A RANDOM FIXED POINT ITERATION FOR THREE RANDOM OPERATORS ON UNIFORMLY CONVEX BANACH SPACES
Institute of Scientific and Technical Information of China (English)
Binayak S. Choudhury
2003-01-01
In the present paper we introduce a random iteration scheme for three random operators defined on a closed and convex subset of a uniformly convex Banach space and prove its convergence to a common fixed point of three random operators. The result is also an extension of a known theorem in the corresponding non-random case.
ITERATIVE SOLUTIONS FOR SYSTEMS OF NONLINEAR OPERATOR EQUATIONS IN BANACH SPACE
Institute of Scientific and Technical Information of China (English)
宋光兴
2003-01-01
By using partial order method, the existence, uniqueness and iterative ap-proximation of solutions for a class of systems of nonlinear operator equations in Banachspace are discussed. The results obtained in this paper extend and improve recent results.
Institute of Scientific and Technical Information of China (English)
魏益民; 吴和兵
2001-01-01
We discuss the incomplete semi-iterative method (ISIM) for an approximate solution of a linear fixed point equations x＝ Tx+c with a bounded linear operator T acting on a complex Banach space X such that its resolvent has a pole of order k at the point 1. Sufficient conditions for the convergence of ISIM to a solution of x=Tx+c , where c belongs to the range space of (I-T)k, are established. We show that the ISIM has an attractive feature that it is usually convergent even when the spectral radius of the operator T is greater than 1 and Ind1T≥ 1. Applications in finite Markov chain is considered and illustrative examples are reported, showing the convergence rate of the ISIM is very high.
Expanding the operating space of ICRF on JET with a view to ITER
DEFF Research Database (Denmark)
Lamalle, P.U.; Mantsinen, M.J.; Noterdaeme, J.M.
2006-01-01
This paper reports on ITER-relevant ion cyclotron resonance frequency (ICRF) physics investigated on JET in 2003 and early 2004. Minority heating of helium three in hydrogen plasmas-(He-3)H-was systematically explored by varying the 3 He concentration and the toroidal phasing of the antenna array...
A New Iterative Scheme of Modified Mann Iteration in Banach Space
Directory of Open Access Journals (Sweden)
Jinzuo Chen
2014-01-01
Full Text Available We introduce the modified iterations of Mann's type for nonexpansive mappings and asymptotically nonexpansive mappings to have the strong convergence in a uniformly convex Banach space. We study approximation of common fixed point of asymptotically nonexpansive mappings in Banach space by using a new iterative scheme. Applications to the accretive operators are also included.
Institute of Scientific and Technical Information of China (English)
曾六川
2002-01-01
In this paper, we investigate the problem of approximating solutions of the equations of Lipschitzian ψ-strongly accretive operators and fixed points of Lipschitzian ψ-hemicontractive operators by lshikawa type iterative sequences with errors. Our results unify, improve and extend the results obtained previously by several authors including Li and Liu (Acta Math. Sinica 41 (4)(1998), 845-850), and Osilike (Nonlinear Anal. TMA, 36(1)(1999), 1-9), and also answer completely the open problems mentioned by Chidume (J. Math. Anal. Appl. 151 (2)(1990), 453-461).
Iterants, Fermions and Majorana Operators
Kauffman, Louis H.
Beginning with an elementary, oscillatory discrete dynamical system associated with the square root of minus one, we study both the foundations of mathematics and physics. Position and momentum do not commute in our discrete physics. Their commutator is related to the diffusion constant for a Brownian process and to the Heisenberg commutator in quantum mechanics. We take John Wheeler's idea of It from Bit as an essential clue and we rework the structure of that bit to a logical particle that is its own anti-particle, a logical Marjorana particle. This is our key example of the amphibian nature of mathematics and the external world. We show how the dynamical system for the square root of minus one is essentially the dynamics of a distinction whose self-reference leads to both the fusion algebra and the operator algebra for the Majorana Fermion. In the course of this, we develop an iterant algebra that supports all of matrix algebra and we end the essay with a discussion of the Dirac equation based on these principles.
CORSICA modelling of ITER hybrid operation scenarios
Kim, S. H.; Bulmer, R. H.; Campbell, D. J.; Casper, T. A.; LoDestro, L. L.; Meyer, W. H.; Pearlstein, L. D.; Snipes, J. A.
2016-12-01
The hybrid operating mode observed in several tokamaks is characterized by further enhancement over the high plasma confinement (H-mode) associated with reduced magneto-hydro-dynamic (MHD) instabilities linked to a stationary flat safety factor (q ) profile in the core region. The proposed ITER hybrid operation is currently aiming at operating for a long burn duration (>1000 s) with a moderate fusion power multiplication factor, Q , of at least 5. This paper presents candidate ITER hybrid operation scenarios developed using a free-boundary transport modelling code, CORSICA, taking all relevant physics and engineering constraints into account. The ITER hybrid operation scenarios have been developed by tailoring the 15 MA baseline ITER inductive H-mode scenario. Accessible operation conditions for ITER hybrid operation and achievable range of plasma parameters have been investigated considering uncertainties on the plasma confinement and transport. ITER operation capability for avoiding the poloidal field coil current, field and force limits has been examined by applying different current ramp rates, flat-top plasma currents and densities, and pre-magnetization of the poloidal field coils. Various combinations of heating and current drive (H&CD) schemes have been applied to study several physics issues, such as the plasma current density profile tailoring, enhancement of the plasma energy confinement and fusion power generation. A parameterized edge pedestal model based on EPED1 added to the CORSICA code has been applied to hybrid operation scenarios. Finally, fully self-consistent free-boundary transport simulations have been performed to provide information on the poloidal field coil voltage demands and to study the controllability with the ITER controllers. Extended from Proc. 24th Int. Conf. on Fusion Energy (San Diego, 2012) IT/P1-13.
Halpern Iteration in CAT(κ) Spaces
Institute of Scientific and Technical Information of China (English)
Bo(z)ena PI(A)TEK
2011-01-01
In this paper we show that an iterative sequence generated by the Halpern algorithm converges to a fixed point in the case of complete CAT(κ) spaces. Similar results for Hadamard manifolds were obtained in[Li,C.,López, G., Martín-Márquez, V.:Iterative algorithms for nonexpansive mappings on Hadamard manifolds. Taiwanese J. Math., 14, 541-559 (2010)], but we study a much more general case. Moreover, we discuss the Halpern iteration procedure for set-valued mappings.
Iterative Solution for Systems of Nonlinear Two Binary Operator Equations
Institute of Scientific and Technical Information of China (English)
ZHANGZhi-hong; LIWen-feng
2004-01-01
Using the cone and partial ordering theory and mixed monotone operator theory, the existence and uniqueness of solutions for some classes of systems of nonlinear two binary operator equations in a Banach space with a partial ordering are discussed. And the error estimates that the iterative sequences converge to solutions are also given. Some relevant results of solvability of two binary operator equations and systems of operator equations are imnroved and generalized.
Directory of Open Access Journals (Sweden)
Ofoedu EU
2008-01-01
Full Text Available Abstract Let be a real reflexive and strictly convex Banach space which has a uniformly Gâteaux differentiable norm and be a closed convex nonempty subset of . Strong convergence theorems for approximation of a common zero of a countably infinite family of -accretive mappings from to are proved. Consequently, we obtained strong convergence theorems for a countably infinite family of pseudocontractive mappings.
Directory of Open Access Journals (Sweden)
E. U. Ofoedu
2008-03-01
Full Text Available Let E be a real reflexive and strictly convex Banach space which has a uniformly GÃƒÂ¢teaux differentiable norm and C be a closed convex nonempty subset of E. Strong convergence theorems for approximation of a common zero of a countably infinite family of m-accretive mappings from C to E are proved. Consequently, we obtained strong convergence theorems for a countably infinite family of pseudocontractive mappings.
The Iterative Method of Generalized -Concave Operators
Directory of Open Access Journals (Sweden)
Zhou Yanqiu
2011-01-01
Full Text Available We define the concept of the generalized -concave operators, which generalize the definition of the -concave operators. By using the iterative method and the partial ordering method, we prove the existence and uniqueness of fixed points of this class of the operators. As an example of the application of our results, we show the existence and uniqueness of solutions to a class of the Hammerstein integral equations.
Halpern's Iteration in CAT(0 Spaces
Directory of Open Access Journals (Sweden)
Satit Saejung
2010-01-01
Full Text Available Motivated by Halpern's result, we prove strong convergence theorem of an iterative sequence in CAT(0 spaces. We apply our result to find a common fixed point of a family of nonexpansive mappings. A convergence theorem for nonself mappings is also discussed.
Institute of Scientific and Technical Information of China (English)
梁嘉宁; 黎永锦
2011-01-01
Let X be a q-normed space, and let T be a Zamfirescu operator. The sequence of Ishikawa iterations with T converges to the fixed point of T is proved, and certain Mann and Ishikawa iterative schemes for Zamfirescu operator T are equivalent.%设X为q-赋范空间,T为Zamfireseu算子.证明了Zamfirescu算子T的Ishikawa迭代收敛于T的不动点,并且某些Ishikawa迭代序列与Mann迭代序列的收敛性是等价的.
ISHIKAWA ITERATIVE PROCESS IN UNIFORMLY SMOOTH BANACH SPACES
Institute of Scientific and Technical Information of China (English)
黄震宇
2001-01-01
Let E be a uniformly smooth Banach space, K be a nonempty closed convex subset of E, and suppose: T: K → K is a continuous φ-strongly pseudocontractive operator with a bounded range. Using a new analytical method, under general cases, the Ishikawa iterative process { xn } converges strongly to the unique fixed point x * of the operator Twere proved. The paper generalizes and extends a lot of recent corresponding results.
The Equivalence of Ishikawa-Mann and Multistep Iterations in Banach Space
Institute of Scientific and Technical Information of China (English)
Liping Yang
2007-01-01
Let E be a real Banach space and T be a continuous Φ-strongly accretive operator. By using a new analytical method,it is proved that the convergence of Mann,Ishikawa and three-step iterations are equivalent to the convergence of multistep iteration.The results of this paper extend the results of Rhoades and Soltuz in some aspects.
Picard iteration converges faster than Mann iteration for a class of quasi-contractive operators
Directory of Open Access Journals (Sweden)
Vasile Berinde
2004-06-01
Full Text Available In the class of quasi-contractive operators satisfying Zamfirescu's conditions, the most used fixed point iterative methods, that is, the Picard, Mann, and Ishikawa iterations, are all known to be convergent to the unique fixed point. In this paper, the comparison of the first two methods with respect to their convergence rate is obtained.
Space station operations management
Cannon, Kathleen V.
1989-01-01
Space Station Freedom operations management concepts must be responsive to the unique challenges presented by the permanently manned international laboratory. Space Station Freedom will be assembled over a three year period where the operational environment will change as significant capability plateaus are reached. First Element Launch, Man-Tended Capability, and Permanent Manned Capability, represent milestones in operational capability that is increasing toward mature operations capability. Operations management concepts are being developed to accomodate the varying operational capabilities during assembly, as well as the mature operational environment. This paper describes operations management concepts designed to accomodate the uniqueness of Space Station Freedoom, utilizing tools and processes that seek to control operations costs.
Operation of JET with an ITER-like Wall
Energy Technology Data Exchange (ETDEWEB)
Horton, Lorne, E-mail: Lorne.Horton@jet.uk [EFDA-CSU Culham, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); European Commission, B-1049 Brussels (Belgium)
2015-10-15
Highlights: • JET has entered the second phase of operation with an ITER-like Wall. • Boundaries of safe plasma operation are being explored. • Studies have focused on material migration and erosion, disruptions and runaway electron beams, and optimisation of plasma and divertor performance. • Strong influence of the wall material on plasma performance but with significant scope for optimisation. - Abstract: The JET Programme in Support of ITER has entered its second phase, in which the boundaries for safe plasma operation with an ITER-like Wall are being explored. A key element of these studies is the benchmarking of the codes that are being used for ITER to predict plasma–wall interactions and, more generally, the influence of wall material on plasma performance and regimes of operation. Studies have focused on material migration and erosion, disruptions and runaway electron beams, and optimisation of plasma and divertor performance. In addition, a dedicated tungsten divertor melt experiment was carried out and provided key information for the ITER decision to begin operation with an all-W divertor. Initial results underline the strong influence that the wall material has on plasma performance and regimes of operation but show that there is significant scope for optimisation by careful discharge design. The future JET programme will concentrate on completing this optimisation and demonstrating the resulting performance in deuterium–tritium plasmas, thus providing the best possible preparation of ITER operation.
Demonstration of ITER Operational Scenarios on DIII-D
Energy Technology Data Exchange (ETDEWEB)
Doyle, E J; Budny, R V; DeBoo, J C; Ferron, J R; Jackson, G L; Luce, T C; Murakami, M; Osborne, T H; Park, J; Politzer, P A; Reimerdes, H; Casper, T A; Challis, C D; Groebner, R J; Holcomb, C T; Hyatt, A W; La Haye, R J; McKee, G R; Petrie, T W; Petty, C C; Rhodes, T L; Shafer, M W; Snyder, P B; Strait, E J; Wade, M R; Wang, G; West, W P; Zeng, L
2008-10-13
The DIII-D program has recently initiated an effort to provide suitably scaled experimental evaluations of four primary ITER operational scenarios. New and unique features of this work are that the plasmas incorporate essential features of the ITER scenarios and anticipated operating characteristics; e.g., the plasma cross-section, aspect ratio and value of I/aB of the DIII-D discharges match the ITER design, with size reduced by a factor of 3.7. Key aspects of all four scenarios, such as target values for {beta}{sub N} and H{sub 98}, have been replicated successfully on DIII-D, providing an improved and unified physics basis for transport and stability modeling, as well as for performance extrapolation to ITER. In all four scenarios normalized performance equals or closely approaches that required to realize the physics and technology goals of ITER, and projections of the DIII-D discharges are consistent with ITER achieving its goals of {ge} 400 MW of fusion power production and Q {ge} 10. These studies also address many of the key physics issues related to the ITER design, including the L-H transition power threshold, the size of ELMs, pedestal parameter scaling, the impact of tearing modes on confinement and disruptivity, beta limits and the required capabilities of the plasma control system. An example of direct influence on the ITER design from this work is a modification of the specified operating range in internal inductance at 15 MA for the poloidal field coil set, based on observations that the measured inductance in the baseline scenario case lay outside the original ITER specification.
Institute of Scientific and Technical Information of China (English)
Zhong Jin RUAN (Zhong-Jin Ruan)
2003-01-01
During the last ten to fifteen years , a lot of progress has been achieved in the study ofcomplex operator spaces. In this paper, we show that a corresponding theory can be developed forreal operator spaces. With some appropriate modifications, many complex results still hold for realoperator spaces.
The ITER Neutral Beam Test Facility towards SPIDER operation
Toigo, V.; Dal Bello, S.; Gaio, E.; Luchetta, A.; Pasqualotto, R.; Zaccaria, P.; Bigi, M.; Chitarin, G.; Marcuzzi, D.; Pomaro, N.; Serianni, G.; Agostinetti, P.; Agostini, M.; Antoni, V.; Aprile, D.; Baltador, C.; Barbisan, M.; Battistella, M.; Boldrin, M.; Brombin, M.; Dalla Palma, M.; De Lorenzi, A.; Delogu, R.; De Muri, M.; Fellin, F.; Ferro, A.; Gambetta, G.; Grando, L.; Jain, P.; Maistrello, A.; Manduchi, G.; Marconato, N.; Pavei, M.; Peruzzo, S.; Pilan, N.; Pimazzoni, A.; Piovan, R.; Recchia, M.; Rizzolo, A.; Sartori, E.; Siragusa, M.; Spada, E.; Spagnolo, S.; Spolaore, M.; Taliercio, C.; Valente, M.; Veltri, P.; Zamengo, A.; Zaniol, B.; Zanotto, L.; Zaupa, M.; Boilson, D.; Graceffa, J.; Svensson, L.; Schunke, B.; Decamps, H.; Urbani, M.; Kushwah, M.; Chareyre, J.; Singh, M.; Bonicelli, T.; Agarici, G.; Garbuglia, A.; Masiello, A.; Paolucci, F.; Simon, M.; Bailly-Maitre, L.; Bragulat, E.; Gomez, G.; Gutierrez, D.; Mico, G.; Moreno, J.-F.; Pilard, V.; Chakraborty, A.; Baruah, U.; Rotti, C.; Patel, H.; Nagaraju, M. V.; Singh, N. P.; Patel, A.; Dhola, H.; Raval, B.; Fantz, U.; Fröschle, M.; Heinemann, B.; Kraus, W.; Nocentini, R.; Riedl, R.; Schiesko, L.; Wimmer, C.; Wünderlich, D.; Cavenago, M.; Croci, G.; Gorini, G.; Rebai, M.; Muraro, A.; Tardocchi, M.; Hemsworth, R.
2017-08-01
SPIDER is one of two projects of the ITER Neutral Beam Test Facility under construction in Padova, Italy, at the Consorzio RFX premises. It will have a 100 keV beam source with a full-size prototype of the radiofrequency ion source for the ITER neutral beam injector (NBI) and also, similar to the ITER diagnostic neutral beam, it is designed to operate with a pulse length of up to 3600 s, featuring an ITER-like magnetic filter field configuration (for high extraction of negative ions) and caesium oven (for high production of negative ions) layout as well as a wide set of diagnostics. These features will allow a reproduction of the ion source operation in ITER, which cannot be done in any other existing test facility. SPIDER realization is well advanced and the first operation is expected at the beginning of 2018, with the mission of achieving the ITER heating and diagnostic NBI ion source requirements and of improving its performance in terms of reliability and availability. This paper mainly focuses on the preparation of the first SPIDER operations—integration and testing of SPIDER components, completion and implementation of diagnostics and control and formulation of operation and research plan, based on a staged strategy.
MIXED MONOTONE ITERATIVE TECHNIQUES FOR SEMILINEAR EVOLUTION EQUATIONS IN BANACH SPACES
Institute of Scientific and Technical Information of China (English)
王良龙; 王志成
2004-01-01
This paper is concerned with initial value problems for semilinear evolution equations in Banach spaces. The abstract iterative schemes are constructed by combining the theory of semigroups of linear operators and the method of mixed monotone iterations. Some existence results on minimal and maximal (quasi)solutions are established for abstract semilinear evolution equations with mixed monotone or mixed quasimonotone nonlinear terms. To illustrate the main results, applications to ordinary differential equations and partial differential equations are also given.
Space-Bounded Complexity Classes and Iterated Deterministic Substitution
Asveld, P.R.J.
1979-01-01
We investigate the effect on the space complexity when a language family $K$ is extended by means of iterated $\\lambda$-free deterministic substitution to a family $\\eta(K)$. If each language in $K$ is accepted by a one-way nondeterministic multi-tape Turing machine within space $S(n)$ for some mono
Applying principles of Design For Assembly to ITER maintenance operations
Heemskerk, C.; Baar, M.de; Elzendoorn, B.; Koning, J.; Verhoeven, T.; Vreede, F.de
2009-01-01
In ITER, maintenance operations in the vessel and in the Hot Cell will be largely done by Remote Handling (RH). Remotely performed maintenance actions tend to be more time-costly than actions performed by direct human access. With a human operator in the control loop and adequate situational feedbac
The Iterated Regularization With Perturbed Operators and Noisy Data
Institute of Scientific and Technical Information of China (English)
陈宏; 侯宗义
1994-01-01
The method of iterated Tikhonov regularization with perturbed operators and noisy data for solving operators equations of the first kind is investigated. The rates of convergence of regularization approximation are achieved by using generalized Arcangeli’s method for the choice of the regularization parameter.
Mann Iteration of Weak Convergence Theorems in Banach Space
Institute of Scientific and Technical Information of China (English)
Liang-gen Hu; Jin-ping Wang
2009-01-01
In this paper, by using Mann's iteration process we will establish several weak convergence theorems for approximating a fixed point of κ-strictly pseudocontractive mappings with respect to p in p-uniformly convex Banach spaces. Our results answer partially the open question proposed by Marino and Xu, and extend Reich's theorem from nonexpausive mappings to κ-strict pseudocontractive mappings.
Iterative convergence theorems for maximal monotone operators and relatively nonexpansive mappings
Institute of Scientific and Technical Information of China (English)
WEI Li; SU Yong-fu; ZHOU Hai-yun
2008-01-01
In this paper, some iterative schemes for approximating the common element of the set of zero points of maximal monotone operators and the set of fixed points of relatively nonexpansive mappings in a real uniformly smooth and uniformly convex Banach space are proposed. Some strong convergence theorems are obtained, to extend the previous work.
Pointwise Approximation for the Iterated Boolean Sums of Bernstein Operators
Institute of Scientific and Technical Information of China (English)
HUO Xiao-yan; LI Cui-xiang; YAO Qiu-mei
2013-01-01
In this paper,with the help of modulus of smoothness ω2r(4)(f,t),we discuss the pointwise approximation properties for the iterated Boolean sums of Bernstein operator Bnn and obtain direct and inverse theorems when 1-1/r ≤ λ ≤ 1,r ∈ N.
Block Monotone Iterative Algorithms for Variational Inequalities with Nonlinear Operators
Institute of Scientific and Technical Information of China (English)
Ming-hui Ren; Jin-ping Zeng
2008-01-01
Some block iterative methods for solving variational inequalities with nonlinear operators are proposed. Monotone convergence of the algorithms is obtained. Some comparison theorems are also established.Compared with the research work in given by Pao in 1995 for nonlinear equations and research work in given by Zeng and Zhou in 2002 for elliptic variational inequalities, the algorithms proposed in this paper are independent of the boundedness of the derivatives of the nonlinear operator.
Commercialization in NASA Space Operations
Gilbert, Charlene E.
1998-01-01
Various issues associated with commercialization in NASA space operations are presented in viewgraph form. Specific topics include: 1) NASA's financial outlook; 2) Space operations; 3) Space operations technology; and 4) Strategies associated with these operations.
Transitive spaces of operators
Davidson, K R; Radjavi, H
2007-01-01
We investigate algebraic and topological transitivity and, more generally, k-transitivity for linear spaces of operators. In finite dimensions, we determine minimal dimensions of k-transitive spaces for every k, and find relations between the degree of transitivity of a product or tensor product on the one hand and those of the factors on the other. We present counterexamples to some natural conjectures. Some infinite dimensional analogues are discussed. A simple proof is given of Arveson's result on the weak-operator density of transitive spaces that are masa bimodules.
Development of ITER non-activation phase operation scenarios
Kim, S. H.; Poli, F. M.; Koechl, F.; Militello-Asp, E.; Polevoi, A. R.; Budny, R.; Casper, T. A.; Loarte, A.; Luce, T. C.; Na, Y.-S.; Romanelli, M.; Schneider, M.; Snipes, J. A.; de Vries, P. C.; The ITPA Topical Group on Integrated Operation Scenarios
2017-08-01
Non-activation phase operations in ITER in hydrogen (H) and helium (He) will be important for commissioning of tokamak systems, such as diagnostics, heating and current drive (HCD) systems, coils and plasma control systems, and for validation of techniques necessary for establishing operations in DT. The assessment of feasible HCD schemes at various toroidal fields (2.65-5.3 T) has revealed that the previously applied assumptions need to be refined for the ITER non-activation phase H/He operations. A study of the ranges of plasma density and profile shape using the JINTRAC suite of codes has indicated that the hydrogen pellet fuelling into He plasmas should be utilized taking the optimization of IC power absorption, neutral beam shine-through density limit and H-mode access into account. The EPED1 estimation of the edge pedestal parameters has been extended to various H operation conditions, and the combined EPED1 and SOLPS estimation has provided guidance for modelling the edge pedestal in H/He operations. The availability of ITER HCD schemes, ranges of achievable plasma density and profile shape, and estimation of the edge pedestal parameters for H/He plasmas have been integrated into various time-dependent tokamak discharge simulations. In this work, various H/He scenarios at a wide range of plasma current (7.5-15 MA) and field (2.65-5.3 T) have been developed for the ITER non-activation phase operation, and the sensitivity of the developed scenarios to the used assumptions has been investigated to provide guidance for further development. Extended from Preprint: 2016 Int. Conf. on Fusion Energy (Kyoto, Japan, 2016) TH/P2-22.
Geometric properties of Banach spaces and nonlinear iterations
Chidume, Charles
2009-01-01
Nonlinear functional analysis and applications is an area of study that has provided fascination for many mathematicians across the world. This monograph delves specifically into the topic of the geometric properties of Banach spaces and nonlinear iterations, a subject of extensive research over the past thirty years. Chapters 1 to 5 develop materials on convexity and smoothness of Banach spaces, associated moduli and connections with duality maps. Key results obtained are summarized at the end of each chapter for easy reference. Chapters 6 to 23 deal with an in-depth, comprehensive and up-to-date coverage of the main ideas, concepts and results on iterative algorithms for the approximation of fixed points of nonlinear nonexpansive and pseudo-contractive-type mappings. This includes detailed workings on solutions of variational inequality problems, solutions of Hammerstein integral equations, and common fixed points (and common zeros) of families of nonlinear mappings. Carefully referenced and full of recent,...
Sunder, V S
2016-01-01
The primarily objective of the book is to serve as a primer on the theory of bounded linear operators on separable Hilbert space. The book presents the spectral theorem as a statement on the existence of a unique continuous and measurable functional calculus. It discusses a proof without digressing into a course on the Gelfand theory of commutative Banach algebras. The book also introduces the reader to the basic facts concerning the various von Neumann–Schatten ideals, the compact operators, the trace-class operators and all bounded operators. .
Toeplitz Operators on Dirichlet Spaces
Institute of Scientific and Technical Information of China (English)
Yu Feng LU; Shun Hua SUN
2001-01-01
In this paper we study Toeplitz operators on Dirichlet spaces and describe the boundedness and compactness of Toeplitz operators on Dirichlet spaces. Meanwhile. we give density theorems for Toeplitz operators on Dirichlet spaces
Autocratic strategies for iterated games with arbitrary action spaces.
McAvoy, Alex; Hauert, Christoph
2016-03-29
The recent discovery of zero-determinant strategies for the iterated prisoner's dilemma sparked a surge of interest in the surprising fact that a player can exert unilateral control over iterated interactions. These remarkable strategies, however, are known to exist only in games in which players choose between two alternative actions such as "cooperate" and "defect." Here we introduce a broader class of autocratic strategies by extending zero-determinant strategies to iterated games with more general action spaces. We use the continuous donation game as an example, which represents an instance of the prisoner's dilemma that intuitively extends to a continuous range of cooperation levels. Surprisingly, despite the fact that the opponent has infinitely many donation levels from which to choose, a player can devise an autocratic strategy to enforce a linear relationship between his or her payoff and that of the opponent even when restricting his or her actions to merely two discrete levels of cooperation. In particular, a player can use such a strategy to extort an unfair share of the payoffs from the opponent. Therefore, although the action space of the continuous donation game dwarfs that of the classic prisoner's dilemma, players can still devise relatively simple autocratic and, in particular, extortionate strategies.
Space Operations Learning Center
Lui, Ben; Milner, Barbara; Binebrink, Dan; Kuok, Heng
2012-01-01
The Space Operations Learning Center (SOLC) is a tool that provides an online learning environment where students can learn science, technology, engineering, and mathematics (STEM) through a series of training modules. SOLC is also an effective media for NASA to showcase its contributions to the general public. SOLC is a Web-based environment with a learning platform for students to understand STEM through interactive modules in various engineering topics. SOLC is unique in its approach to develop learning materials to teach schoolaged students the basic concepts of space operations. SOLC utilizes the latest Web and software technologies to present this educational content in a fun and engaging way for all grade levels. SOLC uses animations, streaming video, cartoon characters, audio narration, interactive games and more to deliver educational concepts. The Web portal organizes all of these training modules in an easily accessible way for visitors worldwide. SOLC provides multiple training modules on various topics. At the time of this reporting, seven modules have been developed: Space Communication, Flight Dynamics, Information Processing, Mission Operations, Kids Zone 1, Kids Zone 2, and Save The Forest. For the first four modules, each contains three components: Flight Training, Flight License, and Fly It! Kids Zone 1 and 2 include a number of educational videos and games designed specifically for grades K-6. Save The Forest is a space operations mission with four simulations and activities to complete, optimized for new touch screen technology. The Kids Zone 1 module has recently been ported to Facebook to attract wider audience.
Iterative feedback tuning of uncertain state space systems
Directory of Open Access Journals (Sweden)
J. K. Huusom
2010-09-01
Full Text Available Iterative Feedback Tuning is a purely data driven tuning algorithm for optimizing control parameters based on closed loop data. The algorithm is designed to produce an unbiased estimate of the performance cost function gradient for iteratively improving the control parameters to achieve optimal loop performance. This tuning method has been developed for systems based on a transfer function representation. This paper presents a state feedback control system with a state observer and its transfer function equivalent in terms of input output dynamics. It is shown how the parameters in the closed loop state space system can be tuned by Iterative Feedback Tuning utilizing this equivalent representation. A simulation example illustrates that the tuning converges to the known analytical solution for the feedback control gain and to the Kalman gain in the state observer. In case of parametric uncertainty, different choices of tuning parameters are investigated. It is shown that the data driven tuning method produces optimal performance for convex problems when it is the model parameter estimates in the observer that are tuned.
Effective metastability of Halpern iterates in CAT(0) spaces
Kohlenbach, Ulrich
2011-01-01
This paper provides an effective uniform rate of metastability (in the sense of Tao) on the strong convergence of Halpern iterations of nonexpansive mappings in CAT(0) spaces. The extraction of this rate from an ineffective proof due to Saejung is an instance of the general proof mining program which uses tools from mathematical logic to uncover hidden computational content from proofs. This methodology is applied here for the first time to a proof that uses Banach limits and hence makes a substantial reference to the axiom of choice.
An Iterative Scheme for the System of Generalized Variational Inequalities in Banach Spaces
Institute of Scientific and Technical Information of China (English)
Ying LIU
2011-01-01
In this paper,we propose an iterative method of approximating solutions for a class of the system of generalized variational inequalities and give a convergence result for the iterative method in uniformly convex and uniformly smooth Banach spaces.
Directory of Open Access Journals (Sweden)
Yeol Je Cho
2008-03-01
Full Text Available Two iterative schemes for finding a common element of the set of zero points of maximal monotone operators and the set of fixed points of nonexpansive mappings in the sense of Lyapunov functional in a real uniformly smooth and uniformly convex Banach space are obtained. Two strong convergence theorems are obtained which extend some previous work. Moreover, the applications of the iterative schemes are demonstrated.
Directory of Open Access Journals (Sweden)
Cho YeolJe
2007-01-01
Full Text Available Two iterative schemes for finding a common element of the set of zero points of maximal monotone operators and the set of fixed points of nonexpansive mappings in the sense of Lyapunov functional in a real uniformly smooth and uniformly convex Banach space are obtained. Two strong convergence theorems are obtained which extend some previous work. Moreover, the applications of the iterative schemes are demonstrated.
Iotti, Robert
2015-04-01
ITER is an international experimental facility being built by seven Parties to demonstrate the long term potential of fusion energy. The ITER Joint Implementation Agreement (JIA) defines the structure and governance model of such cooperation. There are a number of necessary conditions for such international projects to be successful: a complete design, strong systems engineering working with an agreed set of requirements, an experienced organization with systems and plans in place to manage the project, a cost estimate backed by industry, and someone in charge. Unfortunately for ITER many of these conditions were not present. The paper discusses the priorities in the JIA which led to setting up the project with a Central Integrating Organization (IO) in Cadarache, France as the ITER HQ, and seven Domestic Agencies (DAs) located in the countries of the Parties, responsible for delivering 90%+ of the project hardware as Contributions-in-Kind and also financial contributions to the IO, as ``Contributions-in-Cash.'' Theoretically the Director General (DG) is responsible for everything. In practice the DG does not have the power to control the work of the DAs, and there is not an effective management structure enabling the IO and the DAs to arbitrate disputes, so the project is not really managed, but is a loose collaboration of competing interests. Any DA can effectively block a decision reached by the DG. Inefficiencies in completing design while setting up a competent organization from scratch contributed to the delays and cost increases during the initial few years. So did the fact that the original estimate was not developed from industry input. Unforeseen inflation and market demand on certain commodities/materials further exacerbated the cost increases. Since then, improvements are debatable. Does this mean that the governance model of ITER is a wrong model for international scientific cooperation? I do not believe so. Had the necessary conditions for success
Zhou, Nanrun; Hu, Yiqun; Gong, Lihua; Li, Guangyong
2017-06-01
A new quantum image encryption scheme is suggested by using the iterative generalized Arnold transforms and the quantum image cycle shift operations. The times of the quantum image cycle shift operations are controlled by a hyper-chaotic sequence generated by a new 4D hyper-chaotic system. The image pixels are scrambled by the iterative generalized Arnold transform, and the values of the pixels are altered by the quantum image cycle shift operations. The four initial conditions of the new 4D hyper-chaotic system are exploited to control the two parameters, the iterative rounds of the generalized Arnold transform and the times of the quantum image cycle shift operations, respectively. Thus, the main keys of the proposed quantum image encryption scheme are the four initial conditions of the new 4D hyper-chaotic system and the key space is relatively large enough. Simulation results and theoretical analyses demonstrate that the proposed quantum image encryption scheme outperforms its classical counterparts apparently.
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Vittorio Colao
2012-01-01
Full Text Available We prove the equivalence and the strong convergence of iterative processes involving generalized strongly asymptotically -pseudocontractive mappings in uniformly smooth Banach spaces.
Net Operations （Ⅱ）——The Iterated Addition Operation of Petri Nets
Institute of Scientific and Technical Information of China (English)
蒋昌俊
1995-01-01
This paper presents the iterated addition operation of Petri nets and discusses its application in analysis and synthesis of cycle type systems and star type systems.A group of necessary and sufficient conditions for analysis of structural properties is obtained.In addition sufficient conditions for general systems are obtained.
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Uamporn Witthayarat
2012-01-01
Full Text Available The aim of this paper is to introduce an iterative algorithm for finding a common solution of the sets (A+M2−1(0 and (B+M1−1(0, where M is a maximal accretive operator in a Banach space and, by using the proposed algorithm, to establish some strong convergence theorems for common solutions of the two sets above in a uniformly convex and 2-uniformly smooth Banach space. The results obtained in this paper extend and improve the corresponding results of Qin et al. 2011 from Hilbert spaces to Banach spaces and Petrot et al. 2011. Moreover, we also apply our results to some applications for solving convex feasibility problems.
Nonlinear Burn Control and Operating Point Optimization in ITER
Boyer, Mark; Schuster, Eugenio
2013-10-01
Control of the fusion power through regulation of the plasma density and temperature will be essential for achieving and maintaining desired operating points in fusion reactors and burning plasma experiments like ITER. In this work, a volume averaged model for the evolution of the density of energy, deuterium and tritium fuel ions, alpha-particles, and impurity ions is used to synthesize a multi-input multi-output nonlinear feedback controller for stabilizing and modulating the burn condition. Adaptive control techniques are used to account for uncertainty in model parameters, including particle confinement times and recycling rates. The control approach makes use of the different possible methods for altering the fusion power, including adjusting the temperature through auxiliary heating, modulating the density and isotopic mix through fueling, and altering the impurity density through impurity injection. Furthermore, a model-based optimization scheme is proposed to drive the system as close as possible to desired fusion power and temperature references. Constraints are considered in the optimization scheme to ensure that, for example, density and beta limits are avoided, and that optimal operation is achieved even when actuators reach saturation. Supported by the NSF CAREER award program (ECCS-0645086).
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Plern Saipara
2017-03-01
Full Text Available In this paper, we suggest the modified random S-iterative process and prove the common random fixed point theorems of a finite family of random uniformly quasi-Lipschitzian operators in a generalized convex metric space. Our results improves and extends various results in the literature.
Feynman formulas for semigroups generated by an iterated Laplace operator
Buzinov, M. S.
2017-04-01
In the present paper, we find representations of a one-parameter semigroup generated by a finite sum of iterated Laplace operators and an additive perturbation (the potential). Such semigroups and the evolution equations corresponding to them find applications in the field of physics, chemistry, biology, and pattern recognition. The representations mentioned above are obtained in the form of Feynman formulas, i.e., in the form of a limit of multiple integrals as the multiplicity tends to infinity. The term "Feynman formula" was proposed by Smolyanov. Smolyanov's approach uses Chernoff's theorems. A simple form of representations thus obtained enables one to use them for numerical modeling the dynamics of the evolution system as a method for the approximation of solutions of equations. The problems considered in this note can be treated using the approach suggested by Remizov (see also the monograph of Smolyanov and Shavgulidze on path integrals). The representations (of semigroups) obtained in this way are more complicated than those given by the Feynman formulas; however, it is possible to bypass some analytical difficulties.
COMPOSITION OPERATORS ON BERGMAN SPACES
Institute of Scientific and Technical Information of China (English)
J. H. CLIFFORD; ZHENG DECHAO
2003-01-01
The authors obtain function theoretic characterizations of the compactness on the standardweighted Bergman spaces of the two operators formed by multiplying a composition operatorwith the adjoint of another composition operator.
Joint Doctrine for Space Operations
2007-11-02
c. USSPACECOM Space Operations Center ( SPOC ). The SPOC is the focal point with USSPACECOM for obtaining space support. d. Day-to-Day Operations...notify the National Military Command Center (NMCC) and the NORAD and USSPACECOM chains of command (including the NORAD Operation Center and SPOC ), as...commanders from NORAD-USSPACECOM’s CMOC, which is backed up by the SPOC . USSPACECOM will also operate and maintain global and regional satellite
Electrophoresis operations in space
Richman, D. W.
1982-01-01
Application of electrophoresis in space processing is described. Spaceborne experiments in areas such as biological products and FDA approved drugs are discussed. These experiments will be carried on shuttle payloads.
Composition operators on function spaces
Singh, RK
1993-01-01
This volume of the Mathematics Studies presents work done on composition operators during the last 25 years. Composition operators form a simple but interesting class of operators having interactions with different branches of mathematics and mathematical physics. After an introduction, the book deals with these operators on Lp-spaces. This study is useful in measurable dynamics, ergodic theory, classical mechanics and Markov process. The composition operators on functional Banach spaces (including Hardy spaces) are studied in chapter III. This chapter makes contact with the theory of analytic functions of complex variables. Chapter IV presents a study of these operators on locally convex spaces of continuous functions making contact with topological dynamics. In the last chapter of the book some applications of composition operators in isometries, ergodic theory and dynamical systems are presented. An interesting interplay of algebra, topology, and analysis is displayed. This comprehensive and up-to-date stu...
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Yong-Ju Yang
2013-01-01
Full Text Available The local fractional variational iteration method for local fractional Laplace equation is investigated in this paper. The operators are described in the sense of local fractional operators. The obtained results reveal that the method is very effective.
ISHIKAWA ITERATIVE PROCESS FOR CONSTRUCTING SOLUTIONS OF m-ACCRETIVE OPERATOR EQUATIONS
Institute of Scientific and Technical Information of China (English)
曾六川
2002-01-01
The convergence of the Ishikawa iteration sequences with errors for constructing solutions of m-accretive operator equations is characterized. Moreover, the error estimates of approximate solutions for locally Lipschitzian and m-accretive operator equations are established.
Space Toxicology: Human Health during Space Operations
Khan-Mayberry, Noreen; James, John T.; Tyl, ROchelle; Lam, Chiu-Wing
2010-01-01
Space Toxicology is a unique and targeted discipline for spaceflight, space habitation and occupation of celestial bodies including planets, moons and asteroids. Astronaut explorers face distinctive health challenges and limited resources for rescue and medical care during space operation. A central goal of space toxicology is to protect the health of the astronaut by assessing potential chemical exposures during spaceflight and setting safe limits that will protect the astronaut against chemical exposures, in a physiologically altered state. In order to maintain sustained occupation in space on the International Space Station (ISS), toxicological risks must be assessed and managed within the context of isolation continuous exposures, reuse of air and water, limited rescue options, and the need to use highly toxic compounds for propulsion. As we begin to explore other celestial bodies in situ toxicological risks, such as inhalation of reactive mineral dusts, must also be managed.
New iterative schemes for asymptotically quasi-nonexpansive nonself-mappings in Banach spaces
Wang, Chao; Zhu, Jinghao; An, Lili
2010-04-01
In this paper, a new two-step iterative scheme with errors is introduced for two asymptotically quasi-nonexpansive nonself-mappings. Several convergence theorems are established in real Banach spaces and real uniformly convex Banach spaces. Our theorems improve and extend the results due to Thianwan [S. Thianwan, Common fixed point of new iterations for two asymptotically nonexpansive nonself-mappings in a Banach space, J. Comput. Appl. Math. 224 (2009) 685-695] and many other papers.
Hausdorff operators on Euclidean spaces
Institute of Scientific and Technical Information of China (English)
CHEN Jie-cheng; FAN Da-shan; WANG Si-lei
2013-01-01
Hausdorff operator is an important operator raised from the dilation on Euclidean space and rooted in the classical summability of number series and Fourier series. It is also connected to many well known operators in real and complex analysis. This article is a survey of some recent developments and extensions on the Hausdorff operator. Particularly, various boundedness properties of the Hausdorff operators, studied recently by our research group, are addressed.
The General Iterative Methods for Asymptotically Nonexpansive Semigroups in Banach Spaces
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Rabian Wangkeeree
2012-01-01
Full Text Available We introduce the general iterative methods for finding a common fixed point of asymptotically nonexpansive semigroups which is a unique solution of some variational inequalities. We prove the strong convergence theorems of such iterative scheme in a reflexive Banach space which admits a weakly continuous duality mapping. The main result extends various results existing in the current literature.
Convergence of a general iterative method for nonexpansive mappings in Hilbert spaces
Cho, Yeol Je; Qin, Xiaolong
2009-06-01
In this paper, we introduce a modified Ishikawa iterative process for approximating a fixed point of nonexpansive mappings in Hilbert spaces. We establish some strong convergence theorems of the general iteration scheme under some mild conditions. The results improve and extend the corresponding results of many others.
A New General Iterative Method for a Finite Family of Nonexpansive Mappings in Hilbert Spaces
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Singthong Urailuk
2010-01-01
Full Text Available We introduce a new general iterative method by using the -mapping for finding a common fixed point of a finite family of nonexpansive mappings in the framework of Hilbert spaces. A strong convergence theorem of the purposed iterative method is established under some certain control conditions. Our results improve and extend the results announced by many others.
Nuclearity for Dual Operator Spaces
Indian Academy of Sciences (India)
Zhe Dong; Jicheng Tao
2010-02-01
In this short paper, we study the nuclearity for the dual operator space $V^∗$ of an operator space . We show that $V^∗$ is nuclear if and only if $V^{∗∗∗}$ is injective, where $V^{∗∗∗}$ is the third dual of . This is in striking contrast to the situation for general operator spaces. This result is used to prove that $V^{∗∗}$ is nuclear if and only if is nuclear and $V^{∗∗}$ is exact.
Viscosity Approximation Methods for Two Accretive Operators in Banach Spaces
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Jun-Min Chen
2013-01-01
Full Text Available We introduced a viscosity iterative scheme for approximating the common zero of two accretive operators in a strictly convex Banach space which has a uniformly Gâteaux differentiable norm. Some strong convergence theorems are proved, which improve and extend the results of Ceng et al. (2009 and some others.
Two Step Modified Ishikawa Iteration Scheme for Multi-Valued Mappings in CAT(0 Space
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Pankaj Kumar Jhade
2013-11-01
Full Text Available The aim of this paper is to prove some strong convergence theorems for the modified Ishikawa iteration scheme involving quasi-nonexpansive multi-valued mappings in the framework of CAT(0 spaces.
Ishikawa iteration process with errors for nonexpansive mappings in uniformly convex Banach spaces
Deng Lei; Li Shenghong
2000-01-01
We shall consider the behaviour of Ishikawa iteration with errors in a uniformly convex Banach space. Then we generalize the two theorems of Tan and Xu without the restrictions that C is bounded and limsupnsn
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Ali Sevimlican
2010-01-01
Full Text Available He's variational iteration method (VIM is used for solving space and time fractional telegraph equations. Numerical examples are presented in this paper. The obtained results show that VIM is effective and convenient.
Structure of Hilbert space operators
Jiang, Chunlan
2006-01-01
This book exposes the internal structure of non-self-adjoint operators acting on complex separable infinite dimensional Hilbert space, by analyzing and studying the commutant of operators. A unique presentation of the theorem of Cowen-Douglas operators is given. The authors take the strongly irreducible operator as a basic model, and find complete similarity invariants of Cowen-Douglas operators by using K -theory, complex geometry and operator algebra tools. Sample Chapter(s). Chapter 1: Background (153 KB). Contents: Jordan Standard Theorem and K 0 -Group; Approximate Jordan Theorem of Opera
Shlakhter, Oleksandr
2008-01-01
One of the most widely used methods for solving average cost MDP problems is the value iteration method. This method, however, is often computationally impractical and restricted in size of solvable MDP problems. We propose acceleration operators that improve the performance of the value iteration for average reward MDP models. These operators are based on two important properties of Markovian operator: contraction mapping and monotonicity. It is well known that the classical relative value iteration methods for average cost criteria MDP do not involve the max-norm contraction or monotonicity property. To overcome this difficulty we propose to combine acceleration operators with variants of value iteration for stochastic shortest path problems associated average reward problems.
Schöpfer, F.; Schuster, T.; Louis, A. K.
2008-10-01
The split feasibility problem (SFP) consists of finding a common point in the intersection of finitely many convex sets, where some of the sets arise by imposing convex constraints in the range of linear operators. We are concerned with its solution in Banach spaces. To this end we generalize the CQ algorithm of Byrne with Bregman and metric projections to obtain an iterative solution method. In case the sets projected onto are contaminated with noise we show that a discrepancy principle renders this algorithm a regularization method. We measure the distance between convex sets by local versions of the Hausdorff distance, which in contrast to the standard Hausdorff distance allow us to measure the distance between unbounded sets. Hereby we prove a uniform continuity result for both kind of projections. The performance of the algorithm is demonstrated with some numerical experiments.
Thermal-hydraulics of LLCB TBM under different ITER operational conditions
Energy Technology Data Exchange (ETDEWEB)
Chaudhuri, Paritosh, E-mail: paritc@gmail.com; Ranjithkumar, S.; Sharma, Deepak; Danani, Chandan; Kumar, E. Rajendra
2016-11-01
Highlights: • Thermal analysis of LLCB TBM has been performed for different ITER operations during normal and power excursion scenarios. • It is observed that in all ITER operations, the temperatures in all components of LLCB TBM are well within the limits. • The maximum temperature of CB-1 in steady state is 920 °C, which is 72% of the maximum temperature obtained in ITER pulse. - Abstract: Lead–lithium cooled ceramic breeder (LLCB) TBM is the Indian DEMO relevant blanket module, which will be tested in one-half of a designated ITER port from day 1 operation of ITER. LLCB TBM will be tested in various ITER operational phases. Different TBM may be tested corresponding to the four different phases of plasma operation. The paper present a review of thermal analyses based on the various heat loads on the LLCB TBM obtained from neutronics calculations to confirm heat removal and structural integrity under different ITER operational conditions. This includes the normal plasma operation, fusion power excursions, surface heat flux due to MARFES, disruption heat loads during thermal and current quench etc., in inductive and non-inductive plasma operations. Transient events, like plasma disruption, vertical displacement events (VDEs) and edge localized modes (ELMs) deliver considerable heat flux (high power densities) for short durations onto the first wall of TBM. Detailed thermal-hydraulic simulation studies have been performed using ANSYS. These analyses, therefore, will provide important information about the temperature distribution in different materials used in TBM and their temperature-time histories.
Disruption scenarios, their mitigation and operation window in ITER
Sugihara, M.; Shimada, M.; Fujieda, H.; Gribov, Yu.; Ioki, K.; Kawano, Y.; Khayrutdinov, R.; Lukash, V.; Ohmori, J.
2007-04-01
The impacts of plasma disruptions on ITER have been investigated in detail to confirm the robustness of the design of the machine to the potential consequential loads. The loads include both electro-magnetic (EM) and heat loads on the in-vessel components and the vacuum vessel. Several representative disruption scenarios are specified based on newly derived physics guidelines for the shortest current quench time as well as the maximum product of halo current fraction and toroidal peaking factor arising from disruptions in ITER. Disruption simulations with the DINA code and EM load analyses with a 3D finite element method code are performed for these scenarios. Some margins are confirmed in the EM load on in-vessel components due to induced eddy and halo currents for these representative scenarios. However, the margins are not very large. The heat load on various parts of the first wall due to the vertical movement and the thermal quench (TQ) is calculated with a 2D heat conduction code based on the database of heat deposition during disruptions and simulation results with the DINA code. For vertical displacement event, it is found that the beryllium (Be) wall does not melt during the vertical movement, prior to the TQ. Significant melting is anticipated for the upper Be wall and the tungsten divertor baffle due to TQ after the vertical movement. However, its impact could be substantially mitigated by implementing a reliable detection system of the vertical movement and a mitigation system, e.g. massive noble gas injection. Some melting of the upper Be wall is anticipated at major disruptions. At least several tens of unmitigated disruptions must be considered even if an advanced prediction/mitigation system is implemented. With these unmitigated disruptions, the loss of the Be layer is expected to be within ap30-100 µm/event out of a 10 mm thick Be first wall.
Convergence of implicit iterates with errors for mappings with unbounded domain in Banach spaces
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Hafiz Fukhar-Ud-Din
2005-01-01
Full Text Available We prove that an implicit iterative process with errors converges weakly and strongly to a common fixed point of a finite family of asymptotically quasi-nonexpansive mappings on unbounded sets in a uniformly convex Banach space. Our results generalize and improve upon, among others, the corresponding recent results of Sun (2003 in the following two different directions: (i domain of the mappings is unbounded, (ii the iterative sequence contains an error term.
Nikazad, Touraj; Abbasi, Mokhtar
2017-04-01
In this paper, we introduce a subclass of strictly quasi-nonexpansive operators which consists of well-known operators as paracontracting operators (e.g., strictly nonexpansive operators, metric projections, Newton and gradient operators), subgradient projections, a useful part of cutter operators, strictly relaxed cutter operators and locally strongly Féjer operators. The members of this subclass, which can be discontinuous, may be employed by fixed point iteration methods; in particular, iterative methods used in convex feasibility problems. The closedness of this subclass, with respect to composition and convex combination of operators, makes it useful and remarkable. Another advantage with members of this subclass is the possibility to adapt them to handle convex constraints. We give convergence result, under mild conditions, for a perturbation resilient iterative method which is based on an infinite pool of operators in this subclass. The perturbation resilient iterative methods are relevant and important for their possible use in the framework of the recently developed superiorization methodology for constrained minimization problems. To assess the convergence result, the class of operators and the assumed conditions, we illustrate some extensions of existence research works and some new results.
Space-Bounded Complexity Classes and Iterated Deterministic Substitution
Asveld, P.R.J.
1980-01-01
We investigate the effect on the space complexity when a language family $K$ is extended by means of $\\lambda$-free deterministic substitution to the family $\\eta(K)$. If each language in $K$ is accepted by a one-way nondeterministic multi-tape Turing-machine within space $S(n)$ for some monotonic s
Arimoto, Suguru; Sekimoto, Masahiro; Kawamura, Sadao
This paper presents a feasibility study of iterative learning control for a class of redundant multi-joint robotic systems when a desired motion trajectory is specified in task-space with less dimension than that of joint space. First, it is shown that if the desired trajectory described in task-space for a time interval t ∈ [0,T] is twice continuously differentiable then a unique control signal describable in task-space exists despite of the system joint-redundancy. Second, a learning control update law is constructed through transpose of the Jacobian matrix of task-space coordinates with respect to joint coordinates by using measured data of motion trajectories in task-space. Third, the convergence of trajectory trackings through iterative learning is proved theoretically on the basis of original nonlinear robot dynamics in joint space.
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Wangkeeree Rabian
2010-01-01
Full Text Available For a countable family of strictly pseudo-contractions, a strong convergence of viscosity iteration is shown in order to find a common fixed point of in either a p-uniformly convex Banach space which admits a weakly continuous duality mapping or a p-uniformly convex Banach space with uniformly Gâteaux differentiable norm. As applications, at the end of the paper we apply our results to the problem of finding a zero of accretive operators. The main result extends various results existing in the current literature.
非线性二元算子方程组的迭代求解方法%Iterative Solution for Systems of Nonlinear Two Binary Operator Equations
Institute of Scientific and Technical Information of China (English)
张志宏; 李文丰
2004-01-01
Using the cone and partial ordering theory and mixed monotone operator theory,the existence and uniqueness of solutions for some classes of systems of nonlinear two binary operator equations in a Banach space with a partial ordering are discussed. And the error estimates that the iterative sequences converge to solutions are also given. Some relevant results of solvability of two binary operator equations and systems of operator equations are improved and generalized.
Composition Operators on Dirichlet Spaces and Bloch Space
Institute of Scientific and Technical Information of China (English)
Yuan CHENG; Sanjay KUMAR; Ze Hua ZHOU
2014-01-01
In this paper we give a Carleson measure characterization for the compact composition operators between Dirichlet type spaces. We use this characterization to show that every compact composition operator on Dirichlet type spaces is compact on the Bloch space.
Iterative multi-user detection and decoding for space-time block coding systems
Institute of Scientific and Technical Information of China (English)
JIN Yi-dan; ZHANG Feng; WU Wei-ling
2006-01-01
To restrain the interference of co-channel users using space-time block coding (STBC), the proposed Gaussian-forcing soft decision multi-user detection (GFSDMUD) algorithm is applied in flat-fading channels by using the relation among the users' signals, which can enhance the capacity by introducing co-channel users. During iterations, extrinsic information is calculated and exchanged between a soft multi-user detector and a bank of turbo decoders to achieve refined estimates of the users' signals. The simulations show that the proposed iterative receiver techniques provide significant performance improvement around 2 dB over conventional noniterative methods. Furthermore, iterative multi-user space-time processing techniques offer substantial performance gains around 8 dB by adding the number of receiver antennas from 4to 6, and the system performance can be enhanced by using this strategy in multi-user STBC systems, which is very important for enlarging the system capacity.
Chen's Iterated Integral represents the Operator Product Expansion
Kreimer, D
1999-01-01
The recently discovered formalism underlying renormalization theory, the Hopf algebra of rooted trees, allows to generalize Chen's lemma. In its generalized form it describes the change of a scale in Green functions, and hence relates to the operator product expansion. Hand in hand with this generalization goes the generalization of the ordinary factorial $n!$ to the tree factorial $t^!$. Various identities on tree-factorials are derived which clarify the relation between Connes-Moscovici weights and Quantum Field Theory.
Space station operating system study
Horn, Albert E.; Harwell, Morris C.
1988-01-01
The current phase of the Space Station Operating System study is based on the analysis, evaluation, and comparison of the operating systems implemented on the computer systems and workstations in the software development laboratory. Primary emphasis has been placed on the DEC MicroVMS operating system as implemented on the MicroVax II computer, with comparative analysis of the SUN UNIX system on the SUN 3/260 workstation computer, and to a limited extent, the IBM PC/AT microcomputer running PC-DOS. Some benchmark development and testing was also done for the Motorola MC68010 (VM03 system) before the system was taken from the laboratory. These systems were studied with the objective of determining their capability to support Space Station software development requirements, specifically for multi-tasking and real-time applications. The methodology utilized consisted of development, execution, and analysis of benchmark programs and test software, and the experimentation and analysis of specific features of the system or compilers in the study.
Mann Type Implicit Iteration Approximation for Multivalued Mappings in Banach Spaces
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Chen Rudong
2010-01-01
Full Text Available Let be a nonempty compact convex subset of a uniformly convex Banach space and let be a multivalued nonexpansive mapping. For the implicit iterates , , , . We proved that converges strongly to a fixed point of under some suitable conditions. Our results extended corresponding ones and revised a gap in the work of Panyanak (2007.
A General Iterative Method for a Nonexpansive Semigroup in Banach Spaces with Gauge Functions
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Kamonrat Nammanee
2012-01-01
Full Text Available We study strong convergence of the sequence generated by implicit and explicit general iterative methods for a one-parameter nonexpansive semigroup in a reflexive Banach space which admits the duality mapping Jφ, where φ is a gauge function on [0,∞. Our results improve and extend those announced by G. Marino and H.-K. Xu (2006 and many authors.
Non-expansive Mappings and Iterative Methods in Uniformly Convex Banach Spaces
Institute of Scientific and Technical Information of China (English)
Hai Yun ZHOU
2004-01-01
In this article, we will investigate the properties of iterative sequence for non-expansive mappings and present several strong and weak convergence results of successive approximations to fixed points of non-expansive mappings in uniformly convex Banach spaces. The results presented in this article generalize and improve various ones concerned with constructive techniques for the fixed points of non-expansive mappings.
New Hybrid Iterative Schemes for an Infinite Family of Nonexpansive Mappings in Hilbert Spaces
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Guo Baohua
2010-01-01
Full Text Available We propose some new iterative schemes for finding common fixed point of an infinite family of nonexpansive mappings in a Hilbert space and prove the strong convergence of the proposed schemes. Our results extend and improve ones of Nakajo and Takahashi (2003.
Directory of Open Access Journals (Sweden)
Gu Feng
2006-01-01
Full Text Available The purpose of this paper is to study the weak and strong convergence of implicit iteration process with errors to a common fixed point for a finite family of nonexpansive mappings in Banach spaces. The results presented in this paper extend and improve the corresponding results of Chang and Cho (2003, Xu and Ori (2001, and Zhou and Chang (2002.
Iterative Methods for Pseudocontractive Mappings in Banach Spaces
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Jong Soo Jung
2013-01-01
Full Text Available Let E a reflexive Banach space having a uniformly Gâteaux differentiable norm. Let C be a nonempty closed convex subset of E, T:C→C a continuous pseudocontractive mapping with F(T≠∅, and A:C→C a continuous bounded strongly pseudocontractive mapping with a pseudocontractive constant k∈(0,1. Let {αn} and {βn} be sequences in (0,1 satisfying suitable conditions and for arbitrary initial value x0∈C, let the sequence {xn} be generated by xn=αnAxn+βnxn-1+(1-αn-βnTxn, n≥1. If either every weakly compact convex subset of E has the fixed point property for nonexpansive mappings or E is strictly convex, then {xn} converges strongly to a fixed point of T, which solves a certain variational inequality related to A.
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Feng Gu
2012-01-01
Full Text Available The purpose of this paper is to establish a strong convergence of a new parallel iterative algorithm with mean errors to a common fixed point for two finite families of Ćirić quasi-contractive operators in normed spaces. The results presented in this paper generalize and improve the corresponding results of Berinde, Gu, Rafiq, Rhoades, and Zamfirescu.
Very Smooth Points of Spaces of Operators
Indian Academy of Sciences (India)
T S S R K Rao
2003-02-01
In this paper we study very smooth points of Banach spaces with special emphasis on spaces of operators. We show that when the space of compact operators is an -ideal in the space of bounded operators, a very smooth operator attains its norm at a unique vector (up to a constant multiple) and ( ) is a very smooth point of the range space. We show that if for every equivalent norm on a Banach space, the dual unit ball has a very smooth point then the space has the Radon–Nikodým property. We give an example of a smooth Banach space without any very smooth points.
Three-step Iterations with Errors for Nonlinear Strongly Accretive Operator Equations
Institute of Scientific and Technical Information of China (English)
Ke Su
2005-01-01
In this paper, we suggest and analyse a three-step iterative scheme with errors for solving nonlinear strongly accretive operator equation Tx = f without the Lipshitz condition. The results presented in this paper improve and extend current results in the more general setting.
Heating, current drive and energetic particle studies on JET in preparation of ITER operation
Noterdaeme, J. M.; Budny, R.; Cardinali, A.; Castaldo, C.; Cesario, R.; Crisanti, F.; DeGrassie, J.; D' Ippolito, D. A.; Durodie, F.; Ekedahl, A.; Figueiredo, A.; Ingesson, C.; Joffrin, E.; Hartmann, D.; Heikkinen, J.; Hellsten, T.; Jones, T.; Kiptily, V.; Lamalle, P.; Litaudon, X.; Nguyen, F.; Mailloux, J.; Mantsinen, M.; Mayoral, M.; Mazon, D.; Meo, F.; Monakhov, I.; Myra, J. R.; Pamela, J.; Pericoli, V.; Petrov, Y.; Sauter, O.; Sarazin, Y.; Sharapov, S. E.; Tuccillo, A. A.; Van Eester, D.
2003-01-01
This paper summarizes the recent work on JET in the three areas of heating, current drive and energetic particles. The achievements have extended the possibilities of JET, have a direct connection to ITER operation and provide new and interesting physics. Toroidal rotation profiles of plasmas heated
Thianwan, Sornsak
2009-02-01
In this paper, we introduce a new two-step iterative scheme for two asymptotically nonexpansive nonself-mappings in a uniformly convex Banach space. Weak and strong convergence theorems are established for the new two-step iterative scheme in a uniformly convex Banach space.
Directory of Open Access Journals (Sweden)
Murat Ozdemir
2010-01-01
Full Text Available We introduce a new two-step iterative scheme for two asymptotically nonexpansive nonself-mappings in a uniformly convex Banach space. Weak and strong convergence theorems are established for this iterative scheme in a uniformly convex Banach space. The results presented extend and improve the corresponding results of Chidume et al. (2003, Wang (2006, Shahzad (2005, and Thianwan (2008.
Space Station overall management approach for operations
Paules, G.
1986-01-01
An Operations Management Concept developed by NASA for its Space Station Program is discussed. The operational goals, themes, and design principles established during program development are summarized. The major operations functions are described, including: space systems operations, user support operations, prelaunch/postlanding operations, logistics support operations, market research, and cost/financial management. Strategic, tactical, and execution levels of operational decision-making are defined.
Space Station overall management approach for operations
Paules, G.
1986-01-01
An Operations Management Concept developed by NASA for its Space Station Program is discussed. The operational goals, themes, and design principles established during program development are summarized. The major operations functions are described, including: space systems operations, user support operations, prelaunch/postlanding operations, logistics support operations, market research, and cost/financial management. Strategic, tactical, and execution levels of operational decision-making are defined.
An Iterative Power Allocation Algorithm for Group-wise Space-Time Block Coding Systems
Institute of Scientific and Technical Information of China (English)
ZHANG Hong-wei; ZHANG Hai-bin; SONG Wen-tao; LUO Han-wen; LIU Xing-zhao
2007-01-01
An iterative transmit power allocation (PA) algorithm was proposed for group-wise space-time block coding (G-STBC) systems with group-wise successive interference cancellation (GSIC) receivers.Group-wise interference suppression (GIS) filters are employed to separate each group's transmit signals from other interfer ences and noise.While the total power on all transmit symbols is constrained, all transmit PA coefficients are updated jointly according to the channel information at each iteration.Through PA, each detection symbol has the same post-detection signal to interference-and-noise ratio (SINR).The simulation results verify that the proposed PA algorithm converges at the equilibrium quickly after few iterations, and it achieves much lower bit error rates than the previous single symbol SIC PA and the fixed ratio PA algorithms for G-STBC systems with GSIC receivers.
Computationally Efficient Iterative Pose Estimation for Space Robot Based on Vision
Directory of Open Access Journals (Sweden)
Xiang Wu
2013-01-01
Full Text Available In postestimation problem for space robot, photogrammetry has been used to determine the relative pose between an object and a camera. The calculation of the projection from two-dimensional measured data to three-dimensional models is of utmost importance in this vision-based estimation however, this process is usually time consuming, especially in the outer space environment with limited performance of hardware. This paper proposes a computationally efficient iterative algorithm for pose estimation based on vision technology. In this method, an error function is designed to estimate the object-space collinearity error, and the error is minimized iteratively for rotation matrix based on the absolute orientation information. Experimental result shows that this approach achieves comparable accuracy with the SVD-based methods; however, the computational time has been greatly reduced due to the use of the absolute orientation method.
Space Physiology and Operational Space Medicine
Scheuring, Richard A.
2009-01-01
The objectives of this slide presentation are to teach a level of familiarity with: the effects of short and long duration space flight on the human body, the major medical concerns regarding future long duration missions, the environmental issues that have potential medical impact on the crew, the role and capabilities of the Space Medicine Flight Surgeon and the environmental impacts experienced by the Apollo crews. The main physiological effects of space flight on the human body reviewed in this presentation are: space motion sickness (SMS), neurovestibular, cardiovascular, musculoskeletal, immune/hematopoietic system and behavioral/psycho-social. Some countermeasures are discussed to these effects.
Trace Operators on Wiener Amalgam Spaces
Jayson Cunanan; Yohei Tsutsui
2016-01-01
The paper deals with trace operators of Wiener amalgam spaces using frequency-uniform decomposition operators and maximal inequalities, obtaining sharp results. Additionally, we provide the embeddings between standard and anisotropic Wiener amalgam spaces.
Confinement margins for ignition and driven operation in Iter Eda ID
Energy Technology Data Exchange (ETDEWEB)
Johner, J.
1995-09-01
Preliminary calculations for ITER EDA ID have been performed using the 1/2D thermal equilibrium code HELIOS. It is found that: - The maximum ignition margin for ITER ID (29%) is 6% less than for ITER OD (35%) and 5% less than for ITER CDA (34%). - Decreasing the ration {tau}{sup *}{sub He}/{tau}{sub E} from the nominal value 10 to a value of 5 gives a 12% gain in the maximum ignition margin. Increasing the ration from 10 to 15 causes a 22% loss in the margin. Furthermore, ignited equilibria non longer exist for {tau}{sup *}{sub He}/{tau}{sub E} {>=} 17.6. - Operation in driven mode with 50 MW of external power increases the confinement capability by 13%. With 100 MW, the improvement is 24%. - Lowering the fusion power from 1500 to 1000 MW slightly improves the maximum ignition margin (+5%) and allows operation below the Greenwald density limit. - A 10% reduction of the toroidal magnetic field with a correlative diminution of the plasma current for constant safety factor operation, causes a dramatic reduction (-18%) of the maximum ignition margin. - A fraction of neon of 0.68% would completely suppress the ignition margin. Furthermore, ignited equilibria, with the nominal fusion power and {tau}{sup *}{sub He}/{tau}{sub E}, no longer exist when the neon fraction exceeds 0.75%. (Author). 2 refs., 10 figs.
Pseudodifferential operators on alpha-modulation spaces
DEFF Research Database (Denmark)
Borup, Lasse
2004-01-01
We study expansions of pseudodifferential operators from the Hörmander class in a special family of functions called brushlets. We prove that such operators have a sparse representation in a brushlet system. Using this sparsity, we show that a pseudodifferential operator extends to a bounded...... operator between $alpha$-modulation spaces. These spaces were introduced by Gröbner in [15]. They are, in some sense, intermediate spaces between the classical Besov and Modulation spaces....
Advanced Space Surface Systems Operations
Huffaker, Zachary Lynn; Mueller, Robert P.
2014-01-01
The importance of advanced surface systems is becoming increasingly relevant in the modern age of space technology. Specifically, projects pursued by the Granular Mechanics and Regolith Operations (GMRO) Lab are unparalleled in the field of planetary resourcefulness. This internship opportunity involved projects that support properly utilizing natural resources from other celestial bodies. Beginning with the tele-robotic workstation, mechanical upgrades were necessary to consider for specific portions of the workstation consoles and successfully designed in concept. This would provide more means for innovation and creativity concerning advanced robotic operations. Project RASSOR is a regolith excavator robot whose primary objective is to mine, store, and dump regolith efficiently on other planetary surfaces. Mechanical adjustments were made to improve this robot's functionality, although there were some minor system changes left to perform before the opportunity ended. On the topic of excavator robots, the notes taken by the GMRO staff during the 2013 and 2014 Robotic Mining Competitions were effectively organized and analyzed for logistical purposes. Lessons learned from these annual competitions at Kennedy Space Center are greatly influential to the GMRO engineers and roboticists. Another project that GMRO staff support is Project Morpheus. Support for this project included successfully producing mathematical models of the eroded landing pad surface for the vertical testbed vehicle to predict a timeline for pad reparation. And finally, the last project this opportunity made contribution to was Project Neo, a project exterior to GMRO Lab projects, which focuses on rocket propulsion systems. Additions were successfully installed to the support structure of an original vertical testbed rocket engine, thus making progress towards futuristic test firings in which data will be analyzed by students affiliated with Rocket University. Each project will be explained in
Iterative optical vector-matrix processors (survey of selected achievable operations)
Casasent, D.; Neuman, C.
1981-01-01
An iterative optical vector-matrix multiplier with a microprocessor-controlled feedback loop capable of performing a wealth of diverse operations was described. A survey and description of many of its operations demonstrates the versatility and flexibility of this class of optical processor and its use in diverse applications. General operations described include: linear difference and differential equations, linear algebraic equations, matrix equations, matrix inversion, nonlinear matrix equations, deconvolution and eigenvalue and eigenvector computations. Engineering applications being addressed for these different operations and for the IOP are: adaptive phased-array radar, time-dependent system modeling, deconvolution and optimal control.
Certain free products of operator spaces
Institute of Scientific and Technical Information of China (English)
GAO Mingchu
2006-01-01
Certain free products are introduced for operator spaces and dual operator spaces.It is shown that the free product of operator spaces does not preserve the injectivity. The linking C*-algebra of the full free product of two ternary rings of operators (simply, TRO's) is *-isomorphic to the full free product of the linking C*-algebras of the two TRO's. The operator space-reduced free product of the preduals of von Neumann algebras agrees with the predual of the reduced free product of the von Neumann algebras. Each of two operator spaces can be embedded completely isometrically into the reduced free product of the operator spaces. Finally, an example is presented to show that the C*-algebra-reduced free product of two C*-algebras may be contractively isomorphic to a proper subspace of their reduced free product as operator spaces.
Sato, T; Norton, S J; Linzer, M; Ikeda, O; Hirama, M
1981-02-01
An iterative technique is proposed for improving the quality of reconstructions from projections when the number of projections is small or the angular range of projections is limited. The technique consists of transforming repeatedly between image and transform spaces and applying a priori object information at each iteration. The approach is a generalization of the Gerchberg-Papoulis algorithm, a technique for extrapolating in the Fourier domain by imposing a space-limiting constraint on the object in the spatial domain. A priori object data that may be applied, in addition to truncating the image beyond the known boundaries of the object, include limiting the maximum range of variation of the physical parameter being imaged. The results of computer simulations show clearly how the process of forcing the image to conform to a priori object data reduces artifacts arising from limited data available in the Fourier domain.
COMPOSITION OPERATORS ON HARDY-ORLICZ SPACES
Institute of Scientific and Technical Information of China (English)
Liu Lifang; Cao Guangfu; Wang Xiaofeng
2005-01-01
Properties of composition operators induced by analytic self-maps on the unit disk of the complex plane in Hardy-Orlicz spaces are discussed. Results are concerned about boundedness, invertibility, compactness, Fredholm operators and spectra of composition operators.
Elements of Hilbert spaces and operator theory
Vasudeva, Harkrishan Lal
2017-01-01
The book presents an introduction to the geometry of Hilbert spaces and operator theory, targeting graduate and senior undergraduate students of mathematics. Major topics discussed in the book are inner product spaces, linear operators, spectral theory and special classes of operators, and Banach spaces. On vector spaces, the structure of inner product is imposed. After discussing geometry of Hilbert spaces, its applications to diverse branches of mathematics have been studied. Along the way are introduced orthogonal polynomials and their use in Fourier series and approximations. Spectrum of an operator is the key to the understanding of the operator. Properties of the spectrum of different classes of operators, such as normal operators, self-adjoint operators, unitaries, isometries and compact operators have been discussed. A large number of examples of operators, along with their spectrum and its splitting into point spectrum, continuous spectrum, residual spectrum, approximate point spectrum and compressio...
Strongly Irreducible Operators on Banach Spaces
Institute of Scientific and Technical Information of China (English)
Yun Nan ZHANG; Huai Jie ZHONG
2012-01-01
This paper firstly discusses the existence of strongly irreducible operators on Banach spaces.It shows that there exist strongly irreducible operators on Banach spaces with w*-separable dual.It also gives some properties of strongly irreducible operators on Banach spaces. In particular,if T is a strongly irreducible operator on an infinite-dimensional Banach space,then T is not of finite rank and T is not an algebraic operator. On Banach spaces with subsymmetric bases,including infinite-dimensional separable Hilbert spaces,it shows that quasisimilarity does not preserve strong irreducibility.In addition,we show that the strong irreducibility of an operator does not imply the strong irreducibility of its conjugate operator,which is not the same as the property in Hilbert spaces.
Directory of Open Access Journals (Sweden)
Shenghua Wang
2013-01-01
Full Text Available We first introduce the concept of Bregman asymptotically quasinonexpansive mappings and prove that the fixed point set of this kind of mappings is closed and convex. Then we construct an iterative scheme to find a common element of the set of solutions of an equilibrium problem and the set of common fixed points of a countable family of Bregman asymptotically quasinonexpansive mappings in reflexive Banach spaces and prove strong convergence theorems. Our results extend the recent ones of some others.
Mann Type Implicit Iteration Approximation for Multivalued Mappings in Banach Spaces
Directory of Open Access Journals (Sweden)
Huimin He
2010-01-01
Full Text Available Let K be a nonempty compact convex subset of a uniformly convex Banach space E and let T be a multivalued nonexpansive mapping. For the implicit iterates x0∈K, xn=αnxn-1+(1-αnyn, yn∈Txn, n≥1. We proved that {xn} converges strongly to a fixed point of T under some suitable conditions. Our results extended corresponding ones and revised a gap in the work of Panyanak (2007.
A Novel Iterative Algorithm Applied to Totally Asymptotically Nonexpansive Mappings in CAT(0 Spaces
Directory of Open Access Journals (Sweden)
Ali Abkar
2017-02-01
Full Text Available In this paper we introduce a new iterative algorithm for approximating fixed points of totally asymptotically quasi-nonexpansive mappings on CAT(0 spaces. We prove a strong convergence theorem under suitable conditions. The result we obtain improves and extends several recent results stated by many others; they also complement many known recent results in the literature. We then provide some numerical examples to illustrate our main result and to display the efficiency of the proposed algorithm.
MPL - a program for computations with iterated integrals on moduli spaces of curves of genus zero
Bogner, Christian
2015-01-01
We introduce the computer program MPL for computations with homotopy invariant iterated integrals on moduli spaces $\\mathcal{M}_{0,n}$ of curves of genus 0 with $n$ ordered marked points. The program is an implementation of the algorithms presented in [13], based on Maple. It includes the symbol map and procedures for the analytic computation of period integrals on $\\mathcal{M}_{0,n}.$ It supports the automated computation of a certain class of Feynman integrals.
Modified Block Iterative Algorithm for Solving Convex Feasibility Problems in Banach Spaces
Directory of Open Access Journals (Sweden)
Kim JongKyu
2010-01-01
Full Text Available The purpose of this paper is to use the modified block iterative method to propose an algorithm for solving the convex feasibility problems for an infinite family of quasi- -asymptotically nonexpansive mappings. Under suitable conditions some strong convergence theorems are established in uniformly smooth and strictly convex Banach spaces with Kadec-Klee property. The results presented in the paper improve and extend some recent results.
Modified Block Iterative Algorithm for Solving Convex Feasibility Problems in Banach Spaces
Directory of Open Access Journals (Sweden)
Shih-sen Chang
2010-01-01
Full Text Available The purpose of this paper is to use the modified block iterative method to propose an algorithm for solving the convex feasibility problems for an infinite family of quasi-ϕ-asymptotically nonexpansive mappings. Under suitable conditions some strong convergence theorems are established in uniformly smooth and strictly convex Banach spaces with Kadec-Klee property. The results presented in the paper improve and extend some recent results.
WEIGHTED COMPOSITION OPERATORS BETWEEN DIRICHLET SPACES
Institute of Scientific and Technical Information of China (English)
Wang Maofa
2011-01-01
In this article, we study the boundedness of weighted composition operators between different vector-valued Dirichlet spaces. Some sufficient and necessary conditions for such operators to be bounded are obtained exactly, which are different completely from the scalar-valued case. As applications, we show that these vector-valued Dirichlet spaces are different counterparts of the classical scalar-valued Dirichlet space and characterize the boundedness of multiplication operators between these different spaces.
REMARK ON STABILITY OF ISHIKAWA ITERATIVE PROCEDURES
Institute of Scientific and Technical Information of China (English)
薛志群; 田虹
2002-01-01
The stability of the Ishikawa iteration procedures was studied for one class ofcontinuity strong pseudocontraction and continuity strongly accretive operators with boundedrange in real uniformly smooth Banach space. Under parameters satisfying certainconditions, the convergence of iterative sequences was proved. The results improve andextend the recent corresponding results, and supply the basis of theory for further discussingconvergence of iteration procedures with errors.
A path to stable low-torque plasma operation in ITER with test blanket modules
Lanctot, M. J.; Snipes, J. A.; Reimerdes, H.; Paz-Soldan, C.; Logan, N.; Hanson, J. M.; Buttery, R. J.; deGrassie, J. S.; Garofalo, A. M.; Gray, T. K.; Grierson, B. A.; King, J. D.; Kramer, G. J.; La Haye, R. J.; Pace, D. C.; Park, J.-K.; Salmi, A.; Shiraki, D.; Strait, E. J.; Solomon, W. M.; Tala, T.; Van Zeeland, M. A.
2017-03-01
New experiments in the low-torque ITER Q = 10 scenario on DIII-D demonstrate that n = 1 magnetic fields from a single row of ex-vessel control coils enable operation at ITER performance metrics in the presence of applied non-axisymmetric magnetic fields from a test blanket module (TBM) mock-up coil. With n = 1 compensation, operation below the ITER-equivalent injected torque is successful at three times the ITER equivalent toroidal magnetic field ripple for a pair of TBMs in one equatorial port, whereas the uncompensated TBM field leads to rotation collapse, loss of H-mode and plasma current disruption. In companion experiments at high plasma beta, where the n = 1 plasma response is enhanced, uncorrected TBM fields degrade energy confinement and the plasma angular momentum while increasing fast ion losses; however, disruptions are not routinely encountered owing to increased levels of injected neutral beam torque. In this regime, n = 1 field compensation leads to recovery of a dominant fraction of the TBM-induced plasma pressure and rotation degradation, and an 80% reduction in the heat load to the first wall. These results show that the n = 1 plasma response plays a dominant role in determining plasma stability, and that n = 1 field compensation alone not only recovers most of the impact on plasma performance of the TBM, but also protects the first wall from potentially damaging heat flux. Despite these benefits, plasma rotation braking from the TBM fields cannot be fully recovered using standard error field control. Given the uncertainty in extrapolation of these results to the ITER configuration, it is prudent to design the TBMs with as low a ferromagnetic mass as possible without jeopardizing the TBM mission.
Directory of Open Access Journals (Sweden)
Ammar Ali Neamah
2014-01-01
Full Text Available The paper uses the Local fractional variational Iteration Method for solving the second kind Volterra integro-differential equations within the local fractional integral operators. The analytical solutions within the non-differential terms are discussed. Some illustrative examples will be discussed. The obtained results show the simplicity and efficiency of the present technique with application to the problems for the integral equations.
Energy Technology Data Exchange (ETDEWEB)
Takahashi, Yasuyuki; Murase, Kenya [Osaka Medical Coll., Takatsuki (Japan). Graduate School; Higashino, Hiroshi; Sogabe, Ichiro; Sakamoto, Kana
2001-12-01
The quality of images reconstructed by means of the maximum likelihood-expectation maximization (ML-EM) and ordered subset (OS)-EM algorithms, was examined with parameters such as the number of iterations and subsets, then compared with the quality of images reconstructed by the filtered back projection method. Phantoms showing signals inside signals, which mimicked single-photon emission computed tomography (SPECT) images of cerebral blood flow and myocardial perfusion, and phantoms showing signals around the signals obtained by SPECT of bone and tumor were used for experiments. To determine signals for recognition, SPECT images in which the signals could be appropriately recognized with a combination of fewer iterations and subsets of different sizes and densities were evaluated by receiver operating characteristic (ROC) analysis. The results of ROC analysis were applied to myocardial phantom experiments and scintigraphy of myocardial perfusion. Taking the image processing time into consideration, good SPECT images were obtained by OS-EM at iteration No. 10 and subset 5. This study will be helpful for selection of parameters such as the number of iterations and subsets when using the ML-EM or OS-EM algorithms. (author)
Directory of Open Access Journals (Sweden)
Jiancai Huang
2012-01-01
Full Text Available We introduce an implicit and explicit iterative schemes for a finite family of nonexpansive semigroups with the Meir-Keeler-type contraction in a Banach space. Then we prove the strong convergence for the implicit and explicit iterative schemes. Our results extend and improve some recent ones in literatures.
Linear systems and operators in Hilbert space
Fuhrmann, Paul A
2014-01-01
A treatment of system theory within the context of finite dimensional spaces, this text is appropriate for students with no previous experience of operator theory. The three-part approach, with notes and references for each section, covers linear algebra and finite dimensional systems, operators in Hilbert space, and linear systems in Hilbert space. 1981 edition.
Operator representations on quantum spaces
Energy Technology Data Exchange (ETDEWEB)
Bauer, C.; Wachter, H. [Sektion Physik, Ludwig-Maximilians-Universitaet, Theresienstr. 37, 80333, Muenchen (Germany)
2003-11-01
In this article we present explicit formulae for q-differentiation on quantum spaces which could be of particular importance in physics, i.e., q-deformed Minkowski space and q-deformed Euclidean space in three or four dimensions. The calculations are based on the covariant differential calculus of these quantum spaces. Furthermore, our formulae can be regarded as a generalization of Jackson's q-derivative to three and four dimensions. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Ekedahl, A.; Basiuk, V.; Beaumont, B.; Bibet, Ph.; Delpech, L.; Goniche, M.; Imbeaux, F.; Joffrin, E.; Kazarian, F.; Litaudon, X.; Maget, P.; Martin, G.; Mazon, D.; Peysson, Y.; Prou, M.; Rimini, F.G.; VanHoutte, D. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Baranov, Y.; Erents, S.K.; Lomas, P.J.; Mailloux, J.; McDonald, D.C.; Stamp, M. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon (United Kingdom); Granucci, G. [Association Euratom-ENEA sulla Fusione, IFP-CNR, Milano (Italy); Silva, C. [Association Euratom-IST, Centro de Fusao Nuclear, Lisboa (Portugal)
2004-07-01
Lower hybrid current drive (LHCD) is one of the most efficient methods for off-axis non-inductive current drive in tokamaks and is therefore used for shaping the plasma current profile in advanced tokamak scenarios. Its usefulness has been demonstrated in the advanced scenario experiments in JET, but the question has remained about the possibility of coupling lower hybrid (LH) waves in ITER. This paper reports on recent results obtained in JET and Tore-Supra, that both demonstrate operation of LHCD systems in ITER relevant regimes: -) LH coupling on ELMs (edge localized mode) plasmas up to 11 cm distance between the launcher and the separatrix in JET, and -) steady state, full non-inductive LHCD operation during 6 minutes in Tore Supra. The foreseen upgrade of the Tore Supra LHCD system will allow the extension of operating domain to higher power and higher performance, and will demonstrate the long pulse and coupling capability of a passive multijunction (PAM) launcher, as foreseen for ITER.
An operational non destructive examination for ITER divertor plasma facing components
Energy Technology Data Exchange (ETDEWEB)
Durocher, A.; Escourbiac, F.; Farjon, J.L.; Vignal, N.; Cismondi, F. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Merola, M. [ITER International Team, Cadarache, 13 - St Paul Lez Durance (France); Riccardi, B. [CEFDA CSU-Garching, Garching bei Munchen (Germany)
2007-07-01
Full text of publication follows: To meet the power exhaust - heat flux of 20 MW/m{sup 2} - requirements of Plasma Facing Components (PFCs) during plasma operation requires control of their thermal and mechanical integrity. As heat exhaust capability and lifetime of PFCs during in-situ operation are linked to the manufacturing quality, it is an absolute requirement to develop reliable nondestructive examination methods, in particular of the CFC-CuCrZr joint, throughout the manufacturing process. Within the framework of Tokamak Tore Supra upgrade, a pioneering activity has been developed to evaluate the capability of the PFC to be efficiently cooled. In 1998 a test bed - so called SATIR - based on the heat transient method was developed by the CEA and is used today as an inspection tool in order to guarantee the PFCs performances. The technical procurement plan of ITER Divertor targets stated that all Cu cast layers on CFC armour should be subjected to 100% thermographic examination. Each ITER Party should demonstrate its technical capability to carry out the PFC with the required cooling efficiently. The ITER Divertor PFCs pose new challenges especially for the mono-block CFC thickness, and the number of full scale units to be tested which is higher than on any existing or under construction fusion machine. The SATIR method as functional inspection has been identified as the basis test to decide upon the final acceptance of the Divertor PFCs. In order to increase the detection sensitivity of SATIR test bed, several possibilities have been assessed i) the increase of the convective heat transfer coefficient, which improved in a significant way the sensitivity of SATIR diagnostic on ITER components. ii) the installation of a digital infrared camera and the improvement of the thermal signal processing, has led to a considerable increase of performances iii) an innovative process based on spatial image autocorrelation will allow to localize the interlayer defect
Iterative reconstruction in image space (IRIS) in cardiac computed tomography: initial experience.
Bittencourt, Márcio Sommer; Schmidt, Bernhard; Seltmann, Martin; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner Günther; Achenbach, Stephan
2011-10-01
Improvements in image quality in cardiac computed tomography may be achieved through iterative image reconstruction techniques. We evaluated the ability of "Iterative Reconstruction in Image Space" (IRIS) reconstruction to reduce image noise and improve subjective image quality. 55 consecutive patients undergoing coronary CT angiography to rule out coronary artery stenosis were included. A dual source CT system and standard protocols were used. Images were reconstructed using standard filtered back projection and IRIS. Image noise, attenuation within the coronary arteries, contrast, signal to noise and contrast to noise parameters as well as subjective classification of image quality (using a scale with four categories) were evaluated and compared between the two image reconstruction protocols. Subjective image quality (2.8 ± 0.4 in filtered back projection and 2.8 ± 0.4 in iterative reconstruction) and the number of "evaluable" segments per patient 14.0 ± 1.2 in filtered back projection and 14.1 ± 1.1 in iterative reconstruction) were not significant different between the two methods. However iterative reconstruction had a lower image noise (22.6 ± 4.5 HU vs. 28.6 ± 5.1 HU) and higher signal to noise and image to noise ratios in the proximal coronary arteries. IRIS reduces image noise and contrast-to-noise ratio in coronary CT angiography, thus providing potential for reducing radiation exposure.
Institute of Scientific and Technical Information of China (English)
倪仁兴; 叶新涛
2001-01-01
Several more general results on the convergence of the Ishikawa iteration procedures with errors for ψ-strong pseudo-contractions and nonlinear operator equations of ψ-strongly accretive type without Lipschitz assumption in Banach spaces are established, as the direct applications, some stability results of the Ishikawa iteration methods for ψ-strong pseudocontractions and nonlinear operator equations of ψ-strongly accretive type are also given. They unify, improve and extend the recent corresponding results.
Directory of Open Access Journals (Sweden)
Baojian Hong
2014-01-01
Full Text Available Based on He’s variational iteration method idea, we modified the fractional variational iteration method and applied it to construct some approximate solutions of the generalized time-space fractional Schrödinger equation (GFNLS. The fractional derivatives are described in the sense of Caputo. With the help of symbolic computation, some approximate solutions and their iterative structure of the GFNLS are investigated. Furthermore, the approximate iterative series and numerical results show that the modified fractional variational iteration method is powerful, reliable, and effective when compared with some classic traditional methods such as homotopy analysis method, homotopy perturbation method, adomian decomposition method, and variational iteration method in searching for approximate solutions of the Schrödinger equations.
Energy Technology Data Exchange (ETDEWEB)
Na, Y. W.; Park, C. E.; Lee, S. Y. [KOPEC, Daejeon (Korea, Republic of)
2009-10-15
As a part of the Ministry of Knowledge Economy (MKE) project, 'Development of safety analysis codes for nuclear power plants', KOPEC has been developing the hydraulic solver code package applicable to the safety analyses of nuclear power plants (NPP's). The matrices of the hydraulic solver are usually sparse and may be asymmetric. In the earlier stage of this project, typical direct matrix solver packages MA48 and MA28 had been tested as matrix solver for the hydraulic solver code, SPACE. The selection was based on the reasonably reliable performance experience from their former version MA18 in RELAP computer code. In the later stage of this project, the iterative methodologies have been being tested in the SPACE code. Among a few candidate iterative solution methodologies tested so far, the biconjugate gradient stabilization methodology (BICGSTAB) has shown the best performance in the applicability test and in the application to the SPACE code. Regardless of all the merits of using the direct solver packages, there are some other aspects of tackling the iterative solution methodologies. The algorithm is much simpler and easier to handle. The potential problems related to the robustness of the iterative solution methodologies have been resolved by applying pre-conditioning methods adjusted and modified as appropriate to the application in the SPACE code. The application strategy of conjugate gradient method was introduced in detail by Schewchuk, Golub and Saad in the middle of 1990's. The application of his methodology to nuclear engineering in Korea started about the same time and is still going on and there are quite a few examples of application to neutronics. Besides, Yang introduced a conjugate gradient method programmed in C++ language. The purpose of this study is to assess the performance and behavior of the iterative solution methodology compared to those of the direct solution methodology still being preferred due to its robustness and
Rapp, J.; van Rooij, G. J.; Litnovsky, A.; Marot, L.; De Temmerman, G.; Westerhout, J.; Zoethout, E.
2009-01-01
Optical diagnostics in ITER will rely on mirrors near the plasma and the deterioration of the reflectivity is a concern. The effect of temperature on the deposition efficiency of hydrocarbons under long-term operation conditions similar to ITER was investigated in the linear plasma generator
Rapp, J.; van Rooij, G. J.; Litnovsky, A.; Marot, L.; De Temmerman, G.; Westerhout, J.; Zoethout, E.
2009-01-01
Optical diagnostics in ITER will rely on mirrors near the plasma and the deterioration of the reflectivity is a concern. The effect of temperature on the deposition efficiency of hydrocarbons under long-term operation conditions similar to ITER was investigated in the linear plasma generator Pilot-P
Space Flight Resource Management for ISS Operations
Schmidt, Larry; Slack, Kelley; O'Keefe, William; Huning, Therese; Sipes, Walter; Holland, Albert
2011-01-01
This slide presentation reviews the International Space Station (ISS) Operations space flight resource management, which was adapted to the ISS from the shuttle processes. It covers crew training and behavior elements.
Space station short-term mission planning using ontology modelling and time iteration
Institute of Scientific and Technical Information of China (English)
Huijiao Bu; Jin Zhang; Yazhong Luo
2016-01-01
This paper studies the problem of the space station short-term mission planning, which aims to alocate the exe-cuting time of missions effectively, schedule the correspon- ding resources reasonably and arrange the time of the as-tronauts properly. A domain model is developed by using the ontology theory to describe the concepts, constraints and relations of the planning domain formaly, abstractly and normatively. A method based on time iteration is adopted to solve the short-term planning problem. Meanwhile, the re-solving strategies are proposed to resolve different kinds of conflicts induced by the constraints of power, heat, resource, astronaut and relationship. The proposed approach is evalu-ated in a test case with fifteen missions, thirteen resources and three astronauts. The results show that the developed domain ontology model is reasonable, and the time iteration method using the proposed resolving strategies can suc-cessfuly obtain the plan satisfying al considered constraints.
Institute of Scientific and Technical Information of China (English)
张石生
2002-01-01
Some necessary and sufficient conditions for convergence of Ishikawa Mann and steepest descent iterative sequence for accretive and pseudo-contractive type mapping in Banech spaces were obtained. The results improve, extend and include some recent results.
Quantum Iterated Function Systems
Lozinski, A; Slomczynski, W; Lozinski, Artur; Zyczkowski, Karol; Slomczynski, Wojciech
2003-01-01
Iterated functions system (IFS) is defined by specifying a set of functions in a classical phase space, which act randomly on the initial point. In an analogous way, we define quantum iterated functions system (QIFS), where functions act randomly with prescribed probabilities in the Hilbert space. In a more general setting a QIFS consists of completely positive maps acting in the space of density operators. We present exemplary classical IFSs, the invariant measure of which exhibits fractal structure, and study properties of the corresponding QIFSs and their invariant state.
Localization of Toeplitz Operators on Bergman Spaces
Institute of Scientific and Technical Information of China (English)
卢玉峰
2001-01-01
In this paper we characterize the essential spectra of Toeplitz operators on Bergman spaces by using Douglas' localization Theorem and obtain the local decomposition of the essential spectra of Toeplitz operators.
Operational Space Weather Activities in the US
Berger, Thomas; Singer, Howard; Onsager, Terrance; Viereck, Rodney; Murtagh, William; Rutledge, Robert
2016-07-01
We review the current activities in the civil operational space weather forecasting enterprise of the United States. The NOAA/Space Weather Prediction Center is the nation's official source of space weather watches, warnings, and alerts, working with partners in the Air Force as well as international operational forecast services to provide predictions, data, and products on a large variety of space weather phenomena and impacts. In October 2015, the White House Office of Science and Technology Policy released the National Space Weather Strategy (NSWS) and associated Space Weather Action Plan (SWAP) that define how the nation will better forecast, mitigate, and respond to an extreme space weather event. The SWAP defines actions involving multiple federal agencies and mandates coordination and collaboration with academia, the private sector, and international bodies to, among other things, develop and sustain an operational space weather observing system; develop and deploy new models of space weather impacts to critical infrastructure systems; define new mechanisms for the transition of research models to operations and to ensure that the research community is supported for, and has access to, operational model upgrade paths; and to enhance fundamental understanding of space weather through support of research models and observations. The SWAP will guide significant aspects of space weather operational and research activities for the next decade, with opportunities to revisit the strategy in the coming years through the auspices of the National Science and Technology Council.
More on (,-Normal Operators in Hilbert Spaces
Directory of Open Access Journals (Sweden)
Rasoul Eskandari
2012-01-01
Full Text Available We study some properties of (,-normal operators and we present various inequalities between the operator norm and the numerical radius of (,-normal operators on Banach algebra ℬ(ℋ of all bounded linear operators ∶ℋ→ℋ, where ℋ is Hilbert space.
Vertex Operators and Moduli Spaces of Sheaves
Carlsson, Erik
2009-01-01
The Nekrasov partition function in supersymmetric quantum gauge theory is mathematically formulated as an equivariant integral over certain moduli spaces of sheaves on a complex surface. In ``Seiberg-Witten Theory and Random Partitions'', Nekrasov and Okounkov studied these integrals using the representation theory of ``vertex operators'' and the infinite wedge representation. Many of these operators arise naturally from correspondences on the moduli spaces, such as Nakajima's Heisenberg operators, and Grojnowski's vertex operators. In this paper, we build a new vertex operator out of the Chern class of a vector bundle on a pair of moduli spaces. This operator has the advantage that it connects to the partition function by definition. It also incorporates the canonical class of the surface, whereas many other studies assume that the class vanishes. When the moduli space is the Hilbert scheme, we present an explicit expression in the Nakajima operators, and the resulting combinatorial identities. We then apply...
Directory of Open Access Journals (Sweden)
Lu-Chuan Ceng
2013-01-01
Full Text Available We introduce composite implicit and explicit iterative algorithms for solving a general system of variational inequalities and a common fixed point problem of an infinite family of nonexpansive mappings in a real smooth and uniformly convex Banach space. These composite iterative algorithms are based on Korpelevich's extragradient method and viscosity approximation method. We first consider and analyze a composite implicit iterative algorithm in the setting of uniformly convex and 2-uniformly smooth Banach space and then another composite explicit iterative algorithm in a uniformly convex Banach space with a uniformly Gâteaux differentiable norm. Under suitable assumptions, we derive some strong convergence theorems. The results presented in this paper improve, extend, supplement, and develop the corresponding results announced in the earlier and very recent literatures.
Convergence Analysis of Iterative Sequences for a Pair of Mappings in Banach Spaces
Institute of Scientific and Technical Information of China (English)
Liu Chuan ZENG; N. C. WONG; J. C. YAO
2008-01-01
Let C be a nonempty closed convex subset of a real Banach space E Let S :C→C be a quasi-nonexpansive mapping,let T :C→C be an asymptotically demicontractive and uniformly Lipschitzian mapping,and let F := {x∈C :Sx =x and Tx x }≠φ.Let {xn } n≥0 be the sequence generated from an arbitrary x∈C by xn+1 =(1 -cn) Sxn +cnTnxn,n ≥0 . We prove the necessary and su .cient conditions for the strong convergence of the iterative sequence {xn }to an element of F These extend and improve the recent results of Moore and Nnoli.
Convergence on Composite Iterative Schemes for Nonexpansive Mappings in Banach Spaces
Directory of Open Access Journals (Sweden)
Jung JongSoo
2008-01-01
Full Text Available Abstract Let be a reflexive Banach space with a uniformly Gâteaux differentiable norm. Suppose that every weakly compact convex subset of has the fixed point property for nonexpansive mappings. Let be a nonempty closed convex subset of , a contractive mapping (or a weakly contractive mapping, and nonexpansive mapping with the fixed point set . Let be generated by a new composite iterative scheme: , , . It is proved that converges strongly to a point in , which is a solution of certain variational inequality provided that the sequence satisfies and , for some and the sequence is asymptotically regular.
Operational Space Weather in USAF Education
Smithtro, C.; Quigley, S.
2006-12-01
Most education programs offering space weather courses are understandably and traditionally heavily weighted with theoretical space physics that is the basis for most of what is researched and modeled. While understanding the theory is a good and necessary grounding for anyone working the field of space weather, few military or commercial jobs employ such theory in real-time operations. The operations sites/centers are much more geared toward use of applied theory-resultant models, tools and products. To ensure its operations centers personnel, commanders, real-time system operators and other customers affected by the space environment are educated on available and soon-to-be operational space weather models and products, the USAF has developed applicable course/lecture material taught at various institutions to include the Air Force Institute of Technology (AFIT) and the Joint Weather Training Complex (335th/TRS/OUA). Less frequent training of operational space weather is available via other venues that will be discussed, and associated course material is also being developed for potential use at the National Security Space Institute (NSSI). This presentation provides an overview of the programs, locations, courses and material developed and/or taught by or for USAF personnel dealing with operational space weather. It also provides general information on student research project results that may be used in operational support, along with observations regarding logistical and professional benefits of teaching such non-theoretical/non-traditional material.
Little Hankel operators on the Bergman space
Directory of Open Access Journals (Sweden)
Namita Das
2016-01-01
Full Text Available In this paper we obtain a characterization of little Hankel operators defined on the Bergman space of the unit disk and then extend the result to vector valued Bergman spaces. We then derive from it certain asymptotic properties of little Hankel operators.
Nice Surjections on Spaces of Operators
Indian Academy of Sciences (India)
T S S R K Rao
2006-11-01
A bounded linear operator is said to be nice if its adjoint preserves extreme points of the dual unit ball. Motivated by a description due to Labuschagne and Mascioni [9] of such maps for the space of compact operators on a Hilbert space, in this article we consider a description of nice surjections on $\\mathcal{K}(X, Y)$ for Banach spaces , . We give necessary and sufficient conditions when nice surjections are given by composition operators. Our results imply automatic continuity of these maps with respect to other topologies on spaces of operators. We also formulate the corresponding result for $\\mathcal{L}(X, Y)$ thereby proving an analogue of the result from [9] for $L^p(1 < p ≠ 2 < ∞)$ spaces. We also formulate results when nice operators are not of the canonical form, extending and correcting the results from [8].
Quantization over boson operator spaces
Energy Technology Data Exchange (ETDEWEB)
Prosen, Tomaz [Department of Physics, FMF, University of Ljubljana, Ljubljana (Slovenia); Seligman, Thomas H [Instituto de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico)
2010-10-01
The framework of third quantization-canonical quantization in the Liouville space-is developed for open many-body bosonic systems. We show how to diagonalize the quantum Liouvillean for an arbitrary quadratic n-boson Hamiltonian with arbitrary linear Lindblad couplings to the baths and, as an example, explicitly work out a general case of a single boson. (fast track communication)
Quantization over boson operator spaces
Prosen, Tomaz
2010-01-01
The framework of third quantization - canonical quantization in the Liouville space - is developed for open many-body bosonic systems. We show how to diagonalize the quantum Liouvillean for an arbitrary quadratic n-boson Hamiltonian with arbitrary linear Lindblad couplings to the baths and, as an example, explicitly work out a general case of a single boson.
An iterative method to compute the overlap Dirac operator at nonzero chemical potential
Bloch, J; Lang, B; Wettig, T
2007-01-01
The overlap Dirac operator at nonzero quark chemical potential involves the computation of the sign function of a non-Hermitian matrix. In this talk we present an iterative method, first proposed by us in Ref. [1], which allows for an efficient computation of the operator, even on large lattices. The starting point is a Krylov subspace approximation, based on the Arnoldi algorithm, for the evaluation of a generic matrix function. The efficiency of this method is spoiled when the matrix has eigenvalues close to a function discontinuity. To cure this, a small number of critical eigenvectors are added to the Krylov subspace, and two different deflation schemes are proposed in this augmented subspace. The ensuing method is then applied to the sign function of the overlap Dirac operator, for two different lattice sizes. The sign function has a discontinuity along the imaginary axis, and the numerical results show how deflation dramatically improves the efficiency of the method.
Matrices related to some Fock space operators
Directory of Open Access Journals (Sweden)
Krzysztof Rudol
2011-01-01
Full Text Available Matrices of operators with respect to frames are sometimes more natural and easier to compute than the ones related to bases. The present work investigates such operators on the Segal-Bargmann space, known also as the Fock space. We consider in particular some properties of matrices related to Toeplitz and Hankel operators. The underlying frame is provided by normalised reproducing kernel functions at some lattice points.
Operation of an ITER relevant inspection robot on Tore Supra tokamak
Energy Technology Data Exchange (ETDEWEB)
Gargiulo, Laurent [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)], E-mail: laurent.gargiulo@cea.fr; Bayetti, Pascal; Bruno, Vincent; Hatchressian, Jean-Claude; Hernandez, Caroline; Houry, Michael [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Keller, Delphine [CEA, LIST, Service de Robotique Interactive, F-92265 Fontenay aux Roses (France); Martins, Jean-Pierre [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Measson, Yvan; Perrot, Yann [CEA, LIST, Service de Robotique Interactive, F-92265 Fontenay aux Roses (France); Samaille, Frank [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)
2009-06-15
Robotic operations are one of the major maintenance challenges for ITER and future fusion reactors. CEA has developed a multipurpose carrier able to realize deployments in the plasma vessel without breaking the Ultra High Vacuum (UHV) and temperature conditioning. A 6 years R and D programme was jointly conducted by CEA-LIST Interactive Robotics Unit and the Institute for Magnetic Fusion Research (IRFM) in order to demonstrate the feasibility and reliability of an in-vessel inspection robot relevant to ITER requirements. The Articulated Inspection Arm robot (AIA) is an 8-m long multilink carrier with a payload up to 10 kg operable between plasma under tokamak conditioning environment; its geometry allows a complete close inspection of Plasma Facing Components (PFCs) of the Tore Supra vessel. Different tools are being developed by CEA to be plugged at the front head of the carrier. The diagnostic presently in operation consists in a viewing system offering accurate visual inspection of PFCs. Leak detection of first wall based on helium sniffing and laser compact system for carbon co-deposited layers characterizations or treatments are also considered for demonstration. In April 2008, the AIA robot equipped with its vision diagnostic has realized a complete deployment into Tore Supra and the first closed inspection of the vessel under UHV conditions. During the upcoming experimental campaign, the same operation will be performed under relevant conditions (10{sup -6} Pa and 120 deg. C) after a conditioning phase at 200 deg. C to avoid outgassing pollution of the chamber. This paper describes the different steps of the project development, robot capabilities with the present operations conducted on Tore Supra and future requirements for making the robot a tool for tokamak routine operation.
Energy Technology Data Exchange (ETDEWEB)
de Almeida, V.F.
2004-01-28
A phase-space discontinuous Galerkin (PSDG) method is presented for the solution of stellar radiative transfer problems. It allows for greater adaptivity than competing methods without sacrificing generality. The method is extensively tested on a spherically symmetric, static, inverse-power-law scattering atmosphere. Results for different sizes of atmospheres and intensities of scattering agreed with asymptotic values. The exponentially decaying behavior of the radiative field in the diffusive-transparent transition region and the forward peaking behavior at the surface of extended atmospheres were accurately captured. The integrodifferential equation of radiation transfer is solved iteratively by alternating between the radiative pressure equation and the original equation with the integral term treated as an energy density source term. In each iteration, the equations are solved via an explicit, flux-conserving, discontinuous Galerkin method. Finite elements are ordered in wave fronts perpendicularly to the characteristic curves so that elemental linear algebraic systems are solved quickly by sweeping the phase space element by element. Two implementations of a diffusive boundary condition at the origin are demonstrated wherein the finite discontinuity in the radiative intensity is accurately captured by the proposed method. This allows for a consistent mechanism to preserve photon luminosity. The method was proved to be robust and fast, and a case is made for the adequacy of parallel processing. In addition to classical two-dimensional plots, results of normalized radiative intensity were mapped onto a log-polar surface exhibiting all distinguishing features of the problem studied.
de Almeida, Valmor F.
2017-07-01
A phase-space discontinuous Galerkin (PSDG) method is presented for the solution of stellar radiative transfer problems. It allows for greater adaptivity than competing methods without sacrificing generality. The method is extensively tested on a spherically symmetric, static, inverse-power-law scattering atmosphere. Results for different sizes of atmospheres and intensities of scattering agreed with asymptotic values. The exponentially decaying behavior of the radiative field in the diffusive-transparent transition region, and the forward peaking behavior at the surface of extended atmospheres were accurately captured. The integrodifferential equation of radiation transfer is solved iteratively by alternating between the radiative pressure equation and the original equation with the integral term treated as an energy density source term. In each iteration, the equations are solved via an explicit, flux-conserving, discontinuous Galerkin method. Finite elements are ordered in wave fronts perpendicular to the characteristic curves so that elemental linear algebraic systems are solved quickly by sweeping the phase space element by element. Two implementations of a diffusive boundary condition at the origin are demonstrated wherein the finite discontinuity in the radiation intensity is accurately captured by the proposed method. This allows for a consistent mechanism to preserve photon luminosity. The method was proved to be robust and fast, and a case is made for the adequacy of parallel processing. In addition to classical two-dimensional plots, results of normalized radiation intensity were mapped onto a log-polar surface exhibiting all distinguishing features of the problem studied.
Iterative deblending of simultaneous-source data using a coherency-pass shaping operator
Zu, Shaohuan; Zhou, Hui; Mao, Weijian; Zhang, Dong; Li, Chao; Pan, Xiao; Chen, Yangkang
2017-10-01
Simultaneous-source acquisition helps greatly boost an economic saving, while it brings an unprecedented challenge of removing the crosstalk interference in the recorded seismic data. In this paper, we propose a novel iterative method to separate the simultaneous source data based on a coherency-pass shaping operator. The coherency-pass filter is used to constrain the model, that is, the unblended data to be estimated, in the shaping regularization framework. In the simultaneous source survey, the incoherent interference from adjacent shots greatly increases the rank of the frequency domain Hankel matrix that is formed from the blended record. Thus, the method based on rank reduction is capable of separating the blended record to some extent. However, the shortcoming is that it may cause residual noise when there is strong blending interference. We propose to cascade the rank reduction and thresholding operators to deal with this issue. In the initial iterations, we adopt a small rank to severely separate the blended interference and a large thresholding value as strong constraints to remove the residual noise in the time domain. In the later iterations, since more and more events have been recovered, we weaken the constraint by increasing the rank and shrinking the threshold to recover weak events and to guarantee the convergence. In this way, the combined rank reduction and thresholding strategy acts as a coherency-pass filter, which only passes the coherent high-amplitude component after rank reduction instead of passing both signal and noise in traditional rank reduction based approaches. Two synthetic examples are tested to demonstrate the performance of the proposed method. In addition, the application on two field data sets (common receiver gathers and stacked profiles) further validate the effectiveness of the proposed method.
Application of Gauss's law space-charge limited emission model in iterative particle tracking method
Altsybeyev, V. V.; Ponomarev, V. A.
2016-11-01
The particle tracking method with a so-called gun iteration for modeling the space charge is discussed in the following paper. We suggest to apply the emission model based on the Gauss's law for the calculation of the space charge limited current density distribution using considered method. Based on the presented emission model we have developed a numerical algorithm for this calculations. This approach allows us to perform accurate and low time consumpting numerical simulations for different vacuum sources with the curved emitting surfaces and also in the presence of additional physical effects such as bipolar flows and backscattered electrons. The results of the simulations of the cylindrical diode and diode with elliptical emitter with the use of axysimmetric coordinates are presented. The high efficiency and accuracy of the suggested approach are confirmed by the obtained results and comparisons with the analytical solutions.
Prediction Techniques in Operational Space Weather Forecasting
Zhukov, Andrei
2016-07-01
The importance of forecasting space weather conditions is steadily increasing as our society is becoming more and more dependent on advanced technologies that may be affected by disturbed space weather. Operational space weather forecasting is still a difficult task that requires the real-time availability of input data and specific prediction techniques that are reviewed in this presentation, with an emphasis on solar and interplanetary weather. Key observations that are essential for operational space weather forecasting are listed. Predictions made on the base of empirical and statistical methods, as well as physical models, are described. Their validation, accuracy, and limitations are discussed in the context of operational forecasting. Several important problems in the scientific basis of predicting space weather are described, and possible ways to overcome them are discussed, including novel space-borne observations that could be available in future.
NASA Deep Space Network Operations Scheduling
Enari, D. M.
The functioning of the Deep Space Network Operations Scheduling, Jet Propulsion Laboratory, CA is reviewed. The primary objectives of the Operations Scheduling are: to schedule the worldwide global allocation of ground communications, tracking facilities, and equipment; and to provide deep space telecommunications for command, tracking, telemetry, and control in support of flight mission operations and tests. Elements of the earth set are Deep Space Stations (DSS) which provide the telecommunications link between the earth and spacecraft; NASA Communications Network; Network Data Processing Area; Network Operations Control Area which provides operational direction to the DSS; Mission Control and Computing systems; and Mission Support areas which provide flight control of the spacecraft. Elements of the space set include mission priorities and requirements which determine the spacecraft queue for allocating network resources. Scheduling is discussed in terms of long-range (3 years), mid-range (8 weeks), and short-range (2 weeks).
Hierarchical approximate policy iteration with binary-tree state space decomposition.
Xu, Xin; Liu, Chunming; Yang, Simon X; Hu, Dewen
2011-12-01
In recent years, approximate policy iteration (API) has attracted increasing attention in reinforcement learning (RL), e.g., least-squares policy iteration (LSPI) and its kernelized version, the kernel-based LSPI algorithm. However, it remains difficult for API algorithms to obtain near-optimal policies for Markov decision processes (MDPs) with large or continuous state spaces. To address this problem, this paper presents a hierarchical API (HAPI) method with binary-tree state space decomposition for RL in a class of absorbing MDPs, which can be formulated as time-optimal learning control tasks. In the proposed method, after collecting samples adaptively in the state space of the original MDP, a learning-based decomposition strategy of sample sets was designed to implement the binary-tree state space decomposition process. Then, API algorithms were used on the sample subsets to approximate local optimal policies of sub-MDPs. The original MDP was decomposed into a binary-tree structure of absorbing sub-MDPs, constructed during the learning process, thus, local near-optimal policies were approximated by API algorithms with reduced complexity and higher precision. Furthermore, because of the improved quality of local policies, the combined global policy performed better than the near-optimal policy obtained by a single API algorithm in the original MDP. Three learning control problems, including path-tracking control of a real mobile robot, were studied to evaluate the performance of the HAPI method. With the same setting for basis function selection and sample collection, the proposed HAPI obtained better near-optimal policies than previous API methods such as LSPI and KLSPI.
Theory of linear operators in Hilbert space
Akhiezer, N I
1993-01-01
This classic textbook by two mathematicians from the USSR's prestigious Kharkov Mathematics Institute introduces linear operators in Hilbert space, and presents in detail the geometry of Hilbert space and the spectral theory of unitary and self-adjoint operators. It is directed to students at graduate and advanced undergraduate levels, but because of the exceptional clarity of its theoretical presentation and the inclusion of results obtained by Soviet mathematicians, it should prove invaluable for every mathematician and physicist. 1961, 1963 edition.
Differential operators on Hermite Sobolev spaces
Indian Academy of Sciences (India)
Suprio Bhar; B Rajeev
2015-02-01
In this paper, we compute the Hilbert space adjoint * of the derivative operator on the Hermite Sobolev spaces $\\mathcal{S}_{q}$. We use this calculation to give a different proof of the ‘monotonicity inequality’ for a class of differential operators (, ) for which the inequality was proved in Infin. Dimens. Anal. Quantum Probab. Relat. Top. 2(4) (2009) 515–591. We also prove the monotonicity inequality for (, ), when these correspond to the Ornstein–Uhlenbeck diffusion.
Preparation for the operation of ITER: EU study on the plasma control system
Energy Technology Data Exchange (ETDEWEB)
Cavinato, M., E-mail: mario.cavinato@f4e.europa.eu [Fusion for Energy, Barcelona (Spain); Ambrosino, G. [CREATE/ENEA/Euratom Association, Università di Napoli Federico II, Naples (Italy); Figini, L.; Granucci, G. [Associazione EURATOM-ENEA sulla Fusione, IFP-CNR, Via R. Cozzi 53, 20125 Milano (Italy); Gribov, Y. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Koechl, F. [Association EURATOM-ÖAW/ATI, Atominstitut, TU Wien, 1020 Vienna (Austria); Mattei, M. [CREATE/ENEA/Euratom Association, Seconda Università di Napoli, Naples (Italy); Parail, V. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Pironti, A. [CREATE/ENEA/Euratom Association, Università di Napoli Federico II, Naples (Italy); Ricci, D. [Associazione EURATOM-ENEA sulla Fusione, IFP-CNR, Via R. Cozzi 53, 20125 Milano (Italy); Saibene, G.; Sartori, R. [Fusion for Energy, Barcelona (Spain); Zabeo, L. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France)
2014-10-15
In view of the preparation for the operation of the ITER tokamak it is necessary to develop the plasma scenarios taking into account all engineering constraints coming from the plant and including a realistic control system. It is important to consider that, due to the high energy of ITER plasmas, much more stringent requirements are posed on the control of transients in order to avoid machine damage. Several activities are performed in the EU focusing on one side on the scenario optimization from a physics point of view and on the other side on the design and modeling of a realistic plasma control system driving the plasma configuration throughout the whole pulse and suitable for implementation on a real machine. The issues related to the computation of the control feed-forward component are addressed. In particular, the possibility to trigger a feed-forward component to solve controllability problems arising in the transitions from plasma L to H and H to L modes is studied in detail with the support of linear and non-linear simulations. A control strategy is designed and tested on non-linear simulations of the whole pulse, including linear and non-linear effects due to controller switching, plasma shape reconstruction and power supplies. The paper reports on the results of the studies performed and discuss the proposed design of the plasma control system.
Influence of the blanket shield modules geometry on the operation of the ITER ICRF antenna
Energy Technology Data Exchange (ETDEWEB)
Louche, F., E-mail: fabrice.louche@rma.ac.be [Laboratory for Plasma Physics, Royal Military Academy, 30, Avenue de la Renaissance, 1000 Brussels (Belgium); Dumortier, P.; Durodié, F.; Messiaen, A. [Laboratory for Plasma Physics, Royal Military Academy, 30, Avenue de la Renaissance, 1000 Brussels (Belgium)
2013-10-15
Highlights: ► The ITER ICRF antenna and its surrounding blanket shield modules have been modeled with the 3D electromagnetic software Microwave Studio. ► Unexpected resonances are detected in the ITER relevant range of frequencies. ► These resonances are caused by the geometry of the modules, and in particular by the cavity at the back, between the module rear face and the port plug outer face, present in the considered model. ► Simplified modeling and transmission line computations validate this interpretation. ► The resonance is strongly dependent on the detailed geometry of the modules, but large voids should be avoided. -- Abstract: Three-dimensional electromagnetic simulations of the ITER ICRF antenna have been recently performed with the commercial code CST Microwave Studio{sup ®} (MWS) [1]. A detailed model imported from the CATIA{sup ®} file has been considered: it includes the 24 straps array (CY3.1 geometry [2]) and the surrounding blanket shield modules. The transient solver in MWS has detected the presence of a very localized peak in the input impedance matrix at a frequency of approximately 51 MHz in vacuum conditions. The presence of such a resonance in the ITER operating range of frequency is of concern and should be understood as previous analysis reported in [3] concluded that TEM and non-TEM modes are not expected in this frequency band as long as the antenna is grounded to the port at 1 m back from the antenna front face. By using a simplified model of the geometry we demonstrate that the resonance is a consequence of the considered geometry of the blanket shield modules and in particular of the cavity at the back of the modules made of the module attachment and the port plug outer face. We show that the presence of such a cavity locally increases the coaxial line impedance and allows for a TEM mode in the band. This physical analysis is supported by a transmission line model where the system made of the antenna and its surrounding
Erosion corrosion of CuCrZr specimens exposed for simulated ITER operational conditions
Directory of Open Access Journals (Sweden)
C. Obitz
2016-12-01
The erosion corrosion and release rates of CuCrZr and CuCrZr/316L(N-IG joints were derived from weight change data and metallographic examinations of specimens after autoclave exposures at 110°C, 150°C and 250°C at reducing-, oxidizing- and cyclic redox water chemistry conditions. Reducing water chemistry represents periods considered as the nominal off-plasma operational conditions while the oxidizing environment simulates situations when the plasma is active. The cyclic redox conditions represent periods with shorter cycles simulating plasma activations with subsequent periodical variation of the water chemistry from reducing to oxidizing. The erosion corrosion rates for CuCrZr at active plasma conditions were 20 and 40µm/year at 110 and 150°C. At 250°C the corresponding rate was much higher. This result gives important information on what may happen if, for example, a First Wall panel is exposed to an unexpectedly high heat flux. Under reducing conditions the erosion corrosion rates were 3µm/year and 20µm/year at 110°C and 250°C respectively. The results at 250°C under off-plasma conditions reveal that the effect of erosion corrosion also has to be taken into account during baking. Cyclic conditions with respect to oxidant content turned out to be the most demanding environment (more demanding than pure oxidizing conditions for the CuCrZr-alloy. Erosion corrosion rates of 90µm/year and 370µm/year at 110 and 150°C were recorded respectively. The highest temperature 250°C was not tested. This raise the question whether measures should be introduced that renders the system either oxidizing or reducing. In summary, the erosion corrosion rates recorded for CuCrZr under simulated ITER coolant water conditions are high, especially during plasma operation. For comparison it can be mentioned that corrosion rates of structural materials in the primary loop of light water reactors generally are considerably lower than 1µm/year. The estimated rates for Cu
Weighted Composition Operators from Hardy Spaces into Logarithmic Bloch Spaces
Directory of Open Access Journals (Sweden)
Flavia Colonna
2012-01-01
Full Text Available The logarithmic Bloch space Blog is the Banach space of analytic functions on the open unit disk 𝔻 whose elements f satisfy the condition ∥f∥=supz∈𝔻(1-|z|2log (2/(1-|z|2|f'(z|<∞. In this work we characterize the bounded and the compact weighted composition operators from the Hardy space Hp (with 1≤p≤∞ into the logarithmic Bloch space. We also provide boundedness and compactness criteria for the weighted composition operator mapping Hp into the little logarithmic Bloch space defined as the subspace of Blog consisting of the functions f such that lim|z|→1(1-|z|2log (2/(1-|z|2|f'(z|=0.
TOEPLITZ OPERATORS AND ALGEBRAS ON DIRICHLET SPACES
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The automorphism group of the Toeplitz C*- algebra,J(C1),generated by Toeplitz operators with C1-symbols on Dirichlet space D is discussed; the K0,K1-groups and the first cohomology group of J(C1) are computed.In addition,the author proves that the spectra of Toeplitz operators with C1-symbols are always connected,and discusses the algebraic properties of Toeplitz operators.In particular,it is proved that there is no nontrivial selfadjoint Toeplitz operator on D and T* = T if and only if T is a scalar operator.
Multiplication operators on the Bergman space
Guo, Kunyu
2015-01-01
This book deals with various aspects of commutants and reducing subspaces of multiplication operators on the Bergman space, along with relevant von Neumann algebras generated by these operators, which have been the focus of considerable attention from the authors and other experts in recent years. The book reviews past developments and offers insights into cutting-edge developments in the study of multiplication operators. It also provides commentary and comparisons to stimulate research in this area.
Reliability issues for a bolometer detector for ITER at high operating temperatures.
Meister, H; Kannamüller, M; Koll, J; Pathak, A; Penzel, F; Trautmann, T; Detemple, P; Schmitt, S; Langer, H
2012-10-01
The first detector prototypes for the ITER bolometer diagnostic featuring a 12.5 μm thick Pt-absorber have been realized and characterized in laboratory tests. The results show linear dependencies of the calibration parameters and are in line with measurements of prototypes with thinner absorbers. However, thermal cycling tests up to 450 °C of the prototypes with thick absorbers demonstrated that their reliability at these elevated operating temperatures is not yet sufficient. Profilometer measurements showed a deflection of the membrane hinting to stresses due to the deposition processes of the absorber. Finite element analysis (FEA) managed to reproduce the deflection and identified the highest stresses in the membrane in the region around the corners of the absorber. FEA was further used to identify changes in the geometry of the absorber with a positive impact on the intrinsic stresses of the membrane. However, further improvements are still necessary.
Space toxicology: protecting human health during space operations.
Khan-Mayberry, Noreen; James, John T; Tyl, Rochelle; Lam, Chiu-wing
2011-02-01
Space toxicology is a unique and targeted discipline for spaceflight, space habitation, and occupation of celestial bodies including planets, moons, and asteroids. Astronaut explorers face distinctive health challenges and limited resources for rescue and medical care during space operation. A central goal of space toxicology is to protect the health of the astronaut by assessing potential chemical exposures during spaceflight and setting safe limits that will protect the astronaut against chemical exposures while in a physiologically altered state. In order to maintain sustained occupation in space on the International Space Station (ISS), toxicological risks must be assessed and managed within the context of isolation, continuous exposures, reuse of air and water, limited rescue options, and the need to use highly toxic compounds for propulsion and other purposes. As we begin to explore other celestial bodies, in situ toxicological risks, such as inhalation of reactive mineral dusts, must also be managed.
Operation and coupling of LH waves with the ITER-like wall at JET
Kirov, K K; Ekedahl, A; Petrzilka, V; Arnoux, G; Baranov, Yu; Brix, M; Goniche, M; Jachmich, S; Mayoral, M-L; Ongena, J; Rimini, F; Stamp, M; Contributors, JET EFDA
2013-01-01
In this paper important aspects of Lower Hybrid (LH) operation with the ITER Like Wall (ILW) [1] at JET are reported. Impurity release during LH operation was investigated and it was found that there is no significant Be increase with LH power. Concentration of W was analysed in more detail and it was concluded that LH contributes negligibly to its increase. No cases of W accumulation in LH-only heating experiments were observed so far. LH wave coupling was studied and optimised to achieve the level of system performance similar to before ILW installation. Measurements by Li-beam were used to study systematic dependencies of the SOL density on the gas injection rate from a dedicated gas introduction module and the LH power and launcher position. Experimental results are supported by SOL transport modelling. Observations of arcs in front of the LH launcher and hotspots on magnetically connected sections of the vessel are reported. Overall, a relatively troublefree operation of the LH system up to 2.5MW of coup...
Space manufacturing systems and the Space Operations Center
Louviere, A. J.
1982-01-01
For the planned Space Operations Center (SOC) and envisioned space manufacturing and processes systems, the concepts of phased programs, development and operations, station-keeping orbit envelopes, propulsive harbor tugs, and aspects of servicing are discussed. The SOC three-phased program concept includes the servicing of satellites in compatible orbits and in transition to higher energy orbits. Two concepts of a free-flyer satellite are assessed, including the fuel system, and the placement of such a satellite into orbit is discussed. Finally, some services that will be provided by SOC are mentioned.
The Triangle of the Space Launch System Operations
Fayolle, Eric
2010-09-01
Firemen know it as “fire triangle”, mathematicians know it as “golden triangle”, sailormen know it as “Bermuda triangle”, politicians know it as “Weimar triangle”… This article aims to present a new aspect of that shape geometry in the space launch system world: “the triangle of the space launch system operations”. This triangle is composed of these three following topics, which have to be taken into account for any space launch system operation processing: design, safety and operational use. Design performance is of course taking into account since the early preliminary phase of a system development. This design performance is matured all along the development phases, thanks to consecutives iterations in order to respect the financial and timing constraints imposed to the development of the system. This process leads to a detailed and precise design to assess the required performance. Then, the operational use phase brings its batch of constraints during the use of the system. This phase is conducted by specific procedures for each operation. Each procedure has sequences for each sub-system, which have to be conducted in a very precise chronological way. These procedures can be processed by automatic way or manual way, with the necessity or not of the implication of operators, and in a determined environment. Safeguard aims to verify the respect of the specific constraints imposed to guarantee the safety of persons and property, the protection of public health and the environment. Safeguard has to be taken into account above the operational constraints of any space operation, without forgetting the highest safety level for the operators of the space operation, and of course without damaging the facilities or without disturbing the external environment. All space operations are the result of a “win-win” compromise between these three topics. Contrary to the fire triangle where one of the topics has to be suppressed in order to avoid the
Renormalization of Wilson operators in Minkowski space
Andra, A
1996-01-01
We make some comments on the renormalization of Wilson operators (not just vacuum -expectation values of Wilson operators), and the features which arise in Minkowski space. If the Wilson loop contains a straight light-like segment, charge renormalization does not work in a simple graph-by-graph way; but does work when certain graphs are added together. We also verify that, in a simple example of a smooth loop in Minkowski space, the existence of pairs of points which are light-like separated does not cause any extra divergences.
76 FR 20717 - NASA Advisory Council; Space Operations Committee; Meeting.
2011-04-13
... SPACE ADMINISTRATION NASA Advisory Council; Space Operations Committee; Meeting. AGENCY: National Aeronautics and Space Administration. ACTION: Notice of meeting. SUMMARY: In accordance with the Federal... announces a meeting of the NASA Advisory Council (NAC) Space Operations Committee. DATES: Tuesday, May...
75 FR 39974 - NASA Advisory Council; Space Operations Committee; Meeting
2010-07-13
... SPACE ADMINISTRATION NASA Advisory Council; Space Operations Committee; Meeting AGENCY: National... announces a meeting of the Space Operations Committee of the NASA Advisory Council. DATES: Wednesday, July... Aeronautics and Space Administration Headquarters, Washington, DC 20546, 202/358-1507,...
Directory of Open Access Journals (Sweden)
Gurucharan Singh Saluja
2010-01-01
Full Text Available In this paper, we give some necessary and sufficient conditions for an implicit iteration process with errors for a finite family of asymptotically quasi-nonexpansive mappings converging to a common fixed of the mappings in convex metric spaces. Our results extend and improve some recent results of Sun, Wittmann, Xu and Ori, and Zhou and Chang.
Directory of Open Access Journals (Sweden)
Plubtieng Somyot
2009-01-01
Full Text Available Abstract We introduce an iterative scheme for finding a common element of the solution set of a maximal monotone operator and the solution set of the variational inequality problem for an inverse strongly-monotone operator in a uniformly smooth and uniformly convex Banach space, and then we prove weak and strong convergence theorems by using the notion of generalized projection. The result presented in this paper extend and improve the corresponding results of Kamimura et al. (2004, and Iiduka and Takahashi (2008. Finally, we apply our convergence theorem to the convex minimization problem, the problem of finding a zero point of a maximal monotone operator and the complementary problem.
Directory of Open Access Journals (Sweden)
Somyot Plubtieng
2009-01-01
Full Text Available We introduce an iterative scheme for finding a common element of the solution set of a maximal monotone operator and the solution set of the variational inequality problem for an inverse strongly-monotone operator in a uniformly smooth and uniformly convex Banach space, and then we prove weak and strong convergence theorems by using the notion of generalized projection. The result presented in this paper extend and improve the corresponding results of Kamimura et al. (2004, and Iiduka and Takahashi (2008. Finally, we apply our convergence theorem to the convex minimization problem, the problem of finding a zero point of a maximal monotone operator and the complementary problem.
Institute of Scientific and Technical Information of China (English)
田有先; 张石生
2002-01-01
Some convergence theorems of Ishikawa type iterative sequence with errors for nonlinear general quasi-contractive mapping in convex metric spaces are proved. The results not only extend and improve the corresponding results of L. B . Ciric , Q. H. Liu , H. E.Rhoades and H. K . Xu , et al., but also give an affirmative answer to the open question of Rhoades-Naimpally-Singh in convex metric spaces.
On chiral differential operators over homogeneous spaces
Directory of Open Access Journals (Sweden)
Vassily Gorbounov
2001-01-01
Full Text Available We give a classification and construction of chiral algebras of differential operators over semisimple algebraic groups G and over homogeneous spaces G/N and G/P where N is a nilpotent and P a parabolic subgroup.
Toeplitz operators on harmonic Bergman spaces
Choe, Boo Rim; Lee, Young Joo; Na, Kyunguk
2004-01-01
We study Toeplitz operators on the harmonic Bergman spaces on bounded smooth domains. Two classes of symbols are considered; one is the class of positive symbols and the other is the class of uniformly continuous symbols. For positive symbols, boundedness, compactness, and membership in the Schatten classes are characterized. For uniformly continuous symbols, the essential spectra are described.
Space Operations Center orbit altitude selection strategy
Indrikis, J.; Myers, H. L.
1982-01-01
The strategy for the operational altitude selection has to respond to the Space Operation Center's (SOC) maintenance requirements and the logistics demands of the missions to be supported by the SOC. Three orbit strategies are developed: two are constant altitude, and one variable altitude. In order to minimize the effect of atmospheric uncertainty the dynamic altitude method is recommended. In this approach the SOC will operate at the optimum altitude for the prevailing atmospheric conditions and logistics model, provided that mission safety constraints are not violated. Over a typical solar activity cycle this method produces significant savings in the overall logistics cost.
Jeng Hong, Eng; Saudi, Azali; Sulaiman, Jumat
2017-09-01
The demand for image editing in the field of image processing has been increased throughout the world. One of the most famous equations for solving image editing problem is Poisson equation. Due to the advantages of the Successive Over Relaxation (SOR) iterative method with one weighted parameter, this paper examined the efficiency of the Modified Successive Over Relaxation (MSOR) iterative method for solving Poisson image blending problem. As we know, this iterative method requires two weighted parameters by considering the Red-Black ordering strategy, thus comparison of Jacobi, Gauss-Seidel and MSOR iterative methods in solving Poisson image blending problem is carried out in this study. The performance of these iterative methods to solve the problem is examined through assessing the number of iterations and computational time taken. Based on the numerical assessment over several experiments, the findings had shown that MSOR iterative method is able to solve Poisson image blending problem effectively than the other two methods which it requires fewer number of iterations and lesser computational time.
The Structural Design and Analysis of Pallet in ITER Transfer Cask for Remote Handling Operations
Zhou, Zibo; Yao, Damao; Cao, Lei; Li, Ge
2009-06-01
Necessary adjustment ranges and accuracies of the pallet for ITER are presented. Detailed structural designs and structural finite element analyses for pallet components are made to determine whether the results satisfy the requirements of the pallet structure to be used in ITER.
The Structural Design and Analysis of Pallet in ITER Transfer Cask for Remote Handling Operations
Institute of Scientific and Technical Information of China (English)
ZHOU Zibo; YAO Damao; CAO Lei; LI Ge
2009-01-01
Necessary adjustment ranges and accuracies of the pallet for ITER are presented. Detailed structural designs and structural finite element analyses for pallet components are made to determine whether the results satisfy the requirements of the pallet structure to be used in ITER.
Experimental study of ELM-like heat loading on beryllium under ITER operational conditions
Spilker, B.; Linke, J.; Pintsuk, G.; Wirtz, M.
2016-02-01
The experimental fusion reactor ITER, currently under construction in Cadarache, France, is transferring the nuclear fusion research to the power plant scale. ITER’s first wall (FW), armoured by beryllium, is subjected to high steady state and transient power loads. Transient events like edge localized modes not only deposit power densities of up to 1.0 GW m-2 for 0.2-0.5 ms in the divertor of the machine, but also affect the FW to a considerable extent. Therefore, a detailed study was performed, in which transient power loads with absorbed power densities of up to 1.0 GW m-2 were applied by the electron beam facility JUDITH 1 on beryllium specimens at base temperatures of up to 300 °C. The induced damage was evaluated by means of scanning electron microscopy and laser profilometry. As a result, the observed damage was highly dependent on the base temperatures and absorbed power densities. In addition, five different classes of damage, ranging from ‘no damage’ to ‘crack network plus melting’, were defined and used to locate the damage, cracking, and melting thresholds within the tested parameter space.
Technical and operational assessment of molecular nanotechnology for space operations
McKendree, Thomas Lawrence
2001-07-01
This study assesses the performance of conventional technology and three levels of molecular nanotechnology (MNT) for space operations. The measures of effectiveness are technical performance parameters for five space transportation architectures, and the total logistics cost for an evaluation scenario with mining, market and factory locations on the Moon, Mars and asteroids. On these measures of effectiveness, improvements of 2--4 orders of magnitude are seen in chemical rockets, solar electric ion engines, solar sail accelerations (but not transit times), and in structural masses for planetary skyhooks and towers. Improvements in tether performance and logistics costs are nearer to 1 order of magnitude. Appendices suggest additional improvements may be possible in space mining, closed-environment life support, flexible operations, and with other space transportation architectures. In order to assess logistics cost, this research extends the facility location problem of location theory to orbital space. This extension supports optimal siting of a single facility serving circular, coplanar orbits, locations in elliptic planetary and moon orbits, and heuristic siting of multiple facilities. It focuses on conventional rocket transportation, and on high performance rockets supplying at least 1 m/s2 acceleration and 500,000 m/s exhaust velocity. Mathematica implementations are provided in appendices. Simple MNT allows diamond and buckytube construction. The main benefits are in chemical rocket performance, solar panel specific power, solar electric ion engine performance, and skyhook and tower structural masses. Complex MNT allows very small machinery, permitting large increases in solar panel specific power, which enables solar electric ion engines that are high performance rockets, and thus reduces total logistics costs an order of magnitude. Most Advance MNT allows molecular manufacturing, which enables self-repair, provides at least marginal improvements in nearly
Automation of Hubble Space Telescope Mission Operations
Burley, Richard; Goulet, Gregory; Slater, Mark; Huey, William; Bassford, Lynn; Dunham, Larry
2012-01-01
On June 13, 2011, after more than 21 years, 115 thousand orbits, and nearly 1 million exposures taken, the operation of the Hubble Space Telescope successfully transitioned from 24x7x365 staffing to 815 staffing. This required the automation of routine mission operations including telemetry and forward link acquisition, data dumping and solid-state recorder management, stored command loading, and health and safety monitoring of both the observatory and the HST Ground System. These changes were driven by budget reductions, and required ground system and onboard spacecraft enhancements across the entire operations spectrum, from planning and scheduling systems to payload flight software. Changes in personnel and staffing were required in order to adapt to the new roles and responsibilities required in the new automated operations era. This paper will provide a high level overview of the obstacles to automating nominal HST mission operations, both technical and cultural, and how those obstacles were overcome.
ICRF heating in JET during initial operations with the ITER-like wall
Energy Technology Data Exchange (ETDEWEB)
Jacquet, P.; Brix, M.; Graham, M.; Mayoral, M.-L.; Meigs, A.; Monakhov, I.; Sirinelli, A. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Bobkov, V.; Drewelow, P.; Pütterich, T. [Max-Planck-Institut für Plasmaphysik, EURATOM-Assoziation, Garching (Germany); Brezinsek, S. [IEK-4, Forschungszentrum Jülich, Association EURATOM-FZJ (Germany); Campergue, A-L. [Ecole Nationale des Ponts et Chaussées, F77455 Marne-la-Vallée (France); Colas, L. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Czarnecka, A. [Association Euratom-IPPLM, Hery 23, 01-497 Warsaw (Poland); Klepper, C. C. [Oak Ridge National Laboratory, Oak Ridge, TN 37831-6169 (United States); Lerche, E.; Van-Eester, D. [Association EURATOM-Belgian State, ERM-KMS, Brussels (Belgium); Milanesio, D. [Politecnico di Torino, Department of Electronics, Torino (Italy); Mlynar, J. [Association EURATOM-IPP.CR, Za Slovankou 3, 182 21 Praha 8 (Czech Republic); Collaboration: JET-EFDA Contributors
2014-02-12
In 2011/12, JET started operation with its new ITER-Like Wall (ILW) made of a tungsten (W) divertor and a beryllium (Be) main chamber wall. The impact of the new wall material on the JET Ion Cyclotron Resonance Frequency (ICRF) operation was assessed and also the properties of JET plasmas heated with ICRF were studied. No substantial change of the antenna coupling resistance was observed with the ILW as compared with the carbon wall. Heat-fluxes on the protecting limiters close the antennas quantified using Infra-Red (IR) thermography (maximum 4.5 MW/m{sup 2} in current drive phasing) are within the wall power load handling capabilities. A simple RF sheath rectification model using the antenna near-fields calculated with the TOPICA code can well reproduce the heat-flux pattern around the antennas. ICRF heating results in larger tungsten and nickel (Ni) contents in the plasma and in a larger core radiation when compared to Neutral Beam Injection (NBI) heating. Some experimental facts indicate that main-chamber W components could be an important impurity source: the divertor W influx deduced from spectroscopy is comparable when using RF or NBI at same power and comparable divertor conditions; the W content is also increased in ICRF-heated limiter plasmas; and Be evaporation in the main chamber results in a strong and long lasting reduction of the impurity level. The ICRF specific high-Z impurity content decreased when operating at higher plasma density and when increasing the hydrogen concentration from 5% to 20%. Despite the higher plasma bulk radiation, ICRF exhibited overall good plasma heating efficiency; The ICRF power can be deposited at plasma centre and the radiation is mainly from the outer part of the plasma. Application of ICRF heating in H-mode plasmas started, and the beneficial effect of ICRF central electron heating to prevent W accumulation in the plasma core could be observed.
Centaur operations at the space station
Porter, J.; Thompson, W.; Bennett, F.; Holdridge, J.
1987-01-01
A study was conducted on the feasibility of using a Centaur vehicle as a testbed to demonstrate critical OTV technologies at the Space Station. Two Technology Demonstration Missions (TDMs) were identified: (1) Accommodations, and (2) Operations. The Accommodations TDM contained: (1) berthing, (2) checkout, maintenance and safing, and (3) payload integration missions. The Operations TDM contained: (1) a cryogenic propellant resupply mission, and (2) Centaur deployment activities. A modified Space Station Co-Orbiting Platform (COP) was selected as the optimum refueling and launch node due to safety and operational considerations. After completion of the TDMs, the fueled Centaur would carry out a mission to actually test deployment and help offset TDM costs. From the Station, the Centaur could carry a single payload in excess of 20,000 pounds to geosynchronous orbit or multiple payloads.
WEAK AND STRONG CONVERGENCE OF AN ITERATIVE METHOD FOR NONEXPANSIVE MAPPINGS IN HILBERT SPACES
Directory of Open Access Journals (Sweden)
Yu Miao
2008-08-01
Full Text Available In a real {sc Hilbert} space $H$, starting from an arbitrary initialpoint $x_0in H$, an iterative process is defined as follows:$x_{n+1}=a_nx_n+(1-a_nT^{lambda_{n+1}}_fy_n$, $y_n= b_nx_n+(1-b_nT^{eta_{n}}_gx_n$, $nge 0$, where$T^{lambda_{n+1}}_f x= Tx-lambda_{n+1} mu_f f(Tx$,$T^{eta_{n}}_g x= Tx-eta_{n} mu_g g(Tx$, ($forall xinH$, $T: Ho H$ a nonexpansive mappingwith $F(T eemptyset$ and $f$ (resp. $g$ $: Ho H$ an$eta_f$ (resp. $eta_g$-strongly monotone and $k_f$ (resp. $k_g$-Lipschitzianmapping, ${a_n}subset(0,1$, ${b_n}subset(0,1$ and ${lambda_n}subset[0,1$,${eta_n}subset[0,1$. Under some suitable conditions, severalconvergence results of the sequence ${x_n}$ are shown.
Directory of Open Access Journals (Sweden)
Songnian He
2012-01-01
Full Text Available Let C be a nonempty closed convex subset of a real uniformly smooth Banach space X, {Tk}k=1∞:C→C an infinite family of nonexpansive mappings with the nonempty set of common fixed points ⋂k=1∞Fix(Tk, and f:C→C a contraction. We introduce an explicit iterative algorithm xn+1=αnf(xn+(1-αnLnxn, where Ln=∑k=1n(ωk/snTk,Sn=∑k=1nωk, and wk>0 with ∑k=1∞ωk=1. Under certain appropriate conditions on {αn}, we prove that {xn} converges strongly to a common fixed point x* of {Tk}k=1∞, which solves the following variational inequality: 〈x*-f(x*,J(x*-p〉≤0, p∈⋂k=1∞Fix(Tk, where J is the (normalized duality mapping of X. This algorithm is brief and needs less computational work, since it does not involve W-mapping.
Iterative Schemes for Generalized Equilibrium Problem and Two Maximal Monotone Operators
Directory of Open Access Journals (Sweden)
Yao JC
2009-01-01
Full Text Available The purpose of this paper is to introduce and study two new hybrid proximal-point algorithms for finding a common element of the set of solutions to a generalized equilibrium problem and the sets of zeros of two maximal monotone operators in a uniformly smooth and uniformly convex Banach space. We established strong and weak convergence theorems for these two modified hybrid proximal-point algorithms, respectively.
Operations Data Files, driving force behind International Space Station operations
Hoppenbrouwers, Tom; Ferra, Lionel; Markus, Michael; Wolff, Mikael
2017-09-01
Almost all tasks performed by the astronauts on-board the International Space Station (ISS) and by ground controllers in Mission Control Centre, from operation and maintenance of station systems to the execution of scientific experiments or high risk visiting vehicles docking manoeuvres, would not be possible without Operations Data Files (ODF). ODFs are the User Manuals of the Space Station and have multiple faces, going from traditional step-by-step procedures, scripts, cue cards, over displays, to software which guides the crew through the execution of certain tasks. Those key operational documents are standardized as they are used on-board the Space Station by an international crew constantly changing every 3 months. Furthermore this harmonization effort is paramount for consistency as the crew moves from one element to another in a matter of seconds, and from one activity to another. On ground, a significant large group of experts from all International Partners drafts, prepares reviews and approves on a daily basis all Operations Data Files, ensuring their timely availability on-board the ISS for all activities. Unavailability of these operational documents will halt the conduct of experiments or cancel milestone events. This paper will give an insight in the ground preparation work for the ODFs (with a focus on ESA ODF processes) and will present an overview on ODF formats and their usage within the ISS environment today and show how vital they are. Furthermore the focus will be on the recently implemented ODF features, which significantly ease the use of this documentation and improve the efficiency of the astronauts performing the tasks. Examples are short video demonstrations, interactive 3D animations, Execute Tailored Procedures (XTP-versions), tablet products, etc.
Rank theorems of operators between Banach spaces
Institute of Scientific and Technical Information of China (English)
2000-01-01
Let E and F be Banach spaces, and B( E, F) all of bounded linear operators on E into F. Let T0 ∈ B( E, F) with an outer inverse T0# ∈ B( F, E). Then a characteristic condition of S= (I + T0# ( T- T0))-1 T0# with T∈ B( E, F) and || T0# ( T- T0) || < 1, being a generalized inverse of T, is presented, and hence, a rank theorem of operators on E into F is established (which generalizes the rank theorem of matrices to Banach spaces). Consequently, an improved finite rank theorem and a new rank theorem are deduced. These results will be very useful to nonlinear functional analysis.
Rank theorems of operators between Banach spaces
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Let E and F be Banach spaces, and B(E,F) all of bounded linear operators on E into F. Let T0∈B(E,F) with an outer inverse T#0∈B(F,E). Then a characteristic condition of S=(I+T#0(T-T0))-1T#0 with T∈B(E,F) and ‖T#0(T-T0)‖<1, being a generalized inverse of T, is presented, and hence, a rank theorem of operators on E into F is established (which generalizes the rank theorem of matrices to Banach spaces). Consequently, an improved finite rank theorem and a new rank theorem are deduced. These results will be very useful to nonlinear functional analysis.
Quantum iterated function systems.
Łoziński, Artur; Zyczkowski, Karol; Słomczyński, Wojciech
2003-10-01
An iterated function system (IFS) is defined by specifying a set of functions in a classical phase space, which act randomly on an initial point. In an analogous way, we define a quantum IFS (QIFS), where functions act randomly with prescribed probabilities in the Hilbert space. In a more general setting, a QIFS consists of completely positive maps acting in the space of density operators. This formalism is designed to describe certain problems of nonunitary quantum dynamics. We present exemplary classical IFSs, the invariant measure of which exhibits fractal structure, and study properties of the corresponding QIFSs and their invariant states.
Orlicz-Hardy spaces associated with operators
Institute of Scientific and Technical Information of China (English)
JIANG RenJin; YANG DaChun; ZHOU Yuan
2009-01-01
Let L be a linear operator in L2(R2) and generate an analytic semigroup {e-tL}t≥0 with kernel satisfying an upper bound of Poisson type, whose decay is measured by θ(L) ∈ (0, ∞). Let ω on (0, ∞) be of upper type 1 and of critical lower type p0(ω) ∈ (n/(n + θ(L)), 1] and ρ(t) = t-1/ω-1(t-1) for t ∈ (0, ∞). We introduce the Orlicz-Hardy space Hω, L(Rn) and the BMO-type space BMOρ,L(Rn) and establish the John-Nirenberg inequality for BMOρ,L(Rn) functions and the duality relation between Hω,L(Rn) and BMOρ,L* (Rn), where L* denotes the adjoint operator of L in L2(Rn). Using this duality relation, we further obtain the ρ-Carleson measure characterization of BMOρ,L* (Rn) and the molecular characterization of Hω,L(Rn); the latter is used to establish the boundedness of the generalized fractional operator Lρ-γ from Hω,L(Rn) to HL1(Rn or Lq(Rn) with certain q > 1, whereHL1(Rn) is the Hardy space introduced by Auscher, Duong and McIntosh. These results generalize the existing results by taking ω(t) = tp for t ∈ (0, ∞) and p ∈ (n/(n + θ(L)),1].
Matthews, G. F.; Jet Efda Contributors; ASDEX-Upgrade Team
2013-07-01
Installation of the ITER-like Wall (ILW) in JET, has allowed a direct comparison of operation with all carbon plasma facing components (PFCs) to an all metal beryllium/tungsten first-wall under otherwise nearly identical conditions. The JET results are compared with experience from ASDEX-Upgrade where there was a gradual change to a full tungsten first-wall over an extended period. The scope of this review ranges from experience with machine conditioning, impurities and breakdown to material migration, fuel retention, disruptions, impact on operational space, energy confinement and compatibility with impurity seeding. Significant changes are reported, not only in the physics directly related to plasma-surface interactions but also to the main plasma which is strongly affected in unexpected ways, impacting many aspects of tokamak operation.
WEIGHTED COMPOSITION OPERATORS BETWEEN BERS-TYPE SPACES AND BERGMAN SPACES
Institute of Scientific and Technical Information of China (English)
Tang Xiaomin
2007-01-01
This paper characterizes the boundedness and compactness of weighted composition operators between Bers-type space (or little Bers-type space) and Bergman space. Some estimates for the norm of weighted composition operators between those spaces are obtained.
On the Monotone Iterative Method for Set Valued Equation
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This paper deals with the monotone iterative method for set- valued operator equation in ordered normed space. Some results for the case of single valued operator are generalized here, as an application, a discontinuous nonlinear differential equation problem is discussed.
Ion cyclotron resonance frequency heating in JET during initial operations with the ITER-like wall
Energy Technology Data Exchange (ETDEWEB)
Jacquet, P., E-mail: philippe.jacquet@ccfe.ac.uk; Monakhov, I.; Arnoux, G.; Brix, M.; Graham, M.; Meigs, A.; Sirinelli, A. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Bobkov, V.; Devaux, S.; Drewelow, P.; Pütterich, T. [Max-Planck-Institut für Plasmaphysik, EURATOM-Assoziation, Garching (Germany); Colas, L. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Czarnecka, A. [Association Euratom-IPPLM, Hery 23, 01-497 Warsaw (Poland); Lerche, E.; Van-Eester, D. [Association EURATOM-Belgian State, ERM-KMS, Brussels (Belgium); Mayoral, M.-L. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EFDA Close Support Unit, Garching (Germany); Brezinsek, S. [IEK-4, Forschungszentrum Jülich, Association EURATOM-FZJ, Jülich (Germany); Campergue, A.-L. [Ecole Nationale des Ponts et Chaussées, F77455 Marne-la-Vallée (France); Klepper, C. C. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169 (United States); Milanesio, D. [Politecnico di Torino, Department of Electronics, Torino (Italy); and others
2014-06-15
In 2011/12, JET started operation with its new ITER-Like Wall (ILW) made of a tungsten (W) divertor and a beryllium (Be) main chamber wall. The impact of the new wall materials on the JET Ion Cyclotron Resonance Frequency (ICRF) operation is assessed and some important properties of JET plasmas heated with ICRF are highlighted. A ∼ 20% reduction of the antenna coupling resistance is observed with the ILW as compared with the JET carbon (JET-C) wall. Heat-fluxes on the protecting limiters close the antennas, quantified using Infra-Red thermography (maximum 4.5 MW/m{sup 2} in current drive phasing), are within the wall power load handling capabilities. A simple RF sheath rectification model using the antenna near-fields calculated with the TOPICA code can reproduce the heat-flux pattern around the antennas. ICRF heating results in larger tungsten and nickel (Ni) contents in the plasma and in a larger core radiation when compared to Neutral Beam Injection (NBI) heating. The location of the tungsten ICRF specific source could not be identified but some experimental observations indicate that main-chamber W components could be an important impurity source: for example, the divertor W influx deduced from spectroscopy is comparable when using RF or NBI at same power and comparable divertor conditions, and Be evaporation in the main chamber results in a strong reduction of the impurity level. In L-mode plasmas, the ICRF specific high-Z impurity content decreased when operating at higher plasma density and when increasing the hydrogen concentration from 5% to 15%. Despite the higher plasma bulk radiation, ICRF exhibited overall good plasma heating performance; the power is typically deposited at the plasma centre while the radiation is mainly from the outer part of the plasma bulk. Application of ICRF heating in H-mode plasmas has started, and the beneficial effect of ICRF central electron heating to prevent W accumulation in the plasma core has been observed.
Security aspects of space operations data
Schmitz, Stefan
1993-01-01
This paper deals with data security. It identifies security threats to European Space Agency's (ESA) In Orbit Infrastructure Ground Segment (IOI GS) and proposes a method of dealing with its complex data structures from the security point of view. It is part of the 'Analysis of Failure Modes, Effects Hazards and Risks of the IOI GS for Operations, including Backup Facilities and Functions' carried out on behalf of the European Space Operations Center (ESOC). The security part of this analysis has been prepared with the following aspects in mind: ESA's large decentralized ground facilities for operations, the multiple organizations/users involved in the operations and the developments of ground data systems, and the large heterogeneous network structure enabling access to (sensitive) data which does involve crossing organizational boundaries. An IOI GS data objects classification is introduced to determine the extent of the necessary protection mechanisms. The proposal of security countermeasures is oriented towards the European 'Information Technology Security Evaluation Criteria (ITSEC)' whose hierarchically organized requirements can be directly mapped to the security sensitivity classification.
SPACE MEDICINE and Medical Operations Overview
Dervay, Joe
2009-01-01
This presentation is an overview of the function of the work of the Space Medicine & Health Care Systems Office. The objective of the medical operations is to ensure the health, safety and well being of the astronaut corps and ground support team during all phases of space flight. There are many issues that impact the health of the astronauts. Some of them are physiological, and others relate to behavior, psychological issues and issues of the environment of space itself. Reviews of the medical events that have affected both Russian, and Americans while in space are included. Some views of shuttle liftoff, and ascent, the medical training aboard NASA's KC-135 and training in weightlessness, the Shuttle Orbiter Medical system (SOMS), and some of the medical equipment are included. Also included are a graphs showing Fluid loading countermeasures, and vertical pursuit tracking with head and eye. The final views are representations of the future crew exploration vehicle (CEV) approaching the International Space Station, and the moon, and a series of perspective representations of the earth in comparison to the other planets and the Sun, the Sun in relation to other stars, and a view of where in the galaxy the Sun is.
Hilbert Space Operators in Quantum Physics
Blank, Jiří; Havlíček, Miloslav
2008-01-01
The second edition of this course-tested book provides a detailed and in-depth discussion of the foundations of quantum theory as well as its applications to various systems. The exposition is self-contained; in the first part the reader finds the mathematical background in chapters about functional analysis, operators on Hilbert spaces and their spectral theory, as well as operator sets and algebras. This material is used in the second part to a systematic explanation of the foundations, in particular, states and observables, properties of canonical variables, time evolution, symmetries and various axiomatic approaches. In the third part, specific physical systems and situations are discussed. Two chapters analyze Schrödinger operators and scattering, two others added in the second edition are devoted to new important topics, quantum waveguides and quantum graphs. Some praise for the previous edition: "I really enjoyed reading this work. It is very well written, by three real experts in the field. It stands...
Institute of Scientific and Technical Information of China (English)
Xie-ping DING; Zhong-bao WANG
2009-01-01
A new system of the set-valued mixed quasi-variational-like inclusions (SS-MQVLI) involving H-η-monotone operators is studied in general Banach spaces without uniform smoothness. By using the resolvent operator technique of H-η-monotone opera-tors, a new iterative algorithm for finding approximate solutions to SSMQVLI is proposed. It is shown that the iterative sequences generated by the algorithm converge strongly to the exact solution of SSMQVLI under appropriate assumptions. These obtained new re-sults have extended and improved previous results.
75 FR 51853 - NASA Advisory Council; Space Operations Committee; Meeting
2010-08-23
... No: 2010-20821] NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice (10-092)] NASA Advisory Council; Space Operations Committee; Meeting AGENCY: National Aeronautics and Space Administration. ACTION... amended, the National Aeronautics and Space Administration announces a meeting of the NASA...
NASA Space Launch System Operations Strategy
Singer, Joan A.; Cook, Jerry R.
2012-01-01
The National Aeronautics and Space Administration's (NASA) Space Launch System (SLS) Program, managed at the Marshall Space Flight Center, is charged with delivering a new capability for human and scientific exploration beyond Earth orbit. The SLS also will provide backup crew and cargo services to the International Space Station, where astronauts have been training for long-duration voyages to destinations such as asteroids and Mars. For context, the SLS will be larger than the Saturn V, providing 10 percent more thrust at liftoff in its initial 70 metric ton (t) configuration and 20 percent more in its evolved 130 t configuration. The SLS Program knows that affordability is the key to sustainability. This paper will provide an overview of its operations strategy, which includes initiatives to reduce both development and fixed costs by using existing hardware and infrastructure assets to meet a first launch by 2017 within the projected budget. It also has a long-range plan to keep the budget flat using competitively selected advanced technologies that offer appropriate return on investment. To arrive at the launch vehicle concept, the SLS Program conducted internal engineering and business studies that have been externally validated by industry and reviewed by independent assessment panels. A series of design reference missions has informed the SLS operations concept, including launching the Orion Multi-Purpose Crew Vehicle on an autonomous demonstration mission in a lunar flyby scenario in 2017, and the first flight of a crew on Orion for a lunar flyby in 2021. Additional concepts address the processing of very large payloads, using a series of modular fairings and adapters to flexibly configure the rocket for the mission. This paper will describe how the SLS, Orion, and 21st Century Ground Systems programs are working together to create streamlined, affordable operations for sustainable exploration.
MPL-A program for computations with iterated integrals on moduli spaces of curves of genus zero
Bogner, Christian
2016-06-01
We introduce the Maple program MPL for computations with multiple polylogarithms. The program is based on homotopy invariant iterated integrals on moduli spaces M0,n of curves of genus 0 with n ordered marked points. It includes the symbol map and procedures for the analytic computation of period integrals on M0,n. It supports the automated computation of a certain class of Feynman integrals.
Directory of Open Access Journals (Sweden)
Kaewkhao A
2010-01-01
Full Text Available Let be a nonempty compact convex subset of a uniformly convex Banach space , and let and be a single-valued nonexpansive mapping and a multivalued nonexpansive mapping, respectively. Assume in addition that and for all . We prove that the sequence of the modified Ishikawa iteration method generated from an arbitrary by , , where and , are sequences of positive numbers satisfying , , converges strongly to a common fixed point of and ; that is, there exists such that .
Space Flight Resource Management for ISS Operations
Schmidt, Lacey L.; Slack, Kelley; Holland, Albert; Huning, Therese; O'Keefe, William; Sipes, Walter E.
2010-01-01
Although the astronaut training flow for the International Space Station (ISS) spans 2 years, each astronaut or cosmonaut often spends most of their training alone. Rarely is it operationally feasible for all six ISS crewmembers to train together, even more unlikely that crewmembers can practice living together before launch. Likewise, ISS Flight Controller training spans 18 months of learning to manage incredibly complex systems remotely in plug-and-play ground teams that have little to no exposure to crewmembers before a mission. How then do all of these people quickly become a team - a team that must respond flexibly yet decisively to a variety of situations? The answer implemented at NASA is Space Flight Resource Management (SFRM), the so-called "soft skills" or team performance skills. Based on Crew Resource Management, SFRM was developed first for shuttle astronauts and focused on managing human errors during time-critical events (Rogers, et al. 2002). Given the nature of life on ISS, the scope of SFRM for ISS broadened to include teamwork during prolonged and routine operations (O'Keefe, 2008). The ISS SFRM model resembles a star with one competency for each point: Communication, Cross-Culture, Teamwork, Decision Making, Team Care, Leadership/Followership, Conflict Management, and Situation Awareness. These eight competencies were developed with international participation by the Human Behavior and Performance Training Working Group. Over the last two years, these competencies have been used to build a multi-modal SFRM training flow for astronaut candidates and flight controllers that integrates team performance skills into the practice of technical skills. Preliminary results show trainee skill increases as the flow progresses; and participants find the training invaluable to performing well and staying healthy during ISS operations. Future development of SFRM training will aim to help support indirect handovers as ISS operations evolve further with the
Space-based Science Operations Grid Prototype
Bradford, Robert N.; Welch, Clara L.; Redman, Sandra
2004-01-01
Grid technology is the up and coming technology that is enabling widely disparate services to be offered to users that is very economical, easy to use and not available on a wide basis. Under the Grid concept disparate organizations generally defined as "virtual organizations" can share services i.e. sharing discipline specific computer applications, required to accomplish the specific scientific and engineering organizational goals and objectives. Grids are emerging as the new technology of the future. Grid technology has been enabled by the evolution of increasingly high speed networking. Without the evolution of high speed networking Grid technology would not have emerged. NASA/Marshall Space Flight Center's (MSFC) Flight Projects Directorate, Ground Systems Department is developing a Space-based Science Operations Grid prototype to provide to scientists and engineers the tools necessary to operate space-based science payloads/experiments and for scientists to conduct public and educational outreach. In addition Grid technology can provide new services not currently available to users. These services include mission voice and video, application sharing, telemetry management and display, payload and experiment commanding, data mining, high order data processing, discipline specific application sharing and data storage, all from a single grid portal. The Prototype will provide most of these services in a first step demonstration of integrated Grid and space-based science operations technologies. It will initially be based on the International Space Station science operational services located at the Payload Operations Integration Center at MSFC, but can be applied to many NASA projects including free flying satellites and future projects. The Prototype will use the Internet2 Abilene Research and Education Network that is currently a 10 Gb backbone network to reach the University of Alabama at Huntsville and several other, as yet unidentified, Space Station based
ERGODIC THEOREM FOR INFINITE ITERATED FUNCTION SYSTEMS
Institute of Scientific and Technical Information of China (English)
O Hyong-chol; Ro Yong-hwa; Kil Won-gun
2005-01-01
A set of contraction maps of a metric space is called an iterated function systems.Iterated function systems with condensation can be considered infinite iterated function systems. Infinite iterated function systems on compact metric spaces were studied. Using the properties of Banach limit and uniform contractiveness, it was proved that the random iterating algorithms for infinite iterated function systems on compact metric spaces satisfy ergodicity. So the random iterating algorithms for iterated function systems with condensation satisfy ergodicity, too.
Energy Technology Data Exchange (ETDEWEB)
Savoldi, Laura; Bertani, Cristina [Dipartimento Energia, Politecnico di Torino (Italy); Cau, Francesca; Cismondi, Fabio [Fusion for Energy, Barcelona (Spain); Gantenbein, Gerd; Illy, Stefan [KIT, Karlsruhe (Germany); Monni, Grazia [Dipartimento Energia, Politecnico di Torino (Italy); Zanino, Roberto, E-mail: roberto.zanino@polito.it [Dipartimento Energia, Politecnico di Torino (Italy)
2015-11-15
The present gyrotron designs for EC plasma heating in nuclear fusion reactors require the safe exhaust of a power comparable to that injected into the plasma, in order to keep the maximum temperature below the acceptable value of 300 °C. In this paper, the commercial computational fluid dynamics (CFD) software STAR-CCM+{sup ®} is used to analyze the thermal performance of the annular copper collector of a 1 MW ITER gyrotron, equipped with a hypervapotron structure made of annular fins with rectangular cavities of aspect ratio (depth/width) = 3, cooled by highly subcooled (90–100 °C) pressurized water flowing at ∼4 m/s. It is assumed that the simple vertical sweeping strategy is used to reduce the very high peak heat flux on the collector (up to 30 MW/m{sup 2} transient, 5 MW/m{sup 2} time average), due to the spent electron beam. The 2D steady-state conjugate heat transfer problem is solved assuming azimuthal symmetry and accounting for 2-phase flow. The single-cavity flow and heat transfer problem is considered first, to optimize the mesh and the selection of the turbulence model. For the operating conditions considered in this paper, the full collector (100+ cavities) solution shows that boiling occurs only in a limited number of cavities close to the peaks of the heat flux, with the vapor remaining trapped in the bottom of the cavities, i.e. no full hypervapotron regime should be achieved in these operating conditions. The steady-state analysis allows the numerical evaluation of the heat transfer coefficients between Cu and water; these are then used as input for the simplified, purely thermal (solid only) analysis of the actual transient problem for the full collector. The results of the simplified model, which allows a huge reduction of the computational effort, are successfully benchmarked against those of a comprehensive thermal–hydraulic simulation. The computed peak Cu temperature is below the acceptable limit under the steady-state (time averaged
76 FR 3673 - NASA Advisory Council; Space Operations Committee; Meeting.
2011-01-20
... SPACE ADMINISTRATION NASA Advisory Council; Space Operations Committee; Meeting. AGENCY: National... announces a meeting of the NASA Advisory Council (NAC) Space Operations Committee. DATES: Tuesday, February... state that they are attending the NASA Advisory Council Space Operations Committee meeting in the...
75 FR 5630 - NASA Advisory Council; Space Operations Committee; Meeting
2010-02-03
... SPACE ADMINISTRATION NASA Advisory Council; Space Operations Committee; Meeting AGENCY: National... announces a meeting of the Space Operations Committee of the NASA Advisory Council. DATES: Wednesday... state that they are attending the NASA Advisory Council Space Operation Committee meeting in Room...
Nemytskii operator on generalized bounded variation space
Directory of Open Access Journals (Sweden)
René Erlín Castillo
2014-06-01
Full Text Available In this paper we show that if the Nemytskii operator maps the (φ, α-bounded variation space into itself and satisfies some Lipschitz condition, then there are two functions g and h belonging to the (φ, α-bounded variation space such that f(t, y = g(ty + h(t for all t ∈ [a, b], y ∈ R. Resumen. En este artículo demostramos que si el operador de Nemytskii lleva el espacio de variación (φ, α-acotada en sí mismo, y satisface cierta condición de Lipschitz, entonces existen dos funciones g y h perteneciendo al espacio de variación (φ, α-acotada tal que f(t, y = g(ty + h(t para todo t ∈ [a, b], y ∈ R.
Evolved Expendable Launch Vehicles (EELV) for Operationally Responsive Space
2009-02-12
35 Jeff Foust , “Operationally Responsive Space: A Solution Seeking a Problem”, The Space Review, 13 October 2003, 2. http...www.globalsecurity.org/org/news/2001/010127-space2.htm Foust , Jeff. “Operationally Responsive Space: A Solution Seeking a Problem”. The Space Review, 13
Progress in the Integrated Simulation of Thermal-Hydraulic Operation of the ITER Magnet System
Bagnasco, M; Bessette, D; Marinucci, C
2010-01-01
A new integrated computer code is being developed for the simulations of the overall behavior of the ITER magnet cryo-system. The existing THEA, FLOWER and POWER codes, assembled as modules of a computational environment (Super-Magnet) have been upgraded to perform global simulations of the cooling circuit for the ITER magnet system. The thermal coupling resulting from the generic geometric configurations has been implemented to realize quasi-three-dimensional simulations of the winding pack. In this paper we present details on the model.
Fernández-Guasti, M.
The quadratic iteration is mapped within a nondistributive imaginary scator algebra in 1 + 2 dimensions. The Mandelbrot set is identically reproduced at two perpendicular planes where only the scalar and one of the hypercomplex scator director components are present. However, the bound three-dimensional S set projections change dramatically even for very small departures from zero of the second hypercomplex plane. The S set exhibits a rich fractal-like boundary in three dimensions. Periodic points with period m, are shown to be necessarily surrounded by points that produce a divergent magnitude after m iterations. The scator set comprises square nilpotent elements that ineluctably belong to the bound set. Points that are square nilpotent on the mth iteration, have preperiod 1 and period m. Two-dimensional plots are presented to show some of the main features of the set. A three-dimensional rendering reveals the highly complex structure of its boundary.
International Space Station Water Balance Operations
Tobias, Barry; Garr, John D., II; Erne, Meghan
2011-01-01
In November 2008, the Water Regenerative System racks were launched aboard Space Shuttle flight, STS-126 (ULF2) and installed and activated on the International Space Station (ISS). These racks, consisting of the Water Processor Assembly (WPA) and Urine Processor Assembly (UPA), completed the installation of the Regenerative (Regen) Environmental Control and Life Support Systems (ECLSS), which includes the Oxygen Generation Assembly (OGA) that was launched 2 years prior. With the onset of active water management on the US segment of the ISS, a new operational concept was required, that of water balance . In November of 2010, the Sabatier system, which converts H2 and CO2 into water and methane, was brought on line. The Regen ECLSS systems accept condensation from the atmosphere, urine from crew, and processes that fluid via various means into potable water, which is used for crew drinking, building up skip-cycle water inventory, and water for electrolysis to produce oxygen. Specification (spec) rates of crew urine output, condensate output, O2 requirements, toilet flush water, and drinking needs are well documented and used as the best guess planning rates when Regen ECLSS came online. Spec rates are useful in long term planning, however, daily or weekly rates are dependent upon a number of variables. The constantly changing rates created a new challenge for the ECLSS flight controllers, who are responsible for operating the ECLSS systems onboard ISS from Mission Control in Houston. This paper reviews the various inputs to water planning, rate changes, and dynamic events, including but not limited to: crew personnel makeup, Regen ECLSS system operability, vehicle traffic, water storage availability, and Carbon Dioxide Removal Assembly (CDRA), Sabatier, and OGA capability. Along with the inputs that change the various rates, the paper will review the different systems, their constraints, and finally the operational challenges and means by which flight controllers
Convergence on Composite Iterative Schemes for Nonexpansive Mappings in Banach Spaces
Directory of Open Access Journals (Sweden)
Jong Soo Jung
2008-05-01
Full Text Available Let E be a reflexive Banach space with a uniformly GÃƒÂ¢teaux differentiable norm. Suppose that every weakly compact convex subset of E has the fixed point property for nonexpansive mappings. Let C be a nonempty closed convex subset of E, f:CÃ¢Â€Â‰Ã¢Â€Â‰Ã¢Â†Â’Ã¢Â€Â‰Ã¢Â€Â‰C a contractive mapping (or a weakly contractive mapping, and T:CÃ¢Â€Â‰Ã¢Â€Â‰Ã¢Â†Â’Ã¢Â€Â‰Ã¢Â€Â‰C nonexpansive mapping with the fixed point set F(TÃ¢Â€Â‰Ã¢Â€Â‰Ã¢Â‰Â Ã¢Â€Â‰Ã¢Â€Â‰Ã¢ÂˆÂ…. Let {xn} be generated by a new composite iterative scheme: yn=ÃŽÂ»nf(xn+(1Ã¢ÂˆÂ’ÃŽÂ»nTxn, xn+1=(1Ã¢ÂˆÂ’ÃŽÂ²nyn+ÃŽÂ²nTyn, (nÃ¢Â‰Â¥0. It is proved that {xn} converges strongly to a point in F(T, which is a solution of certain variational inequality provided that the sequence {ÃŽÂ»n}Ã¢ÂŠÂ‚(0,1 satisfies limnÃ¢Â†Â’Ã¢ÂˆÂžÃŽÂ»n=0 and Ã¢ÂˆÂ‘n=1Ã¢ÂˆÂžÃŽÂ»n=Ã¢ÂˆÂž, {ÃŽÂ²n}Ã¢ÂŠÂ‚[0,a for some 0
Design, manufacture and initial operation of the beryllium components of the JET ITER-like wall
Riccardo, V; Matthews, G F; Nunes, I; Thompson, V; Villedieu, E; Contributors, JET EFDA
2013-01-01
The aim of the JET ITER-like Wall Project was to provide JET with the plasma facing material combination now selected for the DT phase of ITER (bulk beryllium main chamber limiters and a full tungsten divertor) and, in conjunction with the upgraded neutral beam heating system, to achieve ITER relevant conditions. The design of the bulk Be plasma facing components had to be compatible with increased heating power and pulse length, as well as to reuse the existing tile supports originally designed to cope with disruption loads from carbon based tiles and be installed by remote handling. Risk reduction measures (prototypes, jigs, etc) were implemented to maximize efficiency during the shutdown. However, a large number of clashes with existing components not fully captured by the configuration model occurred. Restarting the plasma on the ITER-like Wall proved much easier than for the carbon wall and no deconditioning by disruptions was observed. Disruptions have been more threatening than expected due to the redu...
Solar thematic maps for space weather operations
Rigler, E. Joshua; Hill, Steven M.; Reinard, Alysha A.; Steenburgh, Robert A.
2012-01-01
Thematic maps are arrays of labels, or "themes", associated with discrete locations in space and time. Borrowing heavily from the terrestrial remote sensing discipline, a numerical technique based on Bayes' theorem captures operational expertise in the form of trained theme statistics, then uses this to automatically assign labels to solar image pixels. Ultimately, regular thematic maps of the solar corona will be generated from high-cadence, high-resolution SUVI images, the solar ultraviolet imager slated to fly on NOAA's next-generation GOES-R series of satellites starting ~2016. These thematic maps will not only provide quicker, more consistent synoptic views of the sun for space weather forecasters, but digital thematic pixel masks (e.g., coronal hole, active region, flare, etc.), necessary for a new generation of operational solar data products, will be generated. This paper presents the mathematical underpinnings of our thematic mapper, as well as some practical algorithmic considerations. Then, using images from the Solar Dynamics Observatory (SDO) Advanced Imaging Array (AIA) as test data, it presents results from validation experiments designed to ascertain the robustness of the technique with respect to differing expert opinions and changing solar conditions.
Advancing Autonomous Operations for Deep Space Vehicles
Haddock, Angie T.; Stetson, Howard K.
2014-01-01
Starting in Jan 2012, the Advanced Exploration Systems (AES) Autonomous Mission Operations (AMO) Project began to investigate the ability to create and execute "single button" crew initiated autonomous activities [1]. NASA Marshall Space Flight Center (MSFC) designed and built a fluid transfer hardware test-bed to use as a sub-system target for the investigations of intelligent procedures that would command and control a fluid transfer test-bed, would perform self-monitoring during fluid transfers, detect anomalies and faults, isolate the fault and recover the procedures function that was being executed, all without operator intervention. In addition to the development of intelligent procedures, the team is also exploring various methods for autonomous activity execution where a planned timeline of activities are executed autonomously and also the initial analysis of crew procedure development. This paper will detail the development of intelligent procedures for the NASA MSFC Autonomous Fluid Transfer System (AFTS) as well as the autonomous plan execution capabilities being investigated. Manned deep space missions, with extreme communication delays with Earth based assets, presents significant challenges for what the on-board procedure content will encompass as well as the planned execution of the procedures.
Bu, Hui-Jiao; Zhang, Jin; Luo, Ya-Zhong
2016-10-01
This article studies the optimization of space station short-term mission planning (STMP) problems. The domain knowledge including description and the concept definitions of the STMP problem are presented, an STMP constraint satisfaction model is developed, and then an iterative conflict-repair method with the resolving strategies is proposed to satisfy complicated constraints. A genetic algorithm (GA) is adopted to optimize the STMP problem. The proposed approach is evaluated using a test case with 15 missions, 13 devices and three astronauts. The results show that the established STMP constraint satisfaction model is effective, and the iterative conflict-repair method can make the plan satisfy all constraints considered and can effectively improve the optimization performance of the GA.
On velocity space interrogation regions of fast-ion collective Thomson scattering at ITER
DEFF Research Database (Denmark)
Salewski, Mirko; Nielsen, Stefan Kragh; Bindslev, Henrik;
2011-01-01
The collective Thomson scattering (CTS) diagnostic proposed for ITER is designed to measure projected 1D fast-ion velocity distribution functions at several spatial locations simultaneously. The frequency shift of scattered radiation and the scattering geometry place fast ions that caused the col...
Institute of Scientific and Technical Information of China (English)
WANG Yanfei; GU Xingfa; YU Tao; FAN Shufang
2005-01-01
The symmetric kernel-driven operator equations play an important role in mathematical physics, engineering, atmospheric image processing and remote sensing sciences. Such problems are usually ill-posed in the sense that even if a unique solution exists, the solution need not depend continuously on the input data. One common technique to overcome the difficulty is applying the Tikhonov regularization to the symmetric kernel operator equations, which is more generally called the Lavrentiev regularization.It has been shown that the iterative implementation of the Tikhonov regularization can improve the rate of convergence. Therefore in this paper, we study the iterative Lavrentiev regularization method in a similar way when applying it to symmetric kernel problems which appears frequently in applications, say digital image restoration problems. We first prove the convergence property, and then under the widely used Morozov discrepancy principle(MDP), we prove the regularity of the method. Numerical performance for digital image restoration is included to confirm the theory. It seems that the iterated Lavrentiev regularization with the MDP strategy is appropriate for solving symmetric kernel problems.
Triebel–Lizorkin Space Estimates for Multilinear Operators of Sublinear Operators
Indian Academy of Sciences (India)
Liu Lanzhe
2003-11-01
In this paper, we obtain the continuity for some multilinear operators related to certain non-convolution operators on the Triebel–Lizorkin space. The operators include Littlewood–Paley operator and Marcinkiewicz operator.
An Ordinal Index on the Space of Strictly Singular Operators
Beanland, Kevin
2009-01-01
Using the notion of $S_\\xi$-strictly singular operator introduced by Androulakis, Dodos, Sirotkin and Troitsky, we define an ordinal index on the subspace of strictly singular operators between two separable Banach spaces. In our main result, we provide a sufficient condition implying that this index is bounded by $\\omega_1$. In particular, we apply this result to study operators on totally incomparable spaces, hereditarily indecomposable spaces and spaces with few operators.
Operators of Approximations and Approximate Power Set Spaces
Institute of Scientific and Technical Information of China (English)
ZHANG Xian-yong; MO Zhi-wen; SHU Lan
2004-01-01
Boundary inner and outer operators are introduced; and union, intersection, complement operators of approximations are redefined. The approximation operators have a good property of maintaining union, intersection, complement operators, so the rough set theory has been enriched from the operator-oriented and set-oriented views. Approximate power set spaces are defined, and it is proved that the approximation operators are epimorphisms from power set space to approximate power set spaces. Some basic properties of approximate power set space are got by epimorphisms in contrast to power set space.
75 FR 16197 - NASA Advisory Council; Space Operations Committee; Meeting
2010-03-31
... SPACE ADMINISTRATION NASA Advisory Council; Space Operations Committee; Meeting AGENCY: National... announces a meeting of the NASA Advisory Council Space Operations Committee. DATES: Tuesday, April 13, 2010, 3-5 p.m. CDT. ADDRESSES: NASA Johnson Space Center's Gilruth Center, Lone Star ] Room, 18753...
Low-Complexity Iterative Receiver for Space-Time Coded Signals over Frequency Selective Channels
Directory of Open Access Journals (Sweden)
Mohamed Siala
2002-05-01
Full Text Available We propose a low-complexity turbo-detector scheme for frequency selective multiple-input multiple-output channels. The detection part of the receiver is based on a List-type MAP equalizer which is a state-reduction algorithm of the MAP algorithm using per-survivor technique. This alternative achieves a good tradeoff between performance and complexity provided a small amount of the channel is neglected. In order to induce the good performance of this equalizer, we propose to use a whitened matched filter (WMF which leads to a white-noise Ã¢Â€Âœminimum phaseÃ¢Â€Â channel model. Simulation results show that the use of the WMF yields significant improvement, particularly over severe channels. Thanks to the iterative turbo processing (detection and decoding are iterated several times, the performance loss due to the use of the suboptimum List-type equalizer is recovered.
JPL Space Telecommunications Radio System Operating Environment
Lux, James P.; Lang, Minh; Peters, Kenneth J.; Taylor, Gregory H.; Duncan, Courtney B.; Orozco, David S.; Stern, Ryan A.; Ahten, Earl R.; Girard, Mike
2013-01-01
A flight-qualified implementation of a Software Defined Radio (SDR) Operating Environment for the JPL-SDR built for the CoNNeCT Project has been developed. It is compliant with the NASA Space Telecommunications Radio System (STRS) Architecture Standard, and provides the software infrastructure for STRS compliant waveform applications. This software provides a standards-compliant abstracted view of the JPL-SDR hardware platform. It uses industry standard POSIX interfaces for most functions, as well as exposing the STRS API (Application Programming In terface) required by the standard. This software includes a standardized interface for IP components instantiated within a Xilinx FPGA (Field Programmable Gate Array). The software provides a standardized abstracted interface to platform resources such as data converters, file system, etc., which can be used by STRS standards conformant waveform applications. It provides a generic SDR operating environment with a much smaller resource footprint than similar products such as SCA (Software Communications Architecture) compliant implementations, or the DoD Joint Tactical Radio Systems (JTRS).
Directory of Open Access Journals (Sweden)
Narin Petrot
2009-01-01
Full Text Available We prove some strong convergence theorems for fixed points of modified Ishikawa and Halpern iterative processes for a countable family of hemi-relatively nonexpansive mappings in a uniformly convex and uniformly smooth Banach space by using the hybrid projection methods. Moreover, we also apply our results to a class of relatively nonexpansive mappings, and hence, we immediately obtain the results announced by Qin and Su's result (2007, Nilsrakoo and Saejung's result (2008, Su et al.'s result (2008, and some known corresponding results in the literatures.
Institute of Scientific and Technical Information of China (English)
魏利; 周海云
2009-01-01
In this paper,two iterative schemes for approximating common element of the set of zero points of maximal monotone operators and the set of fixed points of a kind of generalized nonexpansive mappings in a real uniformly smooth and uniformly convex Banach space are proposed.Two strong convergence theorems are obtained and their applications on finding the minimizer of a kind of convex functiohal are discussed,which extend some previous work.
Integral type operators from normal weighted Bloch spaces to QT,S spaces
Directory of Open Access Journals (Sweden)
Yongyi GU
2016-08-01
Full Text Available Operator theory is an important research content of the analytic function space theory. The discussion of simultaneous operator and function space is an effective way to study operator and function space. Assuming that is an analytic self map on the unit disk Δ, and the normal weighted bloch space μ-B is a Banach space on the unit disk Δ, defining a composition operator C∶C(f=f on μ-B for all f∈μ-B, integral type operator JhC and CJh are generalized by integral operator and composition operator. The boundeness and compactness of the integral type operator JhC acting from normal weighted Bloch spaces to QT,S spaces are discussed, as well as the boundeness of the integral type operators CJh acting from normal weighted Bloch spaces to QT,S spaces. The related sufficient and necessary conditions are given.
Energy Technology Data Exchange (ETDEWEB)
Di Maio, P.A. [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo Viale delle Scienze, 90128 Palermo (Italy); Dell’Orco, G.; Furmanek, A. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Garitta, S. [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo Viale delle Scienze, 90128 Palermo (Italy); Merola, M.; Mitteau, R.; Raffray, R. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France); Spagnuolo, G.A. [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo Viale delle Scienze, 90128 Palermo (Italy); Vallone, E., E-mail: eug.vallone@gmail.com [Dipartimento di Energia, Ingegneria dell’Informazione e Modelli Matematici, Università di Palermo Viale delle Scienze, 90128 Palermo (Italy)
2015-10-15
Highlights: • ITER blanket cooling system hydraulic behaviour is studied under draining transient. • A computational approach based on the finite volume method has been followed. • Draining efficiency has been assessed in term of transient duration and residual water. • Transient duration ranges from ∼40 to 50 s, under the reference draining scenario. • Residual water is predicted to range from few tens of gram up to few kilograms. - Abstract: Within the framework of the research and development activities supported by the ITER Organization on the blanket system issues, an intense analysis campaign has been performed at the University of Palermo with the aim to investigate the thermal-hydraulic behaviour of the cooling system of a standard 20° sector of ITER blanket during the draining transient operational procedure. The analysis has been carried out following a theoretical-computational approach based on the finite volume method and adopting the RELAP5 system code. In a first phase, attention has been focused on the development and validation of the finite volume models of the cooling circuits of the most demanding modules belonging to the standard blanket sector. In later phase, attention has been put to the numerical simulation of the thermal-hydraulic transient behaviour of each cooling circuit during the draining operational procedure. The draining procedure efficiency has been assessed in terms of both transient duration and residual amount of coolant inside the circuit, observing that the former ranges typically between 40 and 120 s and the latter reaches at most ∼8 kg, in the case of the cooling circuit of twinned modules #6–7. Potential variations to operational parameters and/or to circuit lay-out have been proposed and investigated to optimize the circuit draining performances. In this paper, the set-up of the finite volume models is briefly described and the key results are summarized and critically discussed.
Composition Operators Mapping into the E（p,q）Spaces
Institute of Scientific and Technical Information of China (English)
LIUYong-min
2003-01-01
Composition operators are used to study the E(p,q)spaces.The boundedness of these opera-tors is also considered.The criteria for these operators to be bounded are given in terms of the Carleson measure.
Product of Toeplitz Operators on the Harmonic Dirichlet Space
Institute of Scientific and Technical Information of China (English)
Lian Kuo ZHAO
2012-01-01
In this paper,we study Toeplitz operators with harmonic symbols on the harmonic Dirichlet space,and show that the product of two Toeplitz operators is another Toeplitz operator only if one factor is constant.
Effective representations of the space of linear bounded operators
Directory of Open Access Journals (Sweden)
Vasco Brattka
2003-04-01
Full Text Available Representations of topological spaces by infinite sequences of symbols are used in computable analysis to describe computations in topological spaces with the help of Turing machines. From the computer science point of view such representations can be considered as data structures of topological spaces. Formally, a representation of a topological space is a surjective mapping from Cantor space onto the corresponding space. Typically, one is interested in admissible, i.e. topologically well-behaved representations which are continuous and characterized by a certain maximality condition. We discuss a number of representations of the space of linear bounded operators on a Banach space. Since the operator norm topology of the operator space is nonseparable in typical cases, the operator space cannot be represented admissibly with respect to this topology. However, other topologies, like the compact open topology and the Fell topology (on the operator graph give rise to a number of promising representations of operator spaces which can partially replace the operator norm topology. These representations reflect the information which is included in certain data structures for operators, such as programs or enumerations of graphs. We investigate the sublattice of these representations with respect to continuous and computable reducibility. Certain additional conditions, such as finite dimensionality, let some classes of representations collapse, and thus, change the corresponding graph. Altogether, a precise picture of possible data structures for operator spaces and their mutual relation can be drawn.
Directory of Open Access Journals (Sweden)
Mohamad Arnaout
2016-01-01
Full Text Available This work aims to improve the PEA calibration technique through defining a well-conditioned transfer matrix. To this end, a numerical electroacoustic model that allows determining the output voltage of the piezoelectric sensor and the acoustic pressure is developed with the software COMSOL®. The proposed method recovers the charge distribution within the sample using an iterative deconvolution method that uses the transfer matrix obtained with the new calibration technique. The obtained results on theoretical and experimental signals show an improvement in the spatial resolution compared with the standard method usually used.
Directory of Open Access Journals (Sweden)
Yunrui Guo
2008-09-01
Full Text Available The purpose of this paper is to study the strong convergence of a modified iterative scheme to find a common element of the set of common fixed points of a finite family of nonexpansive mappings, the set of solutions of variational inequalities for a relaxed cocoercive mapping, as well as the set of solutions of a mixed-equilibrium problem. Our results extend recent results of Takahashi and Takahashi (2007, Marino and Xu (2006, Combettes and Hirstoaga (2005, Iiduka and Takahashi (2005, and many others.
Directory of Open Access Journals (Sweden)
Gao Xueliang
2008-01-01
Full Text Available Abstract The purpose of this paper is to study the strong convergence of a modified iterative scheme to find a common element of the set of common fixed points of a finite family of nonexpansive mappings, the set of solutions of variational inequalities for a relaxed cocoercive mapping, as well as the set of solutions of a mixed-equilibrium problem. Our results extend recent results of Takahashi and Takahashi (2007, Marino and Xu (2006, Combettes and Hirstoaga (2005, Iiduka and Takahashi (2005, and many others.
Fixed point theorems and stability of iterations in cone metric spaces
Directory of Open Access Journals (Sweden)
Yuan Qing
2012-04-01
Full Text Available In this paper, fixed point problems of weak contractions are investigated in cone metric spaces. Theorems of convergence and theorems of stability for fixed points of some weak contraction are established in cone metric spaces.
Tabarés, F. L.
2013-06-01
In spite of being highly suited for advanced plasma performance operation of tokamaks, as demonstrated over at least two decades of fusion plasma research, carbon is not currently considered as an integrating element of the plasma-facing components (PFCs) for the active phase of ITER. The main reason preventing its use under the very challenging scenarios foreseen in this phase, with edge-localized modes delivering several tens of MW m-2 to the divertor target every second or less, is the existing concern about reaching the tritium inventory value of 1000 g used in safety assessments in a time shorter than the projected lifetime of the divertor materials eroded by the plasma, set at 3000 shots. Although several mechanisms of tritium trapping in carbon components have been identified, co-deposition of the carbon radicals arising from chemically eroded chlorofluorocarbons in remote areas appears to play a dominant role. Several possible ways to keep control of the tritium build-up during the full operation of ITER have been put forward, mostly based on the periodic removal of the co-deposits by chemical (thermo-oxidation, plasma chemistry) or physical (laser, flash lamps) methods. In this work, we review the techniques for the inhibition and removal of tritium-rich co-deposits based on the strong chemical reactivity of some N-bearing molecules with carbon. The integration of these techniques into a possible scheme for tritium inventory control in the active phase of ITER under carbon-based PFCs with minimum down-time is discussed and the existing caveats are addressed.
Application of Gauss's law space-charge limited emission model in iterative particle tracking method
Energy Technology Data Exchange (ETDEWEB)
Altsybeyev, V.V., E-mail: v.altsybeev@spbu.ru; Ponomarev, V.A.
2016-11-01
The particle tracking method with a so-called gun iteration for modeling the space charge is discussed in the following paper. We suggest to apply the emission model based on the Gauss's law for the calculation of the space charge limited current density distribution using considered method. Based on the presented emission model we have developed a numerical algorithm for this calculations. This approach allows us to perform accurate and low time consumpting numerical simulations for different vacuum sources with the curved emitting surfaces and also in the presence of additional physical effects such as bipolar flows and backscattered electrons. The results of the simulations of the cylindrical diode and diode with elliptical emitter with the use of axysimmetric coordinates are presented. The high efficiency and accuracy of the suggested approach are confirmed by the obtained results and comparisons with the analytical solutions.
Space Weather Effects on Range Operations
2013-02-01
www.windows2universe.org/space_weather/space_weather.html What are scientists talking about when they say “space weather”? How is it like weather on...particle events observed by ground level, high latitude neutron monitors and the Concorde observations are summarised in Table 1 (Refs. 12 & 13), which
Hypercyclic Behavior of Translation Operators on Spaces of Analytic Functions on Hilbert Spaces
Directory of Open Access Journals (Sweden)
Zoryana Mozhyrovska
2015-01-01
Full Text Available We consider special Hilbert spaces of analytic functions of many infinite variables and examine composition operators on these spaces. In particular, we prove that under some conditions a translation operator is bounded and hypercyclic.
Gaussian kernel operators on white noise functional spaces
Institute of Scientific and Technical Information of China (English)
骆顺龙; 严加安
2000-01-01
The Gaussian kernel operators on white noise functional spaces, including second quantization, Fourier-Mehler transform, scaling, renormalization, etc. are studied by means of symbol calculus, and characterized by the intertwining relations with annihilation and creation operators. The infinitesimal generators of the Gaussian kernel operators are second order white noise operators of which the number operator and the Gross Laplacian are particular examples.
DEFF Research Database (Denmark)
Dieterle, Mischa; Horstmeyer, Thomas; Berthold, Jost;
2012-01-01
block inside a bigger structure. In this work, we present a general framework for skeleton iteration and discuss requirements and variations of iteration control and iteration body. Skeleton iteration is expressed by synchronising a parallel iteration body skeleton with a (likewise parallel) state...
Analytic Characterization for Hilbert-Schmidt Operators on Fock Space
Institute of Scientific and Technical Information of China (English)
Cai Shi WANG; Zhi Yuan HUANG; Xiang Jun WANG
2005-01-01
In this paper we first introduce and investigate some special classes of nonlinear maps and get several useful results. Then, by using these results, we obtain analytic criteria for checking whether or not an operator defined only on the exponential vectors of a symmetric Fock space becomes a Hilbert-Schmidt operator on the whole space. Additionally, as an application, we also get an analytic criterion for Hilbert-Schmidt operators on a Gaussian probability space through the Wiener-Ito-Segal isomorphism.
Self-Adjointness Criterion for Operators in Fock Spaces
Energy Technology Data Exchange (ETDEWEB)
Falconi, Marco, E-mail: marco.falconi@univ-rennes1.fr [Université de Rennes I, IRMAR and Centre Henri Lebesgue (France)
2015-12-15
In this paper we provide a criterion of essential self-adjointness for operators in the tensor product of a separable Hilbert space and a Fock space. The class of operators we consider may contain a self-adjoint part, a part that preserves the number of Fock space particles and a non-diagonal part that is at most quadratic with respect to the creation and annihilation operators. The hypotheses of the criterion are satisfied in several interesting applications.
AREA INTEGRAL FUNCTIONS FOR SECTORIAL OPERATORS ON Lp SPACES
Institute of Scientific and Technical Information of China (English)
陈泽亁; 孙牧
2014-01-01
Area integral functions are introduced for sectorial operators on Lp-spaces. We establish the equivalence between the square and area integral functions for sectorial operators on Lp spaces. This follows that the results of Cowling, Doust, McIntosh, Yagi, and Le Merdy on H∞ functional calculus of sectorial operators on Lp-spaces hold true when the square functions are replaced by the area integral functions.
Semigroups of Operators on Hardy Spaces and Cocycles of Flows
2008-07-01
SEMIGROUPS OF OPERATORS ON HARDY SPACES AND COCYCLES OF FLOWS By Farhad Jafari Zbigniew Slodkowski and Thomas Tonev IMA Preprint Series # 2220 ( July...SUBTITLE Semigroups of Operators on Hardy Spaces and Cocycles of Flows 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 SEMIGROUPS OF OPERATORS ON HARDY SPACES AND COCYCLES OF FLOWS FARHAD
BOUNDED COMPOSITION OPERATORS ON HARDY SPACES (II)
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
In this paper, the characterization of semi-Fredholm composition operators from H2(Bm) to H2(Bn) is given. As an application of the composition operators, the extension properties of analytic maps are discussed.
U.S. Army Space Operational Narrative
2012-03-20
project space and technically based outcomes, capabilities, and support in volatile, uncertain, complex and ambiguous ( VUCA ) environments...Missions and Growth Space has become more main stream in the last 10 years to the warfighter. USASMDC/ARSTRAT is responsible for providing world
Remark on Regularity of Continuous Operators on AL-Spaces
Institute of Scientific and Technical Information of China (English)
冯勋省; 陈滋利
2004-01-01
Let E and F be Banach lattices. It is known that if every continuous linear operator from E into F is regular, then, under some mild assumptions on E or F, either E is lattice isomorphic to an AL-space or F is lattice isomorphic to an AM-space. Here we present a characterization on an AL-space E such that every bounded linear operator from E into a Banach lattice is regular. A counterexample is also provided, which shows that the results are unexpected even if the domain is an AL-space or the range space is an AM-space.
Directory of Open Access Journals (Sweden)
Banan Maayah
2014-01-01
Full Text Available A new algorithm called multistep reproducing kernel Hilbert space method is represented to solve nonlinear oscillator’s models. The proposed scheme is a modification of the reproducing kernel Hilbert space method, which will increase the intervals of convergence for the series solution. The numerical results demonstrate the validity and the applicability of the new technique. A very good agreement was found between the results obtained using the presented algorithm and the Runge-Kutta method, which shows that the multistep reproducing kernel Hilbert space method is very efficient and convenient for solving nonlinear oscillator’s models.
Space Operations Learning Center Facebook Application
Lui, Ben; Milner, Barbara; Binebrink, Dan; Kuok, Heng
2012-01-01
The proposed Space Operations Learning Center (SOLC) Facebook module, initially code-named Spaceville, is intended to be an educational online game utilizing the latest social networking technology to reach a broad audience base and inspire young audiences to be interested in math, science, and engineering. Spaceville will be a Facebook application/ game with the goal of combining learning with a fun game and social environment. The mission of the game is to build a scientific outpost on the Moon or Mars and expand the colony. Game activities include collecting resources, trading resources, completing simple science experiments, and building architectures such as laboratories, habitats, greenhouses, machine shops, etc. The player is awarded with points and achievement levels. The player s ability increases as his/her points and levels increase. A player can interact with other players using multiplayer Facebook functionality. As a result, a player can discover unexpected treasures through scientific missions, engineering, and working with others. The player creates his/her own avatar with his/her selection of its unique appearance, and names the character. The player controls the avatar to perform activities such as collecting oxygen molecules or building a habitat. From observations of other successful social online games such as Farmville and Restaurant City, a common element of these games is having eye-catching and cartoonish characters, and interesting animations for all activities. This will create a fun, educational, and rewarding environment. The player needs to accumulate points in order to be awarded special items needed for advancing to higher levels. Trophies will be awarded to the player when certain goals are reached or tasks are completed. In order to acquire some special items needed for advancement in the game, the player will need to visit his/her neighboring towns to discover the items. This is the social aspect of the game that requires the
Integral operators in non-standard function spaces
Kokilashvili, Vakhtang; Rafeiro, Humberto; Samko, Stefan
2016-01-01
This book, the result of the authors’ long and fruitful collaboration, focuses on integral operators in new, non-standard function spaces and presents a systematic study of the boundedness and compactness properties of basic, harmonic analysis integral operators in the following function spaces, among others: variable exponent Lebesgue and amalgam spaces, variable Hölder spaces, variable exponent Campanato, Morrey and Herz spaces, Iwaniec-Sbordone (grand Lebesgue) spaces, grand variable exponent Lebesgue spaces unifying the two spaces mentioned above, grand Morrey spaces, generalized grand Morrey spaces, and weighted analogues of some of them. The results obtained are widely applied to non-linear PDEs, singular integrals and PDO theory. One of the book’s most distinctive features is that the majority of the statements proved here are in the form of criteria. The book is intended for a broad audience, ranging from researchers in the area to experts in applied mathematics and prospective students.
Directory of Open Access Journals (Sweden)
Vladimir V. Lyubimov
2007-01-01
Full Text Available The possibility of improving the spatial resolution of diffuse optical tomograms reconstructed by the photon average trajectories (PAT method is substantiated. The PAT method recently presented by us is based on a concept of an average statistical trajectory for transfer of light energy, the photon average trajectory (PAT. The inverse problem of diffuse optical tomography is reduced to a solution of an integral equation with integration along a conditional PAT. As a result, the conventional algorithms of projection computed tomography can be used for fast reconstruction of diffuse optical images. The shortcoming of the PAT method is that it reconstructs the images blurred due to averaging over spatial distributions of photons which form the signal measured by the receiver. To improve the resolution, we apply a spatially variant blur model based on an interpolation of the spatially invariant point spread functions simulated for the different small subregions of the image domain. Two iterative algorithms for solving a system of linear algebraic equations, the conjugate gradient algorithm for least squares problem and the modified residual norm steepest descent algorithm, are used for deblurring. It is shown that a 27% gain in spatial resolution can be obtained.
TWO PROBLEMS ABOUT COMPOSITION OPERATORS ON HARDY SPACE
Institute of Scientific and Technical Information of China (English)
Wu Shuhong; Wang Maofa; Liu Peide
2005-01-01
In this paper, two problems about composition operator on Hardy space are considered. Firstly, a new estimation of the norm of a class of composition operators is given. Secondly, the cyclic behavior of the adjoint operator of a composition operator is discussed.
Weighted BMO Estimates for Toeplitz Operators on Weighted Lebesgue Spaces
Directory of Open Access Journals (Sweden)
Yan Lin
2015-01-01
Full Text Available The authors establish the weighted BMO estimates for a class of Toeplitz operators related to strongly singular Calderón-Zygmund operators on weighted Lebesgue spaces. Moreover, the corresponding result for the Toeplitz operators related to classical Calderón-Zygmund operators can be deduced.
Tethered Satellites as an Enabling Platform for Operational Space Weather Monitoring Systems
Gilchrist, Brian E.; Krause, Linda Habash; Gallagher, Dennis Lee; Bilen, Sven Gunnar; Fuhrhop, Keith; Hoegy, Walt R.; Inderesan, Rohini; Johnson, Charles; Owens, Jerry Keith; Powers, Joseph; Voronka, Nestor; Williams, Scott
2013-01-01
Tethered satellites offer the potential to be an important enabling technology to support operational space weather monitoring systems. Space weather "nowcasting" and forecasting models rely on assimilation of near-real-time (NRT) space environment data to provide warnings for storm events and deleterious effects on the global societal infrastructure. Typically, these models are initialized by a climatological model to provide "most probable distributions" of environmental parameters as a function of time and space. The process of NRT data assimilation gently pulls the climate model closer toward the observed state (e.g., via Kalman smoothing) for nowcasting, and forecasting is achieved through a set of iterative semi-empirical physics-based forward-prediction calculations. Many challenges are associated with the development of an operational system, from the top-level architecture (e.g., the required space weather observatories to meet the spatial and temporal requirements of these models) down to the individual instruments capable of making the NRT measurements. This study focuses on the latter challenge: we present some examples of how tethered satellites (from 100s of m to 20 km) are uniquely suited to address certain shortfalls in our ability to measure critical environmental parameters necessary to drive these space weather models. Examples include long baseline electric field measurements, magnetized ionospheric conductivity measurements, and the ability to separate temporal from spatial irregularities in environmental parameters. Tethered satellite functional requirements are presented for two examples of space environment observables.
Unification and extension of monolithic state space and iterative cochlear models.
Rapson, Michael J; Tapson, Jonathan C; Karpul, David
2012-05-01
Time domain cochlear models have primarily followed a method introduced by Allen and Sondhi [J. Acoust. Soc. Am. 66, 123-132 (1979)]. Recently the "state space formalism" proposed by Elliott et al. [J. Acoust. Soc. Am. 122, 2759-2771 (2007)] has been used to simulate a wide range of nonlinear cochlear models. It used a one-dimensional approach that is extended to two dimensions in this paper, using the finite element method. The recently developed "state space formalism" in fact shares a close relationship to the earlier approach. Working from Diependaal et al. [J. Acoust. Soc. Am. 82, 1655-1666 (1987)] the two approaches are compared and the relationship formalized. Understanding this relationship allows models to be converted from one to the other in order to utilize each of their strengths. A second method to derive the state space matrices required for the "state space formalism" is also presented. This method offers improved numerical properties because it uses the information available about the model more effectively. Numerical results support the claims regarding fluid dimension and the underlying similarity of the two approaches. Finally, the recent advances in the state space formalism [Bertaccini and Sisto, J. Comp. Phys. 230, 2575-2587 (2011)] are discussed in terms of this relationship.
Space-filling curves of self-similar sets (I): iterated function systems with order structures
Rao, Hui; Zhang, Shu-Qin
2016-07-01
This paper is the first part of a series which provides a systematic treatment of the space-filling curves of self-similar sets. In the present paper, we introduce a notion of linear graph-directed IFS (linear GIFS in short). We show that to construct a space-filling curve of a self-similar set, it amounts to exploring its linear GIFS structures. Compared to the previous methods, such as the L-system or recurrent set method, the linear GIFS approach is simpler, more rigorous and leads to further studies on this topic. We also propose a new algorithm for the beautiful visualization of space-filling curves. In a series of papers Dai et al (2015 arXiv:1511.05411 [math.GN]), Rao and Zhang (2015) and Rao and Zhang (2015), we investigate for a given self-similar set how to get ‘substitution rules’ for constructing space-filling curves, which was obscure in the literature. We solve the problem for self-similar sets of finite type, which covers most of the known results on constructions of space-filling curves.
Energy Technology Data Exchange (ETDEWEB)
Ploeckl, B., E-mail: bernhard.ploeckl@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Day, Chr. [Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany); Lamalle, Ph. [ITER Organization, Route de Vinon sur Verdon, CS 90046, 13067 Saint-Paul-lez-Durance (France); Lang, P.T.; Rohde, V.; Viezzer, E. [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)
2015-10-15
The pellet centrifuge at ASDEX Upgrade has served for more than 20 years as a powerful tool for plasma control. Its recently enhanced control system provides more thorough control over parameters and a detailed view of all measured values. A study has recently been initiated on the conceptual design of an optimized DEMO core particle fuelling system. For this approach, first technical tests aimed on an optimized pellet transfer with respect to the preparation of the solid fuel and the transfer systems have been performed. An investigation of the temperature dependence of transfer efficiency (mass loss due to erosion and broken pellets) has revealed a weak dependence. For ITER, in which it is intended to operate a heating scheme with ICRF minority heating of He-3, test injections are performed using D{sub 2}-pellets as carriers for He-4. Admixing of N{sub 2} was investigated as well.
Multi-National Cooperation in Space Operations
2005-06-01
8 Figure 3 Sea Launch System (From: Energia ) .................................................................9 Figure 4 Primary...some lessons may still be drawn. Sea Launch is a joint effort between Boeing (U.S.), RSC Energia (Russia), SDO Yuzhnoye/PO Yuzhmash (Ukraine...operations, and home port management. RSC Energia provides the Block DM upper stage, launch vehicle integration, ground systems and launch operations. SDO
MacArt, Jonathan F.; Mueller, Michael E.
2016-12-01
Two formally second-order accurate, semi-implicit, iterative methods for the solution of scalar transport-reaction equations are developed for Direct Numerical Simulation (DNS) of low Mach number turbulent reacting flows. The first is a monolithic scheme based on a linearly implicit midpoint method utilizing an approximately factorized exact Jacobian of the transport and reaction operators. The second is an operator splitting scheme based on the Strang splitting approach. The accuracy properties of these schemes, as well as their stability, cost, and the effect of chemical mechanism size on relative performance, are assessed in two one-dimensional test configurations comprising an unsteady premixed flame and an unsteady nonpremixed ignition, which have substantially different Damköhler numbers and relative stiffness of transport to chemistry. All schemes demonstrate their formal order of accuracy in the fully-coupled convergence tests. Compared to a (non-)factorized scheme with a diagonal approximation to the chemical Jacobian, the monolithic, factorized scheme using the exact chemical Jacobian is shown to be both more stable and more economical. This is due to an improved convergence rate of the iterative procedure, and the difference between the two schemes in convergence rate grows as the time step increases. The stability properties of the Strang splitting scheme are demonstrated to outpace those of Lie splitting and monolithic schemes in simulations at high Damköhler number; however, in this regime, the monolithic scheme using the approximately factorized exact Jacobian is found to be the most economical at practical CFL numbers. The performance of the schemes is further evaluated in a simulation of a three-dimensional, spatially evolving, turbulent nonpremixed planar jet flame.
An Open Specification for Space Project Mission Operations Control Architectures
Hooke, A.; Heuser, W. R.
1995-01-01
An 'open specification' for Space Project Mission Operations Control Architectures is under development in the Spacecraft Control Working Group of the American Institute for Aeronautics and Astro- nautics. This architecture identifies 5 basic elements incorporated in the design of similar operations systems: Data, System Management, Control Interface, Decision Support Engine, & Space Messaging Service.
Boundedness for multilinear fractional integral operators on Herz type spaces
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
In this paper the boundedness for the multilinear fractional integral operator I(m)a on the product of Herz spaces and Herz-Morrey spaces are founded,which improves the Hardy-Littlewood-Sobolev inequality for classical fractional integral Ia.The method given in the note is useful for more general multilinear integral operators.
Singular integral operators on product Triebel-Lizorkin spaces
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper, we consider the rough singular integral operators on product Triebel-Lizorkin spaces and prove certain boundedness properties on the Triebel-Lizorkin spaces. We also use the same method to study the fractional integral operator and the Littlewood-Paley functions. The results extend some known results.
Computational examples of rational string operations on Gorenstein spaces
Naito, Takahito
2015-01-01
In this paper, we give computational examples of string operations over the rational numbers field on Gorenstein spaces introduced by Félix and Thomas. Especially, we determine the structure of rational string operations on the classifying space of a compact connected Lie group and the Borel construction associated to an action of $S^{1}$ to $S^{2}$.
Space Station - An integrated approach to operational logistics support
Hosmer, G. J.
1986-01-01
Development of an efficient and cost effective operational logistics system for the Space Station will require logistics planning early in the program's design and development phase. This paper will focus on Integrated Logistics Support (ILS) Program techniques and their application to the Space Station program design, production and deployment phases to assure the development of an effective and cost efficient operational logistics system. The paper will provide the methodology and time-phased programmatic steps required to establish a Space Station ILS Program that will provide an operational logistics system based on planned Space Station program logistics support.
Biérent, Rudolph; Velluet, Marie-Thérèse; Védrenne, Nicolas; Michau, Vincent
2013-07-01
Long-range free space optical communications suffer from atmospheric turbulence effects. To mitigate them, a bidirectional full-wave compensation technique seems promising. We present an experimental implementation and characterization of this concept on a laboratory breadboard. Experimental results confirm former numerical results for similar propagation conditions. The effects of measurement and control errors are analyzed by numerical modeling.
OPERATOR-VALUED FOURIER MULTIPLIER THEOREMS ON TRIEBEL SPACES
Institute of Scientific and Technical Information of China (English)
Bu Shangquan; Kim Jin-Myong
2005-01-01
The authors establish operator-valued Fourier multiplier theorems on Triebel spaces on RN, where the required smoothness of the multiplier functions depends on the dimension N and the indices of the Triebel spaces. This is used to give a sufficient condition of the maximal regularity in the sense of Triebel spaces for vector-valued Cauchy problems with Dirichlet boundary conditions.
Operator-valued Fourier Multipliers on Periodic Triebel Spaces
Institute of Scientific and Technical Information of China (English)
Shang Quan BU; Jin Myong KIM
2005-01-01
We establish operator-valued Fourier multiplier theorems on periodic Triebel spaces, where the required smoothness of the multipliers depends on the indices of the Triebel spaces. This is used to give a characterization of the maximal regularity in the sense of Triebel spaces for Cauchy problems with periodic boundary conditions.
Sobolev type spaces associated with the q-Rubin's operator
Directory of Open Access Journals (Sweden)
Neji Bettaibi
2014-05-01
Full Text Available In this paper we introduce and study some $q$-Sobolev type spaces by using the harmonic analysis associated with the q-Rubin operator. In particular, embedding theorems for these spaces are established. Next, we introduce the q-Rubin potential spaces and study some of its properties.
Invitation to linear operators from matrices to bounded linear operators on a Hilbert space
Furuta, Takayuki
2014-01-01
Most books on linear operators are not easy to follow for students and researchers without an extensive background in mathematics. Self-contained and using only matrix theory, Invitation to Linear Operators: From Matricies to Bounded Linear Operators on a Hilbert Space explains in easy-to-follow steps a variety of interesting recent results on linear operators on a Hilbert space. The author first states the important properties of a Hilbert space, then sets out the fundamental properties of bounded linear operators on a Hilbert space. The final section presents some of the more recent developm
Convergence of Composition Operators on Hardy-Smirnov Space
Institute of Scientific and Technical Information of China (English)
Xiang Dong YANG
2011-01-01
We consider the convergence of composition operators on Hardy-Smirnov space over a simply connected domain properly contained in the complex plane.The convergence of the power of a composition operator is also considered.Our approach is a method from Joel H.Shapiro and Wayne Smith's celebrated work (Journal of Functional Analysis 205 (2003) 62-89).The resulting space is usually not the one obtained from the classical Hardy space of the unit disc by conformal mapping.
SINGULAR INTEGRAL OPERATORS IN L2 SPACE WITH CHEBYSHEV WEIGHTS
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This paper defines a class of singular integral operators Iwj on L2wj space,where wights wj(j=1-4) are four kinds of Chebyshev weights.The authors prove that Iwj is an unique linear extension of classic singular integral operator Iwj on Holder space,some important properties of Iwj and some results of singular integral equation in L2wj space.
1980-07-01
4 5 ,/, . LEG - - .... .... . ...................... . "S ’= .. 0 fUNCION EVALUAIONS A 52 i TILITY 50 go BLEST UTILITY TO DATE 73.73 The operator...NS S.. 250 - " \\ M..= . BES UTIIT TO U = 37 -122- l .- - ’. ’-,-,,--/-- ’ I / I5 -- S. *1 3 4 FUNCION (3) BES ’ ) I -.B= .0ś FUCINEV/ALL T IONS 1
Iterative Algorithms for Nonexpansive Mappings
Directory of Open Access Journals (Sweden)
Yao Yonghong
2008-01-01
Full Text Available Abstract We suggest and analyze two new iterative algorithms for a nonexpansive mapping in Banach spaces. We prove that the proposed iterative algorithms converge strongly to some fixed point of .
Revitalizing Space Operations through Total Quality Management
Baylis, William T.
1995-01-01
The purpose of this paper is to show the reader what total quality management (TQM) is and how to apply TQM in the space systems and management arena. TQM is easily understood, can be implemented in any type of business organization, and works.
SOME ROUGH OPERATORS ON PRODUCT SPACES
Institute of Scientific and Technical Information of China (English)
Chen Jiecheng; Wang Silei
2001-01-01
In this survery report, we shall mainly summarize some recent progress, interesting problems and typi cal methods used in the theory related to rough Marcinkiewicz integrals and rough singular integrals on product spaces. In addition, we give new proofs for some known results.
Operational Space Weather Needs - Perspectives from SEASONS 2014
Comberiate, J.; Kelly, M. A.; Paxton, L. J.; Schaefer, R. K.; Bust, G. S.; Sotirelis, T.; Fox, N. J.
2014-12-01
A key challenge for the operational space weather community is the gap between the latest scientific data, models, methods, and indices and those that are currently used in operational systems. The November 2014 SEASONS (Space Environment Applications, Systems, and Operations for National Security) Workshop at JHU/APL in Laurel, Maryland, brings together representatives from the operational and scientific communities. The theme of SEASONS 2014 is "Beyond Climatology," with a focus on how space weather events threaten operational assets and disrupt missions. Here we present perspectives from SEASONS 2014 on new observations, models in development, and forecasting methods that are of interest to the operational space weather community. Highlighted topics include ionospheric data assimilation and forecasting models, HF propagation models, radiation belt observations, and energetic particle modeling. The SEASONS 2014 web site can be found at https://secwww.jhuapl.edu/SEASONS/
Strongly Singular Integral Operators on Weighted Hardy Space
Institute of Scientific and Technical Information of China (English)
Jun Feng LI; Shan Zhen LU
2006-01-01
In this paper, we obtain that a strongly singular integral operator is bounded on Lpw space for 1＜p＜∞.We also obtain that a strongly singular integral operator is a bounded operator from Hpw to Lpw for some weight w and 0＜p≤1. And by an atomic decomposition, we obtain that a strongly singular integral operator is a bounded operator on Hpw, for some w and 0＜p＜1.
Space station operations task force. Panel 4 report: Management integration
1987-01-01
The Management Integration Panel of the Space Station Operations Task Force was chartered to provide a structure and ground rules for integrating the efforts of the other three panels and to address a number of cross cutting issues that affect all areas of space station operations. Issues addressed include operations concept implementation, alternatives development and integration process, strategic policy issues and options, and program management emphasis areas.
Bilinear Pseudo-differential Operators on Local Hardy Spaces
Institute of Scientific and Technical Information of China (English)
Jiang Wei XIAO; Yin Sheng JIANG; Wen Hua GAO
2012-01-01
In this paper,the authors consider a class of bilinear pseudo-differential operators with symbols of order 0 and type (1,0) in the sense of H(o)rmander and use the atomic decompositions of local Hardy spaces to establish the boundedness of the bilinear pseudo-differential operators and the bilinear singular integral operators on the product of local Hardy spaces.
On an Iterative Method for Finding a Zero to the Sum of Two Maximal Monotone Operators
Directory of Open Access Journals (Sweden)
Hongwei Jiao
2014-01-01
Full Text Available In this paper we consider a problem that consists of finding a zero to the sum of two monotone operators. One method for solving such a problem is the forward-backward splitting method. We present some new conditions that guarantee the weak convergence of the forward-backward method. Applications of these results, including variational inequalities and gradient projection algorithms, are also considered.
Directory of Open Access Journals (Sweden)
Ashok Sahai
2010-06-01
Full Text Available This paper aims at constructing a two-phase iterative computerizable numerical algorithm for an improved approximation by ‘Modified Lupas’operator. The algorithm uses the ‘statistical perspectives’ for exploiting the information about the unknown function ‘f’ available in terms of its known values at the ‘equidistant-knots’ in C[0,1] more fully. The improvement, achieved by an aposteriori use of this information, happens iteratively. Any typical iteration uses the concepts of ‘Mean Square Error (MSE’ and ‘Bias’ ; the application of the former being preceded by that of the latter in the algorithm.At any iteration, the statistical concept of ‘MSE’ is used in “Phase II”, after that of the ‘Bias’ in “Phase I”. Like a ‘Sandwich’, the top and bottom-breads are the operations of ‘Bias-Reduction’ per the “Phase I” of our algorithm, and the operation of ‘MSEReduction’per the “Phase II” is the stuffing in the sandwich. The algorithm is an iterative one amounting to a desired-height ‘Docked-Pile’ ofsandwiches with the bottom–bread of the first iteration serving as the top-bread for the seconditeration sandwich, and so-on-and-so forth. The potential of the achievable improvements through the proposed ‘computerizable numerical iterative algorithm’ is illustrated per an ‘empirical study’ for which the function ‘f’ is assumed to be known in the sense of simulation. The illustration has been confined to “Three Iterations” only, for the sake of simplicity of the illustration.
A common fixed point for operators in probabilistic normed spaces
Energy Technology Data Exchange (ETDEWEB)
Ghaemi, M.B. [Faculty of Mathematics, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)], E-mail: mghaemi@iust.ac.ir; Lafuerza-Guillen, Bernardo [Department of Applied Mathematics, University of Almeria, Almeria (Spain)], E-mail: blafuerz@ual.es; Razani, A. [Department of Mathematics, Faculty of Science, I. Kh. International University, P.O. Box 34194-288, Qazvin (Iran, Islamic Republic of)], E-mail: razani@ikiu.ac.ir
2009-05-15
Probabilistic Metric spaces was introduced by Karl Menger. Alsina, Schweizer and Sklar gave a general definition of probabilistic normed space based on the definition of Menger [Alsina C, Schweizer B, Sklar A. On the definition of a probabilistic normed spaces. Aequationes Math 1993;46:91-8]. Here, we consider the equicontinuity of a class of linear operators in probabilistic normed spaces and finally, a common fixed point theorem is proved. Application to quantum Mechanic is considered.0.
Logistics: An integral part of cost efficient space operations
Montgomery, Ann D.
1996-01-01
The logistics of space programs and its history within NASA are discussed, with emphasis on manned space flight and the Space Shuttle program. The lessons learned and the experience gained during these programs are reported on. Key elements of logistics are highlighted, and the problems and issues that can be expected to arise in relation to the support of long-term space operations and future space programs, are discussed. Such missions include the International Space Station program and the reusable launch vehicle. Possible solutions to the problems identified are outlined.
Operations space diagram for ECRH and ECCD
DEFF Research Database (Denmark)
Bindslev, H.
2004-01-01
A Clemmov-Mullaly-Allis (CMA) type diagram, the ECW-CMA diagram, for representing the operational possibilities of electron cyclotron heating and current drive (ECRH/ECCD) systems for fusion plasmas is presented. In this diagram, with normalized density and normalized magnetic field coordinates...
Ground operation of robotics on Space Station Freedom
Wojcik, Z. Alex; Hunter, David G.; Cantin, Marc R.
1993-01-01
This paper reflects work carried out on Ground Operated Telerobotics (GOT) in 1992 to refine further the ideas, procedures, and technologies needed to test the procedures in a high latency environment, and to integrate GOT into Space Station Freedom operations. Space Station Freedom (SSF) will be in operation for 30 years, and will depend on robots to carry out a significant part of the assembly, maintenance, and utilization workload. Current plans call for on-orbit robotics to be operated by on-board crew members. This approach implies that on-orbit robotics operations use up considerable crew time, and that these operations cannot be carried out when SSF is unmanned. GOT will allow robotic operations to be operated from the ground, with on-orbit crew interventions only when absolutely required. The paper reviews how GOT would be implemented, how GOT operations would be planned and supported, and reviews GOT issues, critical success factors, and benefits.
Commuting Toeplitz and Hankel Operators on Harmonic Dirichlet Spaces
Directory of Open Access Journals (Sweden)
Qian Ding
2017-01-01
Full Text Available On the harmonic Dirichlet space of the unit disk, the commutativity of Toeplitz and Hankel operators is studied. We obtain characterizations of commuting Toeplitz and Hankel operators and essentially commuting (semicommuting Toeplitz and Hankel operators with general symbols.
TAMU: A New Space Mission Operations Paradigm
Meshkat, Leila; Ruszkowski, James; Haensly, Jean; Pennington, Granvil A.; Hogle, Charles
2011-01-01
The Transferable, Adaptable, Modular and Upgradeable (TAMU) Flight Production Process (FPP) is a model-centric System of System (SoS) framework which cuts across multiple organizations and their associated facilities, that are, in the most general case, in geographically diverse locations, to develop the architecture and associated workflow processes for a broad range of mission operations. Further, TAMU FPP envisions the simulation, automatic execution and re-planning of orchestrated workflow processes as they become operational. This paper provides the vision for the TAMU FPP paradigm. This includes a complete, coherent technique, process and tool set that result in an infrastructure that can be used for full lifecycle design and decision making during any flight production process. A flight production process is the process of developing all products that are necessary for flight.
Towards a Decision Support System for Space Flight Operations
Meshkat, Leila; Hogle, Charles; Ruszkowski, James
2013-01-01
The Mission Operations Directorate (MOD) at the Johnson Space Center (JSC) has put in place a Model Based Systems Engineering (MBSE) technological framework for the development and execution of the Flight Production Process (FPP). This framework has provided much added value and return on investment to date. This paper describes a vision for a model based Decision Support System (DSS) for the development and execution of the FPP and its design and development process. The envisioned system extends the existing MBSE methodology and technological framework which is currently in use. The MBSE technological framework currently in place enables the systematic collection and integration of data required for building an FPP model for a diverse set of missions. This framework includes the technology, people and processes required for rapid development of architectural artifacts. It is used to build a feasible FPP model for the first flight of spacecraft and for recurrent flights throughout the life of the program. This model greatly enhances our ability to effectively engage with a new customer. It provides a preliminary work breakdown structure, data flow information and a master schedule based on its existing knowledge base. These artifacts are then refined and iterated upon with the customer for the development of a robust end-to-end, high-level integrated master schedule and its associated dependencies. The vision is to enhance this framework to enable its application for uncertainty management, decision support and optimization of the design and execution of the FPP by the program. Furthermore, this enhanced framework will enable the agile response and redesign of the FPP based on observed system behavior. The discrepancy of the anticipated system behavior and the observed behavior may be due to the processing of tasks internally, or due to external factors such as changes in program requirements or conditions associated with other organizations that are outside of
Approximate Modified Policy Iteration
Scherrer, Bruno; Ghavamzadeh, Mohammad; Geist, Matthieu
2012-01-01
Modified policy iteration (MPI) is a dynamic programming (DP) algorithm that contains the two celebrated policy and value iteration methods. Despite its generality, MPI has not been thoroughly studied, especially its approximation form which is used when the state and/or action spaces are large or infinite. In this paper, we propose three approximate MPI (AMPI) algorithms that are extensions of the well-known approximate DP algorithms: fitted-value iteration, fitted-Q iteration, and classification-based policy iteration. We provide an error propagation analysis for AMPI that unifies those for approximate policy and value iteration. We also provide a finite-sample analysis for the classification-based implementation of AMPI (CBMPI), which is more general (and somehow contains) than the analysis of the other presented AMPI algorithms. An interesting observation is that the MPI's parameter allows us to control the balance of errors (in value function approximation and in estimating the greedy policy) in the fina...
Krishna Kumar, P; Araki, Tadashi; Rajan, Jeny; Saba, Luca; Lavra, Francesco; Ikeda, Nobutaka; Sharma, Aditya M; Shafique, Shoaib; Nicolaides, Andrew; Laird, John R; Gupta, Ajay; Suri, Jasjit S
2016-12-10
Monitoring of cerebrovascular diseases via carotid ultrasound has started to become a routine. The measurement of image-based lumen diameter (LD) or inter-adventitial diameter (IAD) is a promising approach for quantification of the degree of stenosis. The manual measurements of LD/IAD are not reliable, subjective and slow. The curvature associated with the vessels along with non-uniformity in the plaque growth poses further challenges. This study uses a novel and generalized approach for automated LD and IAD measurement based on a combination of spatial transformation and scale-space. In this iterative procedure, the scale-space is first used to get the lumen axis which is then used with spatial image transformation paradigm to get a transformed image. The scale-space is then reapplied to retrieve the lumen region and boundary in the transformed framework. Then, inverse transformation is applied to display the results in original image framework. Two hundred and two patients' left and right common carotid artery (404 carotid images) B-mode ultrasound images were retrospectively analyzed. The validation of our algorithm has done against the two manual expert tracings. The coefficient of correlation between the two manual tracings for LD was 0.98 (p < 0.0001) and 0.99 (p < 0.0001), respectively. The precision of merit between the manual expert tracings and the automated system was 97.7 and 98.7%, respectively. The experimental analysis demonstrated superior performance of the proposed method over conventional approaches. Several statistical tests demonstrated the stability and reliability of the automated system.
DEFF Research Database (Denmark)
Dieterle, Mischa; Horstmeyer, Thomas; Berthold, Jost;
2012-01-01
Skeleton-based programming is an area of increasing relevance with upcoming highly parallel hardware, since it substantially facilitates parallel programming and separates concerns. When parallel algorithms expressed by skeletons involve iterations – applying the same algorithm repeatedly...... block inside a bigger structure. In this work, we present a general framework for skeleton iteration and discuss requirements and variations of iteration control and iteration body. Skeleton iteration is expressed by synchronising a parallel iteration body skeleton with a (likewise parallel) state......-based iteration control, where both skeletons offer supportive type safety by dedicated types geared towards stream communication for the iteration. The skeleton iteration framework is implemented in the parallel Haskell dialect Eden. We use example applications to assess performance and overhead....
Energy Technology Data Exchange (ETDEWEB)
Keller, Delphine [CEA, LIST Service de Robotique Interactive, BP6 F-92265 Fontenay aux Roses Cedex (France)], E-mail: delphine.keller@cea.fr; Bayetti, P. [Association Euratom-CEA, DSM/IRFM, CEA/Cadarache F-13108 Saint Paul Lez Durance Cedex (France); Bonnemason, J. [CEA, LIST Service de Robotique Interactive, BP6 F-92265 Fontenay aux Roses Cedex (France); Bruno, V. [Association Euratom-CEA, DSM/IRFM, CEA/Cadarache F-13108 Saint Paul Lez Durance Cedex (France); Chambaud, P.; Friconneau, J.P. [CEA, LIST Service de Robotique Interactive, BP6 F-92265 Fontenay aux Roses Cedex (France); Gargiulo, L. [Association Euratom-CEA, DSM/IRFM, CEA/Cadarache F-13108 Saint Paul Lez Durance Cedex (France); Itchah, M.; Lamy, S. [CEA, LIST Service de Robotique Interactive, BP6 F-92265 Fontenay aux Roses Cedex (France); Le, R. [Association Euratom-CEA, DSM/IRFM, CEA/Cadarache F-13108 Saint Paul Lez Durance Cedex (France); Measson, Y.; Perrot, Y.; Ponsort, D. [CEA, LIST Service de Robotique Interactive, BP6 F-92265 Fontenay aux Roses Cedex (France)
2009-06-15
In 2008, the Articulated Inspection Arm (AIA) performed its first deployment in Tore Supra tokamak vessel, under real vacuum and temperature conditions (10{sup -6} Pa and 120 deg. C) after a conditioning phase to avoid pollution of the chamber. This full demonstration is a turning point in the project, allowing a second phase to start toward the objective to make use of the Remote Handling Equipment as an inspection routine tool. This feasibility demonstration will also be performed on Tore Supra. At this stage, the system requires enhancements of overall technologies and also developments of the Remote Handling control system. Lessons learned in the first phase of the project and experience collected for more than 20 years by Robotics Units of CEA-LIST teams on teleoperated systems enable to identify three main fields to explore to reach the objectives: - Development of a reliable control based on a real time generic command control system. - Development of a graphical supervisor for intuitive steering. - Development of a generic flexible model for realistic computations of the robot localization in the environment. This paper is dedicated to the description of the further developments that shall be done for routine Remote Handling operations. It presents the R and D project roadmap for the next years.
S-Mixing Tuple of Operators on Banach Spaces
Directory of Open Access Journals (Sweden)
Wei Wang
2016-01-01
Full Text Available We consider the question: what is the appropriate formulation of Godefroy-Shapiro criterion for tuples of operators? We also introduce a new notion about tuples of operators, S-mixing, which lies between mixing and weakly mixing. We also obtain a sufficient condition to ensure a tuple of operators to be S-mixing. Moreover, we study some new properties of S-mixing operators on several concrete Banach spaces.
Directory of Open Access Journals (Sweden)
Young-Ye Huang
2013-01-01
Full Text Available We at first raise the so called split feasibility fixed point problem which covers the problems of split feasibility, convex feasibility, and equilibrium as special cases and then give two types of algorithms for finding solutions of this problem and establish the corresponding strong convergence theorems for the sequences generated by our algorithms. As a consequence, we apply them to study the split feasibility problem, the zero point problem of maximal monotone operators, and the equilibrium problem and to show that the unique minimum norm solutions of these problems can be obtained through our algorithms. Since the variational inequalities, convex differentiable optimization, and Nash equilibria in noncooperative games can be formulated as equilibrium problems, each type of our algorithms can be considered as a generalized methodology for solving the aforementioned problems.
Directory of Open Access Journals (Sweden)
TRIFINA, L.
2011-02-01
Full Text Available This paper analyzes the extrinsic information scaling coefficient influence on double-iterative decoding algorithm for space-time turbo codes with large number of antennas. The max-log-APP algorithm is used, scaling both the extrinsic information in the turbo decoder and the one used at the input of the interference-canceling block. Scaling coefficients of 0.7 or 0.75 lead to a 0.5 dB coding gain compared to the no-scaling case, for one or more iterations to cancel the spatial interferences.
关于增生算子零点的修正Mann迭代的注%A Note on Modified Mann Iterations for Zero Points of Accretive Operators
Institute of Scientific and Technical Information of China (English)
魏利; 周海云
2009-01-01
A more general form of modified Mann iterations which converges strongly to a zero point of an m-accretive operator is given.The work in this paper is an extension and complement of the corresponding result of Kim T.H.and Xu H.K in 2005
APPROXIMATION BY GENERALIZED MKZ-OPERATORS IN POLYNOMIAL WEIGHTED SPACES
Institute of Scientific and Technical Information of China (English)
Lucyna Rempulska; Mariola Skorupka
2007-01-01
We prove some approximation properties of generalized Meyer-K(o)nig and Zeller operators for differentiable functions in polynomial weighted spaces. The results extend some results proved in [ 1-3,7-16].
How Long Can the Hubble Space Telescope Operate Reliably?
Xapsos, M. A.; Stauffer, C.; Jordan, T.; Poivey, C.; Lum, G.; Haskins, D. N.; Pergosky, A. M.; Smith, D. C.; LaBel, K. A.
2014-01-01
Total ionizing dose exposure of electronic parts in the Hubble Space Telescope is analyzed using 3-D ray trace and Monte Carlo simulations. Results are discussed along with other potential failure mechanisms for science operations.
The Dirac operator and gamma matrices for quantum Minkowski spaces
1997-01-01
Gamma matrices for quantum Minkowski spaces are found. The invariance of the corresponding Dirac operator is proven. We introduce momenta for spin 1/2 particles and get (in certain cases) formal solutions of the Dirac equation.
Space Electronics Operating at High Temperatures and Radiation Levels Project
National Aeronautics and Space Administration — The proposal represents a radical revolution in Power Management & Distribution (PMAD) that addresses many of the challenges for NASA missions that will operate...
Abdou, M.; Baker, C.; Casini, G.
1991-07-01
The International Thermonuclear Experimental Reactor (ITER) was designed to operate in two phases. The first phase, which lasts for 6 years, is devoted to machine checkout and physics testing. The second phase lasts for 8 years and is devoted primarily to technology testing. This report describes the technology test program development for ITER, the ancillary equipment outside the torus necessary to support the test modules, the international collaboration aspects of conducting the test program on ITER, the requirements on the machine major parameters and the R and D program required to develop the test modules for testing in ITER.
Algebraic Properties of Toeplitz Operators on the Pluriharmonic Bergman Space
Directory of Open Access Journals (Sweden)
Jingyu Yang
2013-01-01
Full Text Available We study some algebraic properties of Toeplitz operators with radial or quasihomogeneous symbols on the pluriharmonic Bergman space. We first give the necessary and sufficient conditions for the product of two Toeplitz operators with radial symbols to be a Toeplitz operator and discuss the zero-product problem for several Toeplitz operators with radial symbols. Next, we study the finite-rank product problem of several Toeplitz operators with quasihomogeneous symbols. Finally, we also investigate finite rank commutators and semicommutators of two Toeplitz operators with quasihomogeneous symbols.
Pasting and reversing operations over some vector spaces
Acosta-Humanez, Primitivo; Chuquen, Adriana; Rodríguez, Angela
2012-01-01
Pasting and Reversing operations have been used successfully over the set of integer numbers, simple permutations, rings and recently over a generalized vector product. In this paper, these operations are defined from a natural way to be applied over vector spaces. In particular we study Pasting and Reversing over vectors, matrices and we rewrite some properties for polynomials as vector space. Finally we study some properties of Reversing through linear transformations as for example an anal...
Compact composition operators on the Bloch space in polydiscs
Institute of Scientific and Technical Information of China (English)
ZHOU; Zehua
2001-01-01
［1］Timoney, R., Bloch function in several complex variables, I, Bull. London Math. Soc., 1980, 12(37): 241.［2］Shi, J. H., Luo, L., Composition operators on the Bloch space of several complex variables, Acta Math. Sinica, 2000, 16(1): 85.［3］Madigan, K., Matheson, A., Compact composition operators on the Bloch space, Trans. Amer. Math. Soc., 1995, 347(7): 2679.
The right inverse of Dirac operator in octonionic space
Wang, Haiyan; Bian, Xiaoli
2017-09-01
The octonion Dirac equation also called wave equation is an important equation which formulates the localization spaces for subluminal and superluminal particles. The purpose of this paper is to look for the right inverse operator of octonion Dirac operator in Hölder space. However, some difficulties will arise in noncommutative and nonassociative setting. We note that the associator is available to overcome the difficulties.
Toeplitz Operators on Dirichlet-Type Space of Unit Ball
Directory of Open Access Journals (Sweden)
Jin Xia
2014-01-01
Full Text Available We construct a function u in L2Bn, dV which is unbounded on any neighborhood of each boundary point of Bn such that Toeplitz operator Tu is a Schatten p-class 0
operator on Dirichlet-type space DBn, dV. Then, we discuss some algebraic properties of Toeplitz operators with radial symbols on the Dirichlet-type space DBn, dV. We determine when the product of two Toeplitz operators with radial symbols is a Toeplitz operator. We investigate the zero-product problem for several Toeplitz operators with radial symbols. Furthermore, the corresponding commuting problem of Toeplitz operators whose symbols are of the form ξku is studied, where k ∈ Zn, ξ ∈ ∂Bn, and u is a radial function.
How the Station will operate. [operation, management, and maintenance in space
Cox, John T.
1988-01-01
Aspects of the upcoming operational phase of the Space Station (SS) are examined. What the crew members will do with their time in their specialized roles is addressed. SS maintenance and servicing and the interaction of the SS Control Center with Johnson Space Center is discussed. The planning of payload operations and strategic planning for the SS are examined.
Directory of Open Access Journals (Sweden)
Bijun Ren
2016-01-01
Full Text Available Let T1 be a generalized Calderón-Zygmund operator or ±I (the identity operator, let T2 and T4 be the linear operators, and let T3=±I. Denote the Toeplitz type operator by Tb=T1MbIαT2+T3IαMbT4, where Mbf=bf and Iα is the fractional integral operator. In this paper, we investigate the boundedness of the operator Tb on weighted Morrey space when b belongs to the weighted BMO spaces.
CYCLIC VECTORS AND CELLULAR INDECOMPOSABLE OPERATORS ON Qp SPACES
Institute of Scientific and Technical Information of China (English)
Ye Shanli; Lou Zengjian
2011-01-01
We identify the functions whose polynomial multiples are weak* dense in Qp spaces and prove that if |f(z)|≥|g(z)| and g is cyclic in Qp, then f is cyclic in Qp. We also show that the multiplication operator Mz on Qp spaces is cellular indecomposable.
Properties of Toeplitz Operators on Some Holomorphic Banach Function Spaces
Directory of Open Access Journals (Sweden)
Ahmed El-Sayed Ahmed
2012-01-01
Full Text Available We characterize complex measures on the unit ball of ℂ, for which the general Toeplitz operator is bounded or compact on the analytic Besov spaces (, also on the minimal Möbius invariant Banach spaces 1( in the unit ball .
Nonuniform exponential unstability of evolution operators in Banach spaces
Megan, Mihail; Sasu, Adina Luminita; Sasu, Bogdan
2001-01-01
In this paper we consider a nonuniform unsrability concept for evolution operators in Banach spaces. The relationship between this concept and the Perron condition is studied. Generalizations to the nonuniform case of some results of Van Minh, Rabiger and Schnaubelt are obtained. The theory we present here is applicable for general time - varying linear equations in Banach spaces.
No Address Space Operating System Prototype and Its Performance Test
Institute of Scientific and Technical Information of China (English)
LIU Fuyan; YOU Jinyuan
2001-01-01
In this paper,we first analyze datastorage models in typical operating systems,the re-lation between distributed shared memory and datastorage model,as well as the relation between mem-ory hierarchy and data storage model.Then we pro-pose the concept of No Address Space Operating Sys-tem,discuss an implementation prototype,and ana-lyze its performance and advantages.We believe thatthe concept of process virtual address space should beabandoned in operating systems,instructions shouldaccess files directly,and processes should run on files.Compared with other operating systems,No AddressSpace Operating System has many advantages andshould be adopted in computer systems.
Tethered Satellites as Enabling Platforms for an Operational Space Weather Monitoring System
Krause, L. Habash; Gilchrist, B. E.; Bilen, S.; Owens, J.; Voronka, N.; Furhop, K.
2013-01-01
Space weather nowcasting and forecasting models require assimilation of near-real time (NRT) space environment data to improve the precision and accuracy of operational products. Typically, these models begin with a climatological model to provide "most probable distributions" of environmental parameters as a function of time and space. The process of NRT data assimilation gently pulls the climate model closer toward the observed state (e.g. via Kalman smoothing) for nowcasting, and forecasting is achieved through a set of iterative physics-based forward-prediction calculations. The issue of required space weather observatories to meet the spatial and temporal requirements of these models is a complex one, and we do not address that with this poster. Instead, we present some examples of how tethered satellites can be used to address the shortfalls in our ability to measure critical environmental parameters necessary to drive these space weather models. Examples include very long baseline electric field measurements, magnetized ionospheric conductivity measurements, and the ability to separate temporal from spatial irregularities in environmental parameters. Tethered satellite functional requirements will be presented for each space weather parameter considered in this study.
Space Operations Cop "It’s Only Logical"
2009-01-01
you to, the SPace Operations Common opera- tional picture, or ( SPOC ). The 8th Army Space Support Element, with the approval of the U.S. Army Space...support of the FWC Models and Simulations Division in Huntsville, Ala., developed the SPOC . 8th Army uses SPOC as a replacement for multiple systems... SPOC takes multiple data feeds that are normal- ly processed by different systems and merges it into one display that can be filtered. (See Figure 1
2011-07-13
... SPACE ADMINISTRATION NASA Advisory Council; Space Operations Committee and Exploration Committee; Joint Meeting AGENCY: National Aeronautics and Space Administration. ACTION: Notice of meeting. SUMMARY: In... and Space Administration announces a joint meeting of the Space Operations Committee and...
2000-05-01
to $l billion. See Jamie G. G. Varni, —Space Operations: Through the Looking Glass ,“ 2025 Study (Maxwell Air Force Base, AL: Air University Press...Aviation, 1945 - 1950 (Washington DC: Naval Historical Center, 1994), p. 121. 134. Jamie G.G Varni et al, —Space Operations: Through the Looking Glass ,“ 2025
Directory of Open Access Journals (Sweden)
Luis Ceferino Franco Arbeláez
2011-01-01
Full Text Available El presente artículo es uno de los resultados obtenidos en proyectos de investigación financiados por la Universidad EAFIT para el año 2011 y se basa en un estudio de Iacus y La Torre [1].Se presenta la estimación fractal, mediante sistemas de funciones iteradas (IFS, como una alternativa para estimar la función de distribución de las pérdidas agregadas, la cual es necesaria para la cuantificación del riesgo operacional. Como se muestra en el análisis, esta técnica puede superar algunas de las dificultades presentadas con las metodologías actuariales clásicas. Además, se presenta una aplicación, y se obtienen conclusiones.This article is one of the results obtain in a research project funded by the University EAFIT in 2011, This paper is based upon a study carried out by Iacus and La Torre [1], it is presented the fractal estimation, through Iterated Function Systems (IFS, as an alternative to estimate the distribution function of added losses which is necessary to quantify the operational risk. As it is shown in the analysis, this technique can deal with some of the difficulties presented with some of the classic actuarial methodologies. Furthermore, an application is presented and conclusions are obtained from it.
Feasibility study of the cut and weld operations by RH on the cooling pipes of ITER NB components
Energy Technology Data Exchange (ETDEWEB)
Pineiro, Oscar; Fernandez, Carlos [TECNATOM Avda. Montes de Oca 28700 S Sebastian de los Reyes, Madrid (Spain); Medrano, Mercedes [EURATOM-CIEMAT Association for Fusion. Avda. Complutense, 22. 28040 Madrid (Spain)], E-mail: mercedes.medrano@ciemat.es; Liniers, Macarena; Botija, Jose; Alonso, Javier; Sarasola, Xabier [EURATOM-CIEMAT Association for Fusion. Avda. Complutense, 22. 28040 Madrid (Spain); Damiani, Carlo [EFDA-Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain)
2009-06-15
The maintenance operations of ITER NB components inside the vessel - Beam Line Components (BLC's) involve the removal of the faulty component, its transport to the hot cell as well as the reverse operations of transport of the repaired/new component and its reinstallation inside the vessel. Prior to the removal of the BLC's the cooling pipes must be detached from the component following a procedure that applies to the cutting of the pipes and subsequent welding when the component is re-installed. The purpose of this study, conducted in the framework of EFDA, is to demonstrate the feasibility of the cut and weld operations on the water pipes of the BLC's using fully remote handling techniques. Viable technologies for the cut and weld operations have been identified within the study; in particular the following aspects will be presented in the paper: - Different strategies can be pursued in the detachment of the components depending on the number of cut and weld operations to be performed on the pipes. The selected strategy will impact on the procedure to be followed likewise on important aspects as the requirements of the flexible joints assembled on the pipes. - The existing cutting techniques have been examined in the light of the remotely performed pipe cutting at the NB cell. Modifications of commercial tools have been proposed in order to adapt them to the BLC's pipes requirements. The debris produced during the cutting process must be controlled and collected, therefore a cleaning system has been integrated in the adapted cutting tool referred above. - The existing welding techniques have been also examined and compared based on different criteria such as complexity, reliability, alignment tolerances, etc. TIG welding is the preferred technique as it stands out for its superior performance. The commercial tools identified need to be adapted to the NB environment. - The alignment of the pipes is a critical issue concerning the remote welding
Weighted Composition Operators from Bergman-Type Spaces into Bloch Spaces
Indian Academy of Sciences (India)
Songxiao Li; Stevo Stević
2007-08-01
Let be an analytic self-map and be a fixed analytic function on the open unit disk in the complex plane $\\mathbb{C}$. The weighted composition operator is defined by $$u C_\\varphi f=u\\cdot p (f\\circ\\varphi), f\\in H(D).$$ Weighted composition operators from Bergman-type spaces into Bloch spaces and little Bloch spaces are characterized by function theoretic properties of their inducing maps.
Survey on nonlocal games and operator space theory
Energy Technology Data Exchange (ETDEWEB)
Palazuelos, Carlos, E-mail: cpalazue@mat.ucm.es [Instituto de Ciencias Matemáticas (ICMAT), Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, Madrid (Spain); Vidick, Thomas, E-mail: vidick@cms.caltech.edu [Department of Computing and Mathematical Sciences, California Institute of Technology, Pasadena, California 91125 (United States)
2016-01-15
This review article is concerned with a recently uncovered connection between operator spaces, a noncommutative extension of Banach spaces, and quantum nonlocality, a striking phenomenon which underlies many of the applications of quantum mechanics to information theory, cryptography, and algorithms. Using the framework of nonlocal games, we relate measures of the nonlocality of quantum mechanics to certain norms in the Banach and operator space categories. We survey recent results that exploit this connection to derive large violations of Bell inequalities, study the complexity of the classical and quantum values of games and their relation to Grothendieck inequalities, and quantify the nonlocality of different classes of entangled states.
Conformal symmetry breaking operators for anti-de Sitter spaces
Kobayashi, Toshiyuki; Pevzner, Michael
2016-01-01
For a pseudo-Riemannian manifold $X$ and a totally geodesic hypersurface $Y$, we consider the problem of constructing and classifying all linear differential operators $\\mathcal{E}^i(X) \\to \\mathcal{E}^j(Y)$ between the spaces of differential forms that intertwine multiplier representations of the Lie algebra of conformal vector fields. Extending the recent results in the Riemannian setting by Kobayashi-Kubo-Pevzner [Lecture Notes in Math.~2170, (2016)], we construct such differential operators and give a classification of them in the pseudo-Riemannian setting where both $X$ and $Y$ are of constant sectional curvature, illustrated by the examples of anti-de Sitter spaces and hyperbolic spaces.
Space station operations task force. Panel 2 report: Ground operations and support systems
1987-01-01
The Ground Operations Concept embodied in this report provides for safe multi-user utilization of the Space Station, eases user integration, and gives users autonomy and flexibility. It provides for meaningful multi-national participation while protecting U.S. interests. The concept also supports continued space operations technology development by maintaining NASA expertise and enabling technology evolution. Given attention here are pre/post flight operations, logistics, sustaining engineering/configuration management, transportation services/rescue, and information systems and communication.
Weighted Inequalities for the Generalized Maximal Operator in Martingale Spaces
Institute of Scientific and Technical Information of China (English)
Wei CHEN; Peide LIU
2011-01-01
The generalized maximal operator M in martingale spaces is considered.For 1 ＜ p ≤ q ＜ ∞,the authors give a necessary and sufficient condition on the pair (（μ),v)for M to be a bounded operator from martingale space LP(v) into Lq(（μ）) or weak-Lq(（μ）),where （μ） is a measure on Ω× N and v a weight on Ω.Moreover,the similar inequalities for usual maximal operator are discussed.
Development of a Space Station Operations Management System
Brandli, A. E.; Mccandless, W. T.
1988-01-01
To enhance the productivity of operations aboard the Space Station, a means must be provided to augment, and frequently to supplant, human effort in support of mission operations and management, both on the ground and onboard. The Operations Management System (OMS), under development at the Johnson Space Center, is one such means. OMS comprises the tools and procedures to facilitate automation of station monitoring, control, and mission planning tasks. OMS mechanizes, and hence rationalizes, execution of tasks traditionally performed by mission planners, the mission control center team, onboard System Management software, and the flight crew.
BOUNDEDNESS OF VECTOR-VALUED OPERATORS ON WEIGHTED HERZ SPACES
Institute of Scientific and Technical Information of China (English)
Tang Lin; Yang Dachun
2000-01-01
In this paper, the authors establish the weighted weak and strong type norm inequalities in the set of weighted Herz-type spaces for a vector-valued analogue of the Hardy-Littlewood maximal operator;and using this ,the authors obtain the weightd inequalies for a wide class of sublinear singular operators definedon Rn which include the Calderón-Zygmund operators as special cases. The fractional versions of these resultsare also given.
BERGMAN TYPE OPERATOR ON MIXED NORM SPACES WITH APPLICATIONS
Institute of Scientific and Technical Information of China (English)
RENGUANGBIN; SHIJIHUAI
1997-01-01
The authors investigate the conditions for the botmdedness of Bergman type operators Pa,t in mixed norm space Lp,q(μ) on the unit ball of Cn (n ≥ 1), and obtain a sufficient conditionand a necessary condition for general normal function μ, and a sufficient and necessary condition for μ(r)=(1-r2)α logβ(2(1-r)-1)(α>0,β≥0), This generalizes the result of Forelli-Rudin[3] on Bergman operator in Bergman space. As applications,a more natural method is given to compute the duality of the mixed norm space,solve the Gleason's problem for mixed norm space and obtain the characterization of mixed norm space in terms of partial derivatives.Moreover,it is proved that f∈L(0) ∞,q(μ) for holomorphic function f,1≤q≤∞.
Martin, Robert J.
The USAF Engineering and Services (E&S) is described in terms of its activities that support ground stations, launch bases, and space-based facilities. E&S is structured according to a master plan for space support and exploitation which includes infrastructure operations and management, infrastructure acquisition, environmental protection, and technology transfer. Also included in the E&S masterplan are personnel education and development, human services, and readiness objectives for the support of space operations and general USAF operations. The USAF E&S operations are expected to support the modernization of space-launch and -range infrastructure, develop training methods and personnel for space support, and improve traditional E&S support technologies and techniques.
Remote manual operator for space station intermodule ventilation valve
Guyaux, James R.
1996-01-01
The Remote Manual Operator (RMO) is a mechanism used for manual operation of the Space Station Intermodule Ventilation (IMV) valve and for visual indication of valve position. The IMV is a butterfly-type valve, located in the ventilation or air circulation ducts of the Space Station, and is used to interconnect or isolate the various compartments. The IMV valve is normally operated by an electric motor-driven actuator under computer or astronaut control, but it can also be operated manually with the RMO. The IMV valve RMO consists of a handle with a deployment linkage, a gear-driven flexible shaft, and a linkage to disengage the electric motor actuator during manual operation. It also provides visual indication of valve position. The IMV valve RMO is currently being prepared for qualification testing.
Compact matrix operators on a new sequence space related to ℓ p $\\ell_{p}$ spaces
Directory of Open Access Journals (Sweden)
Abdullah Alotaibi
2016-08-01
Full Text Available Abstract In this paper, we derive some identities or estimates for the operator norms and the Hausdorff measures of noncompactness of certain matrix operators on the sequence space ℓ p ( r , s , t ; B ( m $\\ell_{p}(r,s,t;B^{(m}$ which is related to ℓ p $\\ell_{p}$ spaces. By applying the Hausdorff measure of noncompactness, we obtain the necessary and sufficient conditions for such operators to be compact. Further, we study some geometric properties of this space.
The effect of He-ash poisoning on L-mode and high ? operations in ITER-like plasma
Tateishi, G.; Itoh, S. I.; Yagi, M.
1997-11-01
The burning performance of the self-ignited steady-state plasma is investigated based on a point model. For the ITER-like parameters, the theoretical model scaling law 0741-3335/39/11/008/img7, which could explain the characteristics of the L-mode and the high 0741-3335/39/11/008/img8 fairly well, and the effect of He-ash poisoning are introduced simultaneously. The solutions are obtained by solving the particle and energy balance equations in steady-state conditions, taking account of the effect of radiation loss due to He ash and fuel ions. Typically, there exist four solutions of the plasma current at fixed temperature. The divergence of the temperature, which is predicted by a previous study (Fukuyama et al 1995 Nucl. Fusion 35 1669) for the pure plasma in the high 0741-3335/39/11/008/img8, disappears under the influence of He ash. In the low-density limit, the L-mode branches and the high 0741-3335/39/11/008/img8 branches are well separated on the plane of the current and the temperature. On the other hand, the merging of two branches occurs at higher densities due to the nonlinear effect contained in the scaling law. Examining the constraints imposed on the core plasma (the density limit, the 0741-3335/39/11/008/img11 limit and so on), we found that the self-ignited state of the high 0741-3335/39/11/008/img8 operation would be difficult.
Operational Concepts for a Generic Space Exploration Communication Network Architecture
Ivancic, William D.; Vaden, Karl R.; Jones, Robert E.; Roberts, Anthony M.
2015-01-01
This document is one of three. It describes the Operational Concept (OpsCon) for a generic space exploration communication architecture. The purpose of this particular document is to identify communication flows and data types. Two other documents accompany this document, a security policy profile and a communication architecture document. The operational concepts should be read first followed by the security policy profile and then the architecture document. The overall goal is to design a generic space exploration communication network architecture that is affordable, deployable, maintainable, securable, evolvable, reliable, and adaptable. The architecture should also require limited reconfiguration throughout system development and deployment. System deployment includes: subsystem development in a factory setting, system integration in a laboratory setting, launch preparation, launch, and deployment and operation in space.
Spectral analysis of difference and differential operators in weighted spaces
Energy Technology Data Exchange (ETDEWEB)
Bichegkuev, M S [North-Ossetia State University, Vladikavkaz (Russian Federation)
2013-11-30
This paper is concerned with describing the spectrum of the difference operator K:l{sub α}{sup p}(Z,X)→l{sub α}{sup p}(Z......athscrKx)(n)=Bx(n−1), n∈Z, x∈l{sub α}{sup p}(Z,X), with a constant operator coefficient B, which is a bounded linear operator in a Banach space X. It is assumed that K acts in the weighted space l{sub α}{sup p}(Z,X), 1≤p≤∞, of two-sided sequences of vectors from X. The main results are obtained in terms of the spectrum σ(B) of the operator coefficient B and properties of the weight function. Applications to the study of the spectrum of a differential operator with an unbounded operator coefficient (the generator of a strongly continuous semigroup of operators) in weighted function spaces are given. Bibliography: 23 titles.
Operator spaces and residually finite-dimensional $C^{*}$-algebras
Pestov, V G
1993-01-01
For every operator space $X$ the $C^\\ast$-algebra containing it in a universal way is residually finite-dimensional (that is, has a separating family of finite-dimensional representations). In particular, the free $C^\\ast$-algebra on any normed space so is. This is an extension of an earlier result by Goodearl and Menal, and our short proof is based on a criterion due to Exel and Loring.
The Index of Dirac Operators on Incomplete Edge Spaces
Albin, Pierre; Gell-Redman, Jesse
2016-09-01
We derive a formula for the index of a Dirac operator on a compact, even-dimensional incomplete edge space satisfying a ''geometric Witt condition''. We accomplish this by cutting off to a smooth manifold with boundary, applying the Atiyah-Patodi-Singer index theorem, and taking a limit. We deduce corollaries related to the existence of positive scalar curvature metrics on incomplete edge spaces.
System security in the space flight operations center
Wagner, David A.
1988-01-01
The Space Flight Operations Center is a networked system of workstation-class computers that will provide ground support for NASA's next generation of deep-space missions. The author recounts the development of the SFOC system security policy and discusses the various management and technology issues involved. Particular attention is given to risk assessment, security plan development, security implications of design requirements, automatic safeguards, and procedural safeguards.
Space system operations and support cost analysis using Markov chains
Unal, Resit; Dean, Edwin B.; Moore, Arlene A.; Fairbairn, Robert E.
1990-01-01
This paper evaluates the use of Markov chain process in probabilistic life cycle cost analysis and suggests further uses of the process as a design aid tool. A methodology is developed for estimating operations and support cost and expected life for reusable space transportation systems. Application of the methodology is demonstrated for the case of a hypothetical space transportation vehicle. A sensitivity analysis is carried out to explore the effects of uncertainty in key model inputs.
Airborne Precision Spacing for Dependent Parallel Operations Interface Study
Volk, Paul M.; Takallu, M. A.; Hoffler, Keith D.; Weiser, Jarold; Turner, Dexter
2012-01-01
This paper describes a usability study of proposed cockpit interfaces to support Airborne Precision Spacing (APS) operations for aircraft performing dependent parallel approaches (DPA). NASA has proposed an airborne system called Pair Dependent Speed (PDS) which uses their Airborne Spacing for Terminal Arrival Routes (ASTAR) algorithm to manage spacing intervals. Interface elements were designed to facilitate the input of APS-DPA spacing parameters to ASTAR, and to convey PDS system information to the crew deemed necessary and/or helpful to conduct the operation, including: target speed, guidance mode, target aircraft depiction, and spacing trend indication. In the study, subject pilots observed recorded simulations using the proposed interface elements in which the ownship managed assigned spacing intervals from two other arriving aircraft. Simulations were recorded using the Aircraft Simulation for Traffic Operations Research (ASTOR) platform, a medium-fidelity simulator based on a modern Boeing commercial glass cockpit. Various combinations of the interface elements were presented to subject pilots, and feedback was collected via structured questionnaires. The results of subject pilot evaluations show that the proposed design elements were acceptable, and that preferable combinations exist within this set of elements. The results also point to potential improvements to be considered for implementation in future experiments.
COMPOSITION OPERATORS ON THE LITTLE BLOCH SPACE IN POLYDISCS
Institute of Scientific and Technical Information of China (English)
Zhou Zehua; Zhu Min; Shi Jihuai
2005-01-01
Let Un be the unit polydisc of Cn and φ = (φ1,…,φn) a holomorphic self map of Un. This paper shows that the composition operator Cφ induced by φ is bounded on the little Bloch space β0*(Un) if and only if φ∈β0*(Un) for every l=1,2,…,n, and also gives a sufficient and necessary condition for the composition operator Cφ to be compact on the little Bloch spaceβ0* (Un).
Orbits of linear operators and Banach space geometry
Augé, Jean-Matthieu
2012-01-01
Let $T$ be a bounded linear operator on a (real or complex) Banach space $X$. If $(a_n)$ is a sequence of non-negative numbers tending to 0. Then, the set of $x \\in X$ such that $\\|T^nx\\| \\geqslant a_n \\|T^n\\|$ for infinitely many $n$'s has a complement which is both $\\sigma$-porous and Haar-null. We also compute (for some classical Banach space) optimal exponents $q>0$, such that for every non nilpotent operator $T$, there exists $x \\in X$ such that $(\\|T^nx\\|/\\|T^n\\|) \
Directory of Open Access Journals (Sweden)
Pongsakorn Sunthrayuth
2011-01-01
Full Text Available We introduce a new general system of variational inclusions in Banach spaces and propose a new iterative scheme for finding common element of the set of solutions of the variational inclusion with set-valued maximal monotone mapping and Lipschitzian relaxed cocoercive mapping and the set of fixed point of nonexpansive semigroups in a uniformly convex and 2-uniformly smooth Banach space. Furthermore, strong convergence theorems are established under some certain control conditions. As applications, finding a common solution for a system of variational inequality problems and minimization problems is given.
Operational considerations for a crewed nuclear powered space transportation vehicle
Borrer, Jerry L.; Hoffman, Stephen J.
1993-01-01
Applying nuclear propulsion technology to human space travel will require new approaches to conducting human operations in space. Due to the remoteness of these types of missions, the crew and their vehicle must be capable of operating independent from Earth-based support. This paper discusses current operational studies which address methods for performing these types of remote and autonomous missions. Methods of managing the hazards to humans who will operate these high-energy nuclear-powered transportation vehicles also is reviewed. Crew training for both normal and contingency operations is considered. Options are evaluated on how best to train crews to operate and maintain the systems associated with a nuclear engine. Methods of maintaining crew proficiency during the long months of space travel are discussed. Vehicle health maintenance also will be a primary concern during these long missions. A discussion is presented on how on-board vehicle health maintenance systems will monitor system trends, identified system weaknesses, and either isolate critical failures or provide the crew with adequate warning of impending problems.
Applications of triggered lightning to space vehicle operations
Jafferis, William; Sanicandro, Rocco; Rompalla, John; Wohlman, Richard
1992-11-01
Kennedy Space Center (KSC) and the USAF Eastern Space Missile Center (ESMC) covering an area of 25 x 40 km are frequently called America's Spaceport. This title is earned through the integration, by labor and management, of many skills in a wide variety of engineering fields to solve many technical problems that occur during the launch processing of space vehicles. Weather is one of these problems, and although less frequent in time and duration when compared to engineering type problems, has caused costly and life threatening situations. This sensitivity to weather, especially lightning, was recognized in the very early pioneer days of space operations. The need to protect the many v\\facilities, space flight hardware, and personnel from electrified clouds capable of producing lightning was a critical element in improving launch operations. A KSC lightning committee was formed and directed to improve lightning protection, detection, and measuring systems and required that all theoretical studies be confirmed by KSC field data. Over the years, there have been several lightning incidents involving flight vehicles during ground processing as well as launch. Subsequent investigations revealed the need to improve these systems as well as the knowledge of the electrical atmosphere and its effects on operations in regard to cost and safety. Presented here is how, KSC Atmospheric Science Field Laboratory (AFSL), in particular Rocket Triggered Lightning, is being used to solve these problems.
Payload Operations Center (POC) for the International Space Station (ISS)
2001-01-01
The International Space Station (ISS) Payload Operations Center (POC) at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, is the world's primary science command post for the International Space Station (ISS), the most ambitious space research facility in human history. The Payload Operations team is responsible for managing all science research experiments aboard the Station. The center is also home for coordination of the mission-plarning work of variety of international sources, all science payload deliveries and retrieval, and payload training and safety programs for the Station crew and all ground personnel. Within the POC, critical payload information from the ISS is displayed on a dedicated workstation, reading both S-band (low data rate) and Ku-band (high data rate) signals from a variety of experiments and procedures operated by the ISS crew and their colleagues on Earth. The POC is the focal point for incorporating research and experiment requirements from all international partners into an integrated ISS payload mission plan. This photograph is an overall view of the MSFC Payload Operations Center displaying the flags of the countries participating the ISS. The flags at the left portray The United States, Canada, France, Switzerland, Netherlands, Japan, Brazil, and Sweden. The flags at the right portray The Russian Federation, Italy, Germany, Belgium, Spain, United Kingdom, Denmark, and Norway.
Compact composition operators on the Bloch space in polydiscs
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Let Un be the unit polydisc of Cn and =(1,…n) a holomorphicself-map of Un. As the main result of the paper, it shows that the composition operator Cφ is compact on the Bloch space β(Un) if and only if for every ε>0, there exists a δ>0, such thatwhenever dist((z),Un)<δ.
Payload Operations Center (POC) for the International Space Station (ISS)
2001-01-01
The International Space Station (ISS) Payload Operations Center (POC) at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, is the world's primary science command post for the International Space Station (ISS), the most ambitious space research facility in human history. The Payload Operations team is responsible for managing all science research experiments aboard the Station. The center is also home for coordination of the mission-plarning work of variety of international sources, all science payload deliveries and retrieval, and payload training and safety programs for the Station crew and all ground personnel. Within the POC, critical payload information from the ISS is displayed on a dedicated workstation, reading both S-band (low data rate) and Ku-band (high data rate) signals from a variety of experiments and procedures operated by the ISS crew and their colleagues on Earth. The POC is the focal point for incorporating research and experiment requirements from all international partners into an integrated ISS payload mission plan. This photograph is an overall view of the MSFC Payload Operations Center displaying the flags of the countries participating the ISS. The flags at the left portray The United States, Canada, France, Switzerland, Netherlands, Japan, Brazil, and Sweden. The flags at the right portray The Russian Federation, Italy, Germany, Belgium, Spain, United Kingdom, Denmark, and Norway.
Generalized ψρ-operations on double fuzzy topological spaces
Mohammed, Fatimah. M.; Noorani, M. S. M.; Ghareeb, A.
2013-11-01
The purpose of this paper is to introduce and characterize the concepts of ψ-operations in double fuzzy topological spaces. Also, we use them to study (r,s)-generalized fuzzy ψρ-closed sets and (r,s)-generalized fuzzy ψρ-open sets. Some characterizations and properties for these concepts are discussed.
Institute of Scientific and Technical Information of China (English)
谷峰
2001-01-01
使用新的分析技巧，研究了一致光滑Banach空间中ψ强增生算子方程的解和ψ强伪压缩算子不动点的Ishikawa迭代逼近问题，改进和扩展了近期的许多相关结果.%In this artice, by virtue of some analysis techniques, we have studied approximation problem of Ishikawa iterative sequence for the solution of ψ-strongly accretive operators and the fixed point.of p-strongly pseudo-contractive operators in uniformly smooth Banach spaces. Our results improve and extend the recent corresponding results.
Energy Technology Data Exchange (ETDEWEB)
Stamoulis, K.C., E-mail: kstamoul@cc.uoi.gr [Archaeometry Center, University of Ioannina, Ioannina 45110 (Greece); Karamanis, D. [Department of Environmental and Natural Resources Management, University of Ioannina, Agrinio 30100 (Greece); Ioannides, K.G. [Archaeometry Center, University of Ioannina, Ioannina 45110 (Greece); Nuclear Physics Laboratory, University of Ioannina, Ioannina 45110 (Greece)
2011-03-15
The project ITER aims to demonstrate that fusion is the energy source of the future. The prototype Tokamak machine is intended to start operation at about 2019 and tritium is one of the major contaminants that can be accidentally released in the environment. Nowadays environmental tritium levels are of natural origin except in the vicinity of nuclear facilities. The evaluation of background tritium levels is essential in the context of a future possibility of accidental tritium releases. For this purpose and also because of the lack of relevant information, an extended programme of river and rain water sampling was implemented in north-western Greece. Water samples from six major rivers in this area and rain water samples were analysed for tritium content. The rivers under investigation were Aliakmonas River, Pinios River, Arachthos River, Kalamas River, Aoos River and Louros River, which originate from the central Greek mountain range Pindos, and flow to Aegean and Ionian Sea. The tritium concentrations were determined by the Liquid Scintillator Analyser Tri-Carb 3170TR/SL. The statistical analysis of data revealed that there is a seasonal variation of tritium concentration in rain samples and a less pronounced seasonal variation in river samples. The weighted mean tritium concentration for rain samples was determined equal to 0.90 {+-} 0.08 Bq L{sup -1} (7.6 {+-} 0.7 TU) and the respective mean value for river samples was 0.94 {+-} 0.04 Bq L{sup -1} (7.9 {+-} 0.3 TU). Further analysis has demonstrated that river waters tend to show lower tritium concentrations than the concurrently measured tritium concentrations in rain samples, during spring and summer (at 47% and 71% of the sampling stations, respectively), while this observation is reversed during autumn and winter (at 44% and 35% of the sampling stations, respectively). This may be attributed to rain water remaining underground for a long period allowing tritium to decay and when it reappears as river water
Implementing Distributed Operations: A Comparison of Two Deep Space Missions
Mishkin, Andrew; Larsen, Barbara
2006-01-01
Two very different deep space exploration missions--Mars Exploration Rover and Cassini--have made use of distributed operations for their science teams. In the case of MER, the distributed operations capability was implemented only after the prime mission was completed, as the rovers continued to operate well in excess of their expected mission lifetimes; Cassini, designed for a mission of more than ten years, had planned for distributed operations from its inception. The rapid command turnaround timeline of MER, as well as many of the operations features implemented to support it, have proven to be conducive to distributed operations. These features include: a single science team leader during the tactical operations timeline, highly integrated science and engineering teams, processes and file structures designed to permit multiple team members to work in parallel to deliver sequencing products, web-based spacecraft status and planning reports for team-wide access, and near-elimination of paper products from the operations process. Additionally, MER has benefited from the initial co-location of its entire operations team, and from having a single Principal Investigator, while Cassini operations have had to reconcile multiple science teams distributed from before launch. Cassini has faced greater challenges in implementing effective distributed operations. Because extensive early planning is required to capture science opportunities on its tour and because sequence development takes significantly longer than sequence execution, multiple teams are contributing to multiple sequences concurrently. The complexity of integrating inputs from multiple teams is exacerbated by spacecraft operability issues and resource contention among the teams, each of which has their own Principal Investigator. Finally, much of the technology that MER has exploited to facilitate distributed operations was not available when the Cassini ground system was designed, although later adoption
Autonomous Payload Operations Onboard the International Space Station
Stetson, Howard K.; Deitsch, David K.; Cruzen, Craig A.; Haddock, Angie T.
2007-01-01
Operating the International Space Station (ISS) involves many complex crew tended, ground operated and combined systems. Over the life of the ISS program, it has become evident that by having automated and autonomous systems on board, more can be accomplished and at the same time reduce the workload of the crew and ground operators. Engineers at the National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center in Huntsville Alabama, working in collaboration with The Charles Stark Draper Laboratory have developed an autonomous software system that uses the Timeliner User Interface Language and expert logic to continuously monitor ISS payload systems, issue commands and signal ground operators as required. This paper describes the development history of the system, its concept of operation and components. The paper also discusses the testing process as well as the facilities used to develop the system. The paper concludes with a description of future enhancement plans for use on the ISS as well as potential applications to Lunar and Mars exploration systems.
On the Riemann Curvature Operators in Randers Spaces
Rafie-Rad, M.
2013-05-01
The Riemann curvature in Riemann-Finsler geometry can be regarded as a collection of linear operators on the tangent spaces. The algebraic properties of these operators may be linked to the geometry and the topology of the underlying space. The principal curvatures of a Finsler space (M, F) at a point x are the eigenvalues of the Riemann curvature operator at x. They are real functions κ on the slit tangent manifold TM0. A principal curvature κ(x, y) is said to be isotropic (respectively, quadratic) if κ(x, y)/F(x, y) is a function of x only (respectively, κ(x, y) is quadratic with respect to y). On the other hand, the Randers metrics are the most popular and prominent metrics in pure and applied disciplines. Here, it is proved that if a Randers metric admits an isotropic principal curvature, then F is of isotropic S-curvature. The same result is also established for F to admit a quadratic principal curvature. These results extend Shen's verbal results about Randers metrics of scalar flag curvature K = K(x) as well as those Randers metrics with quadratic Riemann curvature operator. The Riemann curvature Rik may be broken into two operators Rik and Jik. The isotropic and quadratic principal curvature are characterized in terms of the eigenvalues of R and J.
On Volterra quadratic stochastic operators with continual state space
Energy Technology Data Exchange (ETDEWEB)
Ganikhodjaev, Nasir; Hamzah, Nur Zatul Akmar [Department of Computational and Theoretical Sciences, Faculty of Science, International Islamic University, Jalan Sultan Ahmad Shah, Bandar Indera Mahkota, 25200 Kuantan, Pahang (Malaysia)
2015-05-15
Let (X,F) be a measurable space, and S(X,F) be the set of all probability measures on (X,F) where X is a state space and F is σ - algebraon X. We consider a nonlinear transformation (quadratic stochastic operator) defined by (Vλ)(A) = ∫{sub X}∫{sub X}P(x,y,A)dλ(x)dλ(y), where P(x, y, A) is regarded as a function of two variables x and y with fixed A ∈ F . A quadratic stochastic operator V is called a regular, if for any initial measure the strong limit lim{sub n→∞} V{sup n }(λ) is exists. In this paper, we construct a family of quadratic stochastic operators defined on the segment X = [0,1] with Borel σ - algebra F on X , prove their regularity and show that the limit measure is a Dirac measure.
Generalized space and linear momentum operators in quantum mechanics
Energy Technology Data Exchange (ETDEWEB)
Costa, Bruno G. da, E-mail: bruno.costa@ifsertao-pe.edu.br [Instituto Federal de Educação, Ciência e Tecnologia do Sertão Pernambucano, Campus Petrolina, BR 407, km 08, 56314-520 Petrolina, Pernambuco (Brazil); Instituto de Física, Universidade Federal da Bahia, R. Barão de Jeremoabo s/n, 40170-115 Salvador, Bahia (Brazil); Borges, Ernesto P., E-mail: ernesto@ufba.br [Instituto de Física, Universidade Federal da Bahia, R. Barão de Jeremoabo s/n, 40170-115 Salvador, Bahia (Brazil)
2014-06-15
We propose a modification of a recently introduced generalized translation operator, by including a q-exponential factor, which implies in the definition of a Hermitian deformed linear momentum operator p{sup ^}{sub q}, and its canonically conjugate deformed position operator x{sup ^}{sub q}. A canonical transformation leads the Hamiltonian of a position-dependent mass particle to another Hamiltonian of a particle with constant mass in a conservative force field of a deformed phase space. The equation of motion for the classical phase space may be expressed in terms of the generalized dual q-derivative. A position-dependent mass confined in an infinite square potential well is shown as an instance. Uncertainty and correspondence principles are analyzed.
Flare forecasting at the Met Office Space Weather Operations Centre
Murray, S. A.; Bingham, S.; Sharpe, M.; Jackson, D. R.
2017-04-01
The Met Office Space Weather Operations Centre produces 24/7/365 space weather guidance, alerts, and forecasts to a wide range of government and commercial end-users across the United Kingdom. Solar flare forecasts are one of its products, which are issued multiple times a day in two forms: forecasts for each active region on the solar disk over the next 24 h and full-disk forecasts for the next 4 days. Here the forecasting process is described in detail, as well as first verification of archived forecasts using methods commonly used in operational weather prediction. Real-time verification available for operational flare forecasting use is also described. The influence of human forecasters is highlighted, with human-edited forecasts outperforming original model results and forecasting skill decreasing over longer forecast lead times.
Weighted composition operators from F(p, q, s) spaces to Bers-type spaces in the unit ball
Institute of Scientific and Technical Information of China (English)
L(U) Xiao-fen
2009-01-01
This paper deals with the boundedness and compactness of the weighted compo-sition operators from the F(p, q, s) spaces, including Hardy space, Bergman space, Q~p space,BMOA space, Besov space and α-Bloch space, to Bers-type spaces H_ν~∞( or little Bets-type spaces H_(ν,0)~∞ ), where ν is normal.
Space Mission Operations Ground Systems Integration Customer Service
Roth, Karl
2014-01-01
The facility, which is now the Huntsville Operations Support Center (HOSC) at Marshall Space Flight Center in Huntsville, AL, has provided continuous space mission and related services for the space industry since 1961, from Mercury Redstone through the International Space Station (ISS). Throughout the long history of the facility and mission support teams, the HOSC has developed a stellar customer support and service process. In this era, of cost cutting, and providing more capability and results with fewer resources, space missions are looking for the most efficient way to accomplish their objectives. One of the first services provided by the facility was fax transmission of documents to, then, Cape Canaveral in Florida. The headline in the Marshall Star, the newspaper for the newly formed Marshall Space Flight Center, read "Exact copies of Documents sent to Cape in 4 minutes." The customer was Dr. Wernher von Braun. Currently at the HOSC we are supporting, or have recently supported, missions ranging from simple ISS payloads requiring little more than "bentpipe" telemetry access, to a low cost free-flyer Fast, Affordable, Science and Technology Satellite (FASTSAT), to a full service ISS payload Alpha Magnetic Spectrometer 2 (AMS2) supporting 24/7 operations at three operations centers around the world with an investment of over 2 billion dollars. The HOSC has more need and desire than ever to provide fast and efficient customer service to support these missions. Here we will outline how our customer-centric service approach reduces the cost of providing services, makes it faster and easier than ever for new customers to get started with HOSC services, and show what the future holds for our space mission operations customers. We will discuss our philosophy concerning our responsibility and accessibility to a mission customer as well as how we deal with the following issues: initial contact with a customer, reducing customer cost, changing regulations and security
Friedberg, R; Zhao, W Q
2005-01-01
We present an explicit convergent iterative solution for the lowest energy state of the Schroedinger equation with an $N$-dimensional radial potential $V=\\frac{g^2}{2}(r^2-1)^2$ and an angular momentum $l$. For $g$ large, the rate of convergence is similar to a power series in $g^{-1}$.
Joint Space Operations Center (JSpOC) Mission System (JMS)
Morton, M.; Roberts, T.
2011-09-01
US space capabilities benefit the economy, national security, international relationships, scientific discovery, and our quality of life. Realizing these space responsibilities is challenging not only because the space domain is increasingly congested, contested, and competitive but is further complicated by the legacy space situational awareness (SSA) systems approaching end of life and inability to provide the breadth of SSA and command and control (C2) of space forces in this challenging domain. JMS will provide the capabilities to effectively employ space forces in this challenging domain. Requirements for JMS were developed based on regular, on-going engagement with the warfighter. The use of DoD Architecture Framework (DoDAF) products facilitated requirements scoping and understanding and transferred directly to defining and documenting the requirements in the approved Capability Development Document (CDD). As part of the risk reduction efforts, the Electronic System Center (ESC) JMS System Program Office (SPO) fielded JMS Capability Package (CP) 0 which includes an initial service oriented architecture (SOA) and user defined operational picture (UDOP) along with force status, sensor management, and analysis tools. Development efforts are planned to leverage and integrate prototypes and other research projects from Defense Advanced Research Projects Agency, Air Force Research Laboratories, Space Innovation and Development Center, and Massachusetts Institute of Technology/Lincoln Laboratories. JMS provides a number of benefits to the space community: a reduction in operational “transaction time” to accomplish key activities and processes; ability to process the increased volume of metric observations from new sensors (e.g., SBSS, SST, Space Fence), as well as owner/operator ephemerides thus enhancing the high accuracy near-real-time catalog, and greater automation of SSA data sharing supporting collaboration with government, civil, commercial, and foreign
Activity of Science and Operational Research of NICT Space Weather
Ishii, Mamoru; Nagatsuma, Tsutomu; Watari, Shinichi; Shinagawa, Hiroyuki; Tsugawa, Takuya; Kubo, Yuki
Operational space weather forecast is for contribution to social infrastructure than for academic interests. These user need will determine the target of research, e.g., the precision level, spatial and temporal resolution and/or required lead time. We, NICT, aim two target in the present mid-term strategic plan, which are (1) forecast of ionospheric disturbance influencing to satellite positioning, and (2) forecast of disturbance in radiation belt influencing to satellite operation. We have our own observation network and develop empirical and numerical models for achieving each target. However in actual situation, it is much difficult to know the user needs quantitatively. Most of space weather phenomena makes the performance of social infrastructure poor, for example disconnect of HF communication, increase of GNSS error. Most of organizations related to these operation are negative to open these information. We have personal interviews to solve this issue. In this interview, we try to collect incident information related to space weather in each field, and to retrieve which space weather information is necessary for users. In this presentation we will introduce our research and corresponding new service, in addition to our recent scientific results.
Analysis on singular spaces: Lie manifolds and operator algebras
Nistor, Victor
2016-07-01
We discuss and develop some connections between analysis on singular spaces and operator algebras, as presented in my sequence of four lectures at the conference Noncommutative geometry and applications, Frascati, Italy, June 16-21, 2014. Therefore this paper is mostly a survey paper, but the presentation is new, and there are included some new results as well. In particular, Sections 3 and 4 provide a complete short introduction to analysis on noncompact manifolds that is geared towards a class of manifolds-called "Lie manifolds" -that often appears in practice. Our interest in Lie manifolds is due to the fact that they provide the link between analysis on singular spaces and operator algebras. The groupoids integrating Lie manifolds play an important background role in establishing this link because they provide operator algebras whose structure is often well understood. The initial motivation for the work surveyed here-work that spans over close to two decades-was to develop the index theory of stratified singular spaces. Meanwhile, several other applications have emerged as well, including applications to Partial Differential Equations and Numerical Methods. These will be mentioned only briefly, however, due to the lack of space. Instead, we shall concentrate on the applications to Index theory.
Operational Capabilities and Legal Implications of a Military Space Plane
Charania, A.
2002-01-01
The potential challenges for the United States military in this upcoming century may require new types of capabilities only achievable through the application of new technologies. One of these potential capabilities includes a Military Space Plane (MSP). An MSP is a concept to use reusable launch vehicle (RLV) technologies in a system to provide the military global access and reach in a timely fashion that could be operational within a decade. New awareness is evident from both recent federal commission reports and activities in Afghanistan of the military's possible use of such capabilities to provide asymmetric advantages. The MSP may eventually become part of a new spaceforce that coordinates the broad range of defensive and offensive space assets. In addition, a new emphasis is being placed upon NASA and the U.S. Air Force to coordinate activity on such a space plane/RLV development. The interaction of civilian and defense agencies for such a program has ramifications, not just in terms of the requirements on a final operational vehicle, but also on the legal charters of both entities. This examination presents operational scenarios for a military space plane in order to derive various legal implications.
Leclerc, Arnaud
2015-01-01
A global solution of the Schr\\"odinger equation for explicitly time-dependent Hamiltonians is derived by integrating the non-linear differential equation associated with the time-dependent wave operator. A fast iterative solution method is proposed in which, however, numerous integrals over time have to be evaluated. This internal work is done using a numerical integrator based on Fast Fourier Transforms (FFT). The case of a transition between two potential wells of a model molecule driven by intense laser pulses is used as an illustrative example. This application reveals some interesting features of the integration technique. Each iteration provides a global approximate solution on grid points regularly distributed over the full time propagation interval. Inside the convergence radius, the complete integration is competitive with standard algorithms, especially when high accuracy is required.
Constraint and Flight Rule Management for Space Mission Operations
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.
Extending the International Space Station Life and Operability
Cecil, Andrew J.; Pitts, R. Lee; Sparks, Ray N.; Wickline, Thomas W.; Zoller, David A.
2012-01-01
The International Space Station (ISS) is in an operational configuration with final assembly complete. To fully utilize ISS and extend the operational life, it became necessary to upgrade and extend the onboard systems with the Obsolescence Driven Avionics Redesign (ODAR) project. ODAR enabled a joint project between the Johnson Space Center (JSC) and Marshall Space Flight Center (MSFC) focused on upgrading the onboard payload and Ku-Band systems, expanding the voice and video capabilities, and including more modern protocols allowing unprecedented access for payload investigators to their on-orbit payloads. The MSFC Huntsville Operations Support Center (HOSC) was tasked with developing a high-rate enhanced Functionally Distributed Processor (eFDP) to handle 300Mbps Return Link data, double the legacy rate, and incorporate a Line Outage Recorder (LOR). The eFDP also provides a 25Mbps uplink transmission rate with a Space Link Extension (SLE) interface. HOSC also updated the Payload Data Services System (PDSS) to incorporate the latest Consultative Committee for Space Data Systems (CCSDS) protocols, most notably the use of the Internet Protocol (IP) Encapsulation, in addition to the legacy capabilities. The Central Command Processor was also updated to interact with the new onboard and ground capabilities of Mission Control Center -- Houston (MCC-H) for the uplink functionality. The architecture, implementation, and lessons learned, including integration and incorporation of Commercial Off The Shelf (COTS) hardware and software into the operational mission of the ISS, is described herein. The applicability of this new technology provides new benefits to ISS payload users and ensures better utilization of the ISS by the science community
Application of human error analysis to aviation and space operations
Energy Technology Data Exchange (ETDEWEB)
Nelson, W.R.
1998-03-01
For the past several years at the Idaho National Engineering and Environmental Laboratory (INEEL) the authors have been working to apply methods of human error analysis to the design of complex systems. They have focused on adapting human reliability analysis (HRA) methods that were developed for Probabilistic Safety Assessment (PSA) for application to system design. They are developing methods so that human errors can be systematically identified during system design, the potential consequences of each error can be assessed, and potential corrective actions (e.g. changes to system design or procedures) can be identified. The primary vehicle the authors have used to develop and apply these methods has been a series of projects sponsored by the National Aeronautics and Space Administration (NASA) to apply human error analysis to aviation operations. They are currently adapting their methods and tools of human error analysis to the domain of air traffic management (ATM) systems. Under the NASA-sponsored Advanced Air Traffic Technologies (AATT) program they are working to address issues of human reliability in the design of ATM systems to support the development of a free flight environment for commercial air traffic in the US. They are also currently testing the application of their human error analysis approach for space flight operations. They have developed a simplified model of the critical habitability functions for the space station Mir, and have used this model to assess the affects of system failures and human errors that have occurred in the wake of the collision incident last year. They are developing an approach so that lessons learned from Mir operations can be systematically applied to design and operation of long-term space missions such as the International Space Station (ISS) and the manned Mars mission.
Command and control displays for space vehicle operations
Desjardins, Daniel D.; Zetocha, Paul; Aleva, Denise
2010-04-01
This paper shall examine several command and control facility display architectures supporting space vehicle operations, to include TacSat 2, TacSat 3, STPSat 2, and Communications Navigation Outage Forecasting System (CNOFS), located within the Research Development Test & Evaluation Support Complex (RSC) Satellite Operations Center 97 (SOC-97) at Kirtland Air Force Base. A principal focus is to provide an understanding for the general design class of displays currently supporting space vehicle command and control, e.g., custom, commercial-off-the-shelf, or ruggedized commercial-off-the-shelf, and more specifically, what manner of display performance capabilities, e.g., active area, resolution, luminance, contrast ratio, frame/refresh rate, temperature range, shock/vibration, etc., are needed for particular aspects of space vehicle command and control. Another focus shall be to address the types of command and control functions performed for each of these systems, to include how operators interact with the displays, e.g., joystick, trackball, keyboard/mouse, as well as the kinds of information needed or displayed for each function. [Comparison with other known command and control facilities, such as Cheyenne Mountain and NORAD Operations Center, shall be made.] Future, anticipated display systems shall be discussed.
A Simulation Based Investigation of High Latency Space Systems Operations
Li, Zu Qun; Moore, Michael; Bielski, Paul; Crues, Edwin Z.
2017-01-01
This study was the first in a series of planned tests to use physics-based subsystem simulations to investigate the interactions between a spacecraft's crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation models the life support system of a deep space habitat. It contains models of an environmental control and life support system, an electrical power system, an active thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the subsystems; 2) a mission control center interface with data transport delays up to 15 minute each way; and 3) a real-time simulation test conductor interface used to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission. The NEEMO crew and ground support team performed a number of relevant deep space mission scenarios that included both nominal activities and activities with system malfunctions. While this initial test sequence was focused on test infrastructure and procedures development, the data collected in the study already indicate that long communication delays have notable impacts on the operation of deep space systems. For future human missions beyond cis-lunar, NASA will need to design systems and support tools to meet these challenges. These will be used to train the crew to handle critical malfunctions on their own, to predict malfunctions and assist with vehicle operations. Subsequent more detailed and involved studies will be conducted to continue advancing NASA's understanding of space systems operations across long communications delays.
An algebra of noncommutative differential operators and Sobolev spaces
Beggs, E J
2011-01-01
We consider differential operators over a noncommutative algebra $A$ generated by vector fields. This is shown to form an associative algebra of differential operators, and acts on $A$-modules $E$ with covariant derivative. For bimodule covariant derivatives on $E$, we consider a module map $U_E$ which classifies how similar to the classical case the bimodule covariant derivative is. If this module map vanishes, we give an action of differential operators on tensor products. This turns out to be quite simple, and is related to the braided shuffle product. However technical issues with tensor products mean that we are not yet able to give a form of Hopf algebroid structure to the algebra of differential operators. We end by using the repeated differentials given in the paper to give a definition of noncommutative Sobolev space.
Behavioral Health and Performance Operations During the Space Shuttle Program
Beven, G.; Holland, A.; Moomaw, R.; Sipes, W.; Vander Ark, S.
2011-01-01
Prior to the Columbia STS 107 disaster in 2003, the Johnson Space Center s Behavioral Health and Performance Group (BHP) became involved in Space Shuttle Operations on an as needed basis, occasionally acting as a consultant and primarily addressing crew-crew personality conflicts. The BHP group also assisted with astronaut selection at every selection cycle beginning in 1991. Following STS 107, an event that spawned an increased need of behavioral health support to STS crew members and their dependents, BHP services to the Space Shuttle Program were enhanced beginning with the STS 114 Return to Flight mission in 2005. These services included the presence of BHP personnel at STS launches and landings for contingency support, a BHP briefing to the entire STS crew at L-11 months, a private preflight meeting with the STS Commander at L-9 months, and the presence of a BHP consultant at the L-1.5 month Family Support Office briefing to crew and family members. The later development of an annual behavioral health assessment of all active astronauts also augmented BHP s Space Shuttle Program specific services, allowing for private meetings with all STS crew members before and after each mission. The components of each facet of these BHP Space Shuttle Program support services will be presented, along with valuable lessons learned, and with recommendations for BHP involvement in future short duration space missions
Directory of Open Access Journals (Sweden)
M. Raghunadh Acharya
2009-12-01
Full Text Available A new quadrature formula has been proposed which uses modified weight functions derived from those of ‘Bernstein Polynomial’ using a ‘Two-Phase Modification’ therein. The quadrature formula has been compared empirically with the simple method of numerical integration using the well-known “Bernstein Operator”. The percentage absolute relative errors for the proposed quadrature formula and that with the “Bernstein Operator” have been computed for certain selected functions, with different number of usual equidistant node-points in the interval of integration~ [0, 1]. It has been observed that both of the proposed modified quadrature formulae, respectively after the ‘Phase-I’ and after the ‘Phases-I & II’ of these modifications, produce significantly better results than that using, simply, the “Bernstein Operator”. Inasmuch as the proposed “Two-Phase Improvement” is available iteratively again-and-again at the end of the current iteration, the proposed improvement algorithm, which is ‘Computerizable’, is an “Iterative-Algorithm”, leading to more-and-more efficient “Quadrature-Operator”, till we are pleased!
Space Operations, This document complements Joint Pub 3-56.1
2007-11-02
maintenance of on-orbit space assets. USSPACECOM uses the Space Operations Center ( SPOC ) to publish mission-type orders in the format of operations...operations forces SPACEAF Air Force Space Component [14 AF] SPOC Space Operations Center SPOT Satellite Probatore d’Observation de la Terre SRBM short
FIESTA: An operational decision aid for space network fault isolation
Lowe, Dawn; Quillin, Bob; Matteson, Nadine; Wilkinson, Bill; Miksell, Steve
1987-01-01
The Fault Tolerance Expert System for Tracking and Data Relay Satellite System (TDRSS) Applications (FIESTA) is a fault detection and fault diagnosis expert system being developed as a decision aid to support operations in the Network Control Center (NCC) for NASA's Space Network. The operational objectives which influenced FIESTA development are presented and an overview of the architecture used to achieve these goals are provided. The approach to the knowledge engineering effort and the methodology employed are also presented and illustrated with examples drawn from the FIESTA domain.
The Commutant of Analytic Toeplitz Operators on Bergman Space
Institute of Scientific and Technical Information of China (English)
Yu Cheng LI
2008-01-01
In this paper,using the matrix skills and operator theory techniques we characterize the commutant of analytic Toeplitz operators on Bergman space.For f(z) = zng(z) (n≥1),g(z) = bo +b1zP1+b2zP2+...,bk≠0 (k = 0,1,2...),our main result is (Mf) = (Mzn)∩ (Mg) = (Mzs),where s = g.c.d.(n,p1,p2,...).In the last section,we study the relation between strongly irreducible curve and the winding number W(f,f(a) ),a ∈ D.
Convex analysis and monotone operator theory in Hilbert spaces
Bauschke, Heinz H
2017-01-01
This reference text, now in its second edition, offers a modern unifying presentation of three basic areas of nonlinear analysis: convex analysis, monotone operator theory, and the fixed point theory of nonexpansive operators. Taking a unique comprehensive approach, the theory is developed from the ground up, with the rich connections and interactions between the areas as the central focus, and it is illustrated by a large number of examples. The Hilbert space setting of the material offers a wide range of applications while avoiding the technical difficulties of general Banach spaces. The authors have also drawn upon recent advances and modern tools to simplify the proofs of key results making the book more accessible to a broader range of scholars and users. Combining a strong emphasis on applications with exceptionally lucid writing and an abundance of exercises, this text is of great value to a large audience including pure and applied mathematicians as well as researchers in engineering, data science, ma...
International Space Station operations: New dimensions - October 13, 1987
Paules, Granville E.; Lyman, Peter; Shelley, Carl B.
1987-01-01
One of the principal goals of the participants in the International Space Station program is to provide a management support structure which is equitable and fair to all participants, responsive to the needs of users, responsible to other partners, and mutually supportive to the participation of other partners. Shared-utilization, shared-cost, and shared-operations policies considerations are discussed. Special attention is given to the methodology for identifying costs and benefits of this program, in which each partner should be provided with benefits in proportion to his contribution, and no partner would be forced to share in cost the inefficiencies introduced by other partners. The Space Station hierarchy of operations functions are identified, and the recommended framework planning and control hierarchy is presented.
The HAL 9000 Space Operating System Real-Time Planning Engine Design and Operations Requirements
Stetson, Howard; Watson, Michael D.; Shaughnessy, Ray
2012-01-01
In support of future deep space manned missions, an autonomous/automated vehicle, providing crew autonomy and an autonomous response planning system, will be required due to the light time delays in communication. Vehicle capabilities as a whole must provide for tactical response to vehicle system failures and space environmental effects induced failures, for risk mitigation of permanent loss of communication with Earth, and for assured crew return capabilities. The complexity of human rated space systems and the limited crew sizes and crew skills mix drive the need for a robust autonomous capability on-board the vehicle. The HAL 9000 Space Operating System[2] designed for such missions and space craft includes the first distributed real-time planning / re-planning system. This paper will detail the software architecture of the multiple planning engine system, and the interface design for plan changes, approval and implementation that is performed autonomously. Operations scenarios will be defined for analysis of the planning engines operations and its requirements for nominal / off nominal activities. An assessment of the distributed realtime re-planning system, in the defined operations environment, will be provided as well as findings as it pertains to the vehicle, crew, and mission control requirements needed for implementation.
Operational method for the space-energy slowing down problem
Energy Technology Data Exchange (ETDEWEB)
El Wakil, S.A.; Machali, H.M.; Madkour, M.A.; Saied, E.A.
1988-01-01
The direct operational method and Pade's approximation is used to transform the integro-differential form of the transport equation to differential form. The moment method and the similarity method are used to solve the space-energy problem in the slowing down region with energy-dependent cross section. The energy deposition factor is calculated in terms of the spatial-angular moments, without using the integral transform.
Probable Impacts of Space Operations on Air Force Civil Engineering
1989-05-01
University, Air Command and Staff College, Research Report). Bierling , James R ., Space Operations Professional Development Guide, Maxwell AFB, Alabama, April...basing containerized payloads self ferry Table S. NASP Technical Challenges and Confidence Factors4 1986 1988 1990 Airframe Structures and Materials R ...Y B Thermal Management Y G B Flight Vehicle Integration R G G Inlet/Nozzle Performane R Y 6 Slush Hydrogen Y Y 6 Propulsion Ramjet Y 6 B Scramjet
Moduli spaces of Dirac operators for finite spectral triples
Ćaćić, Branimir
2009-01-01
The structure theory of finite real spectral triples developed by Krajewski and by Paschke and Sitarz is generalised to allow for arbitrary KO-dimension and the failure of orientability and Poincare duality, and moduli spaces of Dirac operators for such spectral triples are defined and studied. This theory is then applied to recent work by Chamseddine and Connes towards deriving the finite spectral triple of the noncommutative-geometric Standard Model.
Operationalizing safe operating space for regional social-ecological systems.
Hossain, Md Sarwar; Dearing, John A; Eigenbrod, Felix; Johnson, Fiifi Amoako
2017-04-15
This study makes a first attempt to operationalize the safe operating space concept at a regional scale by considering the complex dynamics (e.g. non-linearity, feedbacks, and interactions) within a systems dynamic model (SD). We employ the model to explore eight 'what if' scenarios based on well-known challenges (e.g. climate change) and current policy debates (e.g. subsidy withdrawal). The findings show that the social-ecological system in the Bangladesh delta may move beyond a safe operating space when a withdrawal of a 50% subsidy for agriculture is combined with the effects of a 2°C temperature increase and sea level rise. Further reductions in upstream river discharge in the Ganges would push the system towards a dangerous zone once a 3.5°C temperature increase was reached. The social-ecological system in Bangladesh delta may be operated within a safe space by: 1) managing feedback (e.g. by reducing production costs) and the slow biophysical variables (e.g. temperature, rainfall) to increase the long-term resilience, 2) negotiating for transboundary water resources, and 3) revising global policies (e.g. withdrawal of subsidy) that negatively impact at regional scales. This study demonstrates how the concepts of tipping points, limits to adaptations, and boundaries for sustainable development may be defined in real world social-ecological systems.
Research Of Airborne Precision Spacing to Improve Airport Arrival Operations
Barmore, Bryan E.; Baxley, Brian T.; Murdoch, Jennifer L.
2011-01-01
In September 2004, the European Organization for the Safety of Air Navigation (EUROCONTROL) and the United States Federal Aviation Administration (FAA) signed a Memorandum of Cooperation to mutually develop, modify, test, and evaluate systems, procedures, facilities, and devices to meet the need for safe and efficient air navigation and air traffic control in the future. In the United States and Europe, these efforts are defined within the architectures of the Next Generation Air Transportation System (NextGen) Program and Single European Sky Air Traffic Management Research (SESAR) Program respectively. Both programs have identified Airborne Spacing as a critical component, with Automatic Dependent Surveillance Broadcast (ADS-B) as a key enabler. Increased interest in reducing airport community noise and the escalating cost of aviation fuel has led to the use of Continuous Descent Arrival (CDA) procedures to reduce noise, emissions, and fuel usage compared to current procedures. To provide these operational enhancements, arrival flight paths into terminal areas are planned around continuous vertical descents that are closer to an optimum trajectory than those in use today. The profiles are designed to be near-idle descents from cruise altitude to the Final Approach Fix (FAF) and are typically without any level segments. By staying higher and faster than conventional arrivals, CDAs also save flight time for the aircraft operator. The drawback is that the variation of optimized trajectories for different types and weights of aircraft requires the Air Traffic Controller to provide more airspace around an aircraft on a CDA than on a conventional arrival procedure. This additional space decreases the throughput rate of the destination airport. Airborne self-spacing concepts have been developed to increase the throughput at high-demand airports by managing the inter-arrival spacing to be more precise and consistent using on-board guidance. It has been proposed that the
Directory of Open Access Journals (Sweden)
Benjawan Rodjanadid
2013-12-01
Full Text Available In this paper, we introduce an iterative method for finding a common element of the set of solutions of a generalized mixed equilibrium problem (GMEP, the solutions of a general system of equilibrium problem and the set of common fixed points of a finite family of nonexpansive mappings in a real Hilbert space. Then, we prove that the sequence converges strongly to a common element of the above three sets. Furthermore, we apply our result to prove four new strong convergence theorems in fixed point problems, mixed equilibrium problems, generalized equilibrium problems , equilibrium problems and variational inequality.
Zhou, Xiaolin; Zheng, Xiaowei; Zhang, Rong; Hanzo, Lajos
2013-07-01
In this paper, we design a novel Poisson photon-counting based iterative successive interference cancellation (SIC) scheme for transmission over free-space optical (FSO) channels in the presence of both multiple access interference (MAI) as well as Gamma-Gamma atmospheric turbulence fading, shot-noise and background light. Our simulation results demonstrate that the proposed scheme exhibits a strong MAI suppression capability. Importantly, an order of magnitude of BER improvements may be achieved compared to the conventional chip-level optical code-division multiple-access (OCDMA) photon-counting detector.
A Simulation Base Investigation of High Latency Space Systems Operations
Li, Zu Qun; Crues, Edwin Z.; Bielski, Paul; Moore, Michael
2017-01-01
NASA's human space program has developed considerable experience with near Earth space operations. Although NASA has experience with deep space robotic missions, NASA has little substantive experience with human deep space operations. Even in the Apollo program, the missions lasted only a few weeks and the communication latencies were on the order of seconds. Human missions beyond the relatively close confines of the Earth-Moon system will involve missions with durations measured in months and communications latencies measured in minutes. To minimize crew risk and to maximize mission success, NASA needs to develop a better understanding of the implications of these types of mission durations and communication latencies on vehicle design, mission design and flight controller interaction with the crew. To begin to address these needs, NASA performed a study using a physics-based subsystem simulation to investigate the interactions between spacecraft crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation, built with a subsystem modeling tool developed at NASA's Johnson Space Center, models the life support system of a Mars transit vehicle. The simulation contains models of the cabin atmosphere and pressure control system, electrical power system, drinking and waste water systems, internal and external thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the vehicle subsystems; 2) a mission control center interface with data transport delays up to 15 minutes each way; 3) a real-time simulation test conductor interface that can be use to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission between July 18th and Aug 3rd of year 2016. The NEEMO
"Smart" Magnetic Fluids Experiment Operated on the International Space Station
Agui, Juan H.; Lekan, Jack F.
2004-01-01
InSPACE is a microgravity fluid physics experiment that was operated on the International Space Station (ISS) in the Microgravity Science Glovebox from late March 2003 through early July 2003. (InSPACE is an acronym for Investigating the Structure of Paramagnetic Aggregates From Colloidal Emulsions.) The purpose of the experiment is to obtain fundamental data of the complex properties of an exciting class of smart materials termed magnetorheological (MR) fluids. MR fluids are suspensions, or colloids, comprised of small (micrometer-sized) superparamagnetic particles in a nonmagnetic medium. Colloids are suspensions of very small particles suspended in a liquid. (Examples of other colloids are blood, milk, and paint.) These controllable fluids can quickly transition into a nearly solid state when exposed to a magnetic field and return to their original liquid state when the magnetic field is removed. Controlling the strength of the magnetic field can control the relative stiffness of these fluids. MR fluids can be used to improve or develop new seat suspensions, robotics, clutches, airplane landing gear, and vibration damping systems. The principal investigator for InSPACE is Professor Alice P. Gast of the Massachusetts Institute of Technology (MIT). The InSPACE hardware was developed at the NASA Glenn Research Center. The InSPACE samples were delivered to the ISS in November 2002, on the Space Shuttle Endeavour, on Space Station Utilization Flight UF-2/STS113. Operations began on March 31, 2003, with the processing of three different particle size samples at multiple test parameters. This investigation focused on determining the structural organization of MR colloidal aggregates when exposed to a pulsing magnetic field. On Earth, the aggregates take the shape of footballs with spiky tips. This characteristic shape may be influenced by the pull of gravity, which causes most particles initially suspended in the fluid to sediment, (i.e., settle and collect at the
Interactive intelligent remote operations: application to space robotics
Dupuis, Erick; Gillett, G. R.; Boulanger, Pierre; Edwards, Eric; Lipsett, Michael G.
1999-11-01
A set of tolls addressing the problems specific to the control and monitoring of remote robotic systems from extreme distances has been developed. The tools include the capability to model and visualize the remote environment, to generate and edit complex task scripts, to execute the scripts to supervisory control mode and to monitor and diagnostic equipment from multiple remote locations. Two prototype systems are implemented for demonstration. The first demonstration, using a prototype joint design called Dexter, shows the applicability of the approach to space robotic operation in low Earth orbit. The second demonstration uses a remotely controlled excavator in an operational open-pit tar sand mine. This demonstrates that the tools developed can also be used for planetary exploration operations as well as for terrestrial mining applications.
Ground controlled robotic assembly operations for Space Station Freedom
Parrish, Joseph C.
1991-01-01
A number of dextrous robotic systems and associated positioning and transportation devices are available on Space Station Freedom (SSF) to perform assembly tasks that would otherwise need to be performed by extravehicular activity (EVA) crewmembers. The currently planned operating mode for these robotic systems during the assembly phase is teleoperation by intravehicular activity (IVA) crewmembers. While this operating mode is less hazardous and expensive than manned EVA operations, and has insignificant control loop time delays, the amount of IVA time available to support telerobotic operations is much less than the anticipated requirements. Some alternative is needed to allow the robotic systems to perform useful tasks without exhausting the available IVA resources; ground control is one such alternative. The issues associated with ground control of SSF robotic systems to alleviate onboard crew time availability constraints are investigated. Key technical issues include the effect of communication time delays, the need for safe, reliable execution of remote operations, and required modifications to the SSF ground and flight system architecture. Time delay compensation techniques such as predictive displays and world model-based force reflection are addressed and collision detection and avoidance strategies to ensure the safety of the on-orbit crew, Orbiter, and SSF are described. Although more time consuming and difficult than IVA controlled teleoperations or manned EVA, ground controlled telerobotic operations offer significant benefits during the SSF assembly phase, and should be considered in assembly planning activities.
CO2 on the International Space Station: An Operations Update
Law, Jennifer; Alexander, David
2016-01-01
PROBLEM STATEMENT: We describe CO2 symptoms that have been reported recently by crewmembers on the International Space Station and our continuing efforts to control CO2 to lower levels than historically accepted. BACKGROUND: Throughout the International Space Station (ISS) program, anecdotal reports have suggested that crewmembers develop CO2-related symptoms at lower CO2 levels than would be expected terrestrially. Since 2010, operational limits have controlled the 24-hour average CO2 to 4.0 mm Hg, or below as driven by crew symptomatology. In recent years, largely due to increasing awareness by crew and ground team, there have been increased reports of crew symptoms. The aim of this presentation is to discuss recent observations and operational impacts to lower CO2 levels on the ISS. CASE PRESENTATION: Crewmembers are routinely asked about CO2 symptoms in their weekly private medical conferences with their crew surgeons. In recent ISS expeditions, crewmembers have noted symptoms attributable to CO2 starting at 2.3 mmHg. Between 2.3 - 2.7 mm Hg, fatigue and full-headedness have been reported. Between 2.7 - 3.0 mm Hg, there have been self-reports of procedure missed steps or procedures going long. Above 3.0 - 3.4 mm Hg, headaches have been reported. A wide range of inter- and intra-individual variability in sensitivity to CO2 have been noted. OPERATIONAL / CLINICAL RELEVANCE: These preliminary data provide semi-quantitative ranges that have been used to inform a new operational limit of 3.0 mmHg as a compromise between systems capabilities and the recognition that there are human health and performance impacts at recent ISS CO2 levels. Current evidence would suggest that an operational limit between 0.5 and 2.0 mm Hg may maintain health and performance. Future work is needed to establish long-term ISS and future vehicle operational limits.
Institute of Scientific and Technical Information of China (English)
Yu Shu; Min Wang
2015-01-01
In this paper, we prove the boundedness of the fractional maximal opera-tor, Hardy-Littlewood maximal operator and marcinkiewicz integrals associated with Schr ¨odinger operator on Morrey spaces with variable exponent.
Energy Technology Data Exchange (ETDEWEB)
Marqueta, A.; Garcia, I.; Gomez, A.; Garcia, L.; Sedano, E.; Fernandez, I.
2012-07-01
Conceptual Design of a test facility for the remote handling operations of the ITER Test Blanket Modules. Conditions inside a fusion reactor are incompatible with conventional manual maintenance tasks. the same applies for ancillary equipment. As a consequence, it will become necessary to turn to remote visualization and remote handling techniques, which will have in consideration the extreme conditions, both physical and operating, of ITER. Main goal of the project has been the realization of the conceptual design for the test facility for the Test Blanket Modules of ITER and their associated systems, related to the Remote Handling operations regarding the Port Cell area. Besides the definition of the operations and the specification of the main components and ancillary systems of the TBM graphical simulation have been used for the design, verification and validation of the remote handling operations. (Author)
EVA 2010: Preparing for International Space Station EVA Operations Post-Space Shuttle Retirement
Chullen, Cinda; West, William W.
2010-01-01
The expected retirement of the NASA Space Transportation System (also known as the Space Shuttle ) by 2011 will pose a significant challenge to Extra-Vehicular Activities (EVA) on-board the International Space Station (ISS). The EVA hardware currently used to assemble and maintain the ISS was designed assuming that it would be returned to Earth on the Space Shuttle for refurbishment, or if necessary for failure investigation. With the retirement of the Space Shuttle, a new concept of operations was developed to enable EVA hardware (Extra-vehicular Mobility Unit (EMU), Airlock Systems, EVA tools, and associated support hardware and consumables) to perform ISS EVAs until 2015, and possibly beyond to 2020. Shortly after the decision to retire the Space Shuttle was announced, the EVA 2010 Project was jointly initiated by NASA and the OneEVA contractor team. The challenges addressed were to extend the operating life and certification of EVA hardware, to secure the capability to launch EVA hardware safely on alternate launch vehicles, to protect for EMU hardware operability on-orbit, and to determine the source of high water purity to support recharge of PLSSs (no longer available via Shuttle). EVA 2010 Project includes the following tasks: the development of a launch fixture that would allow the EMU Portable Life Support System (PLSS) to be launched on-board alternate vehicles; extension of the EMU hardware maintenance interval from 3 years (current certification) to a minimum of 6 years (to extend to 2015); testing of recycled ISS Water Processor Assembly (WPA) water for use in the EMU cooling system in lieu of water resupplied by International Partner (IP) vehicles; development of techniques to remove & replace critical components in the PLSS on-orbit (not routine); extension of on-orbit certification of EVA tools; and development of an EVA hardware logistical plan to support the ISS without the Space Shuttle. Assumptions for the EVA 2010 Project included no more than
Weighted E-Spaces and Epistemic Information Operators
Directory of Open Access Journals (Sweden)
Mark Burgin
2014-06-01
Full Text Available Information is usually related to knowledge. Here, we present a broader picture in which information is associated with epistemic structures, which form cognitive infological systems as basic recipients and creators of cognitive information. Infological systems are modeled by epistemic spaces, while operators in these spaces are mathematical models of information. Information that acts on epistemic structures is called cognitive information, while information that acts on knowledge structures is called epistemic information. The latter brings new and updates existing knowledge, being of primary importance to people. In this paper, both types of information are studied as operators in epistemic spaces based on the general theory of information. As a synthetic approach, which reveals the essence of information, organizing and encompassing all main directions in information theory, the general theory of information provides efficient means for such a study. Different types of information dynamics representation use tools from various mathematical disciplines, such as the theory of categories, functional analysis, mathematical logic and algebra. In this paper, we base our exploration of information and knowledge dynamics on functional analysis further developing the mathematical stratum of the general theory of information.
Generalized Fractional Integral Operators on Generalized Local Morrey Spaces
Directory of Open Access Journals (Sweden)
V. S. Guliyev
2015-01-01
Full Text Available We study the continuity properties of the generalized fractional integral operator Iρ on the generalized local Morrey spaces LMp,φ{x0} and generalized Morrey spaces Mp,φ. We find conditions on the triple (φ1,φ2,ρ which ensure the Spanne-type boundedness of Iρ from one generalized local Morrey space LMp,φ1{x0} to another LMq,φ2{x0}, 1
space WLMq,φ2{x0}, 1
Jolicard, Georges; Viennot, David; Killingbeck, John P
2016-01-01
A global solution of the Schr\\"odinger equation, obtained recently within the wave operator formalism for explicitly time-dependent Hamiltonians [J. Phys. A: Math. Theor. 48, 225205 (2015)], is generalized to take into account the case of multidimensional active spaces. An iterative algorithm is derived to obtain the Fourier series of the evolution operator issuing from a given multidimensional active subspace and then the effective Hamiltonian corresponding to the model space is computed and analysed as a measure of the cyclic character of the dynamics. Studies of the laser controlled dynamics of diatomic models clearly show that a multidimensional active space is required if the wavefunction escapes too far from the initial subspace. A suitable choice of the multidimensional active space, including the initial and target states, increases the cyclic character and avoids divergences occuring when one-dimensional active spaces are used. The method is also proven to be efficient in describing dissipative proce...
Generalized Browder's and Weyl's theorems for Banach space operators
Curto, Raúl E.; Han, Young Min
2007-12-01
We find necessary and sufficient conditions for a Banach space operator T to satisfy the generalized Browder's theorem. We also prove that the spectral mapping theorem holds for the Drazin spectrum and for analytic functions on an open neighborhood of [sigma](T). As applications, we show that if T is algebraically M-hyponormal, or if T is algebraically paranormal, then the generalized Weyl's theorem holds for f(T), where f[set membership, variant]H((T)), the space of functions analytic on an open neighborhood of [sigma](T). We also show that if T is reduced by each of its eigenspaces, then the generalized Browder's theorem holds for f(T), for each f[set membership, variant]H([sigma](T)).
Dextre: Improving maintenance operations on the International Space Station
Coleshill, Elliott; Oshinowo, Layi; Rembala, Richard; Bina, Bardia; Rey, Daniel; Sindelar, Shelley
2009-05-01
The Special Purpose Dexterous Manipulator (SPDM), known as "Dextre", is currently slated to launch in February 2008 for deployment on the International Space Station (ISS) as the final component of Canada's Mobile Servicing System (MSS). Dextre's primary role on the Space Station is to perform repair and replacement (R&R) maintenance tasks on robotically compatible hardware such as Orbital Replaceable Units (ORUs), thereby eventually easing the burden on the ISS crew. This burden on the on-orbit crew translates practically into crew time being a limited resource on the ISS, and as such, finding ways to assist the crew in performing their tasks or offloading the crew completely when appropriate is a bonus to the ISS program. This is already accomplished very effectively by commanding as many non-critical robotics tasks as possible, such as powering up and free-space maneuvering of the Space Station Remote Manipulator System (SSRMS), known as "Canadarm2", from the Ground. Thus, beyond its primary role, and based on an increasing clarity regarding the challenges of external maintenance on the ISS, Dextre is being considered for use in a number of ways with the objective of improving ISS operations while reducing and optimizing the use of crew time through the use of ground control for various tasks, pre-positioning hardware, acting as a temporary storage platform to break an Extra Vehicular Activity (EVA) day into manageable timelines, and extending the physical reach and range of the Canadarm2. This paper discusses the planned activities and operations for Dextre an rationale for how these will help optimize the use of crew resources on the ISS.
Commutators of Integral Operators with Variable Kernels on Hardy Spaces
Indian Academy of Sciences (India)
Pu Zhang; Kai Zhao
2005-11-01
Let $T_{,}(0≤ < n)$ be the singular and fractional integrals with variable kernel $(x,z)$, and $[b, T_{,}]$ be the commutator generated by $T_{,}$ and a Lipschitz function . In this paper, the authors study the boundedness of $[b, T_{,}]$ on the Hardy spaces, under some assumptions such as the $L^r$-Dini condition. Similar results and the weak type estimates at the end-point cases are also given for the homogeneous convolution operators $T_{\\overline{},}(0≤ < n)$. The smoothness conditions imposed on $\\overline{}$ are weaker than the corresponding known results.
Panoramic Stereoscopic Video System for Remote-Controlled Robotic Space Operations Project
National Aeronautics and Space Administration — This Phase I project will demonstrate the feasibility of providing panoramic stereoscopic images for remote-controlled robotic space operations using three...
ITERATIVE ALGORITHMS FOR DATA ASSIMILATION PROBLEMS
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Iterative algorithms for solving the data assimilation problems are considered, based on the main and adjoint equations. Spectral properties of the control operators of the problem are studied, the iterative algorithms are justified.
Sartori, E; Pavei, M; Marcuzzi, D; Zaccaria, P
2014-02-01
The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.
Sartori, E.; Pavei, M.; Marcuzzi, D.; Zaccaria, P.
2014-02-01
The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.
Energy Technology Data Exchange (ETDEWEB)
Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Pavei, M.; Marcuzzi, D.; Zaccaria, P. [Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy)
2014-02-15
The beam formation and acceleration of the ITER neutral beam injector will be studied in the full-scale ion source, Source for Production of Ions of Deuterium Extracted from a RF plasma (SPIDER). It will be able to sustain 40 A deuterium ion beam during 1-h pulses. The operating conditions of its multi-aperture electrodes will diverge from ideality, as a consequence of inhomogeneous heating and thermally induced deformations in the support structure of the extraction and acceleration grids, which operate at different temperatures. Meeting the requirements on the aperture alignment and distance between the grids with such a large number of apertures (1280) and the huge support structures constitute a challenge. Examination of the structure thermal deformation in transient and steady conditions has been carried out, evaluating their effect on the beam performance: the paper describes the analyses and the solutions proposed to mitigate detrimental effects.
Institute of Scientific and Technical Information of China (English)
侯春兰
2012-01-01
In order to prove our desired result, an Ishikawa iterative CQ deformation is first worked out for the Gradient projection operator, and the strong convergence of which is then proved. And a viscous deformation in Ishikawa form is presented. In combination with certain suitable conditions, the strong convergence of the gradient projection operators is proved, and the results obtained greatly improve the results published in the latest literatures.%为证明所要结果，首先给出一个梯度投影算子的Ishikawa迭代的CQ变形，并证明它的强收敛性．然后给出一个Ishikawa形式的黏性变形，结合适当条件证明梯度投影算子的强收敛性．
On strictly singular operators between separable Banach spaces
Beanland, Kevin
2010-01-01
Let $X$ and $Y$ be separable Banach spaces and denote by $\\sss\\sss(X,Y)$ the subset of $\\llll(X,Y)$ consisting of all strictly singular operators. We study various ordinal ranks on the set $\\sss\\sss(X,Y)$. Our main results are summarized as follows. Firstly, we define a new rank $\\rs$ on $\\sss\\sss(X,Y)$. We show that $\\rs$ is a co-analytic rank and that dominates the rank $\\varrho$ introduced by Androulakis, Dodos, Sirotkin and Troitsky [Israel J. Math., 169 (2009), 221-250]. Secondly, for every $1\\leq p<+\\infty$ we construct a Banach space $Y_p$ with an unconditional basis such that $\\sss\\sss(\\ell_p, Y_p)$ is a co-analytic non-Borel subset of $\\llll(\\ell_p,Y_p)$ yet every strictly singular operator $T:\\ell_p\\to Y_p$ satisfies $\\varrho(T)\\leq 2$. This answers a question of Argyros.
Bradford, Robert N.
2006-01-01
Earth based networking in support of various space agency projects has been based on leased service/circuits which has a high associated cost. This cost is almost always taken from the science side resulting in less science. This is a proposal to use Research and Education Networks (RENs) worldwide to support space flight operations in general and space-based science operations in particular. The RENs were developed to support scientific and educational endeavors. They do not provide support for general Internet traffic. The connectivity and performance of the research and education networks is superb. The connectivity at Layer 3 (IP) virtually encompasses the globe. Most third world countries and all developed countries have their own research and education networks, which are connected globally. Performance of the RENs especially in the developed countries is exceptional. Bandwidth capacity currently exists and future expansion promises that this capacity will continue. REN performance statistics has always exceeded minimum requirements for spaceflight support. Research and Education networks are more loosely managed than a corporate network but are highly managed when compared to the commodity Internet. Management of RENs on an international level is accomplished by the International Network Operations Center at Indiana University at Indianapolis. With few exceptions, each regional and national REN has its own network ops center. The acceptable use policies (AUP), although differing by country, allows any scientific program or project the use of their networks. Once in compliance with the first RENs AUP, all others will accept that specific traffic including regional and transoceanic networks. RENs can support spaceflight related scientific programs and projects. Getting the science to the researcher is obviously key to any scientific project. RENs provide a pathway to virtually any college or university in the world, as well as many governmental institutes and
Operational environments for electrical power wiring on NASA space systems
Stavnes, Mark W.; Hammoud, Ahmad N.; Bercaw, Robert W.
1994-01-01
Electrical wiring systems are used extensively on NASA space systems for power management and distribution, control and command, and data transmission. The reliability of these systems when exposed to the harsh environments of space is very critical to mission success and crew safety. Failures have been reported both on the ground and in flight due to arc tracking in the wiring harnesses, made possible by insulation degradation. This report was written as part of a NASA Office of Safety and Mission Assurance (Code Q) program to identify and characterize wiring systems in terms of their potential use in aerospace vehicles. The goal of the program is to provide the information and guidance needed to develop and qualify reliable, safe, lightweight wiring systems, which are resistant to arc tracking and suitable for use in space power applications. This report identifies the environments in which NASA spacecraft will operate, and determines the specific NASA testing requirements. A summary of related test programs is also given in this report. This data will be valuable to spacecraft designers in determining the best wiring constructions for the various NASA applications.
TAMU: Blueprint for A New Space Mission Operations System Paradigm
Ruszkowski, James T.; Meshkat, Leila; Haensly, Jean; Pennington, Al; Hogle, Charles
2011-01-01
The Transferable, Adaptable, Modular and Upgradeable (TAMU) Flight Production Process (FPP) is a System of System (SOS) framework which cuts across multiple organizations and their associated facilities, that are, in the most general case, in geographically disperse locations, to develop the architecture and associated workflow processes of products for a broad range of flight projects. Further, TAMU FPP provides for the automatic execution and re-planning of the workflow processes as they become operational. This paper provides the blueprint for the TAMU FPP paradigm. This blueprint presents a complete, coherent technique, process and tool set that results in an infrastructure that can be used for full lifecycle design and decision making during the flight production process. Based on the many years of experience with the Space Shuttle Program (SSP) and the International Space Station (ISS), the currently cancelled Constellation Program which aimed on returning humans to the moon as a starting point, has been building a modern model-based Systems Engineering infrastructure to Re-engineer the FPP. This infrastructure uses a structured modeling and architecture development approach to optimize the system design thereby reducing the sustaining costs and increasing system efficiency, reliability, robustness and maintainability metrics. With the advent of the new vision for human space exploration, it is now necessary to further generalize this framework to take into consideration a broad range of missions and the participation of multiple organizations outside of the MOD; hence the Transferable, Adaptable, Modular and Upgradeable (TAMU) concept.
Matty, Christopher M.
2010-01-01
Crewed space vehicles have a common requirement to remove the carbon dioxide (CO2) created by the metabolic processes of the crew. The space shuttle [Space Transportation System (STS)] and International Space Station (ISS) each have systems in place that allow control and removal of CO2 from the habitable cabin environment. During periods in which the space shuttle is docked to the ISS, known as "joint docked operations," the space shuttle and ISS share a common atmosphere environment. During this period, an elevated amount of CO2 is produced through the combined metabolic activity of the STS and ISS crews. This elevated CO2 production, together with the large effective atmosphere created by collective volumes of the docked vehicles, creates a unique set of requirements for CO2 removal. This paper will describe individual CO2 control plans implemented by STS and ISS engineering teams, as well as the integrated plans used when both vehicles are docked. The paper will also discuss some of the issues and anomalies experienced by both engineering teams.
Summability results for operator matrices on topological vector spaces
Institute of Scientific and Technical Information of China (English)
LI; Ronglu
2001-01-01
［1］Robinson, A., On functional transformations and summability, Proc. London Math. Soc., 1950, 52: 132—160.［2］Maddox, I. J., Infinite matrices of operators, Lecture Notes in Math., Berlin-Heidelberg-New York: Springer-Verlag, 1980, 786.［3］Swartz, C., The Schur and Hahn Theorems for operator matrices, Rocky Mountain J. Math., 1985, 15: 61—73.［4］Maddox, I. J., Uniform Toeplitz matrices, Inter. J. Math. & Math. Sci., 1990, 13: 227—232.［5］Swartz, C., Infinite Matrices and the Gliding Hump, Singapore-New Jersey-London-Hong Kong: World Scientific, 1996.［6］Li Ronglu, Swartz, C., A nonlinear Schur theorem, Acta Sci. Math., 1993, 58: 497—508.［7］Li Ronglu, A uniform convergence principle, J. Harbin Institute of Technology, 1992, 24(3): 107—108.［8］Wu Junde, Li Ronglu, An equivalent form of Antosik-Mikusinski basic matrix theorem, Advances in Math., 1999, 28(3): 268.［9］Khaleelulla, S. M., Counterexamples in topological vector spaces, Lecture Notes in Math., Heidelberg: Springer-Verlag, 1982, 936.［10］Li Ronglu, Bu Qingying, Locally convex spaces containing no copy of c0, J. Math. Anal. Appl.,1993, 172: 205—211.［11］Li Ronglu, Cui Chengri, Chao Min-Hyung, Invariants on all admissible polar topologies, Chinese Annals of Math., 1998, 19A(3): 1—6.［12］Swartz, C., Stuart, C., Orlicz-Pettis theorems for multiplier convergent series, J. for Anal. and Its Appl., 1998, 17(4): 805—811.［13］Wu Junde, Li Ronglu, An Orlicz-Pettis theorem with applications to A-spaces, Studia Sci. Math. Hungar., 1999, 35: 353—358.
Flight Dynamics Operations: Methods and Lessons Learned from Space Shuttle Orbit Operations
Cutri-Kohart, Rebecca M.
2011-01-01
The Flight Dynamics Officer is responsible for trajectory maintenance of the Space Shuttle. This paper will cover high level operational considerations, methodology, procedures, and lessons learned involved in performing the functions of orbit and rendezvous Flight Dynamics Officer and leading the team of flight dynamics specialists during different phases of flight. The primary functions that will be address are: onboard state vector maintenance, ground ephemeris maintenance, calculation of ground and spacecraft acquisitions, collision avoidance, burn targeting for the primary mission, rendezvous, deorbit and contingencies, separation sequences, emergency deorbit preparation, mass properties coordination, payload deployment planning, coordination with the International Space Station, and coordination with worldwide trajectory customers. Each of these tasks require the Flight Dynamics Officer to have cognizance of the current trajectory state as well as the impact of future events on the trajectory plan in order to properly analyze and react to real-time changes. Additionally, considerations are made to prepare flexible alternative trajectory plans in the case timeline changes or a systems failure impact the primary plan. The evolution of the methodology, procedures, and techniques used by the Flight Dynamics Officer to perform these tasks will be discussed. Particular attention will be given to how specific Space Shuttle mission and training simulation experiences, particularly off-nominal or unexpected events such as shortened mission durations, tank failures, contingency deorbit, navigation errors, conjunctions, and unexpected payload deployments, have influenced the operational procedures and training for performing Space Shuttle flight dynamics operations over the history of the program. These lessons learned can then be extended to future vehicle trajectory operations.
Ioan Boţ, Radu; Hofmann, Bernd
2016-12-01
In the literature on singular perturbation (Lavrentiev regularization) for the stable approximate solution of operator equations with monotone operators in the Hilbert space the phenomena of conditional stability and local well-posedness or ill-posedness are rarely investigated. Our goal is to present some studies which try to bridge this gap. So we present new results on the impact of conditional stability on error estimates and convergence rates for the Lavrentiev regularization and distinguish for linear problems well-posedness and ill-posedness in a specific manner motivated by a saturation result. Taking into account that the behavior of the bias (regularization error in the noise-free case) is crucial, general convergence rates, including logarithmic rates, are derived for linear operator equations by means of the method of approximate source conditions. This allows us to extend well-known convergence rate results for the Lavrentiev regularization that were based on general source conditions to the case of non-selfadjoint linear monotone forward operators for which general source conditions fail. Examples presenting the self-adjoint multiplication operator as well as the non-selfadjoint fractional integral operator and Cesàro operator illustrate the theoretical results. Extensions to the nonlinear case under specific conditions on the nonlinearity structure complete the paper.
Applications of human error analysis to aviation and space operations
Energy Technology Data Exchange (ETDEWEB)
Nelson, W.R.
1998-07-01
For the past several years at the Idaho National Engineering and Environmental Laboratory (INEEL) we have been working to apply methods of human error analysis to the design of complex systems. We have focused on adapting human reliability analysis (HRA) methods that were developed for Probabilistic Safety Assessment (PSA) for application to system design. We are developing methods so that human errors can be systematically identified during system design, the potential consequences of each error can be assessed, and potential corrective actions (e.g. changes to system design or procedures) can be identified. These applications lead to different requirements when compared with HR.As performed as part of a PSA. For example, because the analysis will begin early during the design stage, the methods must be usable when only partial design information is available. In addition, the ability to perform numerous ''what if'' analyses to identify and compare multiple design alternatives is essential. Finally, since the goals of such human error analyses focus on proactive design changes rather than the estimate of failure probabilities for PRA, there is more emphasis on qualitative evaluations of error relationships and causal factors than on quantitative estimates of error frequency. The primary vehicle we have used to develop and apply these methods has been a series of projects sponsored by the National Aeronautics and Space Administration (NASA) to apply human error analysis to aviation operations. The first NASA-sponsored project had the goal to evaluate human errors caused by advanced cockpit automation. Our next aviation project focused on the development of methods and tools to apply human error analysis to the design of commercial aircraft. This project was performed by a consortium comprised of INEEL, NASA, and Boeing Commercial Airplane Group. The focus of the project was aircraft design and procedures that could lead to human errors during
Stratton, B.; Delgado-Aparicio, L.; Hill, K.; Johnson, D.; Pablant, N.; Barnsley, R.; Bertschinger, G.; de Bock, M. F. M.; Reichle, R.; Udintsev, V. S.; Watts, C.; Austin, M.; Phillips, P.; Beiersdorfer, P.; Biewer, T. M.; Hanson, G.; Klepper, C. C.; Carlstrom, T.; van Zeeland, M. A.; Brower, D.; Doyle, E.; Peebles, A.; Ellis, R.; Levinton, F.; Yuh, H.
2013-10-01
The US is providing 7 diagnostics to ITER: the Upper Visible/IR cameras, the Low Field Side Reflectometer, the Motional Stark Effect diagnostic, the Electron Cyclotron Emission diagnostic, the Toroidal Interferometer/Polarimeter, the Core Imaging X-Ray Spectrometer, and the Diagnostic Residual Gas Analyzer. The front-end components of these systems must operate with high reliability in conditions of long pulse operation, high neutron and gamma fluxes, very high neutron fluence, significant neutron heating (up to 7 MW/m3) , large radiant and charge exchange heat flux (0.35 MW/m2) , and high electromagnetic loads. Opportunities for repair and maintenance of these components will be limited. These conditions lead to significant challenges for the design of the diagnostics. Space constraints, provision of adequate radiation shielding, and development of repair and maintenance strategies are challenges for diagnostic integration into the port plugs that also affect diagnostic design. The current status of design of the US ITER diagnostics is presented and R&D needs are identified. Supported by DOE contracts DE-AC02-09CH11466 (PPPL) and DE-AC05-00OR22725 (UT-Battelle, LLC).
Composition operators on the Lipschitz space in polydiscs
Institute of Scientific and Technical Information of China (English)
ZHOU; Zehua(周泽华)
2003-01-01
Let Un be the unit polydisc of Cn and φ= (φ1,...,φn) a holomorphic self-map of Un. Let0 ≤α＜ 1. This paper shows that the composition operator Cφ is bounded on the Lipschitz space Lipα(Un)if and only if there exists M ＞ 0 such that∑nk,l=1|φl/zk(z)|( 1-|zk|2/1-|φl(z)|2)1-α≤ Mfor z ∈ Un. Moreover Cφ is compact on Lipα(Un) if and only if Cφ is bounded on Lipα(Un) and for everyε＞ 0, there exists a δ＞ 0 such that∑nk,l=1|φl/zk(z)|( 1-|zk|2/1-|φl(z)|2)1-α≤εwhenever dist(φ(z), Un) ＜δ.
Space Station assembly sequence planning - An engineering and operational challenge
Kaidy, James T.; Bastedo, William G.
1988-01-01
This paper discusses the Space Station assembly sequence planning and development process. It presents the planning methodologies from both historial and current perspectives. It is shown that planning the assembly sequence is a new and unique challenge and its solution requires the simultaneous satisfaction of many diverse variables and constants. The considerations which influence the development of the assembly sequence include launch vehicle integration and lift capabilities, on-orbit assembly flight operations, vehicle flight dynamics, spacecraft system capabilities and resource availability. Many of these considerations are described in this paper. In addition, the examples presented demonstrate the current process for assembly sequence planning and show many of the complex trade-offs that must be performed.
Strongly Singular Calderón-Zygmund Operator and Commutator on Morrey Type Spaces
Institute of Scientific and Technical Information of China (English)
Yan LIN
2007-01-01
In this paper, the author considers the boundedness of strongly singular Calderón-Zygmund operator and commutator generated by this operator and Lipschitz function on the classical Morrey space and generalized Morrey space. Moreover, the boundedness of strongly singular CalderónZygmund operator on the predual of Morrey space is discussed.
Assessing the Operationality of Ship Detection from Space
Greidanus, H.
2005-03-01
Since the launch of ERS-1 in 1991, a decade and a half of research has been devoted to automatic detection of ships in satellite radar imagery. However, it is only quite recently that this capability is operationally used; at present primarily in the fields of fisheries control and defence. The key has been the combination of remote sensing data with vessel position data from other sources. In contrast to detection, classification of ships in satellite radar imagery is much less developed, and will likely remain difficult in the near future. Concerning optical imagery, the recent high-resolution systems can readily detect ships from space, and their classification power is much higher than that of radar. However, much less effort has been devoted to development of automatic systems for optical, mostly because these sensors suffer more from the weather and are less suited for wide area surveillance. Nevertheless, there has been a recent catching up, and the first operational systems for automatic ship detection and classification in optical satellite images are starting to appear.
Energy Technology Data Exchange (ETDEWEB)
Kim, Hae Jin, E-mail: haejin@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Wang, Son Jong; Park, Byoung Ho; Kwak, Jong-Gu [National Fusion Research Institute, Daejeon (Korea, Republic of); Hillairet, Julien [CEA/IRFM, Saint-lez-Durance (France); Choi, Jin Joo [Kwangwoon University, Seoul (Korea, Republic of)
2015-10-15
Highlights: • Amplitude balanced 3 dB coaxial hybrid splitter has been designed and rf tested. • The proposed hybrid is applicable to ITER ICRF transmission line for load resilience. • Two-section, broadband coaxial hybrid can be tunable by changing dielectric insulator. - Abstract: RF design and network analyzer tests of broadband, amplitude-balanced coaxial hybrid junctions are presented. We have designed two 3 dB hybrid splitters with 9 and 12 in. coaxial transmission lines applicable to ITER ICRF for load-resilient operations using ANSYS HFSS. Amplitude-balanced broadband responses were obtained with the combination of impedance reductions of longitudinal and transverse branches in unequal proportion, length change of 50 Ω lines and diameter change of high impedance lines connected transversely to the T-section of the hybrid splitter, respectively. We have fabricated and RF tested the 9 in. coaxial hybrid coupler. We obtained an excellent coupling flatness of −3.2 ± 0.2 dB, phase difference of 4 degrees and return loss of 16 dB in 40–55 MHz. The measured data of 9 in. hybrid splitter is highly consistent with HFSS simulations. We found that the proposed 3 dB hybrid splitter can be tunable with amplitude-balanced, broadband response by changing dielectric insulators to keep the inner and outer conductors of coaxial line apart. The proposed 3 dB hybrid splitter can be utilized for load-resilient operations in a wide range of antenna load variations due to mode transitions or edge localized modes (ELMs) in fusion plasmas.
Anomaly Detection for Next-Generation Space Launch Ground Operations
Spirkovska, Lilly; Iverson, David L.; Hall, David R.; Taylor, William M.; Patterson-Hine, Ann; Brown, Barbara; Ferrell, Bob A.; Waterman, Robert D.
2010-01-01
NASA is developing new capabilities that will enable future human exploration missions while reducing mission risk and cost. The Fault Detection, Isolation, and Recovery (FDIR) project aims to demonstrate the utility of integrated vehicle health management (IVHM) tools in the domain of ground support equipment (GSE) to be used for the next generation launch vehicles. In addition to demonstrating the utility of IVHM tools for GSE, FDIR aims to mature promising tools for use on future missions and document the level of effort - and hence cost - required to implement an application with each selected tool. One of the FDIR capabilities is anomaly detection, i.e., detecting off-nominal behavior. The tool we selected for this task uses a data-driven approach. Unlike rule-based and model-based systems that require manual extraction of system knowledge, data-driven systems take a radically different approach to reasoning. At the basic level, they start with data that represent nominal functioning of the system and automatically learn expected system behavior. The behavior is encoded in a knowledge base that represents "in-family" system operations. During real-time system monitoring or during post-flight analysis, incoming data is compared to that nominal system operating behavior knowledge base; a distance representing deviation from nominal is computed, providing a measure of how far "out of family" current behavior is. We describe the selected tool for FDIR anomaly detection - Inductive Monitoring System (IMS), how it fits into the FDIR architecture, the operations concept for the GSE anomaly monitoring, and some preliminary results of applying IMS to a Space Shuttle GSE anomaly.
General Purpose Data-Driven System Monitoring for Space Operations
National Aeronautics and Space Administration — Modern space propulsion and exploration system designs are becoming increasingly sophisticated and complex. Determining the health state of these systems using...
Fixed Points of Non-expansive Operators on Weakly Cauchy Normed Spaces
Directory of Open Access Journals (Sweden)
Sahar M. Ali
2007-01-01
Full Text Available We proved the existence of fixed points of non-expansive operators defined on weakly Cauchy spaces in which parallelogram law holds, the given normed space is not necessarily be uniformly convex Banach space or Hilbert space, we reduced the completeness and the uniform convexity assumptions which imposed on the given normed space.
The Future of Army Space Forces: A Vision to Optimize Tactical and Operational Space Support
2007-01-01
variety of satellite communications capabilities. 5. Expand Army Space Support Team Role in Headquarters Without Space Support Elements. The...Space capabilities, improving Space technical training, modifying FA40 manpower allocations, expanding Army Space Support Team roles in headquar
Kennedy Space Center Orion Processing Team Planning for Ground Operations
Letchworth, Gary; Schlierf, Roland
2011-01-01
Topics in this presentation are: Constellation Ares I/Orion/Ground Ops Elements Orion Ground Operations Flow Orion Operations Planning Process and Toolset Overview, including: 1 Orion Concept of Operations by Phase 2 Ops Analysis Capabilities Overview 3 Operations Planning Evolution 4 Functional Flow Block Diagrams 5 Operations Timeline Development 6 Discrete Event Simulation (DES) Modeling 7 Ground Operations Planning Document Database (GOPDb) Using Operations Planning Tools for Operability Improvements includes: 1 Kaizen/Lean Events 2 Mockups 3 Human Factors Analysis
Strong Metrizability for Closed Operators and the Semi-Fredholm Operators between Two Hilbert Spaces
Directory of Open Access Journals (Sweden)
Mohammed Benharrat
2015-08-01
Full Text Available To be able to refine the completion of C(H1, H2, the of set all closed densely defined linear operators between two Hilbert spaces H1 and H2, we define in this paper some new strictly stronger metrics than the gap metric g and we characterize the closure with respect to theses metrics of the subset L(H1, H2 of bounded elements of C(H1, H2. In addition, several operator norm inequalities concerning the equivalence of some metrics on L(H1, H2 are presented. We also establish the semi-Fredholmness and Fredholmness of unbounded in terms of bounded pure contractions.
Strong Metrizability for Closed Operators and the Semi-Fredholm Operators between Two Hilbert Spaces
Directory of Open Access Journals (Sweden)
Mohammed Benharrat
2015-08-01
Full Text Available To be able to refine the completion of C(H1, H2, the of set all closed densely defined linear operators between two Hilbert spaces H1 and H2, we define in this paper some new strictly stronger metrics than the gap metric g and we characterize the closure with respect to theses metrics of the subset L(H1, H2 of bounded elements of C(H1, H2. In addition, several operator norm inequalities concerning the equivalence of some metrics on L(H1, H2 are presented. We also establish the semi-Fredholmness and Fredholmness of unbounded in terms of bounded pure contractions.
Aggregation-iterative analogues and generalizations of projection-iterative methods
Directory of Open Access Journals (Sweden)
Shuvar B.F.
2013-06-01
Full Text Available Aggregation-iterative algorithms for linear operator equations are constructed and investigated. These algorithms cover methods of iterative aggregation and projection-iterative methods. In convergence conditions there is neither requirement for the corresponding operator of fixed sign no restriction to the spectral radius to be less than one.
Directory of Open Access Journals (Sweden)
Waleed Albusaidi
2015-08-01
Full Text Available This paper introduces a new iterative method to predict the equivalent centrifugal compressor performance at various operating conditions. The presented theoretical analysis and empirical correlations provide a novel approach to derive the entire compressor map corresponding to various suction conditions without a prior knowledge of the detailed geometry. The efficiency model was derived to reflect the impact of physical gas properties, Mach number, and flow and work coefficients. One of the main features of the developed technique is the fact that it considers the variation in the gas properties and stage efficiency which makes it appropriate with hydrocarbons. This method has been tested to predict the performance of two multistage centrifugal compressors and the estimated characteristics are compared with the measured data. The carried comparison revealed a good matching with the actual values, including the stable operation region limits. Furthermore, an optimization study was conducted to investigate the influences of suction conditions on the stage efficiency and surge margin. Moreover, a new sort of presentation has been generated to obtain the equivalent performance characteristics for a constant discharge pressure operation at variable suction pressure and temperature working conditions. A further validation is included in part two of this study in order to evaluate the prediction capability of the derived model at various gas compositions.
Directory of Open Access Journals (Sweden)
Waleed Albusaidi
2015-08-01
Full Text Available This is the second part of a study conducted to model the aerothermodynamic impact of suction parameters and gas properties on a multi-stage centrifugal compressor’s performance. A new iterative method has been developed in the first part to derive the equivalent performance at various operating conditions. This approach has been validated to predict the compressor map at different suction pressures and temperatures using the design characteristics as reference values. A further case is included in this paper in order to emphasize the validity of the developed approach to obtain the performance characteristics at various gas compositions. The provided example shows that the performance parameters at different gas mixtures can be predicted to within ±1.34%. Furthermore, the conducted optimization in this paper reveals that the proposed method can be applied for the compressor design evaluation corresponding to the expected variation in suction conditions. Moreover, the examined case study demonstrates the effect of gas properties’ variation on the operating point and aerodynamic stability of the entire compression system. In order to achieve that, a simple approach has been established to assess the contribution of gas properties’ variation to the inefficient and unstable compressor performance based on the available operational data.
Space station operations task force. Panel 3 report: User development and integration
1987-01-01
The User Development and Integration Panel of the Space Station Operations Task Force was chartered to develop concepts relating to the operations of the Space Station manned base and the platforms, user accommodation and integration activities. The needs of the user community are addressed in the context with the mature operations phase of the Space Station. Issues addressed include space station pricing options, marketing strategies, payload selection and resource allocation options, and manifesting techniques.
Directory of Open Access Journals (Sweden)
Wei-Qi Deng
2013-01-01
Full Text Available Let be a nonempty, closed, and convex subset of a real uniformly convex Banach space . Let and be two infinite families of asymptotically nonexpansive mappings from to itself with . For an arbitrary initial point , is defined as follows: , , , where and with and satisfying the positive integer equation: , ; and are two countable subsets of and respectively; , , , , , and are sequences in for some , satisfying and . Under some suitable conditions, a strong convergence theorem for common fixed points of the mappings and is obtained. The results extend those of the authors whose related researches are restricted to the situation of finite families of asymptotically nonexpansive mappings.
Spatiality of Derivations of Operator Algebras in Banach Spaces
Directory of Open Access Journals (Sweden)
Quanyuan Chen
2011-01-01
Full Text Available Suppose that A is a transitive subalgebra of B(X and its norm closure A¯ contains a nonzero minimal left ideal I. It is shown that if δ is a bounded reflexive transitive derivation from A into B(X, then δ is spatial and implemented uniquely; that is, there exists T∈B(X such that δ(A=TA−AT for each A∈A, and the implementation T of δ is unique only up to an additive constant. This extends a result of E. Kissin that “if A¯ contains the ideal C(H of all compact operators in B(H, then a bounded reflexive transitive derivation from A into B(H is spatial and implemented uniquely.” in an algebraic direction and provides an alternative proof of it. It is also shown that a bounded reflexive transitive derivation from A into B(X is spatial and implemented uniquely, if X is a reflexive Banach space and A¯ contains a nonzero minimal right ideal I.
Operationally Responsive Space (ORS) Architecture for the Year 2025
2008-06-15
each sub-mission area. The goal was to get the “biggest bang for the buck .” Team A underwent two iterations of the “evaluation and selection” loop...three at Cape Canaveral and one at Vandenberg Air Force Base) and “plug and play” technology will be introduced into the Delta boosters . Together...from ten days to three; would decrease post-launch pad refurbishment time from 20 days to ten; and would reduce booster trouble- shooting/ repair
Institute of Scientific and Technical Information of China (English)
白占立; 姜桅
2012-01-01
It is researched that the equivalent problems of the convergence theorems of modified Mann and Ishikawa iterations with errors in real Banach spaces.%在任意实Banach空间中研究了带误差修改的Mann迭代和Ishikawa迭代收敛的等价性问题.
The Fermionic Signature Operator and Quantum States in Rindler Space-Time
Finster, Felix; Röken, Christian
2016-01-01
The fermionic signature operator is constructed in Rindler space-time. It is shown to be an unbounded self-adjoint operator on the Hilbert space of solutions of the massive Dirac equation. In two-dimensional Rindler space-time, we prove that the resulting fermionic projector state coincides with the Fulling-Rindler vacuum. Moreover, the fermionic signature operator gives a covariant construction of general thermal states, in particular of the Unruh state. The fermionic signature operator is shown to be well-defined in asymptotically Rindler space-times. In four-dimensional Rindler space-time, our construction gives rise to new quantum states.
Sibert, D.; Borgeson, D.; Peterson, G.; Jenkin, A.; Sorge, M.
2010-09-01
Even if global space policy successfully curtails on orbit explosions and ASAT demonstrations, studies indicate that the number of debris objects in Low Earth Orbit (LEO) will continue to grow solely from debris on debris collisions and debris generated from new launches. This study examines the threat posed by this growing space debris population over the next 30 years and how improvements in our space tracking capabilities can reduce the number of Collision Avoidance (COLA) maneuvers required keep the risk of operational satellite loss within tolerable limits. Particular focus is given to satellites operated by the Department of Defense (DoD) and Intelligence Community (IC) in Low Earth Orbit (LEO). The following debris field and space tracking performance parameters were varied parametrically in the experiment to study the impact on the number of collision avoidance maneuvers required: - Debris Field Density (by year 2009, 2019, 2029, and 2039) - Quality of Track Update (starting 1 sigma error ellipsoid) - Future Propagator Accuracy (error ellipsoid growth rates - Special Perturbations in 3 axes) - Track Update Rate for Debris (stochastic) - Track Update Rate for Payloads (stochastic) Baseline values matching present day tracking performance for quality of track update, propagator accuracy, and track update rate were derived by analyzing updates to the unclassified Satellite Catalog (SatCat). Track update rates varied significantly for active payloads and debris and as such we used different models for the track update rates for military payloads and debris. The analysis was conducted using the System Effectiveness Analysis Simulation (SEAS) an agent based model developed by the United States Air Force Space Command’s Space and Missile Systems Center to evaluate the military utility of space systems. The future debris field was modeled by The Aerospace Corporation using a tool chain which models the growth of the 10cm+ debris field using high fidelity
Tracking Trajectory Planning of Space Manipulator for Capturing Operation
Directory of Open Access Journals (Sweden)
Panfeng Huang
2008-11-01
Full Text Available On-orbit rescuing uncontrolled spinning satellite (USS using space robot is a great challenge for future space service. This paper mainly present a trajectory planning method of space manipulator that can track, approach and catch the USS in free-floating situation. According to the motion characteristics of USS, we plan a spiral ascending trajectory for space manipulator to approach towards USS in Cartesian space. However, it is difficult to map this trajectory into the joint space and realize feasible motion in joint space because of dynamics singularities and dynamics couple of space robot system. Therefore, we utilize interval algorithm to handle these difficulties. The simulation study verifies that the spiral ascending trajectory can been realized. Moreover, the motion of manipulator is smooth and stable, the disturbance to the base is so limited that the attitude control can compensate it.
Deep Space Network equipment performance, reliability, and operations management information system
Cooper, T.; Lin, J.; Chatillon, M.
2002-01-01
The Deep Space Mission System (DSMS) Operations Program Office and the DeepSpace Network (DSN) facilities utilize the Discrepancy Reporting Management System (DRMS) to collect, process, communicate and manage data discrepancies, equipment resets, physical equipment status, and to maintain an internal Station Log. A collaborative effort development between JPL and the Canberra Deep Space Communication Complex delivered a system to support DSN Operations.
Institute of Scientific and Technical Information of China (English)
刘英; 陈永利; 何震
2008-01-01
In this paper,we first introduce a new class of generalized accretive operators named(H,η)-accretive in Banach space.By studying the properties of(H,η)-accretive,we extend the concept of resolvent operators associated with m-accretive operators to the new(H,η)-accretive operators.In terms of the new resolvent operator technique,we prove the existence and uniqueness of solutions for this new system of variational inclusions.We also construct a new algorithm for approximating the solution of this system and discuss the convergence of the sequence of iterates generated by the algorithm.
Strong Convergence of Cesàro Mean Iterations for Nonexpansive Nonself-Mappings in Banach Spaces
Directory of Open Access Journals (Sweden)
Wangkeeree Rabian
2007-01-01
Full Text Available Let be a real uniformly convex Banach space which admits a weakly sequentially continuous duality mapping from to , a nonempty closed convex subset of which is also a sunny nonexpansive retract of , and a non-expansive nonself-mapping with . In this paper, we study the strong convergence of two sequences generated by and for all , where , is a real sequence in an interval , and is a sunny non-expansive retraction of onto . We prove that and converge strongly to and , respectively, as , where is a sunny non-expansive retraction of onto . The results presented in this paper generalize, extend, and improve the corresponding results of Matsushita and Kuroiwa and many others.
2维空间填充曲线的块矩阵迭代法%Block matrix iteration method for 2-dimension space-filling curves.
Institute of Scientific and Technical Information of China (English)
冯春生
2011-01-01
为解决 2 维空间填充曲线编码的快速生成问题,提出了一种基于块矩阵迭代的 Hilbert 空间填充曲线生成算法 BMIM.该算法也适用于 Z-order 空间填充曲线生成.算法分析得出 BMIM 算法相对于驱动表算法具有较好的时间复杂度和空间复杂度,相应的数值对比实验结果表明,对于相同规模的 2 维 Hilbert 空间填充曲线生成 BMIM 算法的时间效率为驱动表算法的4倍.%A new algorithm is proposed for 2-dimension Hilbert Space-Filling Curve(HSFC) and Z-order Space-Filling Curve (ZSFC).Block Matrix Iteration Method(BMIM)is applied in the new algorithm. Development, applications and some basic knowledge of HSFC are introduced. The matrix express of 2-Dimension HSFC is presented and the new algorithm for HSFC is constructed. Some algorithrm analysis are given,which show that the new algorithm is superior to the State Diagrams Driver Method(SDDM) for HSFC in terms of time and space complexity. Some contrast experiments between BMIM and SDDM are preformed. Numerical results show that computing time(CPUT) of BMIM is only one fourth of SDDM for 2-dimension HSFC at the same scale.
Holonomy Operator and Quantization Ambiguities on Spinor Space
Livine, Etera R
2013-01-01
We construct the holonomy-flux operator algebra in the recently developed spinor formulation of loop gravity. We show that, when restricting to SU(2)-gauge invariant operators, the familiar grasping and Wilson loop operators are written as composite operators built from the gauge-invariant `generalized ladder operators' recently introduced in the U(N) approach to intertwiners and spin networks. We comment on quantization ambiguities that appear in the definition of the holonomy operator and use these ambiguities as a toy model to test a class of quantization ambiguities which is present in the standard regularization and definition of the Hamiltonian constraint operator in loop quantum gravity.
Commuting Dual Toeplitz Operators on the Orthogonal Complement of the Dirichlet Space
Institute of Scientific and Technical Information of China (English)
Tao YU; Shi Yue WU
2009-01-01
In this paper we characterize commuting dual Toeplitz operators with harmonic symbols on the orthogonal complement of the Dirichlet space in the Sobolev space. We also obtain the sufficient and necessary conditions for the product of two dual Toeplitz operators with harmonic symbols to be a finite rank perturbation of a dual Toeplitz operator.
Operational Space Weather Models: Trials, Tribulations and Rewards
Schunk, R. W.; Scherliess, L.; Sojka, J. J.; Thompson, D. C.; Zhu, L.
2009-12-01
There are many empirical, physics-based, and data assimilation models that can probably be used for space weather applications and the models cover the entire domain from the surface of the Sun to the Earth’s surface. At Utah State University we developed two physics-based data assimilation models of the terrestrial ionosphere as part of a program called Global Assimilation of Ionospheric Measurements (GAIM). One of the data assimilation models is now in operational use at the Air Force Weather Agency (AFWA) in Omaha, Nebraska. This model is a Gauss-Markov Kalman Filter (GAIM-GM) model, and it uses a physics-based model of the ionosphere and a Kalman filter as a basis for assimilating a diverse set of real-time (or near real-time) measurements. The physics-based model is the Ionosphere Forecast Model (IFM), which is global and covers the E-region, F-region, and topside ionosphere from 90 to 1400 km. It takes account of five ion species (NO+, O2+, N2+, O+, H+), but the main output of the model is a 3-dimensional electron density distribution at user specified times. The second data assimilation model uses a physics-based Ionosphere-Plasmasphere Model (IPM) and an ensemble Kalman filter technique as a basis for assimilating a diverse set of real-time (or near real-time) measurements. This Full Physics model (GAIM-FP) is global, covers the altitude range from 90 to 30,000 km, includes six ions (NO+, O2+, N2+, O+, H+, He+), and calculates the self-consistent ionospheric drivers (electric fields and neutral winds). The GAIM-FP model is scheduled for delivery in 2012. Both of these GAIM models assimilate bottom-side Ne profiles from a variable number of ionosondes, slant TEC from a variable number of ground GPS/TEC stations, in situ Ne from four DMSP satellites, line-of-sight UV emissions measured by satellites, and occultation data. Quality control algorithms for all of the data types are provided as an integral part of the GAIM models and these models take account of
About radial Toeplitz operators on Segal-Bargmann and $l^2$ spaces
Ramírez, Romina A; Sanmartino, Marcela
2010-01-01
We discuss Toeplitz operators on the Segal-Bargmann space as functional realizations of anti-Wick operators on the Fock space. In the special case of radial symbols we exploit the isometric mapping between the Segal-Bargmann space and $l^2$ complex sequences in order to establish conditions such that an equivalence between Toeplitz operators and diagonal operators on $l^2$ holds. We also analyze the inverse problem of mapping diagonal operators on $l^2$ into Toeplitz form. The composition problem of Toeplitz operators with radial symbols is reviewed as an application. Our notation and basic examples make contact with Quantum Mechanics literature.
Institute of Scientific and Technical Information of China (English)
YANG Qi Xiang
2002-01-01
In the fifties, Calderón established a formal relation between symbol and kernel distribu-the C-Z operators, and Hormander, Kohn and Nirenberg, et al. studied the symbolic operators. Herewe apply a refinement of the Littlewood-Paley (L-P) decomposition, analyse under new wavelet bases,to characterize both symbolic operators spaces OpS1,δm and kernel distributions spaces with other spacescomposed of some almost diagonal matrices, then get an isometric between OpS1,δm and kernel distri-bution spaces
ISS And Space Environment Interactions Without Operating Plasma Contactor
Carruth, M. R., Jr.; Ferguson, Dale; Suggs,Rob; McCollum, Matt
2001-01-01
The International Space Station (ISS) will be the largest, highest power spacecraft placed in orbit. Because of this the design of the electrical power system diverged markedly from previous systems. The solar arrays will operate at 160 V and the power distribution voltage will be 120 V. The structure is grounded to the negative side of the solar arrays so under the right circumstances it is possible to drive the ISS potential very negative. A plasma contactor has been added to the ISS to provide control of the ISS structure potential relative to the ambient plasma. The ISS requirement is that the ISS structure not be greater than 40 V positive or negative of local plasma. What are the ramifications of operating large structures with such high voltage power systems? The application of a plasma contactor on ISS controls the potential between the structure and the local plasma, preventing degrading effects. It is conceivable that there can be situations where the plasma contactor might be non-functional. This might be due to lack of power, the need to turn it off during some of the build-up sequences, the loss of functionality for both plasma contactors before a replacement can be installed, similar circumstances. A study was undertaken to understand how important it is to have the contactor functioning and how long it might be off before unacceptable degradation to ISS could occur. The details of interaction effects on spacecraft have not been addressed until driven by design. This was true for ISS. If the structure is allowed to float highly negative impinging ions can sputter exposed conductors which can degrade the primary surface and also generate contamination due to the sputtered material. Arcing has been known to occur on solar arrays that float negative of the ambient plasma. This can also generate electromagnetic interference and voltage transients. Much of the ISS structure and pressure module surfaces exposed to space is anodized aluminum. The anodization
Remote maintenance development for ITER
Energy Technology Data Exchange (ETDEWEB)
Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Shibanuma, Kiyoshi
1998-04-01
This paper describes the overall ITER remote maintenance design concept developed mainly for in-vessel components such as diverters and blankets, and outlines the ITER R and D program to develop remote handling equipment and radiation hard components. Reactor structures inside the ITER cryostat must be maintained remotely due to DT operation, making remote handling technology basic to reactor design. The overall maintenance scenario and design concepts have been developed, and maintenance design feasibility, including fabrication and testing of full-scale in-vessel remote maintenance handling equipment and tool, is being verified. (author)
Expanded Operational Temperature Range for Space Rated Li-Ion Batteries Project
National Aeronautics and Space Administration — Quallion's response to this solicitation calls for expanding the nominal operation range of its space rated lithium ion cells, while maintaining their long life...
Existence of zeros for operators taking their values in the dual of a Banach space
Directory of Open Access Journals (Sweden)
Ricceri Biagio
2004-01-01
Full Text Available Using continuous selections, we establish some existence results about the zeros of weakly continuous operators from a paracompact topological space into the dual of a reflexive real Banach space.
Weighted Composition Operators between Different Bergman Spaces of Bounded Symmetric Domains
Indian Academy of Sciences (India)
Xiaofen Lv; Xiaomin Tang
2009-09-01
In this paper, we consider the boundedness and compactness of the weighted composition operators between different Bergman spaces of bounded symmetric domains in terms of the Carleson measure. As an application, we study the multipliers between different Bergman spaces.
Expanded Operational Temperature Range for Space Rated Li-Ion Batteries Project
National Aeronautics and Space Administration — Quallion's Phase II proposal calls for expanding the nominal operation range of its space rated lithium ion cells, while maintaining their long life capabilities. To...
Iterative initial condition reconstruction
Schmittfull, Marcel; Baldauf, Tobias; Zaldarriaga, Matias
2017-07-01
Motivated by recent developments in perturbative calculations of the nonlinear evolution of large-scale structure, we present an iterative algorithm to reconstruct the initial conditions in a given volume starting from the dark matter distribution in real space. In our algorithm, objects are first moved back iteratively along estimated potential gradients, with a progressively reduced smoothing scale, until a nearly uniform catalog is obtained. The linear initial density is then estimated as the divergence of the cumulative displacement, with an optional second-order correction. This algorithm should undo nonlinear effects up to one-loop order, including the higher-order infrared resummation piece. We test the method using dark matter simulations in real space. At redshift z =0 , we find that after eight iterations the reconstructed density is more than 95% correlated with the initial density at k ≤0.35 h Mpc-1 . The reconstruction also reduces the power in the difference between reconstructed and initial fields by more than 2 orders of magnitude at k ≤0.2 h Mpc-1 , and it extends the range of scales where the full broadband shape of the power spectrum matches linear theory by a factor of 2-3. As a specific application, we consider measurements of the baryonic acoustic oscillation (BAO) scale that can be improved by reducing the degradation effects of large-scale flows. In our idealized dark matter simulations, the method improves the BAO signal-to-noise ratio by a factor of 2.7 at z =0 and by a factor of 2.5 at z =0.6 , improving standard BAO reconstruction by 70% at z =0 and 30% at z =0.6 , and matching the optimal BAO signal and signal-to-noise ratio of the linear density in the same volume. For BAO, the iterative nature of the reconstruction is the most important aspect.
Strong Convergence of CesÃƒÂ ro Mean Iterations for Nonexpansive Nonself-Mappings in Banach Spaces
Directory of Open Access Journals (Sweden)
Rabian Wangkeeree
2007-10-01
Full Text Available Let E be a real uniformly convex Banach space which admits a weakly sequentially continuous duality mapping from E to E*, C a nonempty closed convex subset of E which is also a sunny nonexpansive retract of E, and T:CÃ¢Â†Â’E a non-expansive nonself-mapping with F(TÃ¢Â‰Â Ã¢ÂˆÂ…. In this paper, we study the strong convergence of two sequences generated by xn+1=ÃŽÂ±nx+(1Ã¢ÂˆÂ’ÃŽÂ±n(1/n+1Ã¢ÂˆÂ‘j=0n(PTjxn and yn+1=(1/n+1Ã¢ÂˆÂ‘j=0nP(ÃŽÂ±ny+(1Ã¢ÂˆÂ’ÃŽÂ±n(TPjyn for all nÃ¢Â‰Â¥0, where x,x0,y,y0Ã¢ÂˆÂˆC, {ÃŽÂ±n} is a real sequence in an interval [0,1], and P is a sunny non-expansive retraction of E onto C. We prove that {xn} and {yn} converge strongly to Qx and Qy, respectively, as nÃ¢Â†Â’Ã¢ÂˆÂž, where Q is a sunny non-expansive retraction of C onto F(T. The results presented in this paper generalize, extend, and improve the corresponding results of Matsushita and Kuroiwa and many others.
2007-03-01
Document, 2006. 26. D. Mehrholz, W. Flury R. Jehn H. Klinkrad M. Landgraf, L. Leushacke. “De- tecting, Tracking and Imaging Space Debris ”. Eurpean Space ...SPACECRAFT PROXIMITY OPERATIONS USED TO ESTIMATE THE DYNAMICAL & PHYSICAL PROPERTIES OF A RESIDENT SPACE OBJECT THESIS Abraham Franz Brunner, First...OPERATIONS USED TO ESTIMATE THE DYNAMICAL & PHYSICAL PROPERTIES OF A RESIDENT SPACE OBJECT THESIS Presented to the Faculty Department of Aeronautics and
WEIGHTED INEQUALITIES FOR THE GEOMETRIC MAXIMAL OPERATOR ON MARTINGALE SPACES
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
In this article, the authors introduce two operators-geometrical maximal operator Mo and the closely related limiting operator M*O, then they give sufficient conditions under which the equality MO = M*O holds, and characterize the equivalent relations between the weak or strong type weighted inequality and the property of W∞-weight or W*∞-weight for the geometrical maximal operator in the case of two-weight condition. What should be mentioned is that the new operator-the geometrical minimal operator is equal to the limitation of the minimal operator sequence, and the results for the minimal operator proved in [12] makes the proof elegant and evident.
Feder, Toni
2003-01-01
After successfully chairing an external review committee for CERN last year, Robert Aymar will leave ITER to become director general of the European particle physics laboratory rom 2004. Before ITER he also successfully managed the startup or Tore Supra. He will attempt to ensure that the LHC begins operating in 2007 - two years late - and is paid for by 2010 and will also start the planning for life after the LHC (1 page)
ITER diagnostic system: Vacuum interface
Energy Technology Data Exchange (ETDEWEB)
Patel, K.M., E-mail: Kaushal.Patel@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Udintsev, V.S.; Hughes, S.; Walker, C.I.; Andrew, P.; Barnsley, R.; Bertalot, L. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Drevon, J.M. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Encheva, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Kashchuk, Y. [Institution “PROJECT CENTER ITER”, 1, Akademika Kurchatova pl., Moscow (Russian Federation); Maquet, Ph. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Pearce, R.; Taylor, N.; Vayakis, G.; Walsh, M.J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France)
2013-10-15
Diagnostics play an essential role for the successful operation of the ITER tokamak. They provide the means to observe control and to measure plasma during the operation of ITER tokamak. The components of the diagnostic system in the ITER tokamak will be installed in the vacuum vessel, in the cryostat, in the upper, equatorial and divertor ports, in the divertor cassettes and racks, as well as in various buildings. Diagnostic components that are placed in a high radiation environment are expected to operate for the life of ITER. There are approx. 45 diagnostic systems located on ITER. Some diagnostics incorporate direct or independently pumped extensions to maintain their necessary vacuum conditions. They require a base pressure less than 10{sup −7} Pa, irrespective of plasma operation, and a leak rate of less than 10{sup −10} Pa m{sup 3} s{sup −1}. In all the cases it is essential to maintain the ITER closed fuel cycle. These directly coupled diagnostic systems are an integral part of the ITER vacuum containment and are therefore subject to the same design requirements for tritium and active gas confinement, for all normal and accidental conditions. All the diagnostics, whether or not pumped, incorporate penetration of the vacuum boundary (i.e. window assembly, vacuum feedthrough etc.) and demountable joints. Monitored guard volumes are provided for all elements of the vacuum boundary that are judged to be vulnerable by virtue of their construction, material, load specification etc. Standard arrangements are made for their construction and for the monitoring, evacuating and leak testing of these volumes. Diagnostic systems are incorporated at more than 20 ports on ITER. This paper will describe typical and particular arrangements of pumped diagnostic and monitored guard volume. The status of the diagnostic vacuum systems, which are at the start of their detailed design, will be outlined and the specific features of the vacuum systems in ports and extensions
Modified Ishikawa Iterative Process with Errors in Normed Linear Spaces%赋范线性空间中修改的具误差的Ishikawa迭代程序
Institute of Scientific and Technical Information of China (English)
姚永红; 陈汝栋; 周海云
2007-01-01
Ishikawa iterative sequences with errors different from the iterative sequences introduced by Liu and Xu are given. Moreover, the problem of approximating the fixed points of (ψ)-hemicontractive mapping in normed linear spaces by the modified Ishikawa iterative sequences with errors is investigated. The results presented in this paper improve and extend the results of the others.%本文给出了有别于刘立山以及徐洪坤的意义下的具误差的Ishikawa迭代程序.进一步,还研究了赋范线性空间中(ψ)-半压缩映象不动点的具误差的Ishikawa迭代逼近问题.所得的结果改进和推广了许多相应的结果.
Operators on Differential Form Spaces for Riemann Surfaces
Institute of Scientific and Technical Information of China (English)
Guang Fu CAO; Xiao Feng WANG
2007-01-01
In the present paper, a problem of Ioana Mihaila is negatively answered on the invertibility of composition operators on Riemann surfaces, and it is proved that the composition operator Cρ is Fredholm if and only if it is invertible if and only ifρ is invertible for some special cases. In addition,the Toeplitz operators on ∧12 a (M) for Riemann surface M are defined and some properties of these operators are discussed.
Commuting Quasihomogeneous Toeplitz Operator and Hankel Operator on Weighted Bergman Space
Directory of Open Access Journals (Sweden)
Jun Yang
2013-01-01
Full Text Available We characterize the commuting Toeplitz operator and Hankel operator with quasihomogeneous symbols. Also, we use it to show the necessary and sufficient conditions for commuting Toeplitz operator and Hankel operator with ordinary functions.
WEIGHTED ESTIMATES FOR COMMUTATORS OF POTENTIAL OPERATORS ON SPACES OF HOMOGENEOUS TYPE
Institute of Scientific and Technical Information of China (English)
Wenming Li; Xiaowu Yu; Xuefang Yan
2009-01-01
We derive some strong type and weak type weighted norm estimates which relate the commutators of potential integral operators to the corresponding maximal operators in the context of spaces of homogeneous type.
Toeplitz Operators with Quasihomogeneous Symbols on the Bergman Space of the Unit Ball
Directory of Open Access Journals (Sweden)
Bo Zhang
2012-01-01
symbols on the Bergman space of the unit ball equals a Toeplitz operator with quasihomogeneous symbols. We also characterize finite-rank semicommutators or commutators of two Toeplitz operators with quasihomogeneous symbols.
Bloch, J; Lang, B; Wettig, T
2007-01-01
The overlap Dirac operator in lattice QCD requires the computation of the sign function of a matrix. While this matrix is usually Hermitian, it becomes non-Hermitian in the presence of a quark chemical potential. We show how the action of the sign function of a non-Hermitian matrix on an arbitrary vector can be computed efficiently on large lattices by an iterative method. A Krylov subspace approximation based on the Arnoldi algorithm is described for the evaluation of a generic matrix function. The efficiency of the method is spoiled when the matrix has eigenvalues close to a function discontinuity. This is cured by adding a small number of critical eigenvectors to the Krylov subspace, for which we propose two different deflation schemes. The ensuing modified Arnoldi method is then applied to the sign function, which has a discontinuity along the imaginary axis. The numerical results clearly show the improved efficiency of the method. Our modification is particularly effective when the action of the sign fun...
Khinchin's Inequality, Dunford-Pettis and Compact Operators on the Space ([0, 1], )
Indian Academy of Sciences (India)
Dumitru Popa
2007-02-01
We prove that if , are Banach spaces, a compact Hausdorff space and :(,) → is a bounded linear operator, and if is a Dunford–Pettis operator the range of the representing measure $G()\\subseteq D P(X, Y)$ is an uniformly Dunford–Pettis family of operators and $\\|G\\|$ is continuous at $\\emptyset$. As applications of this result we give necessary and/or sufficient conditions that some bounded linear operators on the space $C([0,1],X)$ with values in $c_0$ or $l_p,(1≤ p < ∞)$ be Dunford–Pettis and/or compact operators, in which, Khinchin’s inequality plays an important role.
Johnson, Sally
2017-01-01
Trajectory-Based Operations (TBO) is one of the essential paradigm shifts in the NextGen transformation of the National Airspace System. Under TBO, aircraft are managed by 4-dimensional trajectories, and airborne and ground-based metering, merging, and spacing operations are key to managing those trajectories. This paper presents the results of a study of potential metering, merging, and spacing operations within a future TBO environment. A number of operational scenarios for tactical and strategic uses of metering, merging, and spacing are described, and interdependencies between concurrent tactical and strategic operations are identified.
Algebraic Properties of Dual Toeplitz Operators on the Orthogonal Complement of the Dirichlet Space
Institute of Scientific and Technical Information of China (English)
Tao YU; Shi Yue WU
2008-01-01
In this paper we investigate some algebra properties of dual Toeplitz operators on the orthogonal complement of the Dirichlet space in the Sobolev space.We completely characterize commuting dual Toeplitz operators with harmonic symbols,and show that a dual Toeplitz operator commutes with a nonconstant analytic dual Toeplitz operator if and only if its symbol is analytic.We also obtain the sufficient and necessary conditions on the harmonic symbols for SψSψ=Sψψ.
解不适定算子方程的一个定常二步隐式迭代法%STATIONARY TWO-STEP IMPLICIT ITERATIVE METHODFOR ILL-POSED OPERATOR EQUATIONS
Institute of Scientific and Technical Information of China (English)
唐建国; 贺国强
2000-01-01
On the basis of an implicit iterative method for ill-posed operator equations,we introduce a relaxation factor and a weighted factor , and obtain a stationarytwo-step implicit iterative method. The range of the factors which guarantee theconvergence of iteration is explored.We also study the convergence properties and ratesfor both non-perturbed andperturbed equations.An implementable algorithm is presented by using Morozov discrepancy principle.The theoretical results show that the convergence rates of the new methods always lead to optimal convergentrates which are superior to those of the original one after choosing suitable relaxation and weightedfactors. Numerical examplesare also given, which coincide well with the theoretical results.
Embedding and Maximal Regular Differential Operators in Sobolev-Lions Spaces
Institute of Scientific and Technical Information of China (English)
Veli B. SHAKHMUROV
2006-01-01
This study focuses on vector-valued anisotropic Sobolev-Lions spaces associated with Banach spaces E0, E. Several conditions are found that ensure the continuity and compactness of embedding operators that are optimal regular in these spaces in terms of interpolations of spaces E0 and E. In particular, the most regular class of interpolation spaces Eα between E0, E depending on α and the order of space are found and the boundedness of differential operators Dα from this space to Eα -valued Lp,γ spaces is proved. These results are applied to partial differential-operator equationswith parameters to obtain conditions that guarantee the maximal Lp,γ regularity and R-positivity uniformly with respect to these parameters.
Spectrum of the Wilson Dirac operator at finite lattice spacings
DEFF Research Database (Denmark)
Akemann, G.; Damgaard, Poul Henrik; Splittorff, Kim;
2011-01-01
We consider the effect of discretization errors on the microscopic spectrum of the Wilson Dirac operator using both chiral Perturbation Theory and chiral Random Matrix Theory. A graded chiral Lagrangian is used to evaluate the microscopic spectral density of the Hermitian Wilson Dirac operator...... as well as the distribution of the chirality over the real eigenvalues of the Wilson Dirac operator. It is shown that a chiral Random Matrix Theory for the Wilson Dirac operator reproduces the leading zero-momentum terms of Wilson chiral Perturbation Theory. All results are obtained for fixed index...... of the Wilson Dirac operator. The low-energy constants of Wilson chiral Perturbation theory are shown to be constrained by the Hermiticity properties of the Wilson Dirac operator....
Some G-M-type Banach spaces and K-groups of operator algebras on them
Institute of Scientific and Technical Information of China (English)
ZHONG Huaijie; CHEN Dongxiao; CHEN Jianlan
2004-01-01
By providing several new varieties of G-M-type Banachspaces according to decomposable and compoundable properties, this paper discusses the operator structures of thesespaces and the K-theory of the algebra of the operators on these G-M-type Banach spaces throughcalculation of the K-groups of the operator ideals contained in the class of Riesz operators.
On the Spectrum of a Model Operator in Fock Space
Rasulov, Tulkin H; Hasanov, Mahir
2008-01-01
A model operator $H$ associated to a system describing four particles in interaction, without conservation of the number of particles, is considered. We describe the essential spectrum of $H$ by the spectrum of the channel operators and prove the Hunziker-van Winter-Zhislin (HWZ) theorem for the operator $H.$ We also give some variational principles for boundaries of the essential spectrum and interior eigenvalues.
Space/Flight Operable Miniature Six Axis Transducer Project
National Aeronautics and Space Administration — FUTEK will fully design and manufacture a sensor capable of measuring forces in and about each axis. The unit will measure forces up to 300 Newton's in the principle...
Soldier/Warfighter Operationally Responsive Deployer for Space (SWORDS) Project
National Aeronautics and Space Administration — SWORDS will place nanosatellites into precise low earth orbits to provide capabilities both where and when they are needed. Nanosatellites will no longer have to...
Space Electronics Operating at High Temperatures and Radiation Levels Project
National Aeronautics and Space Administration — The objective is to produce high efficiency DC/DC power modules in a small low profile package that can tolerate extreme environment conditions. The primary effort...
Design of ITER vacuum vessel in-wall shielding
Energy Technology Data Exchange (ETDEWEB)
Wang, X., E-mail: xiaoyu.wang@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Ioki, K. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Morimoto, M. [Mitsubishi Heavy Industries, 1-1, Wadasaki-cho 1-chome, Hyogo-ku, Kobe (Japan); Choi, C.H.; Utin, Y.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); TaiLhardat, O. [Assystem EOS, ZAC SAINT MARTIN, 23 rue Benjamin Franklin, 84120 Pertuis (France); Mille, B.; Terasawa, A.; Gribov, Y.; Barabash, V.; Polunovskiy, E.; Dani, S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Pathak, H.; Raval, J. [ITER-India, Institute for Plasma Research, Gandhinagar 382025 (India); Liu, S.; Lu, M.; Du, S. [Institute of Plasma Physics, China Academy of Sciences, Shushanhu Road 350, Hefei (China)
2014-10-15
The ITER vacuum vessel is a torus-shaped, double wall structure. The space between the double walls of the VV is filled with in-wall shielding (IWS) and cooling water. The main purpose of the in-wall shielding is to provide neutron shielding together with the blanket and VV shells and water during ITER plasma operation and to reduce the ripple of the Toroidal magnetic field. Based on ITER vacuum vessel structure and related requirements, in-wall shielding are designed as about 8900 individual blocks with different sizes and several different materials distributed over nine vessel sectors and nine field joints of vessel sectors. This paper presents the design of the IWS, considering loads, structural stresses and assembly method, and also shows neutron shielding effect and TF ripple reduced by the IWS.
Iterative Magnetometer Calibration
Sedlak, Joseph
2006-01-01
This paper presents an iterative method for three-axis magnetometer (TAM) calibration that makes use of three existing utilities recently incorporated into the attitude ground support system used at NASA's Goddard Space Flight Center. The method combines attitude-independent and attitude-dependent calibration algorithms with a new spinning spacecraft Kalman filter to solve for biases, scale factors, nonorthogonal corrections to the alignment, and the orthogonal sensor alignment. The method is particularly well-suited to spin-stabilized spacecraft, but may also be useful for three-axis stabilized missions given sufficient data to provide observability.
Firmly nonexpansive mappings in classes of geodesic spaces
Ariza-Ruiz, David; Lopez-Acedo, Genaro
2012-01-01
Firmly nonexpansive mappings play an important role in metric fixed point theory and optimization due to their correspondence with maximal monotone operators. In this paper we do a thorough study of fixed point theory and the asymptotic behaviour of Picard iterates of these mappings in different classes of geodesic spaces, as (uniformly convex) $W$-hyperbolic spaces, Busemann spaces and CAT(0) spaces. Furthermore, we apply methods of proof mining to obtain effective rates of asymptotic egularity for the Picard iterations.
On the boundedness of operators in LP(ιq and Triebel-Lizorkin Spaces
Directory of Open Access Journals (Sweden)
João Pedro Boto
2008-01-01
Full Text Available Given a bounded linear operator T:LPO(ℝn→Lp1(ℝn, we state conditions under which T defines a bounded operator between corresponding pairs of Lp(ℝn;ιq spaces and Triebel-Lizorkin spaces Fp,qs(ℝn. Applications are given to linear parabolic equations and to Schrödinger semigroups.
Area integral functions and $H^{\\8}$ functional calculus for sectorial operators on Hilbert spaces
Chen, Zeqian; Sun, Mu
2012-01-01
Area integral functions are introduced for sectorial operators on Hilbert spaces. We establish the equivalence relationship between the square and area integral functions. This immediately extends McIntosh/Yagi's results on $H^{\\8}$ functional calculus of sectorial operators on Hilbert spaces to the case when the square functions are replaced by the area integral functions.
On K-groups of Operator Algebra on the 1-shift Space
Institute of Scientific and Technical Information of China (English)
Qiao Fen JIANG; Huai Jie ZHONG
2008-01-01
In this paper we discuss the K-groups of Wiener algebra W.For the 1-shift space XGM2,We obtain a characterization of Fredholm operators on XnGM2 for all n ∈ N.We also calculate the K-groups of operator algebra on the 1-shift space XGM2.
Keynote speech - Manned Space Flights: Lessons Learned from Space Craft Operation and Maintenance
CERN. Geneva
2013-01-01
Following graduation in 1973 from the Ecole de l'Air (the French Air Force Academy), Michel Tognini served in the French Air Force as an operational fighter pilot, flight leader in 1976, flight commander in 1979, test pilot then chief test pilot from 1983 to 1985. In 1985, France opened a recruitment program to expand its astronaut corps, and Michel Tognini was one of seven candidates selected by CNES. In July 1986, he was one of four candidates to undergo medical examinations in Moscow. In August 1986, he was assigned as a back-up crew member for the Soyuz TM-7 mission. Although he remained a French Air Force officer, he was placed on detachment to CNES for his space flight activities from September 1986 onwards. In 1991 he went to Star City, Russia, to start prime crew training for the third Soviet-French ANTARES mission. During his stay in Russia, he linked up with Mir (ANTARES mission) and spent 14 days (July 27–Aug. 10, 1992; Soyuz TM-14 and TM-14)carrying out a program of joint Soviet-French experimen...
Integrated Ground Operations Demonstration for Responsive Space Access
Johnson, Robert G.; Notardonato, William U.
2013-01-01
Integrated Ground Operations Demonstration Units (IGODU) project developed to mature, integrate and demonstrate advancements in cryogenics, system health management and command and control technologies. Two Distinct Testing Environments: a) GODU Integrated Refrigeration and Storage - GODU LH2; b) GODU Autonomous Control - GODU LO2. Scope: I. GODU LH2: a) Investigate alternative storage and distribution architecture for future cryogenic propellant operations. b) Demonstrate advanced cryogenic propellant handling operations (liquefaction, storage and distribution) of normal boiling point and sub-cooled cryogenic propellants. II. GODU L02: a) Develop and demonstrate advanced control and health management technologies and techniques to autonomously control cryogenic propellant servicing operations. b) Investigate modern COTS hardware and control systems in an effort to reduce the "standing army" of engineers associated with maintaining and operating ground systems through the use of health management and autonomous control technologies. Goals: a) Raise Technology Readiness Levels (TRL) and Integration Readiness Levels (IRL) of several key technology development areas. b) Reduce operations lifecycle costs of future test programs and launch complexes. c) Demonstrate technologies for future exploration beyond low earth orbit. d) Serve as test environments for extraterrestrial surface operations.
Debes, John H; Choquet, Elodie; Hines, Dean C; Perrin, Marshall; Golimowski, David A; Lajoie, Charles-Phillipe; Mazoyer, Johan; Pueyo, Laurent; Soummer, Remi; van der Marel, Roeland
2015-01-01
The coronagraphic instrument currently proposed for the WFIRST-AFTA mission will be the first example of a space-based coronagraph optimized for extremely high contrasts that are required for the direct imaging of exoplanets reflecting the light of their host star. While the design of this instrument is still in progress, this early stage of development is a particularly beneficial time to consider the operation of such an instrument. In this paper, we review current or planned operations on the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST) with a focus on which operational aspects will have relevance to the planned WFIRST-AFTA coronagraphic instrument. We identify five key aspects of operations that will require attention: 1) detector health and evolution, 2) wavefront control, 3) observing strategies/post-processing, 4) astrometric precision/target acquisition, and 5) polarimetry. We make suggestions on a path forward for each of these items.
L-Fuzzy Semi-Preopen Operator in L-Fuzzy Topological Spaces
Ghareeb, A
2010-01-01
In this paper, we give the concept of L-fuzzy Semi-Preopen operator in L-fuzzy topological spaces, and use them to score L-fuzzy SP-cmpactnness in L-fuzzy topological spaces. We also study the relationship between L-fuzzy SP-compactness and SP-compactness in L-topological spaces.
Madura, John T.; Bauman, William H., III; Merceret, Francis J.; Roeder, William P.; Brody, Frank C.; Hagemeyer, Bartlett C.
2011-01-01
The Applied Meteorology Unit (AMU) provides technology development and transition services to improve operational weather support to America's space program . The AMU was founded in 1991 and operates under a triagency Memorandum of Understanding (MOU) between the National Aeronautics and Space Administration (NASA), the United States Air Force (USAF) and the National Weather Service (NWS) (Ernst and Merceret, 1995). It is colocated with the 45th Weather Squadron (45WS) at Cape Canaveral Air Force Station (CCAFS) and funded by the Space Shuttle Program . Its primary customers are the 45WS, the Spaceflight Meteorology Group (SMG) operated for NASA by the NWS at the Johnson Space Center (JSC) in Houston, TX, and the NWS forecast office in Melbourne, FL (MLB). The gap between research and operations is well known. All too frequently, the process of transitioning research to operations fails for various reasons. The mission of the AMU is in essence to bridge this gap for America's space program.
Moving Toward Space Internetworking via DTN: Its Operational Challenges, Benefits, and Management
Barkley, Erik; Burleigh, Scott; Gladden, Roy; Malhotra, Shan; Shames, Peter
2010-01-01
The international space community has begun to recognize that the established model for management of communications with spacecraft - commanded data transmission over individual pair-wise contacts - is operationally unwieldy and will not scale in support of increasingly complex and sophisticated missions such as NASA's Constellation project. Accordingly, the international Inter-Agency Operations Advisory Group (IOAG) ichartered a Space Internetworking Strategy Group (SISG), which released its initial recommendations in a November 2008 report. The report includes a recommendation that the space flight community adopt Delay-Tolerant Networking (DTN) to address the problem of interoperability and communication scaling, especially in mission environments where there are multiple spacecraft operating in concert. This paper explores some of the issues that must be addressed in implementing, deploying, and operating DTN as part of a multi-mission, multi-agency space internetwork as well as benefits and future operational scenarios afforded by DTN-based space internetworking.
Realization of the N(odd)-Dimensional Quantum Euclidean Space by Differential Operators
Institute of Scientific and Technical Information of China (English)
LI Yun; JING Si-Cong
2004-01-01
The quantum Euclidean space RNq is a kind of noncommutative space that is obtained from ordinary Euclidean space RN by deformation with parameter q. When N is odd, the structure of this space is similar to R3q.Motivated by realization ofR3q by differential operators in R3, we give such realization for R5q and R7q cases and generalize our results to RNq (N odd) in this paper, that is, we show that the algebra of RNq can be realized by differential operators acting on C∞ functions on undeformed space RN.
The ITER project construction status
Motojima, O.
2015-10-01
The pace of the ITER project in St Paul-lez-Durance, France is accelerating rapidly into its peak construction phase. With the completion of the B2 slab in August 2014, which will support about 400 000 metric tons of the tokamak complex structures and components, the construction is advancing on a daily basis. Magnet, vacuum vessel, cryostat, thermal shield, first wall and divertor structures are under construction or in prototype phase in the ITER member states of China, Europe, India, Japan, Korea, Russia, and the United States. Each of these member states has its own domestic agency (DA) to manage their procurements of components for ITER. Plant systems engineering is being transformed to fully integrate the tokamak and its auxiliary systems in preparation for the assembly and operations phase. CODAC, diagnostics, and the three main heating and current drive systems are also progressing, including the construction of the neutral beam test facility building in Padua, Italy. The conceptual design of the Chinese test blanket module system for ITER has been completed and those of the EU are well under way. Significant progress has been made addressing several outstanding physics issues including disruption load characterization, prediction, avoidance, and mitigation, first wall and divertor shaping, edge pedestal and SOL plasma stability, fuelling and plasma behaviour during confinement transients and W impurity transport. Further development of the ITER Research Plan has included a definition of the required plant configuration for 1st plasma and subsequent phases of ITER operation as well as the major plasma commissioning activities and the needs of the accompanying R&D program to ITER construction by the ITER parties.
Deformed Boson Algebra and Projection Operator of Vacuum in Noncommutative Phase Space
Lin, Bingsheng; Guan, Yong; Jing, Sicong
In this paper we introduce a new formalism to analyze Fock space structure of noncommutative phase space (NCPS). Based on this new formalism, we derive deformed boson commutation relations and study corresponding deformed Fock space, especially its vacuum structure, which leads to get a form of the vacuum projection operator. As an example of applications of such an operator, we define two-mode coherent state in the NCPS and show its completeness relation.