those institutional constraints which are general and pronounced enough to be important for regional assessments. First, attention was focused on the acquisition phase of the water use cycle. Second, constraints were analyzed primarily from a regional, rather than state-by-state, perspective. Emphasis was placed generally on the West - particularly the synfuel-rich Rocky Mountain states, the East, and Mid-West, in that order. Alaska and Hawaii were not surveyed. Third, the study focuses on the constraints associated with groundwater, municipal waste, irrigation return flow, and sea water, in that order. The phrase, institutional constraints, as used in the study, means legal, social, economic, and political restrictions, requirements, circumstances, or conditions that must be anticipated or responded to in order to acquire water for energy development. The study focuses primarily on legal constraints and secondarily on political constraints, because they tend to encompass or reflect other forms of institutional constraints.

  10. Asteroid Rendezvous Mission Design Using Multiobjective Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Ya-zhong Luo

    2014-01-01

    Full Text Available A new preliminary trajectory design method for asteroid rendezvous mission using multiobjective optimization techniques is proposed. This method can overcome the disadvantages of the widely employed Pork-Chop method. The multiobjective integrated launch window and multi-impulse transfer trajectory design model is formulated, which employes minimum-fuel cost and minimum-time transfer as two objective functions. The multiobjective particle swarm optimization (MOPSO is employed to locate the Pareto solution. The optimization results of two different asteroid mission designs show that the proposed approach can effectively and efficiently demonstrate the relations among the mission characteristic parameters such as launch time, transfer time, propellant cost, and number of maneuvers, which will provide very useful reference for practical asteroid mission design. Compared with the PCP method, the proposed approach is demonstrated to be able to provide much more easily used results, obtain better propellant-optimal solutions, and have much better efficiency. The MOPSO shows a very competitive performance with respect to the NSGA-II and the SPEA-II; besides a proposed boundary constraint optimization strategy is testified to be able to improve its performance.

  11. Urinary albumin in space missions

    DEFF Research Database (Denmark)

    Cirillo, Massimo; De Santo, Natale G; Heer, Martina

    2002-01-01

    Proteinuria was hypothesized for space mission but research data are missing. Urinary albumin, as index of proteinuria, was analyzed in frozen urine samples collected by astronauts during space missions onboard MIR station and on ground (control). Urinary albumin was measured by a double antibody...... radioimmunoassay. On average, 24h urinary albumin was 27.4% lower in space than on ground; the difference was statistically significant. Low urinary albumin excretion could be another effect of exposure to weightlessness (microgravity)....

  12. KEPLER Mission: development and overview

    International Nuclear Information System (INIS)

    Borucki, William J

    2016-01-01

    The Kepler Mission is a space observatory launched in 2009 by NASA to monitor 170 000 stars over a period of four years to determine the frequency of Earth-size and larger planets in and near the habitable zone of Sun-like stars, the size and orbital distributions of these planets, and the types of stars they orbit. Kepler is the tenth in the series of NASA Discovery Program missions that are competitively-selected, PI-directed, medium-cost missions. The Mission concept and various instrument prototypes were developed at the Ames Research Center over a period of 18 years starting in 1983. The development of techniques to do the 10 ppm photometry required for Mission success took years of experimentation, several workshops, and the exploration of many ‘blind alleys’ before the construction of the flight instrument. Beginning in 1992 at the start of the NASA Discovery Program, the Kepler Mission concept was proposed five times before its acceptance for mission development in 2001. During that period, the concept evolved from a photometer in an L2 orbit that monitored 6000 stars in a 50 sq deg field-of-view (FOV) to one that was in a heliocentric orbit that simultaneously monitored 170 000 stars with a 105 sq deg FOV. Analysis of the data to date has detected over 4600 planetary candidates which include several hundred Earth-size planetary candidates, over a thousand confirmed planets, and Earth-size planets in the habitable zone (HZ). These discoveries provide the information required for estimates of the frequency of planets in our galaxy. The Mission results show that most stars have planets, many of these planets are similar in size to the Earth, and that systems with several planets are common. Although planets in the HZ are common, many are substantially larger than Earth. (review article)

  13. TRISTAN - mission complete

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The high energy physics mission of the TRISTAN electron-positron collider at the Japanese KEK Laboratory ended in May. TRISTAN was the first accelerator in Japan at the high energy frontier, and its success owes a great deal to help and encouragement from the world high energy physics community. Its success also marks the first step toward the KEKB project now underway and the subsequent Linear Collider scheme. TRISTAN began operation in November 1986 with a collision energy of 50 GeV, the world's highest electron-positron collision energy at that time. With the addition of superconducting radiofrequency cavities, the energy was continuously increased, reaching a maximum of 64 GeV in 1989. In this exploratory era, the three large detectors - AMY,TOPAZ and VENUS - together with the smaller SHIP group made a rapid survey of particle phenomena in this new energy range. The sixth ('top') quark was first on the list of wanted particles, but the three large groups concluded that there were no new quarks below 32 GeV. The CDF and DO Collaborations at Fermilab's Tevatron recently reported the top quark as being six times as heavy as TRISTAN'S physics reach. Although initial experimental results suggested that the event-shape distributions of multi-hadron events were broadly consistent with the production of the five known quarks, the production rate of hadrons, compared to muons, was seen to rise with energy. The increased energy reach of TRISTAN increased the visibility of the subtle virtual effects of the Z (the electrically neutral carrier of the weak force) produced through the interference of weak and electromagnetic interactions. The rise was found to be slightly larger than expected from five quarks and a Z mass of 92 or 93 GeV, the accepted value at that time. This hinted that the Z mass had to be smaller, as later verified when the SLC and LEP electron-positron colliders at SLAC (Stanford) and CERN respectively came into operation in 1989

  14. Executive Summary - Our mission

    International Nuclear Information System (INIS)

    2007-01-01

    Full text: The Henryk Niewodniczanski Institute of Nuclear Physics (Instytut Fizyki Jadrowej im. Henryka Niewodniczanskiego, IFJ PAN) is currently the largest research institution of the Polish Academy of Sciences (Polska Akademia Nauk). The research activity of the Academy is financed mainly from the State budget via the Ministry of Science and Higher Education. The mission of IFJ PAN is stated in its Charter. According to Paragraphs 5, 6, and 7 of the 2004 Charter, the Institute's duty is to carry out research activities in the following areas: 1. High energy and elementary particle physics (including astrophysics), 2. Nuclear physics and strong interaction, 3. Condensed matter physics, 4. Interdisciplinary research, in particular: in radiation and environmental biology, environmental physics, medical physics, dosimetry, nuclear geophysics, radiochemistry and material engineering. The main tasks of the Institute are: 1. To perform research in the above disciplines, 2. To promote the development of scientists and of specialists qualified to carry out research in these disciplines, 3. To organize a Post-Graduate Study Course, 4. To permit, through agreements with national and foreign research institutions, external scholars to train and gain academic qualifications in the Institute's laboratories, 5. To collaborate with national and local authorities in providing them with expertise in the Institute's research topics, especially concerning radiation protection. These tasks are fulfilled by: 1. Performing individual and coordinated research through individual and collective research grant projects, 2. Initiating and maintaining cooperation with laboratories, organizations and institutions performing similar activities, in Poland and abroad, 3. Conferring scientific degrees and titles, 4. Distributing research results obtained, through peer-reviewed publications and other public media, 5. Organizing scientific meetings, conferences, symposia, training workshops, etc

  15. From physical dose constraints to equivalent uniform dose constraints in inverse radiotherapy planning

    International Nuclear Information System (INIS)

    Thieke, Christian; Bortfeld, Thomas; Niemierko, Andrzej; Nill, Simeon

    2003-01-01

    Optimization algorithms in inverse radiotherapy planning need information about the desired dose distribution. Usually the planner defines physical dose constraints for each structure of the treatment plan, either in form of minimum and maximum doses or as dose-volume constraints. The concept of equivalent uniform dose (EUD) was designed to describe dose distributions with a higher clinical relevance. In this paper, we present a method to consider the EUD as an optimization constraint by using the method of projections onto convex sets (POCS). In each iteration of the optimization loop, for the actual dose distribution of an organ that violates an EUD constraint a new dose distribution is calculated that satisfies the EUD constraint, leading to voxel-based physical dose constraints. The new dose distribution is found by projecting the current one onto the convex set of all dose distributions fulfilling the EUD constraint. The algorithm is easy to integrate into existing inverse planning systems, and it allows the planner to choose between physical and EUD constraints separately for each structure. A clinical case of a head and neck tumor is optimized using three different sets of constraints: physical constraints for all structures, physical constraints for the target and EUD constraints for the organs at risk, and EUD constraints for all structures. The results show that the POCS method converges stable and given EUD constraints are reached closely

  16. Metric approach to quantum constraints

    International Nuclear Information System (INIS)

    Brody, Dorje C; Hughston, Lane P; Gustavsson, Anna C T

    2009-01-01

    A framework for deriving equations of motion for constrained quantum systems is introduced and a procedure for its implementation is outlined. In special cases, the proposed new method, which takes advantage of the fact that the space of pure states in quantum mechanics has both a symplectic structure and a metric structure, reduces to a quantum analogue of the Dirac theory of constraints in classical mechanics. Explicit examples involving spin-1/2 particles are worked out in detail: in the first example, our approach coincides with a quantum version of the Dirac formalism, while the second example illustrates how a situation that cannot be treated by Dirac's approach can nevertheless be dealt with in the present scheme.

  17. Psychosocial interactions during ISS missions

    Science.gov (United States)

    Kanas, N. A.; Salnitskiy, V. P.; Ritsher, J. B.; Gushin, V. I.; Weiss, D. S.; Saylor, S. A.; Kozerenko, O. P.; Marmar, C. R.

    2007-02-01

    Based on anecdotal reports from astronauts and cosmonauts, studies of space analog environments on Earth, and our previous research on the Mir Space Station, a number of psychosocial issues have been identified that can lead to problems during long-duration space expeditions. Several of these issues were studied during a series of missions to the International Space Station. Using a mood and group climate questionnaire that was completed weekly by crewmembers in space and personnel in mission control, we found no evidence to support the presence of predicted decrements in well-being during the second half or in any specific quarter of the missions. The results did support the predicted displacement of negative feelings to outside supervisors among both crew and ground subjects. There were several significant differences in mood and group perceptions between Americans and Russians and between crewmembers and mission control personnel. Crewmembers related cohesion to the support role of their leader, and mission control personnel related cohesion to both the task and support roles of their leader. These findings are discussed with reference to future space missions.

  18. Social Tagging of Mission Data

    Science.gov (United States)

    Norris, Jeffrey S.; Wallick, Michael N.; Joswig, Joseph C.; Powell, Mark W.; Torres, Recaredo J.; Mittman, David S.; Abramyan, Lucy; Crockett, Thomas M.; Shams, Khawaja S.; Fox, Jason M.; hide

    2010-01-01

    Mars missions will generate a large amount of data in various forms, such as daily plans, images, and scientific information. Often, there is a semantic linkage between images that cannot be captured automatically. Software is needed that will provide a method for creating arbitrary tags for this mission data so that items with a similar tag can be related to each other. The tags should be visible and searchable for all users. A new routine was written to offer a new and more flexible search option over previous applications. This software allows users of the MSLICE program to apply any number of arbitrary tags to a piece of mission data through a MSLICE search interface. The application of tags creates relationships between data that did not previously exist. These tags can be easily removed and changed, and contain enough flexibility to be specifically configured for any mission. This gives users the ability to quickly recall or draw attention to particular pieces of mission data, for example: Give a semantic and meaningful description to mission data; for example, tag all images with a rock in them with the tag "rock." Rapidly recall specific and useful pieces of data; for example, tag a plan as"driving template." Call specific data to a user s attention; for example, tag a plan as "for:User." This software is part of the MSLICE release, which was written in Java. It will run on any current Windows, Macintosh, or Linux system.

  19. Space missions to the exoplanets: Will they ever be possible

    Science.gov (United States)

    Genta, Giancarlo

    using a spacecraft to physically transfer back the information on a support of some type (the so called data clippers) may make missions of type 2 to be only marginally less complex than missions of type 3. Missions of type 3 are at least twice as demanding than those of type 2 for what propulsion is required, and are also much more demanding also from the viewpoint of autonomy. On the contrary, they may be simpler from the viewpoint of communications. Finally, missions of type 4 are often regarded as belonging to the science fiction domain more than to that of feasible realities. However, they might be the only possibility if the progress in the field of robotics and artificial intelligence will fall short from making it possible to proceed with robotic missions. As a conclusion, we can assess that, short of unpredictable technological breakthroughs, missions to the exoplanets are still far away in the future and educated guesses can set them centuries away from now. What can be done is to identify critical technologies and assess a roadmap to increase their technological readiness. This effort is really worthwhile, since aiming at a very difficult task like interstellar missions, will yield a positive fallout on space exploration in general. --- This paper is meant for the Panel on Exoplanetary Exploration (PEPE) which is not included in the list above, so it was included in PEX.1

  20. Liquidity constraints, risk premia, and themacroeconomic effects of liquidity shocks

    OpenAIRE

    Jaccard, Ivan

    2013-01-01

    We study the transmission of liquidity shocks in a dynamic general equilibrium model where firms and households are subject to liquidity risk. The provision of liquidity services is undertaken by financial intermediaries that allocate the stock of liquid asset between the different sectors of the economy. We find that the macroeconomic effects of liquidity shocks are considerably larger in the model economy that generates a realistic equity premium. Liquidity constraints amplify business cycl...

  1. Gauge transformations in relativistic two-particle constraint theory

    International Nuclear Information System (INIS)

    Jallouli, H.; Sazdjian, H.

    1996-01-01

    The forms of the local potentials in linear covariant gauges are investigated and relationships are found between them. The gauge transformation properties of the Green's function and of the Bethe-Salpeter wave function are reviewed. The infinitesimal gauge transformation laws of the constraint theory wave functions and potentials are determined. The case of the local approximation of potentials is considered. The general properties of the gauge transformations in the local approximation are studied. (K.A.)

  2. The Schwinger Dyson equations and the algebra of constraints of random tensor models at all orders

    International Nuclear Information System (INIS)

    Gurau, Razvan

    2012-01-01

    Random tensor models for a generic complex tensor generalize matrix models in arbitrary dimensions and yield a theory of random geometries. They support a 1/N expansion dominated by graphs of spherical topology. Their Schwinger Dyson equations, generalizing the loop equations of matrix models, translate into constraints satisfied by the partition function. The constraints have been shown, in the large N limit, to close a Lie algebra indexed by colored rooted D-ary trees yielding a first generalization of the Virasoro algebra in arbitrary dimensions. In this paper we complete the Schwinger Dyson equations and the associated algebra at all orders in 1/N. The full algebra of constraints is indexed by D-colored graphs, and the leading order D-ary tree algebra is a Lie subalgebra of the full constraints algebra.

  3. Development and application of a unified balancing approach with multiple constraints

    Science.gov (United States)

    Zorzi, E. S.; Lee, C. C.; Giordano, J. C.

    1985-01-01

    The development of a general analytic approach to constrained balancing that is consistent with past influence coefficient methods is described. The approach uses Lagrange multipliers to impose orbit and/or weight constraints; these constraints are combined with the least squares minimization process to provide a set of coupled equations that result in a single solution form for determining correction weights. Proper selection of constraints results in the capability to: (1) balance higher speeds without disturbing previously balanced modes, thru the use of modal trial weight sets; (2) balance off-critical speeds; and (3) balance decoupled modes by use of a single balance plane. If no constraints are imposed, this solution form reduces to the general weighted least squares influence coefficient method. A test facility used to examine the use of the general constrained balancing procedure and application of modal trial weight ratios is also described.

  4. Automated and Adaptive Mission Planning for Orbital Express

    Science.gov (United States)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel; Koblick, Darin

    2008-01-01

    The Orbital Express space mission was a Defense Advanced Research Projects Agency (DARPA) lead demonstration of on-orbit satellite servicing scenarios, autonomous rendezvous, fluid transfers of hydrazine propellant, and robotic arm transfers of Orbital Replacement Unit (ORU) components. Boeing's Autonomous Space Transport Robotic Operations (ASTRO) vehicle provided the servicing to the Ball Aerospace's Next Generation Serviceable Satellite (NextSat) client. For communication opportunities, operations used the high-bandwidth ground-based Air Force Satellite Control Network (AFSCN) along with the relatively low-bandwidth GEO-Synchronous space-borne Tracking and Data Relay Satellite System (TDRSS) network. Mission operations were conducted out of the RDT&E Support Complex (RSC) at the Kirtland Air Force Base in New Mexico. All mission objectives were met successfully: The first of several autonomous rendezvous was demonstrated on May 5, 2007; autonomous free-flyer capture was demonstrated on June 22, 2007; the fluid and ORU transfers throughout the mission were successful. Planning operations for the mission were conducted by a team of personnel including Flight Directors, who were responsible for verifying the steps and contacts within the procedures, the Rendezvous Planners who would compute the locations and visibilities of the spacecraft, the Scenario Resource Planners (SRPs), who were concerned with assignment of communications windows, monitoring of resources, and sending commands to the ASTRO spacecraft, and the Mission planners who would interface with the real-time operations environment, process planning products and coordinate activities with the SRP. The SRP position was staffed by JPL personnel who used the Automated Scheduling and Planning ENvironment (ASPEN) to model and enforce mission and satellite constraints. The lifecycle of a plan began three weeks outside its execution on-board. During the planning timeframe, many aspects could change the plan

  5. Causality Constraints in Conformal Field Theory

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂φ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinni...

  6. Constraint Embedding for Multibody System Dynamics

    Science.gov (United States)

    Jain, Abhinandan

    2009-01-01

    This paper describes a constraint embedding approach for the handling of local closure constraints in multibody system dynamics. The approach uses spatial operator techniques to eliminate local-loop constraints from the system and effectively convert the system into tree-topology systems. This approach allows the direct derivation of recursive O(N) techniques for solving the system dynamics and avoiding the expensive steps that would otherwise be required for handling the closedchain dynamics. The approach is very effective for systems where the constraints are confined to small-subgraphs within the system topology. The paper provides background on the spatial operator O(N) algorithms, the extensions for handling embedded constraints, and concludes with some examples of such constraints.

  7. Use of dose constraints in public exposure

    International Nuclear Information System (INIS)

    Tageldein, Amged

    2015-02-01

    An overview of the dose constraints in public exposures has been carried out in this project. The establishment, development and the application of the concept of dose constraints are reviewed with regards to public exposure. The role of dose constraints in the process of optimization of radiation protection was described and has been showed that the concept of the dose constraints along with many other concept of radiation protection is widely applied in the optimization of exposure to radiation. From the beginning of the establishment of dose constraints as a concept in radiation protection, the International Commission of Radiological Protection (ICRP) has published a number of documents that provides detailed application related to radiation protection and safety of public exposure from ionizing radiation. This work provides an overview of such publications and related documents with special emphasis on optimization of public exposure using dose constraints. (au)

  8. Causality constraints in conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Thomas; Jain, Sachin; Kundu, Sandipan [Department of Physics, Cornell University,Ithaca, New York (United States)

    2016-05-17

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂ϕ){sup 4} coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning operators.

  9. STUDY REGARDING DIFFERENT TYPES OF AUDITOR’S MISSIONS

    Directory of Open Access Journals (Sweden)

    Daniel Botez

    2013-12-01

    Full Text Available After the involvement of the audit profession in several financial scandals, the international body of the profession, International Federation of Accountants – IFAC, has developed and published a conceptual framework and reviewed most of the reference standards in auditing to provide references regarding the responsibility of the professionals and the extent of their missions. Thus was established the use of a general term for professionals, the “practitioner”, in the context of specific missions using the “auditor”, “practitioner” or “accountant”. On the other hand, have been revised professional standards establish insurance missions and non-insurance operations, with their specific missions that do not provide insurance, including the recoding. The use of these references by audit professionals constitutes one of the “keys” to their success.

  10. A framework for employing femtosatellites in planetary science missions, including a proposed mission concept for Titan

    Science.gov (United States)

    Perez, Tracie Renea Conn

    correction (FEC) method called low-density parity-check (LDPC) codes is recommended. A specific low-complexity encoder, and accompanying decoder, have been implemented in the open-source software radio library, GNU Radio. Simulation results demonstrating bit error rate (BER) improvement are presented. Hardware for implementing the LDPC methods in a benchtop test are described and future work on this topic is suggested. Third, the power and spatial constraints of femtosatellite designs likely restrict the payload to one or two sensors. Therefore, it is desired to extract as much useful scientific data as possible from secondary sources, such as radiometric data. Estimating the atmospheric density model from different measurement sources is simulated; results are presented. The overall goal for this effort is to advance the field of miniature spacecraft-based technology and to highlight the advantages of using femtosatellites in future planetary exploration missions. By addressing several subsystem design challenges in this context, such a femtosat mission concept is one step closer to being feasible.

  11. Low Thrust Trajectory Design for GSFC Missions

    Data.gov (United States)

    National Aeronautics and Space Administration — The Evolutionary Mission Trajectory Generator (EMTG) is a global trajectory optimization tool. EMTG is intended for use in designing interplanetary missions which...

  12. A review of Spacelab mission management approach

    Science.gov (United States)

    Craft, H. G., Jr.

    1979-01-01

    The Spacelab development program is a joint undertaking of the NASA and ESA. The paper addresses the initial concept of Spacelab payload mission management, the lessons learned, and modifications made as a result of the actual implementation of Spacelab Mission 1. The discussion covers mission management responsibilities, program control, science management, payload definition and interfaces, integrated payload mission planning, integration requirements, payload specialist training, payload and launch site integration, payload flight/mission operations, and postmission activities. After 3.5 years the outlined overall mission manager approach has proven to be most successful. The approach does allow the mission manager to maintain the lowest overall mission cost.

  13. Constraints on perturbative f(R) gravity via neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Arapoğlu, Savaş; Ekşi, K. Yavuz [İstanbul Technical University, Faculty of Science and Letters, Physics Engineering Department, Maslak 34469, İstanbul (Turkey); Deliduman, Cemsinan, E-mail: arapoglu@itu.edu.tr, E-mail: cemsinan@msgsu.edu.tr, E-mail: eksi@itu.edu.tr [Mimar Sinan Fine Arts University, Department of Physics, Beşiktaş 34349, İstanbul (Turkey)

    2011-07-01

    We study the structure of neutron stars in perturbative f(R) gravity models with realistic equations of state. We obtain mass-radius relations in a gravity model of the form f(R) = R+αR{sup 2}. We find that deviations from the results of general relativity, comparable to the variations due to using different equations of state (EoS'), are induced for |α| ∼ 10{sup 9} cm{sup 2}. Some of the soft EoS' that are excluded within the framework of general relativity can be reconciled with the 2 solar mass neutron star recently observed for certain values of α within this range. For some of the EoS' we find that a new solution branch, which allows highly massive neutron stars, exists for values of α greater than a few 10{sup 9} cm{sup 2}. We find constraints on α for a variety of EoS' using the recent observational constraints on the mass-radius relation. These are all 5 orders of magnitude smaller than the recent constraint obtained via Gravity Probe B for this gravity model. The associated length scale √(alpha)approx 10{sup 5} cm is only an order of magnitude smaller than the typical radius of a neutron star, the probe used in this test. This implies that real deviations from general relativity can be even smaller.

  14. Constraint-based Word Segmentation for Chinese

    DEFF Research Database (Denmark)

    Christiansen, Henning; Bo, Li

    2014-01-01

    -hoc and statistically based methods. In this paper, we show experiments of implementing different approaches to CWSP in the framework of CHR Grammars [Christiansen, 2005] that provides a constraint solving approach to language analysis. CHR Grammars are based upon Constraint Handling Rules, CHR [Frühwirth, 1998, 2009......], which is a declarative, high-level programming language for specification and implementation of constraint solvers....

  15. Stability Constraints for Robust Model Predictive Control

    Directory of Open Access Journals (Sweden)

    Amanda G. S. Ottoni

    2015-01-01

    Full Text Available This paper proposes an approach for the robust stabilization of systems controlled by MPC strategies. Uncertain SISO linear systems with box-bounded parametric uncertainties are considered. The proposed approach delivers some constraints on the control inputs which impose sufficient conditions for the convergence of the system output. These stability constraints can be included in the set of constraints dealt with by existing MPC design strategies, in this way leading to the “robustification” of the MPC.

  16. Some cosmological constraints on gauge theories

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1983-01-01

    In these lectures, a review is made of various constraints cosmology may place on gauge theories. Particular emphasis is placed on those constraints obtainable from Big Bang Nucleosynthesis, with only brief mention made of Big Bang Baryosynthesis. There is also a considerable discussion of astrophysical constraints on masses and lifetimes of neutrinos with specific mention of the 'missing mass (light)' problem of galactic dynamics. (orig./HSI)

  17. Constraints on Covariant Horava-Lifshitz Gravity from frame-dragging experiment

    Energy Technology Data Exchange (ETDEWEB)

    Radicella, Ninfa; Lambiase, Gaetano; Parisi, Luca; Vilasi, Gaetano, E-mail: ninfa.radicella@sa.infn.it, E-mail: lambiase@sa.infn.it, E-mail: parisi@sa.infn.it, E-mail: vilasi@sa.infn.it [Dipartimento di Fisica ' ' E.R. Caianiello" , Università di Salerno, Via Giovanni Paolo II 132, 84081 Fisciano (Italy)

    2014-12-01

    The effects of Horava-Lifshitz corrections to the gravito-magnetic field are analyzed. Solutions in the weak field, slow motion limit, referring to the motion of a satellite around the Earth are considered. The post-newtonian paradigm is used to evaluate constraints on the Horava-Lifshitz parameter space from current satellite and terrestrial experiments data. In particular, we focus on GRAVITY PROBE B, LAGEOS and the more recent LARES mission, as well as a forthcoming terrestrial project, GINGER.

  18. Production Team Maintenance: Systemic Constraints Impacting Implementation

    National Research Council Canada - National Science Library

    Moore, Terry

    1997-01-01

    .... Identified constraints included: integrating the PTM positioning strategy into the AMC corporate strategic planning process, manpower modeling simulator limitations, labor force authorizations and decentralization...

  19. Toward an automaton Constraint for Local Search

    Directory of Open Access Journals (Sweden)

    Jun He

    2009-10-01

    Full Text Available We explore the idea of using finite automata to implement new constraints for local search (this is already a successful technique in constraint-based global search. We show how it is possible to maintain incrementally the violations of a constraint and its decision variables from an automaton that describes a ground checker for that constraint. We establish the practicality of our approach idea on real-life personnel rostering problems, and show that it is competitive with the approach of [Pralong, 2007].

  20. Notes on Timed Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia, Frank D.

    2004-01-01

    and program reactive systems. This note provides a comprehensive introduction to the background for and central notions from the theory of tccp. Furthermore, it surveys recent results on a particular tccp calculus, ntcc, and it provides a classification of the expressive power of various tccp languages.......A constraint is a piece of (partial) information on the values of the variables of a system. Concurrent constraint programming (ccp) is a model of concurrency in which agents (also called processes) interact by telling and asking information (constraints) to and from a shared store (a constraint...

  1. Planck constraints on monodromy inflation

    International Nuclear Information System (INIS)

    Easther, Richard; Flauger, Raphael

    2014-01-01

    We use data from the nominal Planck mission to constrain modulations in the primordial power spectrum associated with monodromy inflation. The largest improvement in fit relative to the unmodulated model has Δχ 2 ≈ 10 and we find no evidence for a primordial signal, in contrast to a previous analysis of the WMAP9 dataset, for which Δχ 2 ≈ 20. The Planck and WMAP9 results are broadly consistent on angular scales where they are expected to agree as far as best-fit values are concerned. However, even on these scales the significance of the signal is reduced in Planck relative to WMAP, and is consistent with a fit to the ''noise'' associated with cosmic variance. Our results motivate both a detailed comparison between the two experiments and a more careful study of the theoretical predictions of monodromy inflation

  2. The Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed

  3. Mission aware energy saving strategies for Army ground vehicles

    Science.gov (United States)

    Dattathreya, Macam S.

    Fuel energy is a basic necessity for this planet and the modern technology to perform many activities on earth. On the other hand, quadrupled automotive vehicle usage by the commercial industry and military has increased fuel consumption. Military readiness of Army ground vehicles is very important for a country to protect its people and resources. Fuel energy is a major requirement for Army ground vehicles. According to a report, a department of defense has spent nearly $13.6 billion on fuel and electricity to conduct ground missions. On the contrary, energy availability on this plant is slowly decreasing. Therefore, saving energy in Army ground vehicles is very important. Army ground vehicles are embedded with numerous electronic systems to conduct missions such as silent and normal stationary surveillance missions. Increasing electrical energy consumption of these systems is influencing higher fuel consumption of the vehicle. To save energy, the vehicles can use any of the existing techniques, but they require complex, expensive, and time consuming implementations. Therefore, cheaper and simpler approaches are required. In addition, the solutions have to save energy according to mission needs and also overcome size and weight constraints of the vehicle. Existing research in the current literature do not have any mission aware approaches to save energy. This dissertation research proposes mission aware online energy saving strategies for stationary Army ground vehicles to save energy as well as to meet the electrical needs of the vehicle during surveillance missions. The research also proposes theoretical models of surveillance missions, fuzzy logic models of engine and alternator efficiency data, and fuzzy logic algorithms. Based on these models, two energy saving strategies are proposed for silent and normal surveillance type of missions. During silent mission, the engine is on and batteries power the systems. During normal surveillance mission, the engine is

  4. Mission Data System Java Edition Version 7

    Science.gov (United States)

    Reinholtz, William K.; Wagner, David A.

    2013-01-01

    The Mission Data System framework defines closed-loop control system abstractions from State Analysis including interfaces for state variables, goals, estimators, and controllers that can be adapted to implement a goal-oriented control system. The framework further provides an execution environment that includes a goal scheduler, execution engine, and fault monitor that support the expression of goal network activity plans. Using these frameworks, adapters can build a goal-oriented control system where activity coordination is verified before execution begins (plan time), and continually during execution. Plan failures including violations of safety constraints expressed in the plan can be handled through automatic re-planning. This version optimizes a number of key interfaces and features to minimize dependencies, performance overhead, and improve reliability. Fault diagnosis and real-time projection capabilities are incorporated. This version enhances earlier versions primarily through optimizations and quality improvements that raise the technology readiness level. Goals explicitly constrain system states over explicit time intervals to eliminate ambiguity about intent, as compared to command-oriented control that only implies persistent intent until another command is sent. A goal network scheduling and verification process ensures that all goals in the plan are achievable before starting execution. Goal failures at runtime can be detected (including predicted failures) and handled by adapted response logic. Responses can include plan repairs (try an alternate tactic to achieve the same goal), goal shedding, ignoring the fault, cancelling the plan, or safing the system.

  5. Kalman Filter Constraint Tuning for Turbofan Engine Health Estimation

    Science.gov (United States)

    Simon, Dan; Simon, Donald L.

    2005-01-01

    Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints are often neglected because they do not fit easily into the structure of the Kalman filter. Recently published work has shown a new method for incorporating state variable inequality constraints in the Kalman filter, which has been shown to generally improve the filter s estimation accuracy. However, the incorporation of inequality constraints poses some risk to the estimation accuracy as the Kalman filter is theoretically optimal. This paper proposes a way to tune the filter constraints so that the state estimates follow the unconstrained (theoretically optimal) filter when the confidence in the unconstrained filter is high. When confidence in the unconstrained filter is not so high, then we use our heuristic knowledge to constrain the state estimates. The confidence measure is based on the agreement of measurement residuals with their theoretical values. The algorithm is demonstrated on a linearized simulation of a turbofan engine to estimate engine health.

  6. Prospects for nuclear terrorism: psychological motivations and constraints

    International Nuclear Information System (INIS)

    Post, J.M.

    1987-01-01

    In considering the implications of psychological understandings to the specific case of nuclear terrorism, it is emphasized that distorted decision making does not equate to totally irrational decision making. In certain circumstances, however, the distorted individual and group decision-making psychology could influence the group toward a high-risk option such as nuclear terrorism. For terrorists operating within their own national boundaries, a terrorist act producing mass casualties would generally be counterproductive. For groups acting across national boundaries, however, this constraint does not apply to nearly the same degree. Although the opprobrium of the West will be a constraint for some, it will not be equally so for all terrorist groups. The degree of disincentive will relate in particular to the major audience of influence. Also, there are the terrorist losers who are being shunted aside and losing the recognition they seek. Such a group could justify a terrorist spectacular in order to regain influence on the basis of a what have we got to lose rationale. In thinking about the possibility of nuclear terrorism, it is important to distinguish between the actual detonation of a device and the use of a device for extortion and influence. The constraints against the latter are significantly reduced in contrast to acts producing mass casualties. The constraints are even more reduced in the case of the plausible nuclear hoax, an option that can be expected to become more frequent

  7. Planning For Multiple NASA Missions With Use Of Enabling Radioisotope Power

    Energy Technology Data Exchange (ETDEWEB)

    S.G. Johnson; K.L. Lively; C.C. Dwight

    2013-02-01

    Since the early 1960’s the Department of Energy (DOE) and its predecessor agencies have provided radioisotope power systems (RPS) to NASA as an enabling technology for deep space and various planetary missions. They provide reliable power in situations where solar and/or battery power sources are either untenable or would place an undue mass burden on the mission. In the modern era of the past twenty years there has been no time that multiple missions have been considered for launching from Kennedy Space Center (KSC) during the same year. The closest proximity of missions that involved radioisotope power systems would be that of Galileo (October 1989) and Ulysses (October 1990). The closest that involved radioisotope heater units would be the small rovers Spirit and Opportunity (May and July 2003) used in the Mars Exploration Rovers (MER) mission. It can be argued that the rovers sent to Mars in 2003 were essentially a special case since they staged in the same facility and used a pair of small launch vehicles (Delta II). This paper examines constraints on the frequency of use of radioisotope power systems with regard to launching them from Kennedy Space Center using currently available launch vehicles. This knowledge may be useful as NASA plans for its future deep space or planetary missions where radioisotope power systems are used as an enabling technology. Previous descriptions have focused on single mission chronologies and not analyzed the timelines with an emphasis on multiple missions.

  8. Learning from the Mars Rover Mission: Scientific Discovery, Learning and Memory

    Science.gov (United States)

    Linde, Charlotte

    2005-01-01

    Purpose: Knowledge management for space exploration is part of a multi-generational effort. Each mission builds on knowledge from prior missions, and learning is the first step in knowledge production. This paper uses the Mars Exploration Rover mission as a site to explore this process. Approach: Observational study and analysis of the work of the MER science and engineering team during rover operations, to investigate how learning occurs, how it is recorded, and how these representations might be made available for subsequent missions. Findings: Learning occurred in many areas: planning science strategy, using instrumen?s within the constraints of the martian environment, the Deep Space Network, and the mission requirements; using software tools effectively; and running two teams on Mars time for three months. This learning is preserved in many ways. Primarily it resides in individual s memories. It is also encoded in stories, procedures, programming sequences, published reports, and lessons learned databases. Research implications: Shows the earliest stages of knowledge creation in a scientific mission, and demonstrates that knowledge management must begin with an understanding of knowledge creation. Practical implications: Shows that studying learning and knowledge creation suggests proactive ways to capture and use knowledge across multiple missions and generations. Value: This paper provides a unique analysis of the learning process of a scientific space mission, relevant for knowledge management researchers and designers, as well as demonstrating in detail how new learning occurs in a learning organization.

  9. Xenon Acquisition Strategies for High-Power Electric Propulsion NASA Missions

    Science.gov (United States)

    Herman, Daniel A.; Unfried, Kenneth G.

    2015-01-01

    The benefits of high-power solar electric propulsion (SEP) for both NASA's human and science exploration missions combined with the technology investment from the Space Technology Mission Directorate have enabled the development of a 50kW-class SEP mission. NASA mission concepts developed, including the Asteroid Redirect Robotic Mission, and those proposed by contracted efforts for the 30kW-class demonstration have a range of xenon propellant loads from 100's of kg up to 10,000 kg. A xenon propellant load of 10 metric tons represents greater than 10% of the global annual production rate of xenon. A single procurement of this size with short-term delivery can disrupt the xenon market, driving up pricing, making the propellant costs for the mission prohibitive. This paper examines the status of the xenon industry worldwide, including historical xenon supply and pricing. The paper discusses approaches for acquiring on the order of 10 MT of xenon propellant considering realistic programmatic constraints to support potential near-term NASA missions. Finally, the paper will discuss acquisitions strategies for mission campaigns utilizing multiple high-power solar electric propulsion vehicles requiring 100's of metric tons of xenon over an extended period of time where a longer term acquisition approach could be implemented.

  10. A critical review of the life sciences project management at Ames Research Center for the Spacelab Mission development test 3

    Science.gov (United States)

    Helmreich, R. L.; Wilhelm, J. M.; Tanner, T. A.; Sieber, J. E.; Burgenbauch, S. F.

    1979-01-01

    A management study was initiated by ARC (Ames Research Center) to specify Spacelab Mission Development Test 3 activities and problems. This report documents the problems encountered and provides conclusions and recommendations to project management for current and future ARC life sciences projects. An executive summary of the conclusions and recommendations is provided. The report also addresses broader issues relevant to the conduct of future scientific missions under the constraints imposed by the space environment.

  11. Planetary protection issues related to human missions to Mars

    Science.gov (United States)

    Debus, A.; Arnould, J.

    2008-09-01

    the mission, sending astronauts to Mars will entail meeting all these constraints. Astronauts present huge sources of contamination for Mars and are also potential carriers of biohazardous material on their return to Earth. If they were to have the misfortune of being contaminated, they themselves would become a biohazard, and, as a consequence, in addition to the technical constraints, human and ethical considerations must also be taken into account.

  12. Attitude Design for the LADEE Mission

    Science.gov (United States)

    Galal, Ken; Nickel, Craig; Sherman, Ryan

    2015-01-01

    The Lunar Atmosphere and Dust Environment Explorer (LADEE) satellite successfully completed its 148-day science investigation in a low-altitude, near-equatorial lunar orbit on April 18, 2014. The LADEE spacecraft was built, managed and operated by NASA's Ames Research Center (ARC). The Mission Operations Center (MOC) was located at Ames and was responsible for activity planning, command sequencing, trajectory and attitude design, orbit determination, and spacecraft operations. The Science Operations Center (SOC) was located at Goddard Space Flight Center and was responsible for science planning, data archiving and distribution. This paper details attitude design and operations support for the LADEE mission. LADEE's attitude design was shaped by a wide range of instrument pointing requirements that necessitated regular excursions from the baseline one revolution per orbit "Ram" attitude. Such attitude excursions were constrained by a number of flight rules levied to protect instruments from the Sun, avoid geometries that would result in simultaneous occlusion of LADEE's two star tracker heads, and maintain the spacecraft within its thermal and power operating limits. To satisfy LADEE's many attitude requirements and constraints, a set of rules and conventions was adopted to manage the complexity of this design challenge and facilitate the automation of ground software that generated pointing commands spanning multiple days of operations at a time. The resulting LADEE Flight Dynamics System (FDS) that was developed used Visual Basic scripts that generated instructions to AGI's Satellite Tool Kit (STK) in order to derive quaternion commands at regular intervals that satisfied LADEE's pointing requirements. These scripts relied heavily on the powerful "align and constrain" capability of STK's attitude module to construct LADEE's attitude profiles and the slews to get there. A description of the scripts and the attitude modeling they embodied is provided. One particular

  13. Dimensional modeling: beyond data processing constraints.

    Science.gov (United States)

    Bunardzic, A

    1995-01-01

    The focus of information processing requirements is shifting from the on-line transaction processing (OLTP) issues to the on-line analytical processing (OLAP) issues. While the former serves to ensure the feasibility of the real-time on-line transaction processing (which has already exceeded a level of up to 1,000 transactions per second under normal conditions), the latter aims at enabling more sophisticated analytical manipulation of data. The OLTP requirements, or how to efficiently get data into the system, have been solved by applying the Relational theory in the form of Entity-Relation model. There is presently no theory related to OLAP that would resolve the analytical processing requirements as efficiently as Relational theory provided for the transaction processing. The "relational dogma" also provides the mathematical foundation for the Centralized Data Processing paradigm in which mission-critical information is incorporated as 'one and only one instance' of data, thus ensuring data integrity. In such surroundings, the information that supports business analysis and decision support activities is obtained by running predefined reports and queries that are provided by the IS department. In today's intensified competitive climate, businesses are finding that this traditional approach is not good enough. The only way to stay on top of things, and to survive and prosper, is to decentralize the IS services. The newly emerging Distributed Data Processing, with its increased emphasis on empowering the end user, does not seem to find enough merit in the relational database model to justify relying upon it. Relational theory proved too rigid and complex to accommodate the analytical processing needs. In order to satisfy the OLAP requirements, or how to efficiently get the data out of the system, different models, metaphors, and theories have been devised. All of them are pointing to the need for simplifying the highly non-intuitive mathematical constraints found

  14. Global Precipitation Measurement Mission: Architecture and Mission Concept

    Science.gov (United States)

    Bundas, David

    2005-01-01

    The Global Precipitation Measurement (GPM) Mission is a collaboration between the National Aeronautics and Space Administration (NASA) and the Japanese Aerospace Exploration Agency (JAXA), and other partners, with the goal of monitoring the diurnal and seasonal variations in precipitation over the surface of the earth. These measurements will be used to improve current climate models and weather forecasting, and enable improved storm and flood warnings. This paper gives an overview of the mission architecture and addresses some of the key trades that have been completed, including the selection of the Core Observatory s orbit, orbit maintenance trades, and design issues related to meeting orbital debris requirements.

  15. Habitable Exoplanet Imaging Mission (HabEx): Architecture of the 4m Mission Concept

    Science.gov (United States)

    Kuan, Gary M.; Warfield, Keith R.; Mennesson, Bertrand; Kiessling, Alina; Stahl, H. Philip; Martin, Stefan; Shaklan, Stuart B.; amini, rashied

    2018-01-01

    The Habitable Exoplanet Imaging Mission (HabEx) study is tasked by NASA to develop a scientifically compelling and technologically feasible exoplanet direct imaging mission concept, with extensive general astrophysics capabilities, for the 2020 Decadal Survey in Astrophysics. The baseline architecture of this space-based observatory concept encompasses an unobscured 4m diameter aperture telescope flying in formation with a 72-meter diameter starshade occulter. This large aperture, ultra-stable observatory concept extends and enhances upon the legacy of the Hubble Space Telescope by allowing us to probe even fainter objects and peer deeper into the Universe in the same ultraviolet, visible, and near infrared wavelengths, and gives us the capability, for the first time, to image and characterize potentially habitable, Earth-sized exoplanets orbiting nearby stars. Revolutionary direct imaging of exoplanets will be undertaken using a high-contrast coronagraph and a starshade imager. General astrophysics science will be undertaken with two world-class instruments – a wide-field workhorse camera for imaging and multi-object grism spectroscopy, and a multi-object, multi-resolution ultraviolet spectrograph. This poster outlines the baseline architecture of the HabEx flagship mission concept.

  16. Communicating the Science from NASA's Astrophysics Missions

    Science.gov (United States)

    Hasan, Hashima; Smith, Denise A.

    2015-01-01

    Communicating science from NASA's Astrophysics missions has multiple objectives, which leads to a multi-faceted approach. While a timely dissemination of knowledge to the scientific community follows the time-honored process of publication in peer reviewed journals, NASA delivers newsworthy research result to the public through news releases, its websites and social media. Knowledge in greater depth is infused into the educational system by the creation of educational material and teacher workshops that engage students and educators in cutting-edge NASA Astrophysics discoveries. Yet another avenue for the general public to learn about the science and technology through NASA missions is through exhibits at museums, science centers, libraries and other public venues. Examples of the variety of ways NASA conveys the excitement of its scientific discoveries to students, educators and the general public will be discussed in this talk. A brief overview of NASA's participation in the International Year of Light will also be given, as well as of the celebration of the twenty-fifth year of the launch of the Hubble Space Telescope.

  17. Cosmological constraints on spontaneous R-symmetry breaking models

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Yuta; Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research and Dept. of Physics

    2012-11-15

    We study general constraints on spontaneous R-symmetry breaking models coming from the cosmological effects of the pseudo Nambu-Goldstone bosons, R-axions. They are substantially produced in the early Universe and may cause several cosmological problems. We focus on relatively long-lived R-axions and find that in a wide range of parameter space, models are severely constrained. In particular, R-axions with mass less than 1 MeV are generally ruled out for relatively high reheating temperature, T{sub R}>10 GeV.

  18. A Design for an Orbital Assembly Facility for Complex Missions

    Science.gov (United States)

    Feast, S.; Bond, A.

    A design is presented for an Operations Base Station (OBS) in low earth orbit that will function as an integral part of a space transportation system, enabling assembly and maintenance of a Cis-Lunar transportation infrastructure and integration of vehicles for other high energy space missions to be carried out. Construction of the OBS assumes the use of the SKYLON Single-Stage-to-Orbit (SSTO) spaceplane, which imposes design and assembly constraints due to its payload mass limits and payload bay dimensions. It is assumed that the space transport infrastructure and high mission energy vehicles would also make use of SKYLON to deploy standard transport equipment and stages bound by these same constraints. The OBS is therefore a highly modular arrangement, incorporating some of these other vehicle system elements in its layout design. Architecturally, the facilities of the OBS are centred around the Assembly Dock which is in the form of a large cylindrical spaceframe structure with two large doors on either end incorporating a skin of aluminised Mylar to enclose the dock. Longitudinal rails provide internal tether attachments to anchor vehicles and components while manipulators are used for the handling and assembling of vehicle structures. The exterior of the OBS houses the habitation modules for workforce and vehicle crews along with propellant farms and other operational facilities.

  19. Propulsive Maneuver Design for the 2007 Mars Phoenix Lander Mission

    Science.gov (United States)

    Raofi, Behzad; Bhat, Ramachandra S.; Helfrich, Cliff

    2008-01-01

    On May 25, 2008, the Mars Phoenix Lander (PHX) successfully landed in the northern planes of Mars in order to continue and complement NASA's "follow the water" theme as its predecessor Mars missions, such as Mars Odyssey (ODY) and Mars Exploration Rovers, have done in recent years. Instruments on the lander, through a robotic arm able to deliver soil samples to the deck, will perform in-situ and remote-sensing investigations to characterize the chemistry of materials at the local surface, subsurface, and atmosphere. Lander instruments will also identify the potential history of key indicator elements of significance to the biological potential of Mars, including potential organics within any accessible water ice. Precise trajectory control and targeting were necessary in order to achieve the accurate atmospheric entry conditions required for arriving at the desired landing site. The challenge for the trajectory control maneuver design was to meet or exceed these requirements in the presence of spacecraft limitations as well as other mission constraints. This paper describes the strategies used, including the specialized targeting specifically developed for PHX, in order to design and successfully execute the propulsive maneuvers that delivered the spacecraft to its targeted landing site while satisfying the planetary protection requirements in the presence of flight system constraints.

  20. GPHS-RTG performance on the Galileo mission

    International Nuclear Information System (INIS)

    Hemler, R.J.; Cockfield, R.D.

    1991-01-01

    The Galileo spacecraft, launched in October, 1989, is powered by two General Purpose Heat source-Radioisotope Thermoelectric Generator (GPHS-RTGs). These RTGs were designed, built, and tested by General Electric under contract from the Office of Special Applications of the Department of Energy (DOE). Isotope heat source installation and additional testing of these RTGs were performed at DOE's EG ampersand G Mound Facility in Miamisburg, Ohio. This paper provides a report on performance of the RTGs during launch and the early phases of the eight year Galileo mission.The effect of long term storage of the RTGs on power output, since the originally scheduled launch data in May, 1986, will be dicussed, including the effects of helium buildup and subsequent purging with xenon. The RTGs performed as expected during the launch transient, met all specified power requirements for Beginning of Mission (BOM), and continue to follow prediced performance characteristics during the first year of the Galileo mission