Nishimura, Hirokazu
2009-01-01
It is well known that the category of Frolicher spaces and smooth mappings is Cartesian-closed. The principal objective in this paper is to show that the full subcategory of Frolicher spaces that believe that every Weil functor is really an exponentiation by the corresponding infinitesimal object in fantasy is also Cartesian-closed. Under the assumption that a conjecture holds, it is shown that these Frolicher spaces embed into the Cahier topos with the Cartesian-closed structure preserved.
Free topological vector spaces
Gabriyelyan, Saak S.; Morris, Sidney A.
2016-01-01
We define and study the free topological vector space $\\mathbb{V}(X)$ over a Tychonoff space $X$. We prove that $\\mathbb{V}(X)$ is a $k_\\omega$-space if and only if $X$ is a $k_\\omega$-space. If $X$ is infinite, then $\\mathbb{V}(X)$ contains a closed vector subspace which is topologically isomorphic to $\\mathbb{V}(\\mathbb{N})$. It is proved that if $X$ is a $k$-space, then $\\mathbb{V}(X)$ is locally convex if and only if $X$ is discrete and countable. If $X$ is a metrizable space it is shown ...
Narici, Lawrence
2011-01-01
BackgroundTopology Valuation Theory Algebra Linear Functionals Hyperplanes Measure Theory Normed SpacesCommutative Topological GroupsElementary ConsiderationsSeparation and Compactness Bases at 0 for Group Topologies Subgroups and Products Quotients S-Topologies Metrizability CompletenessCompleteness Function Groups Total BoundednessCompactness and Total Boundedness Uniform Continuity Extension of Uniformly Continuous Maps CompletionTopological Vector SpacesAbsorbent and Balanced Sets Convexity-AlgebraicBasic PropertiesConvexity-Topological Generating Vector Topologies A Non-Locally Convex Spa
Akcoglu, Mustafa A; Ha, Dzung Minh
2011-01-01
A rigorous introduction to calculus in vector spaces The concepts and theorems of advanced calculus combined with related computational methods are essential to understanding nearly all areas of quantitative science. Analysis in Vector Spaces presents the central results of this classic subject through rigorous arguments, discussions, and examples. The book aims to cultivate not only knowledge of the major theoretical results, but also the geometric intuition needed for both mathematical problem-solving and modeling in the formal sciences. The authors begin with an outline of key concepts, ter
Synthetic Space Vector Modulation
2013-06-01
Modulation RF Radio Frequency SVM Space Vector Modulation VCO Voltage Controlled Oscillator VSI Voltage Source Inverter xvi THIS PAGE...examining the literature, an NE566 voltage controlled oscillator ( VCO ) chip as seen in Figure 10 was used to design a circuit that produced the
Semitopological Vector Spaces and Hyperseminorms
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Mark Burgin
2013-11-01
Full Text Available In this paper, we introduce and study semitopological vector spaces. The goal is to provide an efficient base for developing the theory of extrafunction spaces in an abstract setting of algebraic systems and topological spaces. Semitopological vector spaces are more general than conventional topological vector spaces, which proved to be very useful for solving many problems in functional analysis. To study semitopological vector spaces, hypermetrics and hyperpseudometrics are introduced and it is demonstrated that hyperseminorms, studied in previous works of the author, induce hyperpseudometrics, while hypernorms induce hypermetrics. Sufficient and necessary conditions for a hyperpseudometric (hypermetric to be induced by a hyperseminorm (hypernorm are found. We also show that semitopological vector spaces are closely related to systems of hyperseminorms. Then defining boundedness and continuity relative to associated systems of hyperseminorms, we study relations between relative boundedness and relative continuity for mappings of vector spaces with systems of hyperseminorms and systems of hypernorms.
Vector cross product in n-dimensional vector space
Tian, Xiu-Lao; Yang, Chao; Hu, Yang; Tian, Chao
2013-01-01
The definition of vector cross product (VCP) introduced by Eckmann only exists in thethree- and the seven- dimensional vector space. In this paper, according to the orthogonal completeness, magnitude of basis vector cross product and all kinds of combinations of basis vector $\\hat{e}_i$, the generalized definition of VCP in the odd n-dimensional vector space is given by introducing a cross term $X_{AB}$. In addition, the definition is validated by reducing the generalization definition to the...
A convenient differential category
Blute, Richard; Tasson, Christine
2010-01-01
In this paper, we show that the category of Mackey-complete, separated, topological convex bornological vector spaces and bornological linear maps is a differential category. Such spaces were introduced by Fr\\"olicher and Kriegl, where they were called convenient vector spaces. While much of the structure necessary to demonstrate this observation is already contained in Fr\\"olicher and Kriegl's book, we here give a new interpretation of the category of convenient vector spaces as a model of the differential linear logic of Ehrhard and Regnier. Rather than base our proof on the abstract categorical structure presented by Fr\\"olicher and Kriegl, we prefer to focus on the bornological structure of convenient vector spaces. We believe bornological structures will ultimately yield a wide variety of models of differential logics.
Vector Spaces of Non-measurable Functions
Institute of Scientific and Technical Information of China (English)
Francisco J. GARC(I)A-PACHECO; Juan B. SEOANE-SEP(U)LVEDA
2006-01-01
We show that there exists an infinite dimensional vector space every non-zero element of which is a non-measurable function. Moreover, this vector space can be chosen to be closed and to have dimensionβ for any cardinalityβ. Some techniques involving measure theory and density characters of Banach spaces are used.
Affine conformal vectors in space-time
Coley, A. A.; Tupper, B. O. J.
1992-05-01
All space-times admitting a proper affine conformal vector (ACV) are found. By using a theorem of Hall and da Costa, it is shown that such space-times either (i) admit a covariantly constant vector (timelike, spacelike, or null) and the ACV is the sum of a proper affine vector and a conformal Killing vector or (ii) the space-time is 2+2 decomposable, in which case it is shown that no ACV can exist (unless the space-time decomposes further). Furthermore, it is proved that all space-times admitting an ACV and a null covariantly constant vector (which are necessarily generalized pp-wave space-times) must have Ricci tensor of Segré type {2,(1,1)}. It follows that, among space-times admitting proper ACV, the Einstein static universe is the only perfect fluid space-time, there are no non-null Einstein-Maxwell space-times, and only the pp-wave space-times are representative of null Einstein-Maxwell solutions. Otherwise, the space-times can represent anisotropic fluids and viscous heat-conducting fluids, but only with restricted equations of state in each case.
DSm Vector Spaces of Refined Labels
Kandasamy, W B Vasantha
2011-01-01
In this book the authors introduce the notion of DSm vector spaces of refined labels. They also realize the refined labels as a plane and a n-dimensional space. Further, using these refined labels, several algebraic structures are defined. Finally DSm semivector space or refined labels is described. Authors also propose some research problems.
Bartosik, Aneta A; Glabski, Krzysztof; Kulinska, Anna; Lewicka, Ewa; Godziszewska, Jolanta; Markowska, Aleksandra; Jagura-Burdzy, Grazyna
2016-04-05
Low-copy-number vectors of potential wide application in biotechnology need to encode stabilization modules ensuring their stable inheritance. The efficiency of stabilization may vary depending on the plasmid host so a thorough analysis of stabilization functions is required before use. To facilitate such analysis highly unstable, mobilizable, broad-host-range (BHR) vectors based on RK2 replicon were constructed. The vectors are suitable for testing of various stabilization functions, including plasmid and chromosomal partitioning cassettes encoding ParB homologues capable of spreading on DNA. The xylE or lacZ reporter systems facilitate easy monitoring of plasmid segregation. The range of BHR vectors with different reporter cassettes and alternative mobilization systems expands their application in diverse bacterial species.
A COMPREHENSIVE ANALYSIS OF SPACE VECTOR PWM TECHNIQUE BASED ON PLACEMENT OF ZERO-SPACE VECTOR
Directory of Open Access Journals (Sweden)
G.SAMBASIVA RAO,
2011-04-01
Full Text Available In this paper, the effect of placement of zero-space vector for the implementation of space vector based Pulse Width Modulation techniques for 3-phase Voltage Source Inverter is presented. Several pulse width modulation (PWM control strategies have been proposed for 3-phase voltage source inverter (VSI in the past. It is known that space vector modulation (SVM offers a degree of freedom in its implementation with regard to the placement of the zero-space vector. Apart from constructing a consistent theoretical framework, simulation results with conventional continuous SVM and various discontinuous SVM techniques are presented and all the cases are compared in this paper.
Probability Ranking in Vector Spaces
Melucci, Massimo
2011-01-01
The Probability Ranking Principle states that the document set with the highest values of probability of relevance optimizes information retrieval effectiveness given the probabilities are estimated as accurately as possible. The key point of the principle is the separation of the document set into two subsets with a given level of fallout and with the highest recall. The paper introduces the separation between two vector subspaces and shows that the separation yields a more effective performance than the optimal separation into subsets with the same available evidence, the performance being measured with recall and fallout. The result is proved mathematically and exemplified experimentally.
Elements of mathematics topological vector spaces
Bourbaki, Nicolas
2003-01-01
This is a softcover reprint of the English translation of 1987 of the second edition of Bourbaki's Espaces Vectoriels Topologiques (1981). This second edition is a brand new book and completely supersedes the original version of nearly 30 years ago. But a lot of the material has been rearranged, rewritten, or replaced by a more up-to-date exposition, and a good deal of new material has been incorporated in this book, all reflecting the progress made in the field during the last three decades. Table of Contents. Chapter I: Topological vector spaces over a valued field. Chapter II: Convex sets and locally convex spaces. Chapter III: Spaces of continuous linear mappings. Chapter IV: Duality in topological vector spaces. Chapter V: Hilbert spaces (elementary theory). Finally, there are the usual "historical note", bibliography, index of notation, index of terminology, and a list of some important properties of Banach spaces. (Based on Math Reviews, 1983).
Topological vector spaces and their applications
Bogachev, V I
2017-01-01
This book gives a compact exposition of the fundamentals of the theory of locally convex topological vector spaces. Furthermore it contains a survey of the most important results of a more subtle nature, which cannot be regarded as basic, but knowledge which is useful for understanding applications. Finally, the book explores some of such applications connected with differential calculus and measure theory in infinite-dimensional spaces. These applications are a central aspect of the book, which is why it is different from the wide range of existing texts on topological vector spaces. In addition, this book develops differential and integral calculus on infinite-dimensional locally convex spaces by using methods and techniques of the theory of locally convex spaces. The target readership includes mathematicians and physicists whose research is related to infinite-dimensional analysis.
Countable Fuzzy Topological Space and Countable Fuzzy Topological Vector Space
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Apu Kumar Saha
2015-06-01
Full Text Available This paper deals with countable fuzzy topological spaces, a generalization of the notion of fuzzy topological spaces. A collection of fuzzy sets F on a universe X forms a countable fuzzy topology if in the definition of a fuzzy topology, the condition of arbitrary supremum is relaxed to countable supremum. In this generalized fuzzy structure, the continuity of fuzzy functions and some other related properties are studied. Also the class of countable fuzzy topological vector spaces as a generalization of the class of fuzzy topological vector spaces has been introduced and investigated.
A vector space approach to geometry
Hausner, Melvin
2010-01-01
The effects of geometry and linear algebra on each other receive close attention in this examination of geometry's correlation with other branches of math and science. In-depth discussions include a review of systematic geometric motivations in vector space theory and matrix theory; the use of the center of mass in geometry, with an introduction to barycentric coordinates; axiomatic development of determinants in a chapter dealing with area and volume; and a careful consideration of the particle problem. 1965 edition.
GENERALIZED VECTOR VARIATIONAL-TYPE INEQUALITIES IN FC-SPACES
Institute of Scientific and Technical Information of China (English)
FANG Min; DING Xie-ping
2006-01-01
A class of generalized vector variational-type inequality problems (GVVTIP) are studied in FC-spaces, which includes the most of vector equilibrium problems, vector variational inequality problems, generalized vector equilibrium problems and generalized vector variational inequality problem as special cases. By using F-KKM theorem,some new existence results for GVVTIP are established in noncompact FC-space. As consequences, some recent known results in literature are obtained under much weaker assumption.
Vector bundles on complex projective spaces
Okonek, Christian; Spindler, Heinz
1980-01-01
This expository treatment is based on a survey given by one of the authors at the Séminaire Bourbaki in November 1978 and on a subsequent course held at the University of Göttingen. It is intended to serve as an introduction to the topical question of classification of holomorphic vector bundles on complex projective spaces, and can easily be read by students with a basic knowledge of analytic or algebraic geometry. Short supplementary sections describe more advanced topics, further results, and unsolved problems.
Topological vector spaces admissible in economic equilibrium theory
DEFF Research Database (Denmark)
Keiding, Hans
2009-01-01
In models of economic equilibrium in markets with infinitely many commodities, the commodity space is an ordered topological vector space endowed with additional structure. In the present paper, we consider ordered topological vector spaces which are admissible (for equilibrium analysis) in the s......In models of economic equilibrium in markets with infinitely many commodities, the commodity space is an ordered topological vector space endowed with additional structure. In the present paper, we consider ordered topological vector spaces which are admissible (for equilibrium analysis...
Concircular $\\pi$-Vector Fields and Special Finsler Spaces
Youssef, Nabil L.; Soleiman, A
2012-01-01
The aim of the present paper is to investigate intrinsically the notion of a concircular $\\pi$-vector field in Finsler geometry. This generalizes the concept of a concircular vector field in Riemannian geometry and the concept of a concurrent vector field in Finsler geometry. Some properties of concircular $\\pi$-vector fields are obtained. Different types of recurrence are discussed. The effect of the existence of a concircular $\\pi$-vector field on some important special Finsler spaces is in...
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...
Isometric Reflection Vectors and Characterizations of Hilbert Spaces
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Donghai Ji
2014-01-01
Full Text Available A known characterization of Hilbert spaces via isometric reflection vectors is based on the following implication: if the set of isometric reflection vectors in the unit sphere SX of a Banach space X has nonempty interior in SX, then X is a Hilbert space. Applying a recent result based on well-known theorem of Kronecker from number theory, we improve this by substantial reduction of the set of isometric reflection vectors needed in the hypothesis.
The basic geometry of Witt vectors, II: Spaces
Borger, James
2010-01-01
This is an account of the algebraic geometry of Witt vectors and related constructions. The theory of the usual, "p-typical" Witt vectors of p-adic schemes of finite type is already reasonably well understood. The main point here is to generalize this theory in two different ways. We allow not just p-typical Witt vectors but also, for example, those taken with respect to any set of primes in any ring of integers in any global field. In particular, this includes the "big" Witt vectors. We also allow not just p-adic schemes of finite type but arbitrary algebraic spaces over the ring of integers in the global field. We give similar generalizations of Buium's formal arithmetic jet spaces, which are dual to the Witt vector construction. We also give concrete geometric descriptions of Witt spaces and arithmetic jet spaces and investigate whether many standard geometric properties are preserved by these functors.
Vector space model for document representation in information retrieval
Directory of Open Access Journals (Sweden)
Dan MUNTEANU
2007-12-01
Full Text Available This paper presents the basics of information retrieval: the vector space model for document representation with Boolean and term weighted models, ranking methods based on the cosine factor and evaluation measures: recall, precision and combined measure.
Fuzzy Generalized Variational Like Inequality problems in Topological Vector Spaces
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M. K. Ahmad
2013-01-01
Full Text Available This paper is devoted to the existence of solutions for generalized variational like inequalities with fuzzy mappings in topological vector spaces by using a particular form of the generalized KKM-Theorem.
Total Harmonic Distortion of Dodecagonal Space Vector Modulation
2014-01-01
Space vector modulation technique is one of the best PWM technique which has been implemented to the Multilevel inverter circuit to get the purely sinusoidal cuurent .This is a important algorithm which is implemented in open wind induction motor.This type of I.M has great impact on Electric Drive system. SVM is nothing but the technique of switching algorithm .The Hexagonal space vector modulation has been implemented before , but elimination of higher order harmonics are not possible. Torqu...
Surfaces with parallel mean curvature vector in complex space forms
Fetcu, Dorel
2010-01-01
We consider a quadratic form defined on the surfaces with parallel mean curvature vector of an any dimensional complex space form and prove that its $(2,0)$-part is holomorphic. When the complex dimension of the ambient space is equal to $2$ we define a second quadratic form with the same property and then determine those surfaces with parallel mean curvature vector on which the $(2,0)$-parts of both of them vanish. We also provide a reduction of codimension theorem and prove a non-existence result for $2$-spheres with parallel mean curvature vector.
Great Ellipse Route Planning Based on Space Vector
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LIU Wenchao
2015-07-01
Full Text Available Aiming at the problem of navigation error caused by unified earth model in great circle route planning using sphere model and modern navigation equipment using ellipsoid mode, a method of great ellipse route planning based on space vector is studied. By using space vector algebra method, the vertex of great ellipse is solved directly, and description of great ellipse based on major-axis vector and minor-axis vector is presented. Then calculation formulas of great ellipse azimuth and distance are deduced using two basic vectors. Finally, algorithms of great ellipse route planning are studied, especially equal distance route planning algorithm based on Newton-Raphson(N-R method. Comparative examples show that the difference of route planning between great circle and great ellipse is significant, using algorithms of great ellipse route planning can eliminate the navigation error caused by the great circle route planning, and effectively improve the accuracy of navigation calculation.
Directory of Open Access Journals (Sweden)
Chen Guoqiang
2016-01-01
Full Text Available Aiming at analysis complexity, a simulation model is built and presented to analyze and demonstrate the characteristics of the direct current (DC link current of the three-phase two-level inverter with the random space vector pulse width modulation (SVPWM strategy. The developing procedure and key subsystems of the simulation model are given in detail. Several experiments are done using the simulation model. The results verify the efficiency and convenience of the simulation model and show that the random SVPWM scheme, especially the random switching frequency scheme, can efficiently suppress the harmonic peaks of the DC link current.
Directory of Open Access Journals (Sweden)
Liu Qing-you
2011-01-01
Full Text Available Abstract In this paper, a scalarization result of ε-weak efficient solution for a vector equilibrium problem (VEP is given. Using this scalarization result, the connectedness of ε-weak efficient and ε-efficient solutions sets for the VEPs are proved under some suitable conditions in real Hausdorff topological vector spaces. The main results presented in this paper improve and generalize some known results in the literature.
Additive subgroups of topological vector spaces
Banaszczyk, Wojciech
1991-01-01
The Pontryagin-van Kampen duality theorem and the Bochner theorem on positive-definite functions are known to be true for certain abelian topological groups that are not locally compact. The book sets out to present in a systematic way the existing material. It is based on the original notion of a nuclear group, which includes LCA groups and nuclear locally convex spaces together with their additive subgroups, quotient groups and products. For (metrizable, complete) nuclear groups one obtains analogues of the Pontryagin duality theorem, of the Bochner theorem and of the Lévy-Steinitz theorem on rearrangement of series (an answer to an old question of S. Ulam). The book is written in the language of functional analysis. The methods used are taken mainly from geometry of numbers, geometry of Banach spaces and topological algebra. The reader is expected only to know the basics of functional analysis and abstract harmonic analysis.
Lemieux, Colette
1980-01-01
Defines the meaning of the American expression "convenience food," quoting definitions given by dictionaries and specialized publications. Discusses the problem of finding the exact equivalent of this expression in French, and recommends some acceptable translations. (MES)
Vector spaces on non-extendable holomorphic functions
Bernal-González, Luis
2014-01-01
In this paper, the linear structure of the family $H_e(G)$ of holomorphic functions in a domain $G$ of the complex plane that are not analytically continuable beyond the boundary of $G$ is analyzed. We prove that $H_e(G)$ contains, except for zero, a dense algebra; and, under appropriate conditions, the subfamily of $H_e(G)$ consisting of boundary-regular functions contains dense vector spaces with maximal dimension, as well as infinite dimensional closed vector spaces and large algebras. The...
Difference of Function on Vector Space over F
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Arai Kenichi
2014-09-01
Full Text Available In [11], the definitions of forward difference, backward difference, and central difference as difference operations for functions on R were formalized. However, the definitions of forward difference, backward difference, and central difference for functions on vector spaces over F have not been formalized. In cryptology, these definitions are very important in evaluating the security of cryptographic systems [3], [10]. Differential cryptanalysis [4] that undertakes a general purpose attack against block ciphers [13] can be formalized using these definitions. In this article, we formalize the definitions of forward difference, backward difference, and central difference for functions on vector spaces over F. Moreover, we formalize some facts about these definitions.
Nonlinear Parabolic Equations with Singularities in Colombeau Vector Spaces
Institute of Scientific and Technical Information of China (English)
Mirjana STOJANOVI(C)
2006-01-01
We consider nonlinear parabolic equations with nonlinear non-Lipschitz's term and singular initial data like Dirac measure, its derivatives and powers. We prove existence-uniqueness theorems in Colombeau vector space gC1,w2,2([O,T),Rn),n ≤ 3. Due to high singularity in a case of parabolic equation with nonlinear conservative term we employ the regularized derivative for the conservative term, in order to obtain the global existence-uniqueness result in Colombeau vector space gC1,L2([O,T),Rn),n ≤ 3.
Some Common Fixed Point Theorems in Generalized Vector Metric Spaces
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Rajesh Shrivastava
2013-11-01
Full Text Available In this paper we give some theorems on point of coincidence and common fixed point for two self mappings satisfying some general contractive conditions in generalized vector spaces. Our results generalize some well-known recent results in this direction.
An Asymmetrical Space Vector Method for Single Phase Induction Motor
DEFF Research Database (Denmark)
Cui, Yuanhai; Blaabjerg, Frede; Andersen, Gert Karmisholt
2002-01-01
the motor torque performance is not good enough. This paper addresses a new control method, an asymmetrical space vector method with PWM modulation, also a three-phase inverter is used for the main winding and the auxiliary winding. This method with PWM modulation is implemented to control the motor speed...
Dynamic Vector Space Secret Sharing Based on Certificates
Institute of Scientific and Technical Information of China (English)
XU Chunxiang; LI Jiajia; LIU Dongsu
2006-01-01
A vector space secret sharing scheme based on certificates is proposed in this paper. The difficulties of solving discrete logarithm assure confidential information's security, and the use of each participant's certificate makes the dealer have no need to transfer secret information to the participants. The proposed scheme is dynamic. It can effectively check cheaters and does not have secure channel requirements.
Model Based Defect Detection in Multi-Dimensional Vector Spaces
Honda, Toshifumi; Obara, Kenji; Harada, Minoru; Igarashi, Hajime
A highly sensitive inspection algorithm is proposed that extracts defects in multidimensional vector spaces from multiple images. The proposed algorithm projects subtraction vectors calculated from test and reference images to control the noise by reducing the dimensionality of vector spaces. The linear projection vectors are optimized using a physical defect model, and the noise distribution is calculated from the images. Because the noise distribution varies with the intensity or texture of the pixels, the target image is divided into small regions and the noise distribution of the subtraction images are calculated for each divided region. The bidirectional local perturbation pattern matching (BD-LPPM) which is an enhanced version of the LPPM, is proposed to increase the sensitivity when calculating the subtraction vectors, especially when the reference image contains more high-frequency components than the test image. The proposed algorithm is evaluated using defect samples for three different scanning electron microscopy images. The results reveal that the proposed algorithm increases the signal-to-noise ratio by a factor of 1.32 relative to that obtained using the Mahalanobis distance algorithm.
Vectors, Cyclic Submodules and Projective Spaces Linked with Ternions
Havlicek, Hans
2008-01-01
Given a ring of ternions $R$, i. e., a ring isomorphic to that of upper triangular $2\\times 2$ matrices with entries from an arbitrary commutative field $F$, a complete classification is performed of the vectors from the free left $R$-module $R^{n+1}$, $n \\geq 1$, and of the cyclic submodules generated by these vectors. The vectors fall into $5 + |F|$ and the submodules into 6 distinct orbits under the action of the general linear group $\\GL_{n+1}(R)$. Particular attention is paid to {\\it free} cyclic submodules generated by \\emph{non}-unimodular vectors, as these are linked with the lines of $\\PG(n,F)$, the $n$-dimensional projective space over $F$. In the finite case, $F$ = $\\GF(q)$, explicit formulas are derived for both the total number of non-unimodular free cyclic submodules and the number of such submodules passing through a given vector. These formulas yield a combinatorial approach to the lines and points of $\\PG(n,q)$, $n\\geq 2$, in terms of vectors and non-unimodular free cyclic submodules of $R^{n...
Krohs, Ulrich
2012-03-01
Systems biology aims at explaining life processes by means of detailed models of molecular networks, mainly on the whole-cell scale. The whole cell perspective distinguishes the new field of systems biology from earlier approaches within molecular cell biology. The shift was made possible by the high throughput methods that were developed for gathering 'omic' (genomic, proteomic, etc.) data. These new techniques are made commercially available as semi-automatic analytic equipment, ready-made analytic kits and probe arrays. There is a whole industry of supplies for what may be called convenience experimentation. My paper inquires some epistemic consequences of strong reliance on convenience experimentation in systems biology. In times when experimentation was automated to a lesser degree, modeling and in part even experimentation could be understood fairly well as either being driven by hypotheses, and thus proceed by the testing of hypothesis, or as being performed in an exploratory mode, intended to sharpen concepts or initially vague phenomena. In systems biology, the situation is dramatically different. Data collection became so easy (though not cheap) that experimentation is, to a high degree, driven by convenience equipment, and model building is driven by the vast amount of data that is produced by convenience experimentation. This results in a shift in the mode of science. The paper shows that convenience driven science is not primarily hypothesis-testing, nor is it in an exploratory mode. It rather proceeds in a gathering mode. This shift demands another shift in the mode of evaluation, which now becomes an exploratory endeavor, in response to the superabundance of gathered data.
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.
Topological Vector Space-Valued Cone Metric Spaces and Fixed Point Theorems
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Radenović Stojan
2010-01-01
Full Text Available We develop the theory of topological vector space valued cone metric spaces with nonnormal cones. We prove three general fixed point results in these spaces and deduce as corollaries several extensions of theorems about fixed points and common fixed points, known from the theory of (normed-valued cone metric spaces. Examples are given to distinguish our results from the known ones.
Total Harmonic Distortion of Dodecagonal Space Vector Modulation
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Babita Nanda
2014-05-01
Full Text Available Space vector modulation technique is one of the best PWM technique which has been implemented to the Multilevel inverter circuit to get the purely sinusoidal cuurent .This is a important algorithm which is implemented in open wind induction motor.This type of I.M has great impact on Electric Drive system. SVM is nothing but the technique of switching algorithm .The Hexagonal space vector modulation has been implemented before , but elimination of higher order harmonics are not possible. Torque pulsation arises. Speed control of Induction motor was not smooth .so Dodecagonal (12 structure developed. A 12 side polygonal space vector structure is meant for eliminating (6n±1 harmonics in the phase current waveform throughout the modulating range. A high resolution of PWM technique is proposed involving multiple 12 sided polygonal (Dodecagonal structure that can generate highly sinusoidal voltage at a reduced switching frequency. In this paper different values of frequencies have been taken for harmonic analysis. SVM method features a higher level of dc-bus voltage utilization compared to the conventional PWM.
Generalized space vector control for current source inverters and rectifiers
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Roseline J. Anitha
2016-06-01
Full Text Available Current source inverters (CSI is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI are dealt in this paper. As space vector pulse width modulation (SVPWM features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.
DEFF Research Database (Denmark)
Rodriguez, Pedro; Busquets-Monge, Sergio; Blaabjerg, Frede;
2011-01-01
This work presents the development of the space vector pulse width modulation (SVPWM) of a new multi-level converter topology. First, the proposed converter and its natural space vector diagram are presented. Secondly, a modified space vector diagram based on the virtual-vectors technique is show...
Semisupervised Support Vector Machines With Tangent Space Intrinsic Manifold Regularization.
Sun, Shiliang; Xie, Xijiong
2016-09-01
Semisupervised learning has been an active research topic in machine learning and data mining. One main reason is that labeling examples is expensive and time-consuming, while there are large numbers of unlabeled examples available in many practical problems. So far, Laplacian regularization has been widely used in semisupervised learning. In this paper, we propose a new regularization method called tangent space intrinsic manifold regularization. It is intrinsic to data manifold and favors linear functions on the manifold. Fundamental elements involved in the formulation of the regularization are local tangent space representations, which are estimated by local principal component analysis, and the connections that relate adjacent tangent spaces. Simultaneously, we explore its application to semisupervised classification and propose two new learning algorithms called tangent space intrinsic manifold regularized support vector machines (TiSVMs) and tangent space intrinsic manifold regularized twin SVMs (TiTSVMs). They effectively integrate the tangent space intrinsic manifold regularization consideration. The optimization of TiSVMs can be solved by a standard quadratic programming, while the optimization of TiTSVMs can be solved by a pair of standard quadratic programmings. The experimental results of semisupervised classification problems show the effectiveness of the proposed semisupervised learning algorithms.
Digital Simulation of Space Vector Modulation Based Induction Motor Drive
Directory of Open Access Journals (Sweden)
G.V. Siva Krishna Rao and T.S. Surendra
2011-04-01
Full Text Available This study deals with simulation of Space vector modulated inverter fed induction motor drive. The drive system is modeled using matlab simulink and the results are presented. This drive has advantages like reduced harmonics and heating. Fixed AC is converted into DC and this DC is converted into variable voltage and variable frequency AC using SVM inverter. The output of SVM is applied to the stator of induction motor. The simulation results are compared with the analytical results. The FFT analysis shows that the current spectrum has reduced harmonics compared to the conventional system.
A Group Oriented Cryptosystem for the Vector Space Access Structure
Institute of Scientific and Technical Information of China (English)
XU Chun-xiang; MA Hua; ZHOU Jun-hui; XIAO Guo-zheng
2006-01-01
A group oriented cryptosystem for the vector space access structure was proposed. This cryptosystem adopts self-certified public keys. It allows the participants of an authorized subset to cooperatively access an en crypted message. All data delivered in the cryptosystem are public. Therefore it does not need a partial decrypting results combiner and any secure communication channel. The security of the group oriented cryptosystem is based on the intractability of the discrete log problem and difficulty of factoring large integers. The suspected attacks can not break it.
DEFF Research Database (Denmark)
Rodriguez, Pedro; Busquets-Monge, Sergio; Blaabjerg, Frede
2011-01-01
This work presents the development of the space vector pulse width modulation (SVPWM) of a new multi-level converter topology. First, the proposed converter and its natural space vector diagram are presented. Secondly, a modified space vector diagram based on the virtual-vectors technique is shown....... Simulation results by using a space vector approach are presented. Special emphasis is given on the total harmonic distortion (THD) by making a comparison with those of the classical NPC topologies....
On vector autoregressive modeling in space and time
di Giacinto, Valter
2010-06-01
Despite the fact that it provides a potentially useful analytical tool, allowing for the joint modeling of dynamic interdependencies within a group of connected areas, until lately the VAR approach had received little attention in regional science and spatial economic analysis. This paper aims to contribute in this field by dealing with the issues of parameter identification and estimation and of structural impulse response analysis. In particular, there is a discussion of the adaptation of the recursive identification scheme (which represents one of the more common approaches in the time series VAR literature) to a space-time environment. Parameter estimation is subsequently based on the Full Information Maximum Likelihood (FIML) method, a standard approach in structural VAR analysis. As a convenient tool to summarize the information conveyed by regional dynamic multipliers with a specific emphasis on the scope of spatial spillover effects, a synthetic space-time impulse response function (STIR) is introduced, portraying average effects as a function of displacement in time and space. Asymptotic confidence bands for the STIR estimates are also derived from bootstrap estimates of the standard errors. Finally, to provide a basic illustration of the methodology, the paper presents an application of a simple bivariate fiscal model fitted to data for Italian NUTS 2 regions.
A New Vector-Valued Padé-Type Approximation in the Inner Space
Institute of Scientific and Technical Information of China (English)
Chunjing Li
2006-01-01
A new vector-valued Padé-type approximation is defined by introducing a generalized vector-valued linear functional from a scalar polynomial space to a vector space. Some proximants are provided with the generating function form and the determinant form.
Variable Vector Countermeasure Suit (V2Suit) for Space Habitation and Exploration Project
National Aeronautics and Space Administration — The “Variable Vector Countermeasure Suit (V2Suit) for Space Habitation and Exploration” is a visionary system concept that will revolutionize space...
Limited Holism and Real-Vector-Space Quantum Theory
Hardy, Lucien
2010-01-01
Quantum theory has the property of "local tomography": the state of any composite system can be reconstructed from the statistics of measurements on the individual components. In this respect the holism of quantum theory is limited. We consider in this paper a class of theories more holistic than quantum theory in that they are constrained only by "bilocal tomography": the state of any composite system is determined by the statistics of measurements on pairs of components. Under a few auxiliary assumptions, we derive certain general features of such theories. In particular, we show how the number of state parameters can depend on the number of perfectly distinguishable states. We also show that real-vector-space quantum theory, while not locally tomographic, is bilocally tomographic.
Limited Holism and Real-Vector-Space Quantum Theory
Hardy, Lucien; Wootters, William K.
2012-03-01
Quantum theory has the property of "local tomography": the state of any composite system can be reconstructed from the statistics of measurements on the individual components. In this respect the holism of quantum theory is limited. We consider in this paper a class of theories more holistic than quantum theory in that they are constrained only by "bilocal tomography": the state of any composite system is determined by the statistics of measurements on pairs of components. Under a few auxiliary assumptions, we derive certain general features of such theories. In particular, we show how the number of state parameters can depend on the number of perfectly distinguishable states. We also show that real-vector-space quantum theory, while not locally tomographic, is bilocally tomographic.
Kakeya-type sets in finite vector spaces
Kopparty, Swastik; Saraf, Shubhangi; Sudan, Madhu
2010-01-01
For a finite vector space $V$ and a non-negative integer $r\\le\\dim V$ we estimate the smallest possible size of a subset of $V$, containing a translate of every $r$-dimensional subspace. In particular, we show that if $K\\subset V$ is the smallest subset with this property, $n$ denotes the dimension of $V$, and $q$ is the size of the underlying field, then for $r$ bounded and $r
Discrete Fourier Transform Analysis in a Complex Vector Space
Dean, Bruce H.
2009-01-01
Alternative computational strategies for the Discrete Fourier Transform (DFT) have been developed using analysis of geometric manifolds. This approach provides a general framework for performing DFT calculations, and suggests a more efficient implementation of the DFT for applications using iterative transform methods, particularly phase retrieval. The DFT can thus be implemented using fewer operations when compared to the usual DFT counterpart. The software decreases the run time of the DFT in certain applications such as phase retrieval that iteratively call the DFT function. The algorithm exploits a special computational approach based on analysis of the DFT as a transformation in a complex vector space. As such, this approach has the potential to realize a DFT computation that approaches N operations versus Nlog(N) operations for the equivalent Fast Fourier Transform (FFT) calculation.
New space vector modulation technique for single-phase multilevel converters
León Galván, José Ignacio; Portillo Guisado, Ramón Carlos; García Franquelo, Leopoldo; Vázquez Pérez, Sergio; Carrasco Solís, Juan Manuel; Domínguez, E
2007-01-01
Single-phase multilevel converters are suitable for medium power applications as photovoltaic systems and switched reluctance machines. An overview of possible modulation methods including carrier-based pulse width modulation and space vector modulation techniques for multilevel single-phase converters is presented. A new space vector modulation for this type of converters is proposed. This space vector modulation method is very simple presenting low computational cost. Different solutions fo...
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.
2016-01-01
Documento que contiene la explicación sobre las temáticas de Sistemas coordenados, Cantidades vectoriales y escalares, Algunas propiedades de los vectores, Componentes de un vector y vectores unitarios
New Space Vector Selection Scheme for VSI Supplied Dual Three-Phase Induction Machine
Directory of Open Access Journals (Sweden)
MILICEVIC, D.
2013-02-01
Full Text Available This paper presents a novel space vector selection scheme applicable for the control of dual three-phase induction motor drives supplied from a six-phase voltage source inverter (VSI. The vector selection method is based on the vector space decomposition technique (VSD. Unique vector selection pattern simplifies problems related to complicated implementation of standard VSD in commercially available digital signals processors (DSP. The proposed vector selection scheme is verified through a theoretical analysis, computer simulations and practical experimental results conducted on a dual three-phase test rig prototype with control algorithm implemented in Texas Instrument?s TMS320F2808 DSP.
Sistem Temu Kembali Informasi dengan Metode Vector Space Model
Directory of Open Access Journals (Sweden)
Fatkhul Amin
2014-02-01
Full Text Available The information retrieval system (IRS now provides document search results with abundant results of documents (high recall and low accuracy (low precision. The objective of designing IRS with Vector Space Model (VSM Method is to facilitate users to searchIndonesian documents. IRS Software is designed to provide search results with the optimum number of documents (low recall and accuracy (high precision with VSM method that users may get fast and accurate results. VSM method provides a different credit for each document stored in a database which in turns to determine the document most similar to the query, where the documents with the highest credits are placed on the top of the search results. The evaluation of search results with IRS is conducted under recall andprecision tests. This study fascinatingly creates a system which can preprocess (tokenizing, filtering, and stemming within computation time of four minutes forty-one seconds. The system can search the documents and display them in the search results with an averagecomputation time of 1.5 seconds, with an average recall of 0.19, and an average precision of 0.54. The system is equipped with a credit for each document, and the value is positioned on which a user may easily search the Indonesian text.Keywords: IRS, Vector Space Model, Recall, Precision
Variable Vector Countermeasure Suit (V2Suit) for Space Habitation and Exploration Project
National Aeronautics and Space Administration — The Variable Vector Countermeasure Suit (V2Suit) is a specialized spacesuit designed to keep astronauts healthy during long-duration space exploration missions and...
An adaptive method of averaging the space-vectors location in DSP controlled drives
Energy Technology Data Exchange (ETDEWEB)
Debowski, A.; Chudzik, P. [Technical University of Lodz, Institute of Automatic Control, Lodz (Poland)
2000-08-01
In the paper a practical method of averaging the space- vector location for electrical drives controlled with digital signal processors (DSP) is demonstrated. This method enables to approximate the step movement of the given real space-vector with a smooth rotation of a conventional one in given time subintervals by any field rotation speed. The method is suitable for many practical applications in vector controlled electrical drives. In the paper some experimental examples of estimation the space-vectors of stator current and rotor flux in an inverter-fed induction motor drive are shown. (orig.)
A Class of Cone Bounded Quasiconvex Mappings in Topological Vector Spaces
Institute of Scientific and Technical Information of China (English)
Yu-da Hu; Chen Ling
2003-01-01
Within the context of cone-ordered topological vector spaces, this paper introduces the concepts of cone bounded point and cone bounded set for vector set. With their aid, a class of new cone quasiconvex mappings in topological vector spaces is defined, and their fundamental properties are presented. The relationships between the cone bounded quasiconvex mapping defined in this paper and cone convex mapping, and other known cone quasiconvex mapping are also discussed.
Estimates for Vector-valued Commutators on Weighted Morrey Space and Applications
Institute of Scientific and Technical Information of China (English)
Shao Guang SHI
2013-01-01
In this paper,we introduce weighted vector-valued Morrey spaces and obtain some estimates for vector-valued commutators on these spaces.Applications to Calderón-Zygmund singular integral operators,oscillatory singular integral operators and parabolic difference equations are considered.
Muralidhar, K.
2014-03-01
Elementary particles are considered as local oscillators under the influence of zeropoint fields. Such oscillatory behavior of the particles leads to the deviations in their path of motion. The oscillations of the particle in general may be considered as complex rotations in complex vector space. The local particle harmonic oscillator is analyzed in the complex vector formalism considering the algebra of complex vectors. The particle spin is viewed as zeropoint angular momentum represented by a bivector. It has been shown that the particle spin plays an important role in the kinematical intrinsic or local motion of the particle. From the complex vector formalism of harmonic oscillator, for the first time, a relation between mass and bivector spin has been derived in the form . Where, is the angular velocity bivector of complex rotations, is the velocity of light. The unit vector acts as an operator on the idempotents and to give the eigen values The constant represents two fold nature of the equation corresponding to particle and antiparticle states. Further the above relation shows that the mass of the particle may be interpreted as a local spatial complex rotation in the rest frame. This gives an insight into the nature of fundamental particles. When a particle is observed from an arbitrary frame of reference, it has been shown that the spatial complex rotation dictates the relativistic particle motion. The mathematical structure of complex vectors in space and spacetime is developed.
Propagation property of the non-paraxial vector Lissajous singularity beams in free space
Chen, Haitao; Gao, Zenghui
2016-12-01
The analytic expressions for the free-space propagation of paraxial and non-paraxial vector Lissajous singularity beams are derived, and used to compare the propagation property of a Lissajous singularity carried by paraxial and non-paraxial vector beams in free space. It is found that the creation of a single Lissajous singularity, the creation and annihilation of pairs Lissajous singularities may take place for the both cases. However, after the annihilation of a pair of singularities, no Lissajous singularities appear in the output field for non-paraxial vector Lissajous singularity beams, which is different from the paraxial vector Lissajous singularity beams.
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The reputation of ITMA ASIA+ClTME 2010 as Asia’s premier textile industry platform has been given a further boost following an announcement from the show organizers that all exhibition space has now been sold. Over 1,100 textile and garment machinery manufacturers have applied successfully to exhibit at the second combined show,taking up 100,000 square meters of Shanghai New International Expo Centre.
Generalized Köthe-Toeplitz Duals of Some Vector-Valued Sequence Spaces
Directory of Open Access Journals (Sweden)
Yılmaz Yılmaz
2013-01-01
Full Text Available We know from the classical sequence spaces theory that there is a useful relationship between continuous and -duals of a scalar-valued FK-space originated by the AK-property. Our main interest in this work is to expose relationships between the operator space and and the generalized -duals of some -valued AK-space where and are Banach spaces and . Further, by these results, we obtain the generalized -duals of some vector-valued Orlicz sequence spaces.
DEFF Research Database (Denmark)
Swierczynski, Dariusz; Kazmierkowski, Marian P.; Blaabjerg, Frede
2002-01-01
DSP Based Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) using Space Vector Modulation (DTC-SVM)......DSP Based Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) using Space Vector Modulation (DTC-SVM)...
DEFF Research Database (Denmark)
Swierczynski, Dariusz; Kazmierkowski, Marian P.; Blaabjerg, Frede
2002-01-01
DSP Based Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) using Space Vector Modulation (DTC-SVM)......DSP Based Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) using Space Vector Modulation (DTC-SVM)...
State-Vector Space and Canonical Coherent States in Noncommutative Plane
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose-Einstein statistics the commutation relations of phase space variables should simultaneously include coordinate-coordinate non-commutativity and momentum-momentum non-commutativity, which leads to a kind of de-formed Heisenberg-Weyl algebra. Although there is no ordinary number representation in this state-vector space, several set of orthogonal and complete state-vectors can be derived which are common eigenvectors of corresponding pairs of commuting Hermitian operators. As a simple application of this state-vector space, an explicit form of two-dimensional canonical coherent state is constructed and its properties are discussed.
DEFF Research Database (Denmark)
Boeriis, Morten; van Leeuwen, Theo
2017-01-01
This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...... on the most salient vectors, and this works well, but many images contain a plethora of vectors, which makes their structure quite different from the linguistic transitivity structures with which Kress and van Leeuwen have compared ‘narrative’ images. It can also be asked whether facial expression vectors...... should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined...
DEFF Research Database (Denmark)
Hulot, Gauthier; Vigneron, Pierre; Leger, Jean-Michel;
2015-01-01
ESA's Swarm satellites carry a new generation of 4He absolute magnetometers (ASM), designed by CEA-Leti and developed in partnership with CNES. These instruments are the rst-ever space-born magnetometers to use a common sensor to simultaneously deliver 1Hz independent absolute scalar and vector r...... be monitored from space with such absolute vector magnetometers.......ESA's Swarm satellites carry a new generation of 4He absolute magnetometers (ASM), designed by CEA-Leti and developed in partnership with CNES. These instruments are the rst-ever space-born magnetometers to use a common sensor to simultaneously deliver 1Hz independent absolute scalar and vector...
GENERALIZED VECTOR QUASI-EQUILIBRIUM PROBLEMS IN LOCALLY G-CONVEX SPACES
Institute of Scientific and Technical Information of China (English)
DING Xie-ping
2005-01-01
Some classes of generalized vector quasi-equilibrium problems (in short,GVQEP) are introduced and studied in locally G-convex spaces which includes most of generalized vector equilibrium problems, generalized vector variational inequality problems,quasi-equilibrium problems and quasi-variational inequality problems as special cases. First,an equilibrium existence theorem for one person games is proved in locally G-convex spaces.As applications, some new existence theorems of solutions for the GVQEP are established in noncompact locally G-convex spaces. These results and argument methods are new and completely different from that in recent literature.
Space Vector Pulse Width Modulation Scheme for a Seven-Phase Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Mohd. Arif Khan
2011-09-01
Full Text Available This paper analyses a simple space vector PWM (SVPWM scheme for a seven-phase voltage source inverter. At first the conventional method of producing sinusoidal output voltage by utilizing six active and a zero space vectors are used to synthesis the input reference and then new PWM scheme called time equivalent space vector PWM is presented. A comparison of the proposed scheme with the conventional scheme is presented based on various performance indices. Extensive Simulation results are provided to validate the findings
Directory of Open Access Journals (Sweden)
A. El Janati El Idrissi
2011-08-01
Full Text Available In recent years, permanent magnet synchronous motors (PMSM have gained variety industrial applications, because of simple structures, high efficiency and ease of maintenance. But these motors have a nonlinear mathematical model. To resolve this problem several studies have suggested the application of soft-computing technique. This paper presents vector control of PMSM fed by space vector modulation inverter using genetic algorithm (GA controllers to improve speed, currents and the electric torque by significantly reducing their ripples, which offer an extra advantage of this study. The proposed method effectiveness has been verified by computer simulations using Matlab/Simulink®. These results are compared with the ones obtained with a vector control using PI controllers for speed and current [1] and the second obtained with adaptive controller based speed estimation technique [2].
Glockner, Helge
2006-01-01
We prove an implicit function theorem for Keller C^k_c-maps from arbitrary real or complex topological vector spaces to Frechet spaces, imposing only a certain metric estimate on the partial differentials. As a tool, we show the C^k-dependence of fixed points on parameters for suitable families of contractions of a Frechet space. The investigations were stimulated by a recent metric approach to differentiability in Frechet spaces by Olaf Mueller. Our results also subsume generalizations of Mu...
On the reproducing kernel of a Pontryagin space of vector valued polynomials
Ćurgus, B.; Dijksma, A.
2012-01-01
We give necessary and sufficient conditions under which the reproducing kernel of a Pontryagin space of d x 1 vector polynomials is determined by a generalized Nevanlinna pair of d x d matrix polynomials. Published by Elsevier Inc.
Fixed Point Theorem of Half-Continuous Mappings on Topological Vector Spaces
Directory of Open Access Journals (Sweden)
Imchit Termwuttipong
2010-01-01
Full Text Available Some fixed point theorems of half-continuous mappings which are possibly discontinuous defined on topological vector spaces are presented. The results generalize the work of Philippe Bich (2006 and several well-known results.
On the Statistics of Noisy Space Vector in Power Quality Analysis
Directory of Open Access Journals (Sweden)
Diego Bellan
2016-10-01
Full Text Available This work deals with the analysis of the impact of additive noise on the geometrical features of the space vector shape on the complex plane. The space vector shape is of great importance in the power quality analysis of modern three-phase power systems since its geometrical features are closely related to the voltage supply quality. In case of voltage sag or swell the space vector shape changes accordingly. In case of additive noise the geometrical parameters of the space vector shape can be treated as random variables. In the paper, the mean values and the variances of such parameters are derived in closed form as functions of the noise level and of the sampling conditions. Analytical results are validated through numerical simulation of the whole measurement process.
Full Space Vectors Modulation for Nine-Switch Converters Including CF & DF Modes
DEFF Research Database (Denmark)
Dehghan Dehnavi, Seyed Mohammad; Mohamadian, Mustafa; Andersen, Michael A. E.
2010-01-01
converter. As a space vector modulation for DF mode has already been proposed by authors. This paper proposes a full space vector modulation (SVM) for both CF and DF modes. Also practical methods are presented for SVM proposed. In addition a special SVM is proposed that offers minimum total harmonic...... distortion (THD) in DF mode. The performance of the proposed SVM is verified by simulation results....
Twistor quantization of the space of half-differentiable vector functions on the circle revisited
Institute of Scientific and Technical Information of China (English)
SERGEEV; Armen
2009-01-01
We discuss the twistor quantization problem for the classical system(Vd,Ad),represented by the phase space Vd,identified with the Sobolev space H 1/2 0 (S1,Rd)of half-differentiable vector functions on the circle,and the algebra of observables Ad,identified with the semi-direct product of the Heisenberg algebra of Vd and the algebra Vect(S1)of tangent vector fields on the circle.
Analysis of Discontinuous Space Vector PWM Techniques for a Seven-Phase Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Mohd. Arif Khan
2012-03-01
Full Text Available This paper presents discontinuous space vector PWM (DPWM techniques for a seven-phase voltage source inverter (VSI. Space vector model of a seven-phase VSI shows that there exist 128 space vectors with different lengths and maps into fourteen sided polygons. A number of possibilities could arise to implement modulation of inverter legs due to large number of available space voltage vectors. Two strategies are adopted here; one utilising large and two middle sets of space vectors to implement discontinuous space vector PWM. Clamping of legs of inverter to either positive or negative dc bus leads to discontinuity in the switching and consequently offers reduced switching loss modulation strategy. A significant reduction in switching losses can be achieved while employing DPWM in a seven-phase VSI. A generalised method is also proposed to realize the DPWM in a seven-phase VSI. Comparison of continuous and discontinuous PWM is presented in terms of switching current ripple. The experimental set-up is illustrated and the experimental results are presented.
Phase Space Prediction of Chaotic Time Series with Nu-Support Vector Machine Regression
Institute of Scientific and Technical Information of China (English)
YE Mei-Ying; WANG Xiao-Dong
2005-01-01
A new class of support vector machine, nu-support vector machine, is discussed which can handle both classification and regression. We focus on nu-support vector machine regression and use it for phase space prediction of compares nu-support vector machine with back propagation (BP) networks in order to better evaluate the performance of the proposed methods. The experimental results show that the nu-support vector machine regression obtains lower root mean squared error than the BP networks and provides an accurate chaotic time series prediction. These results can be attributable to the fact that nu-support vector machine implements the structural risk minimization principle and this leads to better generalization than the BP networks.
Vector-like deformations of Minkowski space and relativistic kinematics
Loret, Niccoló; Mercati, Flavio; Pikutić, Danijel
2016-01-01
We study a family of noncommutative spacetimes constructed by one four-vector. The large set of coordinate commutation relations described in this way includes many cases that are widely studied in the literature. The Hopf-algebra symmetries of these noncommutative spacetimes, as well as the structures of star product and twist, are introduced and considered at first order in the deformation, described by four parameters. We also study the deformations to relativistic kinematics implied by this framework, and calculate the most general expression for the backreaction factors of momenta on boosts. At the end of the paper we analyse the phenomenological consequences of this large family of vector-like deformations on particles propagation in spacetime. This leads to a set of characteristic phenomenological effects.
α-模糊向量空间%α-Fuzzy Vector Spaces
Institute of Scientific and Technical Information of China (English)
刚家泰
2001-01-01
给出了α-模糊向量空间的定义，讨论了α-模糊向量空间的一些性质，给出了向量空间V的 一个模糊子集成为α-模糊向量空间的充分必要条件．最后给出了α-模糊线性无关的定义， 推广了有关文献中的结果.%Definition of α-fuzzy vector space is giv en. some properties of α-fuzzy vector space are discussed. Sufficient and nece ssary conditions that a fuzzy subset of a vector space makes a α-fuzzy vector s pace are proposed.Finally, concepts of α-fuzzy linear independe nce is given,which generalizes some results of related references.
SYSTEM OF GENERALIZED VECTOR QUASI-EQUILIBRIUM PROBLEMS ON PRODUCT FC-SPACES
Institute of Scientific and Technical Information of China (English)
Ding Xieping
2007-01-01
By applying a maximal element theorem on product FC-space due to author, some new equilibrium existence theorems for generalized games with fuzzy constraint correspondences are proved in FC-spaces. By using these equilibrium existence theorems, some new existence theorems of solutions for the system of generalized vector quasi-equilibrium problems are established in noncompact product FC-spaces. These results improve and generalize some recent results in literature to product FC-spaces without any convexity structure.
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.
Nocera, A.; Alvarez, G.
2016-11-01
Frequency-dependent correlations, such as the spectral function and the dynamical structure factor, help illustrate condensed matter experiments. Within the density matrix renormalization group (DMRG) framework, an accurate method for calculating spectral functions directly in frequency is the correction-vector method. The correction vector can be computed by solving a linear equation or by minimizing a functional. This paper proposes an alternative to calculate the correction vector: to use the Krylov-space approach. This paper then studies the accuracy and performance of the Krylov-space approach, when applied to the Heisenberg, the t-J, and the Hubbard models. The cases studied indicate that the Krylov-space approach can be more accurate and efficient than the conjugate gradient, and that the error of the former integrates best when a Krylov-space decomposition is also used for ground state DMRG.
Nocera, A; Alvarez, G
2016-11-01
Frequency-dependent correlations, such as the spectral function and the dynamical structure factor, help illustrate condensed matter experiments. Within the density matrix renormalization group (DMRG) framework, an accurate method for calculating spectral functions directly in frequency is the correction-vector method. The correction vector can be computed by solving a linear equation or by minimizing a functional. This paper proposes an alternative to calculate the correction vector: to use the Krylov-space approach. This paper then studies the accuracy and performance of the Krylov-space approach, when applied to the Heisenberg, the t-J, and the Hubbard models. The cases studied indicate that the Krylov-space approach can be more accurate and efficient than the conjugate gradient, and that the error of the former integrates best when a Krylov-space decomposition is also used for ground state DMRG.
Do the Kontsevich tetrahedral flows preserve or destroy the space of Poisson bi-vectors?
Bouisaghouane, Anass; Kiselev, Arthemy V.
2017-01-01
From the paper “Formality Conjecture” (Ascona 1996): I am aware of only one such a class, it corresponds to simplest good graph, the complete graph with 4 vertices (and 6 edges). This class gives a remarkable vector field on the space of bi-vector fields on ℝd . The evolution with respect to the time t is described by the following non-linear partial differential equation: …, where α = ∑i,j αij∂ / ∂ xi ∧ ∂ / ∂ xj is a bi-vector field on ℝd. It follows from general properties of cohomology that 1) this evolution preserves the class of ( real-analytic ) Poisson structures , … In fact, I cheated a little bit. In the formula for the vector field on the space of bivector fields which one get from the tetrahedron graph, an additional term is present. … It is possible to prove formally that if α is a Poisson bracket, i.e. if [α, α] = 0 ∈ T2(ℝ d ), then the additional term shown above vanishes . By using twelve Poisson structures with high-degree polynomial coefficients as explicit counter-examples, we show that both the above claims are false: neither does the first flow preserve the property of bi-vectors to be Poisson nor does the second flow vanish identically at Poisson bi-vectors. The counterexamples at hand suggest a correction to the formula for the “exotic” flow on the space of Poisson bi-vectors; in fact, this flow is encoded by the balanced sum involving both the Kontsevich tetrahedral graphs (that give rise to the flows mentioned above). We reveal that it is only the balance 1 : 6 for which the flow does preserve the space of Poisson bi-vectors.
LAPLACE-RUNGE-LENZ VECTOR IN QUANTUM MECHANICS IN NONCOMMUTATIVE SPACE
Directory of Open Access Journals (Sweden)
Peter Prešnajder
2014-04-01
Full Text Available The object under scrutiny is the dynamical symmetry connected with conservation of the Laplace-Runge-Lenz vector (LRL in the hydrogen atom problem solved by means of noncommutative quantum mechanics (NCQM. The considered noncommutative configuration space has such a “fuzzy”structure that the rotational invariance is not spoilt. An analogy with the LRL vector in the NCQM is brought to provide our results and also a comparison with the standard QM predictions.
Revised single-spacecraft method for determining wave vector k and resolving space-time ambiguity
Bellan, P. M.
2016-09-01
A practical method is proposed for determining the wave vector of waves from single-spacecraft measurements. This wave vector knowledge can then be used to remove the space-time ambiguity produced by frequency Doppler shift associated with spacecraft motion. The method involves applying the Wiener-Khinchin theorem to cross correlations of the current and magnetic field oscillations and to autocorrelations of the magnetic field oscillations. The method requires that each wave frequency component map to a unique wave vector, a condition presumed true in many spacecraft measurement situations. Examples validating the method are presented.
Approximation of Besov vectors by Paley-Wiener vectors in Hilbert spaces
Pesenson, Isaac Z
2011-01-01
We develop an approximation theory in Hilbert spaces that generalizes the classical theory of approximation by entire functions of exponential type. The results advance harmonic analysis on manifolds and graphs, thus facilitating data representation, compression, denoising and visualization. These tasks are of great importance to machine learning, complex data analysis and computer vision.
Directory of Open Access Journals (Sweden)
Nandakumar Sundararaju
2014-05-01
Full Text Available This paper proposes novel hybrid asymmetric space vector modulation technique for inverter operated direct torque control induction motor drive. The hybridization process is performed by the combination of continuous asymmetric space vector modulation pulse width technique (ASVPWM and fuzzy operated discontinuous ASVPWM technique. Combination process is based on pulse mismatching technique. Pulse mismatching technique helps to reduce the active region of the switch. Finally, optimal pulses are applied to control the inverter. The optimal hybrid pulse condense switching losses of the inverter and also improves the operating performance of the direct torque control (DTC based drive system like smooth dynamic response in speed reversal, minimum torque error, settling time of speed. Simulation results of proposed hybrid asymmetric space vector pulse width modulation technique to direct torque control (HASVPWM-DTC approach has been carried out by using Matlab-Simulink environment.
A convenient category for directed homotopy
DEFF Research Database (Denmark)
Fajstrup, Lisbeth; Rosický, J.
We propose a convenient category for directed homotopy consisting of preordered topological spaces generated by cubes. Its main advantage is that, like the category of topological spaces generated by simplices suggested by J. H. Smith, it is locally presentable.......We propose a convenient category for directed homotopy consisting of preordered topological spaces generated by cubes. Its main advantage is that, like the category of topological spaces generated by simplices suggested by J. H. Smith, it is locally presentable....
A convenient category for directed homotopy
DEFF Research Database (Denmark)
Fajstrup, Lisbeth; Rosický, J.
2008-01-01
We propose a convenient category for directed homotopy consisting of "directed" topological spaces generated by "directed" cubes. Its main advantage is that, like the category of topological spaces generated by simplices suggested by J. H. Smith, it is locally presentable.......We propose a convenient category for directed homotopy consisting of "directed" topological spaces generated by "directed" cubes. Its main advantage is that, like the category of topological spaces generated by simplices suggested by J. H. Smith, it is locally presentable....
Full Space Vectors Modulation for Nine-Switch Converters Including CF & DF Modes
DEFF Research Database (Denmark)
Dehghan Dehnavi, Seyed Mohammad; Mohamadian, Mustafa; Andersen, Michael A. E.
2010-01-01
Recently, nine-switch inverter was presented as dual output inverter. Two constant frequency (CF) and different frequency (DF) modes are defined for nine-switch inverter. However CF mode is more interesting because reasonable rating. Several switching methods have been presented for nine switch...... converter. As a space vector modulation for DF mode has already been proposed by authors. This paper proposes a full space vector modulation (SVM) for both CF and DF modes. Also practical methods are presented for SVM proposed. In addition a special SVM is proposed that offers minimum total harmonic...... distortion (THD) in DF mode. The performance of the proposed SVM is verified by simulation results....
Comparison of Performance of VSI and Z-Source Inverter for Space Vector PWM
Directory of Open Access Journals (Sweden)
E. Sai Prateek
2014-05-01
Full Text Available Z-Source Inverters have the ability to boost the dc link voltage, thus increasing the output ac voltage beyond the values reached by conventional inverters. The enhanced ratio from ac output voltage to dc link voltage is possible due to an impedance network connected between the dc power supply and the main converter. The space vector pulse width modulation techniques gives more dc bus utilisation and low harmonics than other pulse width modulation techniques. In this paper space vector pwm is implemented for conventional VSI and Zsource inverter. The results are supported by SIMULINK simulation
Space Vector Based Generalized Dpwm Algorithms for Vsi Fed Induction Motor Drive
Directory of Open Access Journals (Sweden)
N. Praveena
2013-09-01
Full Text Available This paper presents Space Vector based Generalized DiscontinuousPulse width modulation (GDPWM algorithms for VSI fed Induction motor drive. To avoid the complexity due to angle calculation and sector identification involved in Conventional space vector pulse width modulation (CSVPWM. The Proposed algorithms use the concept of Imaginary Switching times and a constant variable µ and modulation phase angle δ are used to generate modulating waveforms.The proposed algorithms results in reduced current ripple over CSVPWM. To validate the proposed methods, simulation is carried on V/f controlled Induction Motor drive in MATLAB/SIMULINK environment and the results are discussed.
Formation of Vortex Structures in the Prenozzle Space of an Engine with a Vectorable Thrust Nozzle
Volkov, K. N.; Emel'yanov, V. N.; Denisikhin, S. V.
2016-05-01
A numerical simulation of the hydrodynamic effects arising in the process of work of the vectorable thrust nozzle of a solid-propellant rocket engine has been performed. The fields of the flows of combustion products in the channel of a charge, the prenozzle space, and the nozzle unit were calculated for different angles of vectoring of the nozzle. The distributions of the gasdynamic parameters of the flow of combustion products in the prenozzle space, corresponding to their efflux from the cylindrical and star-shaped channels of charges, were compared. The formation of a vortex flow in the neighborhood of the back cover of the nozzle was considered.
Discrete Fourier Transform in a Complex Vector Space
Dean, Bruce H. (Inventor)
2015-01-01
An image-based phase retrieval technique has been developed that can be used on board a space based iterative transformation system. Image-based wavefront sensing is computationally demanding due to the floating-point nature of the process. The discrete Fourier transform (DFT) calculation is presented in "diagonal" form. By diagonal we mean that a transformation of basis is introduced by an application of the similarity transform of linear algebra. The current method exploits the diagonal structure of the DFT in a special way, particularly when parts of the calculation do not have to be repeated at each iteration to converge to an acceptable solution in order to focus an image.
Gabor, Andre
1980-01-01
Discusses a study undertaken by the Nottingham University Consumer Study Group to determine market operation for popular convenience foods in England. Information is presented on distribution of purchases, brand loyalties of respondents to a questionnaire regarding convenience foods, and market fluctuation due to inflation. (Author/DB)
Jackson, Peter; Viehoff, Valerie
2016-03-01
This paper provides a critical review of recent research on the consumption of 'convenience' food, highlighting the contested nature of the term and exploring its implications for public health and environmental sustainability. It distinguishes between convenience food in general and particular types of convenience food, such as ready-meals, tracing the structure and growth of the market for such foods with a particular emphasis on the UK which currently has the highest rate of ready-meal consumption in Europe. Having established the definitional complexities of the term, the paper presents the evidence from a systematic review of the literature, highlighting the significance of convenience food in time-saving and time-shifting, the importance of recent changes in domestic labour and family life, and the way the consumption of convenience food is frequently moralized. The paper shows how current debates about convenience food are part of a longer discursive history about food, health and nutrition. It discusses current levels of public understanding about the links between convenience food, environmental sustainability and food waste. The paper concludes by making a case for understanding the consumption of convenience food in terms of everyday social practices, emphasising its habitual and routine character.
DEFF Research Database (Denmark)
Halkier, Bente
2017-01-01
habits among Danes aged 20–25. The article presents two types of empirical patterns. The first types of patterns are the degree to which and the different ways in which convenience food is normalised to use among the young Danes. The second types of patterns are the normative places of convenient food......The construction of convenience food as a social and cultural category for food provisioning, cooking and eating seems to slide between or across understandings of what is considered “proper food” in the existing discourses in everyday life and media. This article sheds light upon some...... of the social and cultural normativities around convenience food by describing the ways in which convenience food forms part of the daily life of young Danes. Theoretically, the article is based on a practice theoretical perspective. Empirically, the article builds upon a qualitative research project on food...
Mutational analysis a joint framework for Cauchy problems in and beyond vector spaces
Lorenz, Thomas
2010-01-01
Ordinary differential equations play a central role in science and have been extended to evolution equations in Banach spaces. For many applications, however, it is difficult to specify a suitable normed vector space. Shapes without a priori restrictions, for example, do not have an obvious linear structure. This book generalizes ordinary differential equations beyond the borders of vector spaces with a focus on the well-posed Cauchy problem in finite time intervals. Here are some of the examples: - Feedback evolutions of compact subsets of the Euclidean space - Birth-and-growth processes of random sets (not necessarily convex) - Semilinear evolution equations - Nonlocal parabolic differential equations - Nonlinear transport equations for Radon measures - A structured population model - Stochastic differential equations with nonlocal sample dependence and how they can be coupled in systems immediately - due to the joint framework of Mutational Analysis. Finally, the book offers new tools for modelling.
Vector Cascade Algorithms with Infinitely Supported Masks in Weighted L2-Spaces
Institute of Scientific and Technical Information of China (English)
Jian Bin YANG
2013-01-01
In this paper,we shall study the solutions of functional equations of the form φ =Σ a(α) φ(M.-α),α∈Zswhere φ =(Φ1,...,Φr)T is an r × 1 column vector of functions on the s-dimensional Euclidean space,a:=(a(α))α∈zs is an exponentially decaying sequence of r × r complex matrices called refinement mask and M is an s × s integer matrix such that limn→∞ M-n =0.We are interested in the question,for a mask a with exponential decay,if there exists a solution Φ to the functional equation with each function Φj,j =1,...,r,belonging to L2(IRs) and having exponential decay in some sense? Our approach will be to consider the convergence of vector cascade algorithms in weighted L2 spaces.The vector cascade operator Qa,M associated with mask a and matrix M is defined by Qa,Mf:=Σ a(α)f(M.-α),f =(f1,...,fr)T ∈ (L2,μ(IRs))r.αα∈ZsThe iterative scheme (Qna,Mf)n=1,2 is called a vector cascade algorithm or a vector subdivision scheme.The purpose of this paper is to provide some conditions for the vector cascade algorithm to converge in (L2,μ(IRs))r,the weighted L2 space.Inspired by some ideas in [Jia,R.Q.,Li,S.:Refinable functions with exponential decay:An approach via cascade algorithms.J.Fourier Anal.Appl.,17,1008-1034 (2011)],we prove that if the vector cascade algorithm associated with a and M converges in (L2(IRs))r,then its limit function belongs to (L2,μ(IRs))r for some μ ＞ 0.
State vector solutions for nonaxisymmetric problem of multilayered half space piezoelectric medium
Institute of Scientific and Technical Information of China (English)
王建国
1999-01-01
A state space formulation is established for the nonaxisymmetric space problem of transversely isotropic piezoelectric media in a system of cylindrical coordinate by introducing the state vector. Using the Hankel transform and the Fourier series, the state vector equations are transformed into ordinary differential equations. By the use of the matrix methods, the analytical solutions of a single piezoelectric layer are presented in the form of the product of initial state variables and transfer matrix. The applications of state vector solutions are discussed. An analytical solution for a semiinfinite piezoelectric medium subjected to the vertical point force P_z, horizontal point force P_x along x-direction and point electric charge Q at the origin of the surface is presented. According to the continuity conditions at the interfaces, the general solution formulation for N-layered transversely isotropic piezoelectric media is given.
Composition Operators with Linear Fractional Symbols on Vector-Valued Bergman Spaces
Institute of Scientific and Technical Information of China (English)
WangMao-fa; UuPei-de; ZhouShao-bo
2003-01-01
Letψ and ψ be linear fractional self-maps of the unit disk D and X a separable Hilbert space. In this paper we completely characterize the weak compactness of the product operators of a composition operation Cψ with another one’s adjoint Cψ* on the vector-valued Bergman space B1(X) for forms CψCψ* and Cψ* Cψ.
Composition Operators with Linear Fractional Symbols on Vector-Valued Bergman Spaces
Institute of Scientific and Technical Information of China (English)
Zhou Shao-bo
2003-01-01
Let ψ and ψ be linear fractional self-maps of the unit disk D and X a separable Hilbert space. In this paper we completely characterize the weak compactness of the product operators of a composition operation Cψ with another one' s adjoint C*ψ on the vector-valued Bergman space B1 (X) for forms CψC*ψ and C*ψ Cψ.
Space vector-based modeling and control of a modular multilevel converter in HVDC applications
DEFF Research Database (Denmark)
Bonavoglia, M.; Casadei, G.; Zarri, L.;
2013-01-01
Modular multilevel converter (MMC) is an emerging multilevel topology for high-voltage applications that has been developed in recent years. In this paper, the modeling and the control of MMCs are restated in terms of space vectors, which may allow a deeper understanding of the converter behavior...
Institute of Scientific and Technical Information of China (English)
丁协平
2014-01-01
A new bilevel generalized mixed equilibrium problem (BGMEP) is introduced and studied in topological vector spaces. By using a minimax inequality, the existence of solutions and the behavior of solution set for the BGMEP are studied under quite mild conditions. These results are new and generalize some recent results in this field.
Modular space-vector pulse-width modulation for nine-switch converters
DEFF Research Database (Denmark)
Dehghan, Seyed Mohammad; Amiri, Arash; Mohamadian, Mustafa
2013-01-01
Recently, nine-switch inverter (NSI) has been presented as a dual-output inverter with constant frequency (CF) or different frequency (DF) operation modes. However, the CF mode is more interesting because of its lower switching device rating. This study proposes a new space-vector modulation (SVM...
Active and reactive power control of a current-source PWM-rectifier using space vectors
Energy Technology Data Exchange (ETDEWEB)
Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics
1997-12-31
In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.
Unifying and generating of space vector modulation sequences for multilevel converter
DEFF Research Database (Denmark)
Ma, Ke; Blaabjerg, Frede
2014-01-01
Space Vector Modulation (SVM) is a powerful method which enables some freedom to generate the modulation sequences and modify the performances of converter. However, in the multi-level converter structures, the number of switching state redundancies significantly increases, and the determination...
DEFF Research Database (Denmark)
Zelechowski, M.; Kazmierkowski, M.P.; Blaabjerg, Frede
2005-01-01
In this paper two different methods of PI controllers for direct torque controlled-space vector modulated induction motor drives have been studied. The first one is simple method based only on symmetric optimum criterion. The second approach takes into account the full model of induction motor in...
On Rationality of Moduli Spaces of Vector Bundles on Real Hirzebruch Surfaces
Indian Academy of Sciences (India)
Indranil Biswas; Ronnie Sebastian
2013-05-01
Let be a real form of a Hirzebruch surface. Let $M_H(r,c_1,c_2)$ be the moduli space of vector bundles on . Under some numerical conditions on $r,c_1$ and $c_2$, we identify those $M_H(r,c_1,c_2)$ that are rational.
Dynamic Voltage Restorer Based on Space Vector Pulse Width Modulation Technique
Directory of Open Access Journals (Sweden)
B.N S P Venkatesh
2011-07-01
Full Text Available Power Quality problems encompass a wide range of disturbances such as voltage sags, swells, flicker,harmonics distortion and interruptions. The strategic deployment of custom power devices has been proposed asone of the means to protect sensitive loads from power quality problems such as voltage sags and swells. The Dynamic Voltage Restorer (DVR is a power electronic device that is used to inject 3-phase voltage in series and in synchronism with the distribution feeder voltages in order to compensate voltage sag and similarly itreacts quickly to inject the appropriate voltage component (negative voltage magnitude in order to compensate voltage swell. The principal component of the DVR is a voltage source inverter that generates three phase voltages and provides the voltage support to a sensitive load during voltage sags and swells. Pulse Width Modulation Technique is very critical for proper control of DVR. Sinusoidal Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM control techniques are used for controlling the DVR. Inthis work, the operation of DVR is presented and the control technique used for voltage source inverter is Space Vector PWM technique. Space vector PWM can utilize the better dc voltage and generates the fewer harmonic in inverter output voltage than Sinusoidal PWM technique. This work describes the DVR based on Space Vector PWM which provides voltage support to sensitive loads and is simulated by using MATLAB/SIMULINK. Simulation results show that the control approach is able to compensate for any type of voltage sags and swells.
Atmospheric correction of remote sensing imagery based on the surface spectrum's vector space
Institute of Scientific and Technical Information of China (English)
CHEN Chun; LIU ChengYu; ZHANG ShuQing
2012-01-01
Due to the atmosphere effect,the qualities of images decrease conspicuously,practically in the visible bands,in the processing of earth observation by the satellite-borne sensors.Thus,removing the atmosphere effects has become a key step to improve the qualities of images and to retrieve the actual reflectivity of surface features.An atmospheric correction approach,called ACVSS (Atmospheric Correction based Vector Space of Spectrum),is proposed here based on the vector space of the features'spectrum.The reflectance image of each band is retrieved first according to the radiative transfer equation,then the spectrum's vector space is constructed using the infrared bands,and finally the residual errors of the reflectance images in the visible bands are corrected based on the pixel position in the spectrum's vector space.The proposed methodology is verified through atmospheric correction on Landsat-7 ETM+ imagery.The experimental results show that our method is more accurate and the corrected image is more distinct,compared with those offered by current popular atmospheric correction software.
Anisotropic fractal media by vector calculus in non-integer dimensional space
Energy Technology Data Exchange (ETDEWEB)
Tarasov, Vasily E., E-mail: tarasov@theory.sinp.msu.ru [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation)
2014-08-15
A review of different approaches to describe anisotropic fractal media is proposed. In this paper, differentiation and integration non-integer dimensional and multi-fractional spaces are considered as tools to describe anisotropic fractal materials and media. We suggest a generalization of vector calculus for non-integer dimensional space by using a product measure method. The product of fractional and non-integer dimensional spaces allows us to take into account the anisotropy of the fractal media in the framework of continuum models. The integration over non-integer-dimensional spaces is considered. In this paper differential operators of first and second orders for fractional space and non-integer dimensional space are suggested. The differential operators are defined as inverse operations to integration in spaces with non-integer dimensions. Non-integer dimensional space that is product of spaces with different dimensions allows us to give continuum models for anisotropic type of the media. The Poisson's equation for fractal medium, the Euler-Bernoulli fractal beam, and the Timoshenko beam equations for fractal material are considered as examples of application of suggested generalization of vector calculus for anisotropic fractal materials and media.
A Novel Space Vector Technique for the Direct Three-level Matrix Converter
Directory of Open Access Journals (Sweden)
C. Agees Kumar
2014-10-01
Full Text Available This study proposes a novel Direct Torque Control (DTC method for the Direct Three level Matrix Converter (DTMC, which uses both the input phase voltage vectors (short vectors and the input line voltage vectors (long vectors. The problem of voltage imbalance at the input filter capacitance due to the use of the short vectors is addressed with an additional voltage hysteresis comparator. With the errors of torque, flux, sin Ψ and the neutral point voltage, an Optimum Switching Table (OST is designed for the DTMC. The OST generates the necessary switching signals for the DTC of the DTMC. The DTMC topology with the modified ISVM technique reduces the THD at the output. The proposed DTMC Indirect Space Vector pulse width Modulation (ISVM technique uses the idea of multilevel inverter SVM technique along with the proposed neutral current balancing strategy for generating the firing pulses. The switching loss model for the DTMC is developed and the performance of the DTMC is compared with that of the Conventional Matrix Converter (CMC. The performance of the proposed DTC technique for the DTMC is evaluated through simulation to explain the reduced torque ripple characteristics. To validate the proposed DTMC ISVM technique, a 3 kVA direct multilevel matrix converter prototype was developed.
BOUNDEDNESS OF VECTOR-VALUED CALDER(O)N-ZYGMUND OPERATORS ON HERZ SPACES WITH NON-DOUBLING MEASURES
Institute of Scientific and Technical Information of China (English)
Baode Li; Yinsheng Jiang; Hui Cao
2007-01-01
In the paper we obtain vector-valued inequalities for Calderon-Zygmund operator,simply CZO On Herz space and weak Herz space.In particular,we obtain vector-valued inequalities for CZO on Lq(Rd,│x│αdμ)space,with 1＜q＜∞,-n＜α＜n(q-1),and on L1,∞(Rd,│x│αdμ)space,with -n＜α＜0.
On n-ary algebras, branes and poly-vector gauge theories in noncommutative Clifford spaces
Castro, Carlos
2010-09-01
In this paper, poly-vector-valued gauge field theories in noncommutative Clifford spaces are presented. They are based on noncommutative (but associative) star products that require the use of the Baker-Campbell-Hausdorff formula. Using these star products allows the construction of actions for noncommutative p-branes (branes moving in noncommutative spaces). Noncommutative Clifford-space gravity as a poly-vector-valued gauge theory of twisted diffeomorphisms in Clifford spaces would require quantum Hopf algebraic deformations of Clifford algebras. We proceed with the study of n-ary algebras and find an important relationship among the n-ary commutators of the noncommuting spacetime coordinates [X1, X2, ..., Xn] with the poly-vector-valued coordinates X123sdotsdotsdotn in noncommutative Clifford spaces given by [X1, X2, ..., Xn] = n!X123sdotsdotsdotn. The large N limit of n-ary commutators of n hyper-matrices {\\bf X}_{i_1 i_2 \\cdots i_n} leads to Eguchi-Schild p-brane actions for p + 1 = n. A noncomutative n-ary • product of n functions is constructed which is a generalization of the binary star product * of two functions and is associated with the deformation quantization of n-ary structures and deformations of the Nambu-Poisson brackets.
Institute of Scientific and Technical Information of China (English)
杨金中; 李新
1993-01-01
The purpose of this article is to present by using vector space methods,a formula as how to calculate the covariance of the outer product of two independent random vecters in inter product space and to makes a discussion on the covariance of the orthogonally invariant random vector and that of the weakly spherically distributed outer produt.
Vector model for mapping of visual space to subjective 4-D sphere
Matuzevicius, Dalius; Vaitkevicius, Henrikas
2014-03-01
Here we present a mathematical model of binocular vision that maps a visible physical world to a subjective perception of it. The subjective space is a set of 4-D vectors whose components are outputs of four monocular neurons from each of the two eyes. Monocular neurons have one of the four types of concentric receptive fields with Gabor-like weighting coefficients. Next this vector representation of binocular vision is implemented as a pool of neurons where each of them is selective to the object's particular location in a 3-D visual space. Formally each point of the visual space is being projected onto a 4-D sphere. Proposed model allows determination of subjective distances in depth and direction, provides computational means for determination of Panum's area and explains diplopia and allelotropia.
Space-time properties of Gram-Schmidt vectors in classical Hamiltonian evolution.
Green, Jason R; Jellinek, Julius; Berry, R Stephen
2009-12-01
Not all tangent space directions play equivalent roles in the local chaotic motions of classical Hamiltonian many-body systems. These directions are numerically represented by basis sets of mutually orthogonal Gram-Schmidt vectors, whose statistical properties may depend on the chosen phase space-time domain of a trajectory. We examine the degree of stability and localization of Gram-Schmidt vector sets simulated with trajectories of a model three-atom Lennard-Jones cluster. Distributions of finite-time Lyapunov exponent and inverse participation ratio spectra formed from short-time histories reveal that ergodicity begins to emerge on different time scales for trajectories spanning different phase-space regions, in a narrow range of total energy and history length. Over a range of history lengths, the most localized directions were typically the most unstable and corresponded to atomic configurations near potential landscape saddles.
Fradkin-Bacry-Ruegg-Souriau vector in kappa-deformed space-time
Guha, Partha; S, Zuhair N
2015-01-01
We study presence of an additional symmetry of a generic central potential in the $\\kappa$-space-time. An explicit construction of Fradkin and Bacry, Ruegg, Souriau (FBRS) for a central potential is carried out and the piece-wise conserved nature of the vector is established. We also extend the study to Kepler systems with a drag term, particularly Gorringe-Leach equation is generalized to the $\\kappa$-deformed space. The possibility of mapping Gorringe-Leach equation to an equation with out drag term is exploited in associating a similar conserved vector to system with a drag term. An extension of duality between two class of central potential is introduced in the $\\kappa$-deformed space and is used to investigate the duality existing between two class of Gorringe-Leach equations. All the results obtained can be retraced to the correct commutative limit as we let $a \\rightarrow 0$.
Fradkin-Bacry-Ruegg-Souriau vector in kappa-deformed space-time
Guha, Partha; Harikumar, E.; Zuhair, N. S.
2015-10-01
We study the presence of an additional symmetry of a generic central potential in the κ space-time. An explicit construction of Fradkin, Bacry, Ruegg and Souriau (FBRS) for a central potential is carried out and the piecewise conserved nature of the vector is established. We also extend the study to Kepler systems with a drag term, particularly the Gorringe-Leach equation is generalized to the κ-deformed space. The possibility of mapping a Gorringe-Leach equation to an equation without drag term is exploited associating a similar conserved vector to the system with a drag term. An extension of the duality between two classes of central potential is introduced in the κ-deformed space and is used to investigate the duality existing between two classes of Gorringe-Leach equations. All the results obtained can be retraced to the correct commutative limit as we let a → 0.
Synchronized Scheme of Continuous Space-Vector PWM with the Real-Time Control Algorithms
DEFF Research Database (Denmark)
Oleschuk, V.; Blaabjerg, Frede
2004-01-01
This paper describes in details the basic peculiarities of a new method of feedforward synchronous pulsewidth modulation (PWM) of three-phase voltage source inverters for adjustable speed ac drives. It is applied to a continuous scheme of voltage space vector modulation. The method is based...... on a representation of the pulse patterns as a function of the fundamental and switching frequencies of the drive system. Accurate trigonometric algorithms of vector PWM have been analysed, and also compared with the algebraic ones based on linear approximation of the durations of active switching states from...
Space vector modulation strategy for neutral-point voltage balancing in three-level inverter systems
DEFF Research Database (Denmark)
Choi, Uimin; Lee, Kyo Beum
2013-01-01
This study proposes a space vector modulation (SVM) strategy to balance the neutral-point voltage of three-level inverter systems. The proposed method is implemented by combining conventional symmetric SVM with nearest three-vector (NTV) modulation. The conventional SVM is converted to NTV...... modulation by properly adding or subtracting a minimum gate-on time. In addition, using this method, the switching frequency is reduced and a decrease of switching loss would be yielded. The neutral-point voltage is balanced by the proposed SVM strategy without additional hardware or complex calculations...
Flows Associated to Cameron-martin Type Vector Fields on Path Spaces Over a Riemannian Manifold
Institute of Scientific and Technical Information of China (English)
Jing-xiao ZHANG
2013-01-01
The flow on the Wiener space associated to a tangent process constructed by Cipriano and Cruzeiro,as well as by Gong and Zhang does not allow to recover Driver's Cameron-Martin theorem on Riemannian path space.The purpose of this work is to refine the method of the modified Picard iteration used in the previous work by Gong and Zhang and to try to recapture and extend the result of Driver.In this paper,we establish the existence and uniqueness of a flow associated to a Cameron-Martin type vector held on the path space over a Riemannian manifold.
On Quadratic Scalarization of One Class of Vector Optimization Problems in Banach Spaces
Directory of Open Access Journals (Sweden)
V. M. Bogomaz
2012-01-01
Full Text Available We study vector optimization problems in partially ordered Banach Spaces. We suppose that the objective mapping possesses a weakened property of lower semicontinuity and make no assumptions on the interior of the ordering cone. We discuss the ”classical” scalarization of vector optimization problems in the form of weighted sum and also we propose other type of scalarization for vector optimization problem, the socalled adaptive scalarization, which inherits some ideas of Pascoletti-Serafini approach. As a result, we show that the scalar nonlinear optimization problems can byturn approximated by the quadratic minimization problems. The advantage of such regularization is especially interesting from a numerical point of view because it gives a possibility to apply rather simple computational methods for the approximation of the whole set of efficient solutions.
Reflection and transmission of full-vector X-waves normally incident on dielectric half spaces
Salem, Mohamed
2011-08-01
The reflection and transmission of full-vector X-Waves incident normally on a planar interface between two lossless dielectric half-spaces are investigated. Full-vector X-Waves are obtained by superimposing transverse electric and magnetic polarization components, which are derived from the scalar X-Wave solution. The analysis of transmission and reflection is carried out via a straightforward but yet effective method: First, the X-Wave is decomposed into vector Bessel beams via the Bessel-Fourier transform. Then, the reflection and transmission coefficients of the beams are obtained in the spectral domain. Finally, the transmitted and reflected X-Waves are obtained via the inverse Bessel-Fourier transform carried out on the X-wave spectrum weighted with the corresponding coefficient. © 2011 IEEE.
Hysteresis Current Control technique based on Space Vector Modulation for Active Power Filter
Directory of Open Access Journals (Sweden)
Wang Yun-liang
2011-09-01
Full Text Available In this paper, the hysteresis current control (HCC technique based on space vector modulation (SVM for shunt active power filter (APF is proposed. The switching control algorithms of the HCC based SVM manage to generate compensated current according to the reference current. Harmonics extraction is based on the instantaneous active and reactive power theorem in time domain by calculating the power compensation. A closed loop control system is carried out and the error current is the difference between the reference current which is obtained from the power compensation and the actual current needs to be injected back into the power grid. By implementing this control strategy, the APF manages to generate better compensated harmonics currents to the power grid. Keywords: active power filter, hysteresis current control, space vector modulation ,matlab/simulink
Directory of Open Access Journals (Sweden)
Fatih Korkmaz
2013-11-01
Full Text Available The induction motors are indispensable motor types for industrial applications due to its wellknown advantages. Therefore, many kind of control scheme are proposed for induction motors over the past years and direct torque control has gained great importance inside of them due to fast dynamic torque response behavior and simple control structure. This paper suggests a new approach on the direct torque controlled induction motors, Fuzzy logic based space vector modulation, to overcome disadvantages of conventional direct torque control like high torque ripple. In the proposed approach, optimum switching states are calculated by fuzzy logic controller and applied by space vector pulse width modulator to voltage source inverter. In order to test and compare the proposed DTC scheme with conventional DTC scheme simulations, in Matlab/Simulink, have been carried out in different speed and load conditions. The simulation results showed that a significant improvement in the dynamic torque and speed responses when compared to the conventional DTC scheme.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
2007年8月28日至31日，西门子电子装配系统有限公司将在深圳NEPCON上展示其最新的SIPLACE Convenience Shop。SIPLACE Convenience Shop是一个能够使中国客户极大受益的全新一站式解决方案。凭借该解决方案，西门子将能够为其客户提供现场备件库存，
A DSP-based discrete space vector modulation direct torque control of sensorless induction machines
Energy Technology Data Exchange (ETDEWEB)
Khoucha, F.; Marouani, K.; Kheloui, A.; Aliouane, K.
2004-07-01
In this paper, we present a Direct Torque Control scheme of an induction motor operating without speed sensor. The estimation of the stator flux and the rotor speed is performed by an adaptive observer. In order to reduce the torque, flux, current and speed ripple a Discrete Space Vector Modulation (DSVM-DTC) strategy is implemented using a DSP-based hardware. To illustrate the performances of this control scheme, experimental results are presented. (author)
Application of Space Vector Modulation in Direct Torque Control of PMSM
Directory of Open Access Journals (Sweden)
Michal Malek
2008-01-01
Full Text Available The paper deals with an improvement of direct torque control method for permanent magnet synchronous motor drives. Electrical torque distortion of the machine under original direct torque control is relatively high and if proper measures are taken it can be substantially decreased. The proposed solution here is to combine direct torque control with the space vector modulation technique. Such approach can eliminate torque distortion while preserving the simplicity of the original method.
Perancangan Email Client Dengan Pengklasifikasian Email Menggunakan Algoritma Vector Space Model
Christian, Moses
2015-01-01
On today's age of technology, widely used email to send information throughout the world. During the classification of the email is still done manually and less objective. So in this study, the authors apply the method of Vector Space Model (VSM) to make an automatic email classification and more objective. With this method of email classification can be done automatically based on address, subject, and body of an email that allows users to email in the organization of every incoming email in...
Modelling of a double star induction motor for space vector PWM control
Energy Technology Data Exchange (ETDEWEB)
Hadiouche, D.; Razik, H.; Rezzoug, A. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, G.R.E.E.N. - CNRS UPRES, University H. Poincare, Vandoeuvre-les-Nancy (France)
2000-08-01
In this paper, we present the analysis and the modelling of a Double-Star Induction Motor (DSIM). A steady-state model is first established in order to analyse its harmonic behaviour. Then, a new transformation matrix is proposed in order to develop a suitable dynamic model. In both cases, the study is made using an arbitrary shift angle between the two stars. At last, a space vector Pulse Width Modulation (PWM) control or the DSIM is simulated. (orig.)
Applying two channels to vector space secret sharing based multi-signature scheme
Institute of Scientific and Technical Information of China (English)
XIAO Qing-hua; PING Ling-di; CHEN Xiao-ping; PAN Xue-zeng
2005-01-01
Secret sharing and digital signature is an important research area in information security and has wide applications in such fields as safeguarding and legal use of confidential information, secure multiparty computation and electronic commerce. But up to now, study of signature based on general vector space secret sharing is very weak. Aiming at this drawback, the authors did some research on vector space secret sharing against cheaters, and proposed an efficient but secure vector space secret sharing based multi-signature scheme, which is implemented in two channels. In this scheme, the group signature can be easily produced if an authorized subset of participants pool their secret shadows and it is impossible for them to generate a group signature if an unauthorized subset of participants pool their secret shadows. The validity of the group signature can be verified by means of verification equations. A group signature of authorized subset of participants cannot be impersonated by any other set of participants. Moreover, the suspected forgery can be traced, and the malicious participants can be detected in the scheme. None of several possible attacks can successfully break this scheme.
Nonlocal multi-scale traffic flow models: analysis beyond vector spaces
Directory of Open Access Journals (Sweden)
Peter E. Kloeden
2016-08-01
Full Text Available Abstract Realistic models of traffic flow are nonlinear and involve nonlocal effects in balance laws. Flow characteristics of different types of vehicles, such as cars and trucks, need to be described differently. Two alternatives are used here, $$L^p$$ L p -valued Lebesgue measurable density functions and signed Radon measures. The resulting solution spaces are metric spaces that do not have a linear structure, so the usual convenient methods of functional analysis are no longer applicable. Instead ideas from mutational analysis will be used, in particular the method of Euler compactness will be applied to establish the well-posedness of the nonlocal balance laws. This involves the concatenation of solutions of piecewise linear systems on successive time subintervals obtained by freezing the nonlinear nonlocal coefficients to their values at the start of each subinterval. Various compactness criteria lead to a convergent subsequence. Careful estimates of the linear systems are needed to implement this program.
Directory of Open Access Journals (Sweden)
Ayse KOCALMIS BILHAN
2013-01-01
Full Text Available A space vector PWM method for a two level inverter is proposed in this paper. A two level inverter using space vector modulation strategy has been modeled and simulated with a passive R-L load. Photovoltaic cells are used as DC source for input of two-level inverter. Simulation results are presented for various operation conditions to verify the system model. In this paper, MATLAB/Simulink package program has been used for modeling and simulation of PV cells and two-level space vector pulse width modulation (SVPWM inverter.
The Bloch-vector space for N-level systems -- the spherical-coordinate point of view --
Kimura, G
2003-01-01
The Bloch-vector spaces for $N$-level systems are investigated from the spherical-coordinate point of view. We find that the maximum radius in each direction, which is due to the construction of the Bloch-vector space, is determined by the minimum eigenvalue of the corresponding observable (generator of SU(N)). As one of the applications of this, we reveal the dual properties of the structure of the Bloch-vector space; if one of the direction of the Bloch vector reaches the large ball (pure state), the opposite direction can only reach the small ball, and vice versa. This also leads us to the new representation of quantum states which generalize the Bloch vector.
DEFF Research Database (Denmark)
Lu, Yong; Xiao, Guochun; Wang, Xiongfei
2016-01-01
The unified power quality conditioner (UPQC) is known as an effective compensation device to improve PQ for sensitive end-users. This paper investigates the operation and control of a single-phase three-leg UPQC (TL-UPQC), where a novel space vector modulation method is proposed for naturally...... solving the coupling problem introduced by the common switching leg. The modulation method is similar to the well-known space vector modulation widely used with three-phase voltage source converters, which thus brings extra flexibility to the TL-UPQC system. Two optimized modulation modes with either...... reduced switching loss or harmonic distortion are derived, evaluated, and discussed, in order to demonstrate the flexibility brought by the space vector modulated TL-UPQC. Simulations and experimental results are presented to verify the feasibility and effectiveness of the proposed space vector modulation...
Stability of Picard Bundle Over Moduli Space of Stable Vector Bundles of Rank Two Over a Curve
Indian Academy of Sciences (India)
Indranil Biswas; Tomás L Gómez
2001-08-01
Answering a question of [BV] it is proved that the Picard bundle on the moduli space of stable vector bundles of rank two, on a Riemann surface of genus at least three, with fixed determinant of odd degree is stable.
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Power Quality (PQ) combined disturbances become common along with ubiquity of voltage flickers and harmonics. This paper presents a novel approach to classify the different patterns of PQ combined disturbances. The classification system consists of two parts, namely the feature extraction and the automatic recognition. In the feature extraction stage, Phase Space Reconstruction (PSR), a time series analysis tool, is utilized to construct disturbance signal trajectories. For these trajectories, several indices are proposed to form the feature vectors. Support Vector Machines (SVMs) are then implemented to recognize the different patterns and to evaluate the efficiencies. The types of disturbances discussed include a combination of short-term disturbances (voltage sags, swells) and long-term disturbances (flickers, harmonics), as well as their homologous single ones. The feasibilities of the proposed approach are verified by simulation with thousands of PQ events. Comparison studies based on Wavelet Transform (WT) and Artificial Neural Network (ANN) are also reported to show its advantages.
Directory of Open Access Journals (Sweden)
Qinghai He
2013-01-01
Full Text Available In general Banach spaces, we consider a vector optimization problem (SVOP in which the objective is a set-valued mapping whose graph is the union of finitely many polyhedra or the union of finitely many generalized polyhedra. Dropping the compactness assumption, we establish some results on structure of the weak Pareto solution set, Pareto solution set, weak Pareto optimal value set, and Pareto optimal value set of (SVOP and on connectedness of Pareto solution set and Pareto optimal value set of (SVOP. In particular, we improved and generalize, Arrow, Barankin, and Blackwell’s classical results in Euclidean spaces and Zheng and Yang’s results in general Banach spaces.
Land-use/land-cover change detection using change-vector analysis in posterior probability space
Chen, Xuehong; Chen, Jin; Shen, Miaogen; Yang, Wei
2008-10-01
Land use/land cover change is an important field in global environmental change research. Remote sensing is a valuable data source from which land use/land cover change information can be extracted efficiently. A number of techniques for accomplishing change detection using satellite imagery have been formulated, applied, and evaluated, which can be generally grouped into two types. (1) Those based on spectral classification of the input data such as post-classification comparison and direct two-date classification; and (2) those based on radiometric change between different acquisition dates. The shortage of type 1 is cumulative error in image classification of an individual date. However, radiometric change approaches has a strict requirement for reliable image radiometry. In light of the above mentioned drawbacks of those two types of change detection methods, this paper presents a new method named change vector analysis in posterior probability space (CVAPS). Change-vector analysis (CVA) is one of the most successful radiometric change-based approaches. CVAPS approach incorporates post-classification comparison method and CVA approach, which is expected to inherit the advantages of two traditional methods and avoid their defects at the same time. CVAPS includes the following four steps. (1) Images in different periods are classified by certain classifier which can provide posterior probability output. Then, the posterior probability can be treated as a vector, the dimension of which is equal to the number of classes. (2) A procedure similar with CVA is employed. Compared with traditional CVA, new method analyzes the change vector in posterior probability space instead of spectral feature space. (3) A semiautomatic method, named Double-Window Flexible Pace Search (DFPS), is employed to determine the threshold of change magnitude. (4) Change category is discriminated by cosines of the change vectors. CVAPS approach was applied and validated by a case study of
Pooling designs with surprisingly high degree of error correction in a finite vector space
Guo, Jun
2011-01-01
Pooling designs are standard experimental tools in many biotechnical applications. It is well-known that all famous pooling designs are constructed from mathematical structures by the "containment matrix" method. In particular, Macula's designs (resp. Ngo and Du's designs) are constructed by the containment relation of subsets (resp. subspaces) in a finite set (resp. vector space). Recently, we generalized Macula's designs and obtained a family of pooling designs with more high degree of error correction by subsets in a finite set. In this paper, as a generalization of Ngo and Du's designs, we study the corresponding problems in a finite vector space and obtain a family of pooling designs with surprisingly high degree of error correction. Our designs and Ngo and Du's designs have the same number of items and pools, respectively, but the error-tolerant property is much better than that of Ngo and Du's designs, which was given by D'yachkov et al. \\cite{DF}, when the dimension of the space is large enough.
Utilizing Conceptual Indexing to Enhance the Effectiveness of Vector Space Model
Directory of Open Access Journals (Sweden)
Aya M. Al-Zoghby
2013-10-01
Full Text Available One of the main purposes of the semantic Web is to improve the retrieval performance of search systems. Unlike keyword based search systems, the semantic search systems aim to discover pages related to the query's concepts rather than merely collecting all pages instantiating its keywords. To that end, the concepts must be defined to be used as a semantic index instead of the traditional lexical one. In fact, The Arabic language is still far from being semantically searchable. Therefore, this paper proposed a model that exploits the Universal Word Net ontology for producing an Arabic Concepts-Space to be used as the index of Semantic Vector Space Model. The Vector Space Model is one of the most common information retrieval models due to its capability of expressing the documents' structure. However, like all keyword-based search systems, its sensitivity to the query's keywords reduces its retrieval effectiveness. The proposed model allows the VSM to represent Arabic documents by their topic, and thus classify them semantically. This, consequently, enhances the retrieval effectiveness of the search system.
The Laplace-Stieltjes transformation on ordered topological vector space of generalized functions
Directory of Open Access Journals (Sweden)
N. R. Mangalambal
2011-09-01
Full Text Available We have combined the Laplace transform and the Stieltjes transform of the form $hat{f} (x = int_0^infty frac{f(t}{(x^m+t^m^ho} dt$, $m,ho>0$ and applied it to an ordered vector space of generalized functions to which the topology of bounded convergence is assigned. Some of the order properties of the transform and its inverse are studied. Also we solve an initial value problem and compare different solutions of the problem.
Jackson, John David
2006-01-01
Advanced undergraduates and graduate students studying quantum mechanics will find this text a valuable guide to mathematical methods. Emphasizing the unity of a variety of different techniques, it is enduringly relevant to many physical systems outside the domain of quantum theory.Concise in its presentation, this text covers eigenvalue problems in classical physics, orthogonal functions and expansions, the Sturm-Liouville theory and linear operators on functions, and linear vector spaces. Appendixes offer useful information on Bessel functions and Legendre functions and spherical harmonics.
Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation
Directory of Open Access Journals (Sweden)
MILOUD, Y.
2010-08-01
Full Text Available This paper proposes the space vector pulse width modulation (SVPWM control scheme for three-phase voltage source PWM rectifier. The control system based on SVPWM includes two PI controllers which are used to regulate the AC currents and DC-link voltage. The proposed control can stabilize the minimum of the systems storage function at the desired equilibrium point determined by unity power factor and sinusoidal current on the AC side, and constant output voltage on the DC side. So the stable state performance and robustness against the load�s disturbance of PWM rectifiers are both improved. The simulation result shows feasibility of this strategy.
Directory of Open Access Journals (Sweden)
Nagalingam RAJESWARAN
2014-02-01
Full Text Available Nowadays VLSI (Very Large Scale Integration technology is being successfully implemented by using Pulse Width Modulation (PWM in applications like power electronics and drives. The main problems in PWM viz. harmonic distortion and switching speed are overcome by implementing the Space-Vector PWM (SVPWM technique by using the Xilinx tool VHDL (Verilog High Speed Integrated Circuit (VHSIC Hardware Description Language and tested in programmable Integrated Circuits of Field Programmable Gate Array (FPGA. The results are provided along with simulation analysis in terms of hardware utilization and schematic, power report, computing time and usage of memory.
New conserved currents for vacuum space-times in dimension four with a Killing vector
Gómez-Lobo, Alfonso García-Parrado
2016-01-01
A new family of conserved currents for vacuum space-times with a Killing vector is presented. The currents are constructed from the superenergy tensor of the Mars-Simon tensor and using the positivity properties of the former we find that the conserved charges associated to the currents have natural positivity properties in certain cases. Given the role played by the Mars-Simon tensor in local and semi-local characterisations of the Kerr solution, the currents presented in this work are useful to construct non-negative scalar quantities characterising Kerr initial data (known in the literature as non-Kerrness) which in addition are conserved charges.
New conserved currents for vacuum space-times in dimension four with a Killing vector
Gómez-Lobo, Alfonso García-Parrado
2016-10-01
A new family of conserved currents for vacuum space-times with a Killing vector is presented. The currents are constructed from the superenergy tensor of the Mars-Simon tensor and using the positivity properties of the former we find that the conserved charges associated to the currents have natural positivity properties in certain cases. Given the role played by the Mars-Simon tensor in local and semi-local characterisations of the Kerr solution, the currents presented in this work are useful to construct non-negative scalar quantities characterising Kerr initial data (known in the literature as non-Kerrness) which in addition are conserved charges.
Vector bundles on complex projective spaces with an appendix by S. I. Gelfand
Okonek, Christian; Spindler, Heinz
1980-01-01
This expository treatment is based on a survey given by one of the authors at the Séminaire Bourbaki in November 1978 and on a subsequent course held at the University of Göttingen. It is intended to serve as an introduction to the topical question of classification of holomorphic vector bundles on complex projective spaces, and can easily be read by students with a basic knowledge of analytic or algebraic geometry. Short supplementary sections describe more advanced topics, further results, and unsolved problems. This is a corrected third printing with an Appendix by S. I. Gelfand. ------ The present book is the first one, within the extensive literature on algebraic vector bundles, to give both a self-contained introduction to the basic methods and an exposition of the current state of the classification theory of algebraic vector bundles over Pn(C). (…) The reviewer thinks that readers should be grateful to the authors for presenting the first detailed, self-contained and systematic textbook on ve...
Equivalence classes of the 3rd Grassman space over a 5-dimensional vector space
Directory of Open Access Journals (Sweden)
Kuldip Singh
1978-01-01
Full Text Available An equivalence relation is defined on ΛrV, the rth Grassman space over V and the problem of the determnation of the equivalence classes defined by this relation is considered. For any r and V, the decomposable elements form an equivalence class. For r=2, the length of the element determines the equivalence class that it is in. Elements of the same length are equivalent, those of unequal lengths are inequivalent. When r≥3, the length is no longer a sufficient indicator, except when the length is one. Besides these general questions, the equivalence classes of Λ3V, when dimV=5 are determined.
14 CFR 1273.44 - Termination for convenience.
2010-01-01
... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Termination for convenience. 1273.44 Section 1273.44 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION UNIFORM ADMINISTRATIVE... Reports, Records, Retention, and Enforcement § 1273.44 Termination for convenience. Except as provided...
Indian Academy of Sciences (India)
Manoj Kumar Modi; S Venugopal; G Narayanan
2013-06-01
The equivalence of triangle-comparison-based pulse width modulation (TCPWM) and space vector based PWM (SVPWM) during linear modulation is well-known. This paper analyses triangle-comparison based PWM techniques (TCPWM) such as sine-triangle PWM (SPWM) and common-mode voltage injection PWM during overmodulation from a space vector point of view. The average voltage vector produced by TCPWM during overmodulation is studied in the stationary (a–b) reference frame. This is compared and contrasted with the average voltage vector corresponding to the well-known standard two-zone algorithm for space vector modulated inverters. It is shown that the two-zone overmodulation algorithm itself can be derived from the variation of average voltage vector with TCPWM. The average voltage vector is further studied in a synchronously revolving (d-q) reference frame. The RMS value of low-order voltage ripple can be estimated, and can be used to compare harmonic distortion due to different PWM methods during overmodulation. The measured values of the total harmonic distortion (THD) in the line currents are presented at various fundamental frequencies. The relative values of measured current THD pertaining to different PWM methods tally with those of analytically evaluated RMS voltage ripple.
Clark, JL; Konda, KA; Silva-Santisteban, A.; Peinado, J; Lama, JR; Kusunoki, L; Perez-Brumer, A; Pun, M.; Cabello, R.; Sebastian, JL; Suarez-Ognio, L.; Sanchez, J.
2014-01-01
Alternatives to convenience sampling (CS) are needed for HIV/STI surveillance of most-at-risk populations in Latin America. We compared CS, time space sampling (TSS), and respondent driven sampling (RDS) for recruitment of men who have sex with men (MSM) and transgender women (TW) in Lima, Peru. During concurrent 60-day periods from June–August, 2011, we recruited MSM/TW for epidemiologic surveillance using CS, TSS, and RDS. A total of 748 participants were recruited through CS, 233 through T...
METHOD OF CONSTRUCTING BORNOLOGICAL SPACES FROM L*-VECTOR SPACES%从L-空间构造包囿空间的方法
Institute of Scientific and Technical Information of China (English)
张志尧
2001-01-01
讨论了一种在向量空间上构造包囿拓扑的新方法．收敛序列和有界集一般是拓扑空间中的概念，文章首先引入序列收敛C和L-空间(给出某种序列收敛关系的向量空间)，然后在其中定义有界集．设C为一序列收敛关系，T(C)是由C确定的拓扑，B(C)是由C确定的有界集族，则有B(C)=B(T(C))，并进一步从L*-空间构造了包囿拓扑向量空间．%A new method of constructing bornological vector topologies for vector spaces is discussed.In general,the convergent sequence and bounded set are concepts only in topological spaces.However,in this paper,it is first introduced sequential convergence C and L*- space which is a vector space giving some relation:xｍCx between sequences and points in it,then the bounded set is defined in vector space.Let C be a sequential convergence,T(C) be a vector topology on X determined by C and B(C) be the collection of bounded sets determined by C.Then B(C)=B(T(C)).Furthermore,the bornological locally convex topological vector space is constructed by L*-vector space.
All ASD complex and real 4-dimensional Einstein spaces with Λ≠0 admitting a nonnull Killing vector
Chudecki, Adam
2016-12-01
Anti-self-dual (ASD) 4-dimensional complex Einstein spaces with nonzero cosmological constant Λ equipped with a nonnull Killing vector are considered. It is shown that any conformally nonflat metric of such spaces can be always brought to a special form and the Einstein field equations can be reduced to the Boyer-Finley-Plebański equation (Toda field equation). Some alternative forms of the metric are discussed. All possible real slices (neutral, Euclidean and Lorentzian) of ASD complex Einstein spaces with Λ≠0 admitting a nonnull Killing vector are found.
Generalization of Phelps' Lemma to Bornological Vector Spaces%有界线性空间中的Phelps引理
Institute of Scientific and Technical Information of China (English)
贺飞; 丘京辉
2011-01-01
将Phelps引理推广到有界线性空间.一个直接的应用是获得了Wong推广到有界线性空间中的Ekeland变分原理.而且Ng和郑在拓扑线性空间中的有效点存在性定理也容易得到.同时,给出了一个局部凸空间中的Phelps引理.%Phelps' lemma is extended to bornological vector spaces. An immediate application is to re-establish Wong's generalization of Ekeland variational principle to bornological vector spaces. And Ng and Zheng's result on existence of efficient points in topological vector spaces is easily achieved. Meanwhile, a Phelps' lemma in locally convex spaces is obtained.
Schroer, Bert
2016-01-01
The Hilbert space formulation of interacting spin 1 vector-potentials stands in an interesting contrast with the point-local Krein space setting.of gauge theory. Already in the absence of interactions the Wilson loop in a Hilbert space setting has a topological property which is missing in the gauge theoretic description (Haag duality, Aharonov-Bohm effect); the conceptual differences increase in the presence of interactions. The Hilbert space positivity weakens the causal localization properties if interacting fields from point- to string-like, but it also improves the short distance properties in that the scale dimensions of string-local fields fields is independent of spin. This makes it possible to find interaction densities within the power-counting bound of renormalizability for any spin, But for string-local interacting fields there is a new requirement (existence of a L,V pair) which has no analog for point-local fields.It insures the preservation of string-localization in higher orders and secures th...
Directory of Open Access Journals (Sweden)
Hehua Jiao
2014-01-01
Full Text Available In this paper, a new class of semilocal E-preinvex and related maps in Banach spaces is introduced for a nondiﬀerentiable vector optimization problem with restrictions of inequalities and some of its basic properties are studied. Furthermore, as its applications, some optimality conditions and duality results are established for a nondiﬀerentiable vector optimization under the aforesaid maps assumptions.
2T/5T Two-Axis Cryogen Free Superconducting Vector Magnet With Variable Temperature Space
Demikhov, E. I.; Demikhov, T. E.; Kostrov, E. A.; Lysenko, V. V.; Piskunov, N. A.
2014-05-01
A conduction cooled 2T / 5T superconducting vector magnetic system with a variable temperature space was developed and tested. The system is based on a commercial two-stage 4 K Gifford-McMahon cryocooler with the cooling power of 1.5 W at 4.2 K. The cool down time of the magnet from room temperature to 3.2 K is 17 hours. The system provides sample temperature range of 6.0-300 K. The clear diameter of variable temperature space is 39 mm. A 5 T solenoid generates magnetic field in the vertical axis and a 2 T split coil generates field in the horizontal axis. The magnets are made of niobium-titanium wire wound on a copper former. A PC controlled rotary drive is applied to rotate a sample holder around the vertical axis. Thus the measured sample can be exposed to the magnetic field in any desired direction. A helium gas gap heat switch is used as a controllable thermal link between the variable temperature space and the 2nd stage to avoid overheating of the magnet at high temperatures of the sample. The system design, manufacturing and test results are presented.
Quantization of the minimal and non-minimal vector field in curved space
Toms, David J
2015-01-01
The local momentum space method is used to study the quantized massive vector field (the Proca field) with the possible addition of non-minimal terms. Heat kernel coefficients are calculated and used to evaluate the divergent part of the one-loop effective action. It is shown that the naive expression for the effective action that one would write down based on the minimal coupling case needs modification. We adopt a Faddeev-Jackiw method of quantization and consider the case of an ultrastatic spacetime for simplicity. The operator that arises for non-minimal coupling to the curvature is shown to be non-minimal in the sense of Barvinsky and Vilkovisky. It is shown that when a general non-minimal term is added to the theory the result is not renormalizable with the addition of a local Lagrangian counterterm.
Directory of Open Access Journals (Sweden)
Ion Balaceanu
2013-03-01
Full Text Available European integration and cooperation, basic vectors of European space of freedom, security and justiceAbstract: The European countries joining to the Schengen area had the effect elimination of internal border controls between Schengen member countries, that use permenent provisions of the Schengen acquis, being a single external border where operational checks are carried out according to a set of clear rules on immigration, visas, the asylum, as well as some decisions concerning police cooperation, judicial or customs. This means that the border crossing can be made at any time through many places, and citizens of member countries who are traveling in the Schengen area must present a valid ID. Overcoming internal border can be equated with a journey through the country.
Space Vector Modulation Based Direct Matrix Converter for Stand-Alone system
Directory of Open Access Journals (Sweden)
Chandra Sekhar Ajin Sekhar
2014-02-01
Full Text Available In this paper Permanent Magnet Synchronous Generator (PMSG is used for wind power generation in standalone system due to their feature of high efficiency and low maintenance cost, which was fed with smart direct matrix converter for direct AC-AC conversion, It provides sinusoidal output waveforms with minimal higher order harmonics and no sub harmonics and also it eliminate the usage of dc-link and other passive elements. Space vector modulation (SVM controlled technique is used for matrix converter switching which can eliminate the switching loses by selected switching states.Proposed work are often seen as a future concept for variable speed drives technology.The proposed model for RL load was analysed and verified by varying the resistor and inductance value and analysed using MATLAB simulation.
Vector Nonlocal Euclidean Median: Principal Bundle Captures The Nature of Patch Space
Lin, Chen-Yun; Qi, Xin Jessica; Wu, Hau-Tieng
2016-01-01
We extensively study the rotational group structure inside the patch space by introducing the fiber bundle structure. The rotational group structure leads to a new image denoising algorithm called the \\textit{vector non-local Euclidean median} (VNLEM). The theoretical aspect of VNLEM is studied, which explains why the VNLEM and traditional non-local mean/non-local Euclidean median (NLEM) algorithm work. The numerical issue of the VNLEM is improved by taking the orientation feature in the commonly applied scale-invariant feature transform (SIFT), and a theoretical analysis of the robustness of the orientation feature in the SIFT is provided. The VNLEM is applied to an image database of 1,361 images and compared with the NLEM. Different image quality assessments based on the error-sensitivity or the human visual system are applied to evaluate the performance. The results confirmed the potential of the VNLEM algorithm.
High Performance Direct Torque Control of Induction Motor Drives Using Space Vector Modulation
Directory of Open Access Journals (Sweden)
S. Allirani
2010-11-01
Full Text Available This paper presents a simple approach to design and implement Direct Torque Control technique for voltage source inverter fed induction motor drives. The direct torque control is one of the excellent strategies available for torque control of induction machine. It is considered as an alternative to field oriented control technique. The Direct Torque Control scheme is characterized by the absence of PI regulators, co-ordinate transformations, current regulators and pulse width modulated signal generators. Direct Torque Control allows a good torque control in steady state and transient operating conditions. The direct torque control technique based on space vector modulation and switching table has been developed and presented in this paper.
Groups, matrices, and vector spaces a group theoretic approach to linear algebra
Carrell, James B
2017-01-01
This unique text provides a geometric approach to group theory and linear algebra, bringing to light the interesting ways in which these subjects interact. Requiring few prerequisites beyond understanding the notion of a proof, the text aims to give students a strong foundation in both geometry and algebra. Starting with preliminaries (relations, elementary combinatorics, and induction), the book then proceeds to the core topics: the elements of the theory of groups and fields (Lagrange's Theorem, cosets, the complex numbers and the prime fields), matrix theory and matrix groups, determinants, vector spaces, linear mappings, eigentheory and diagonalization, Jordan decomposition and normal form, normal matrices, and quadratic forms. The final two chapters consist of a more intensive look at group theory, emphasizing orbit stabilizer methods, and an introduction to linear algebraic groups, which enriches the notion of a matrix group. Applications involving symm etry groups, determinants, linear coding theory ...
Directory of Open Access Journals (Sweden)
Ahmet Mete Vural
2016-09-01
Full Text Available This paper presents the design details of a two-level space vector pulse width modulation algorithm in PSCAD that is able to generate pulses for three-phase two-level DC/AC converters with two different switching patterns. The presented FORTRAN code is generic and can be easily modified to meet many other kinds of space vector modulation strategies. The code is also editable for hardware programming. The new component is tested and verified by comparing its output as six gating signals with those of a similar component in MATLAB library. Moreover the component is used to generate digital signals for closed-loop control of STATCOM for reactive power compensation in PSCAD. This add-on can be an effective tool to give students better understanding of the space vector modulation algorithm for different control tasks in power electronics area, and can motivate them for learning.
Directory of Open Access Journals (Sweden)
Joanna DUDEK
Full Text Available One of the basic ingredients of the city tissue are streets. Closely related to the buildings, they defined the pattern of the tissue, or constituted its derivative. The street has always been an important element shaping the character of a city. It played not only the role of transport, but also served as a place for meetings and trade exchange. According to the contemporary urban planning trends, while designing building complexes one should employ an interdisciplinary approach. Apart from classical engineering one should also use the achievements of sociology and psychology. Besides the proportions of a horizontal surface, the architectural solutions of buildings in a street have the most significant influence on the way that a street is perceived by its users. The examples of guidelines on shaping the right space of a street are as follows: the right height of buildings, their location relative to the street or the right arrangement of window and door openings. The purpose of the article is to introduce and compile the sources describing the urban planning and architectural guidelines that influence the creation of a people-friendly street. The analyzed texts concern both architectural solutions and issues from the field of psychology of space.
Directory of Open Access Journals (Sweden)
Fahim Mohammadi
2013-07-01
Full Text Available Focused crawlers are programs designed to browse the Web anddownload pages on a specific topic. They are used for answeringuser queries or for building digital libraries on a topic specifiedby the user. In this article we will show how summarizing of webpages is needed for improving performance of a crawler whichuses vector space model to rank the web pages. A neural networkis trained to learn the relevant characteristics of sentences thatshould be included in the summary of a web page. Then theneural network will be used as a filter to summarize web pages.Finally, the crawler will use vector space model to ranksummaries instead of web pages.
14 CFR 152.507 - Termination for convenience.
2010-01-01
... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Termination for convenience. 152.507 Section 152.507 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... convenience. (a) When the continuation of the project would not produce beneficial results commensurate...
On sets of vectors of a finite vector space in which every subset of basis size is a basis II
Ball, Simeon
2012-01-01
This article contains a proof of the MDS conjecture for $k \\leq 2p-2$. That is, that if $S$ is a set of vectors of ${\\mathbb F}_q^k$ in which every subset of $S$ of size $k$ is a basis, where $q=p^h$, $p$ is prime and $q$ is not and $k \\leq 2p-2$, then $|S| \\leq q+1$. It also contains a short proof of the same fact for $k\\leq p$, for all $q$.
Hohenstein, Edward G.
2016-11-01
The floating occupation molecular orbital complete active space configuration interaction (FOMO-CASCI) method is quite promising for the study of nonadiabatic processes. Use of this method directly in nonadiabatic dynamics simulations has been limited by the lack of available first-order nonadiabatic coupling vectors. Here, an analytic formulation of these derivative coupling vectors is presented for FOMO-CASCI wavefunctions using a simple Lagrangian-based approach. The derivative coupling vectors are applied in the optimization of minimum energy conical intersections of an aqueously solvated model compound for the chromophore of the green fluorescent protein (including 100 water molecules). The computational cost of the FOMO-CASCI derivative coupling vector is shown to scale quadratically, O ( N 2 ) , with system size and is applied to systems with up to 1000 atoms.
de Melo, Diogo Portella Ornelas; Scherrer, Luciano Rios; Eiras, Álvaro Eduardo
2012-01-01
The use of vector surveillance tools for preventing dengue disease requires fine assessment of risk, in order to improve vector control activities. Nevertheless, the thresholds between vector detection and dengue fever occurrence are currently not well established. In Belo Horizonte (Minas Gerais, Brazil), dengue has been endemic for several years. From January 2007 to June 2008, the dengue vector Aedes (Stegomyia) aegypti was monitored by ovitrap, the sticky-trap MosquiTRAP™ and larval surveys in an study area in Belo Horizonte. Using a space-time scan for clusters detection implemented in SaTScan software, the vector presence recorded by the different monitoring methods was evaluated. Clusters of vectors and dengue fever were detected. It was verified that ovitrap and MosquiTRAP vector detection methods predicted dengue occurrence better than larval survey, both spatially and temporally. MosquiTRAP and ovitrap presented similar results of space-time intersections to dengue fever clusters. Nevertheless ovitrap clusters presented longer duration periods than MosquiTRAP ones, less acuratelly signalizing the dengue risk areas, since the detection of vector clusters during most of the study period was not necessarily correlated to dengue fever occurrence. It was verified that ovitrap clusters occurred more than 200 days (values ranged from 97.0±35.35 to 283.0±168.4 days) before dengue fever clusters, whereas MosquiTRAP clusters preceded dengue fever clusters by approximately 80 days (values ranged from 65.5±58.7 to 94.0±14. 3 days), the former showing to be more temporally precise. Thus, in the present cluster analysis study MosquiTRAP presented superior results for signaling dengue transmission risks both geographically and temporally. Since early detection is crucial for planning and deploying effective preventions, MosquiTRAP showed to be a reliable tool and this method provides groundwork for the development of even more precise tools.
de Melo, Diogo Portella Ornelas; Scherrer, Luciano Rios; Eiras, Álvaro Eduardo
2012-01-01
The use of vector surveillance tools for preventing dengue disease requires fine assessment of risk, in order to improve vector control activities. Nevertheless, the thresholds between vector detection and dengue fever occurrence are currently not well established. In Belo Horizonte (Minas Gerais, Brazil), dengue has been endemic for several years. From January 2007 to June 2008, the dengue vector Aedes (Stegomyia) aegypti was monitored by ovitrap, the sticky-trap MosquiTRAP™ and larval surveys in an study area in Belo Horizonte. Using a space-time scan for clusters detection implemented in SaTScan software, the vector presence recorded by the different monitoring methods was evaluated. Clusters of vectors and dengue fever were detected. It was verified that ovitrap and MosquiTRAP vector detection methods predicted dengue occurrence better than larval survey, both spatially and temporally. MosquiTRAP and ovitrap presented similar results of space-time intersections to dengue fever clusters. Nevertheless ovitrap clusters presented longer duration periods than MosquiTRAP ones, less acuratelly signalizing the dengue risk areas, since the detection of vector clusters during most of the study period was not necessarily correlated to dengue fever occurrence. It was verified that ovitrap clusters occurred more than 200 days (values ranged from 97.0±35.35 to 283.0±168.4 days) before dengue fever clusters, whereas MosquiTRAP clusters preceded dengue fever clusters by approximately 80 days (values ranged from 65.5±58.7 to 94.0±14. 3 days), the former showing to be more temporally precise. Thus, in the present cluster analysis study MosquiTRAP presented superior results for signaling dengue transmission risks both geographically and temporally. Since early detection is crucial for planning and deploying effective preventions, MosquiTRAP showed to be a reliable tool and this method provides groundwork for the development of even more precise tools. PMID:22848729
Directory of Open Access Journals (Sweden)
Diogo Portella Ornelas de Melo
Full Text Available The use of vector surveillance tools for preventing dengue disease requires fine assessment of risk, in order to improve vector control activities. Nevertheless, the thresholds between vector detection and dengue fever occurrence are currently not well established. In Belo Horizonte (Minas Gerais, Brazil, dengue has been endemic for several years. From January 2007 to June 2008, the dengue vector Aedes (Stegomyia aegypti was monitored by ovitrap, the sticky-trap MosquiTRAP™ and larval surveys in an study area in Belo Horizonte. Using a space-time scan for clusters detection implemented in SaTScan software, the vector presence recorded by the different monitoring methods was evaluated. Clusters of vectors and dengue fever were detected. It was verified that ovitrap and MosquiTRAP vector detection methods predicted dengue occurrence better than larval survey, both spatially and temporally. MosquiTRAP and ovitrap presented similar results of space-time intersections to dengue fever clusters. Nevertheless ovitrap clusters presented longer duration periods than MosquiTRAP ones, less acuratelly signalizing the dengue risk areas, since the detection of vector clusters during most of the study period was not necessarily correlated to dengue fever occurrence. It was verified that ovitrap clusters occurred more than 200 days (values ranged from 97.0±35.35 to 283.0±168.4 days before dengue fever clusters, whereas MosquiTRAP clusters preceded dengue fever clusters by approximately 80 days (values ranged from 65.5±58.7 to 94.0±14. 3 days, the former showing to be more temporally precise. Thus, in the present cluster analysis study MosquiTRAP presented superior results for signaling dengue transmission risks both geographically and temporally. Since early detection is crucial for planning and deploying effective preventions, MosquiTRAP showed to be a reliable tool and this method provides groundwork for the development of even more precise tools.
DEFF Research Database (Denmark)
Rasmussen, Tonny Wederberg
1999-01-01
The paper describes a full space vector control stradegy. The synchronisation used to improveboth the control speed of reactive power and reduce the sensitivity to large phase jumps in the grid caused by switching arge loads. The control stradegy is tested with a 5-level 10kvar laboratory model....
A support vector machine based test for incongruence between sets of trees in tree space
2012-01-01
Background The increased use of multi-locus data sets for phylogenetic reconstruction has increased the need to determine whether a set of gene trees significantly deviate from the phylogenetic patterns of other genes. Such unusual gene trees may have been influenced by other evolutionary processes such as selection, gene duplication, or horizontal gene transfer. Results Motivated by this problem we propose a nonparametric goodness-of-fit test for two empirical distributions of gene trees, and we developed the software GeneOut to estimate a p-value for the test. Our approach maps trees into a multi-dimensional vector space and then applies support vector machines (SVMs) to measure the separation between two sets of pre-defined trees. We use a permutation test to assess the significance of the SVM separation. To demonstrate the performance of GeneOut, we applied it to the comparison of gene trees simulated within different species trees across a range of species tree depths. Applied directly to sets of simulated gene trees with large sample sizes, GeneOut was able to detect very small differences between two set of gene trees generated under different species trees. Our statistical test can also include tree reconstruction into its test framework through a variety of phylogenetic optimality criteria. When applied to DNA sequence data simulated from different sets of gene trees, results in the form of receiver operating characteristic (ROC) curves indicated that GeneOut performed well in the detection of differences between sets of trees with different distributions in a multi-dimensional space. Furthermore, it controlled false positive and false negative rates very well, indicating a high degree of accuracy. Conclusions The non-parametric nature of our statistical test provides fast and efficient analyses, and makes it an applicable test for any scenario where evolutionary or other factors can lead to trees with different multi-dimensional distributions. The
Directory of Open Access Journals (Sweden)
BELMADANI, B.
2009-06-01
Full Text Available This paper proposes the design and implementation of a novel direct torque controlled induction machine drive system. The control system enjoys the advantages of stator vector control and conventional direct torque control and avoids some of the implementation difficulties of either of the two control methods. The stator vector control principal is used to keep constant the amplitude of stator flux vector at rated value, and to develop the relationship between the machine torque and the rotating speed of the stator flux vector. Thus, the machine torque can be regulated to generate the stator angular speed, which becomes a command signal and permits to overcome the problem of its estimation. Furthermore, with the combined control methods, the reference stator voltage vector can be generated and proportional-integral controllers and space vector modulation technique can be used to obtain fixed switching frequency and low torque ripple. Simulation experiments results indicate that, with the proposed scheme, a precise control of the stator flux and machine torque can be achieved. Compared to conventional direct torque control, presented method is easily implemented, and the steady performances of ripples of both torque and flux are considerably improved.
The Variable Vector Countermeasure Suit (V2Suit) for space habitation and exploration.
Duda, Kevin R; Vasquez, Rebecca A; Middleton, Akil J; Hansberry, Mitchell L; Newman, Dava J; Jacobs, Shane E; West, John J
2015-01-01
The "Variable Vector Countermeasure Suit (V2Suit) for Space Habitation and Exploration" is a novel system concept that provides a platform for integrating sensors and actuators with daily astronaut intravehicular activities to improve health and performance, while reducing the mass and volume of the physiologic adaptation countermeasure systems, as well as the required exercise time during long-duration space exploration missions. The V2Suit system leverages wearable kinematic monitoring technology and uses inertial measurement units (IMUs) and control moment gyroscopes (CMGs) within miniaturized modules placed on body segments to provide a "viscous resistance" during movements against a specified direction of "down"-initially as a countermeasure to the sensorimotor adaptation performance decrements that manifest themselves while living and working in microgravity and during gravitational transitions during long-duration spaceflight, including post-flight recovery and rehabilitation. Several aspects of the V2Suit system concept were explored and simulated prior to developing a brassboard prototype for technology demonstration. This included a system architecture for identifying the key components and their interconnects, initial identification of key human-system integration challenges, development of a simulation architecture for CMG selection and parameter sizing, and the detailed mechanical design and fabrication of a module. The brassboard prototype demonstrates closed-loop control from "down" initialization through CMG actuation, and provides a research platform for human performance evaluations to mitigate sensorimotor adaptation, as well as a tool for determining the performance requirements when used as a musculoskeletal deconditioning countermeasure. This type of countermeasure system also has Earth benefits, particularly in gait or movement stabilization and rehabilitation.
The Variable Vector Countermeasure Suit (V2Suit for Space Habitation and Exploration
Directory of Open Access Journals (Sweden)
Kevin R Duda
2015-04-01
Full Text Available The Variable Vector Countermeasure Suit (V2Suit for Space Habitation and Exploration is a novel system concept that provides a platform for integrating sensors and actuators with daily astronaut intravehicular activities to improve health and performance, while reducing the mass and volume of the physiologic adaptation countermeasure systems, as well as the required exercise time during long-duration space exploration missions. The V2Suit system leverages wearable kinematic monitoring technology and uses inertial measurement units (IMUs and control moment gyroscopes (CMGs within miniaturized modules placed on body segments to provide a viscous resistance during movements against a specified direction of down – initially as a countermeasure to the sensorimotor adaptation performance decrements that manifest themselves while living and working in microgravity and during gravitational transitions during long-duration spaceflight, including post-flight recovery and rehabilitation. Several aspects of the V2Suit system concept were explored and simulated prior to developing a brassboard prototype for technology demonstration. This included a system architecture for identifying the key components and their interconnects, initial identification of key human-system integration challenges, development of a simulation architecture for CMG selection and parameter sizing, and the detailed mechanical design and fabrication of a module. The brassboard prototype demonstrates closed-loop control from down initialization through CMG actuation, and provides a research platform for human performance evaluations to mitigate sensorimotor adaptation, as well as a tool for determining the performance requirements when used as a musculoskeletal deconditioning countermeasure. This type of countermeasure system also has Earth benefits, particularly in gait or movement stabilization and rehabilitation.
Phytoplankton global mapping from space with a support vector machine algorithm
de Boissieu, Florian; Menkes, Christophe; Dupouy, Cécile; Rodier, Martin; Bonnet, Sophie; Mangeas, Morgan; Frouin, Robert J.
2014-11-01
In recent years great progress has been made in global mapping of phytoplankton from space. Two main trends have emerged, the recognition of phytoplankton functional types (PFT) based on reflectance normalized to chlorophyll-a concentration, and the recognition of phytoplankton size class (PSC) based on the relationship between cell size and chlorophyll-a concentration. However, PFTs and PSCs are not decorrelated, and one approach can complement the other in a recognition task. In this paper, we explore the recognition of several dominant PFTs by combining reflectance anomalies, chlorophyll-a concentration and other environmental parameters, such as sea surface temperature and wind speed. Remote sensing pixels are labeled thanks to coincident in-situ pigment data from GeP&CO, NOMAD and MAREDAT datasets, covering various oceanographic environments. The recognition is made with a supervised Support Vector Machine classifier trained on the labeled pixels. This algorithm enables a non-linear separation of the classes in the input space and is especially adapted for small training datasets as available here. Moreover, it provides a class probability estimate, allowing one to enhance the robustness of the classification results through the choice of a minimum probability threshold. A greedy feature selection associated to a 10-fold cross-validation procedure is applied to select the most discriminative input features and evaluate the classification performance. The best classifiers are finally applied on daily remote sensing datasets (SeaWIFS, MODISA) and the resulting dominant PFT maps are compared with other studies. Several conclusions are drawn: (1) the feature selection highlights the weight of temperature, chlorophyll-a and wind speed variables in phytoplankton recognition; (2) the classifiers show good results and dominant PFT maps in agreement with phytoplankton distribution knowledge; (3) classification on MODISA data seems to perform better than on SeaWIFS data
Adams, M. L.; Hagyard, M. J.; West, E. A.; Smith, J. E.; Whitaker, Ann F. (Technical Monitor)
2001-01-01
The Marshall Space Flight Center's (MSFC) solar group announces the successful upgrade of our tower vector magnetograph. In operation since 1973, the last major alterations to the system (which includes telescope, filter, polarizing optics, camera, and data acquisition computer) were made in 1982, when we upgraded from an SEC Vidicon camera to a CCD. In 1985, other changes were made which increased the field-of-view from 5 x 5 arc min (2.4 arc sec per pixel) to 6 x 6 arc min with a resolution of 2.81 arc sec. In 1989, the Apollo Telescope Mount H-alpha telescope was coaligned with the optics of the magnetograph. The most recent upgrades (year 2000), funded to support the High Energy Solar Spectroscopic Imager (HESSI) mission, have resulted in a pixel size of 0.64 arc sec over a 7 x 5.2 arc min field-of-view (binning 1x1). This poster describes the physical characteristics of the new system and compares spatial resolution, timing, and versatility with the old system. Finally, we provide a description of our Internet web site, which includes images of our most recent observations, and links to our data archives, as well as the history of magnetography at MSFC and education outreach pages.
Development and evaluation of a biomedical search engine using a predicate-based vector space model.
Kwak, Myungjae; Leroy, Gondy; Martinez, Jesse D; Harwell, Jeffrey
2013-10-01
Although biomedical information available in articles and patents is increasing exponentially, we continue to rely on the same information retrieval methods and use very few keywords to search millions of documents. We are developing a fundamentally different approach for finding much more precise and complete information with a single query using predicates instead of keywords for both query and document representation. Predicates are triples that are more complex datastructures than keywords and contain more structured information. To make optimal use of them, we developed a new predicate-based vector space model and query-document similarity function with adjusted tf-idf and boost function. Using a test bed of 107,367 PubMed abstracts, we evaluated the first essential function: retrieving information. Cancer researchers provided 20 realistic queries, for which the top 15 abstracts were retrieved using a predicate-based (new) and keyword-based (baseline) approach. Each abstract was evaluated, double-blind, by cancer researchers on a 0-5 point scale to calculate precision (0 versus higher) and relevance (0-5 score). Precision was significantly higher (psearching than keywords, laying the foundation for rich and sophisticated information search.
Directory of Open Access Journals (Sweden)
Hiram Ponce
2014-01-01
Full Text Available Most of machine-operated industrial processes implement electric machinery as their work sources, implying the necessary improvement of control techniques and power electronics drivers. Many years have passed since the control conflicts related to induction motors have been overcome through torque-flux control techniques so their advantages over direct current motors have made them to be the most common electric actuator found behind industrial automation. In fact, induction motors can be easily operated using a Direct Torque Control (DTC. Since, it is based on a hysteresis control of the torque and flux errors, its performance is characterized by a quick reaching of the set point, but also a high ripple on both torque and flux. In order to enhance that technique, this study introduces a novel hybrid fuzzy controller with artificial hydrocarbon networks (FMC that is used in a Space Vector Pulse Width Modulation (SVPWM technique, so-called FMC-SVPWM-DTC. In fact, this study describes the proposal and its design method. Experimental results over a velocity-torque cascade topology proved that the proposed FMC-SVPWM-DTC responses highly effective almost suppressing rippling in torque and flux. It also performed a faster speed response than in a conventional DTC. In that sense, the proposed FMC-SVPWM-DTC can be used an alternative approach for controlling induction motors.
Directory of Open Access Journals (Sweden)
Włodarczyk K
2005-01-01
Full Text Available Let be a real Hausdorff topological vector space. In the present paper, the concepts of the transfer positive hemicontinuity and strictly transfer positive hemicontinuity of set-valued maps in are introduced (condition of strictly transfer positive hemicontinuity is stronger than that of transfer positive hemicontinuity and for maps and defined on a nonempty compact convex subset of , we describe how some ideas of K. Fan have been used to prove several new, and rather general, conditions (in which transfer positive hemicontinuity plays an important role that a single-valued map has a zero, and, at the same time, we give various characterizations of the class of those pairs and maps that possess coincidences and fixed points, respectively. Transfer positive hemicontinuity and strictly transfer positive hemicontinuity generalize the famous Fan upper demicontinuity which generalizes upper semicontinuity. Furthermore, a new type of continuity defined here essentially generalizes upper hemicontinuity (the condition of upper demicontinuity is stronger than the upper hemicontinuity. Comparison of transfer positive hemicontinuity and strictly transfer positive hemicontinuity with upper demicontinuity and upper hemicontinuity and relevant connections of the results presented in this paper with those given in earlier works are also considered. Examples and remarks show a fundamental difference between our results and the well-known ones.
Space-geodetic estimation of the nazca-south america euler vector
Angermann, D.; Klotz, J.; Reigber, C.
1999-09-01
GPS data from four sites in the Nazca Plate (Easter Island, Galapagos, Robinson Crusoe and San Felix Islands) and from five sites in the stable core of the South American Plate enabled us to estimate the Euler vector of the Nazca Plate with respect to South America. The observed velocities of Easter Island (6.6 cm/yr at 102.3°), Galapagos (5.1 cm/yr at 90.0°), Robinson Crusoe (6.6 cm/yr at 80.1°) and San Felix (6.0 cm/yr at 82.1°) are significantly slower than the global plate model NUVEL-1A velocites for those four sites. Our estimated Euler pole is located at 48.8°N, 91.7°W with a rate of 0.59°/m.y. The NUVEL-1A and earlier space-geodetic studies give rotation rates that are 20% faster.
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
The authors first establish a quantum microscopic scattering matrix model in multidimen-sional wave-vector space, which relates the phase space density of each superlattice cell withthat of the neighbouring cells. Then, in the limit of a large number of cells, a SHE (SphericalHarmonics Expansion)-type model of diffusion equations for the particle number density in theposition-energy space is obtained. The crucial features of diffusion constants on retaining thememory of the quantum scattering characteristics of the superlattice elementary cell (like e.g.transmission resonances) are shown in order. Two examples are treated with the analyticallycomputation of the diffusion constants.
Directory of Open Access Journals (Sweden)
Marouane El Azzaoui
2016-07-01
Full Text Available The vector control performance applied to rotating machines depends largely on static and dynamic characteristics of the inverter associated with it. The development of the pulse-width modulation (PWM provided greater flexibility in the control of the converters. The objective of this work is to construct a simplified and practical space vector modulation (SVM based on the selection of the sequence and the calculation of the conduction time or extinction. We have presented the blocks of the simulation vector modulation on the Matlab / Simulink with a new method for determining conduction time and analyzed its application on a load RL supplied by a voltage inverter. The performance of the proposed method has been presented by the simulation results.
Institute of Scientific and Technical Information of China (English)
Ghulam Shabbir; Suhail Khan; Amjad Ali
2011-01-01
In this paper we classify spatially homogeneous rotating space-times according to their teleparallel Killing vector fields using direct integration technique.It turns out that the dimension of the teleparallel Killing vector fields is 5 or 10.In the case of 10 teleparallel Killing vector fields the space-time becomes Minkowski and all the torsion components are zero.Teleparallel Killing vector fields in this case are exactly the same as in general relativity.In the cases of 5 teleparallel Killing vector fields we get two more conservation laws in the teleparallel theory of gravitation.Here we also discuss some well-known examples of spatially homogeneous rotating space-times according to their teleparallel Killing vector fields.
Convenient measurement of small impulses
Brost, G.; Deaton, T.; Duvall, B.; Boyle, W.; Tinsley, J.; Bohn, C.; Stephen, M.; Souders, J.
1986-01-01
This paper describes a convenient method which has been used for the measurement of small impulses (1-20 dyn s). An inductive displacement gauge was used to monitor displacement of a ballistic pendulum.
The Convenient Setting for Denjoy--Carleman Differentiable Mappings of Beurling and Roumieu Type
Kriegl, Andreas; Rainer, Armin
2011-01-01
We prove in a uniform way that all Denjoy--Carleman differentiable function classes of Beurling type $C^{(M)}$ and of Roumieu type $C^{\\{M\\}}$, admit a convenient setting if the weight sequence $M=(M_k)$ is log-convex and of moderate growth: For $\\mathcal C$ denoting either $C^{(M)}$ or $C^{\\{M\\}}$, the category of $\\mathcal C$-mappings is cartesian closed in the sense that $\\mathcal C(E,\\mathcal C(F,G))\\cong \\mathcal C(E\\x F, G)$ for convenient vector spaces. Applications to manifolds of mappings are given: The group of $\\mathcal C$-diffeomorphisms is a regular $\\mathcal C$-Lie group if $\\mathcal C \\supseteq C^\\om$, but not better.
Analysis of Space Characteristics and Problems of Beijing Traffic Convenience%北京城区交通便捷性空间分异特征及问题分析
Institute of Scientific and Technical Information of China (English)
王德利; 杨青山
2012-01-01
The urban traffic conditions is one of the important marks of city habitability, and solving the problem of traffic congestion is the most important construction of "livable Beijing". Based on the definition of study area, establishing city traffic index, through questionnaire survey method, we survey the part district of Beijing. Based on the Beijing traffic satisfaction comprehensive evaluation model, we analyze Beijing transportation structure and space characteristics of travel satisfaction. We analyze data of evaluation traffic convenient of subjective and objective of the study area using ArcGIS comparatively. Through the analysis of transportation convenience of space characteristics of Beijing, it shows the city construction and urban transportation infrastructure development is not harmonious; road network planning is not rational. "The separation between jobs and residential locations" leads to traffic problems. Public passenger transport is difficult to deal with private transportation challenge; the urban traffic system management is lack of effective integration.%城市交通条件是反映城市宜居性的重要标志之一，解决城市交通拥堵问题是建设“宜居北京”的重中之重。在界定研究区域，建立城市交通便捷性指标的基础上，通过对北京市部分区域进行问卷调查，基于北京市交通满意度综合评价模型，对北京市交通出行结构、出行满意度等空间分异特征进行分析。利用ArcGIS空间分析工具，将主观交通便捷性评价和客观交通相关数据进行对比分析，用以分析研究区范围内交通便捷性。结果表明，北京市交通发展中存在的问题有：城市建设与城市交通基础设施发展不协调；道路网络规划不尽合理；“职住分离”导致交通问题的加剧；公共客运交通难以应对私人交通工具的强劲挑战；城市交通管理系统缺乏有效整合。
Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter
DEFF Research Database (Denmark)
Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede
2016-01-01
This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance of the inver......This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance...... of the inverter, the strategy was compared the traditional pulse-width modulation. It is shown that the approach proposed has fewer switching states and does not suffer from neutral point misbalance....
Achalhi, A.; Bezza, M.; Belbounaguia, N.; Boujoudi, B.
2017-03-01
The performances of Direct Torque Control (DTC) of Induction machine are highly related to the inverter used therewith. The purpose of this paper is to highlight the efficiency of the space vector modulation (SVM) control of three level inverter associated with the direct torque control. The first part of this work is devoted to present the mathematical models of the DTC associated with 2-levels inverter then 3-levels inverter. Simulations on Matlab/Simulink will allow a comparative study to highlight advantages of the use of three levels inverter. The second part is devoted to the improvement of the DTC associated with a 3-levels inverter by application of the space vector modulation strategy (SVM) in order to manage the switching frequency and reduce harmonics. The efficiency of this solution will be attested by simulation on Matlab/Simulink.
Directory of Open Access Journals (Sweden)
S. Elangovan
2014-07-01
Full Text Available The main aim of this study is to control a multivariable coupled system by choosing sliding mode switching function. A Sliding mode control approach is developed to control a three phase three wire voltage source inverter operating as a shunt active power filter. Hence, no need to divide the system model developed in the synchronous ‘dq’ reference frame into two separate loops. Furthermore, the proposed control strategy allows a better stability and robustness over a wide range of operation. When sine PWM is used for generation of pulses for the switches, a variable switching nature is exhibited. The pulses for the active filter are fed by a Space Vector Modulation in order to have a constant switching of converter switches. But, the conventional space vector modulation, if implemented practically, needs a complicated algorithm which uses the trigonometric functions such as arctan, Sine and Cosine functions which in turn needs look up tables to store the pre-calculated trigonometric values. In this study, a very simplified algorithm is proposed for generating Space vector modulated pulse for all six switches without the use of look up tables and only by sensing the voltages and currents of the voltage source inverter acting as shunt active filter. The simulation using PSIM and MATLAB software verifies the results very well.
Clark, J L; Konda, K A; Silva-Santisteban, A; Peinado, J; Lama, J R; Kusunoki, L; Perez-Brumer, A; Pun, M; Cabello, R; Sebastian, J L; Suarez-Ognio, L; Sanchez, J
2014-12-01
Alternatives to convenience sampling (CS) are needed for HIV/STI surveillance of most-at-risk populations in Latin America. We compared CS, time space sampling (TSS), and respondent driven sampling (RDS) for recruitment of men who have sex with men (MSM) and transgender women (TW) in Lima, Peru. During concurrent 60-day periods from June-August, 2011, we recruited MSM/TW for epidemiologic surveillance using CS, TSS, and RDS. A total of 748 participants were recruited through CS, 233 through TSS, and 127 through RDS. The TSS sample included the largest proportion of TW (30.7 %) and the lowest percentage of subjects who had previously participated in HIV/STI research (14.9 %). The prevalence of newly diagnosed HIV infection, according to participants' self-reported previous HIV diagnosis, was highest among TSS recruits (17.9 %) compared with RDS (12.6 %) and CS (10.2 %). TSS identified diverse populations of MSM/TW with higher prevalences of HIV/STIs not accessed by other methods.
(α,β)-空间中的Killing向量场%Killing vector fields on(α,β)-space
Institute of Scientific and Technical Information of China (English)
沈斌; 康琳
2011-01-01
In this paper, it is proved that the maximum dimension of the Killing vector space in a non-Riemannian (α,β)-space is n(n -1)/2+1. The non-Riemannian (α,β)-metric which admits the maximum dimension of Killing vector space is determined. At last, if we further assume that α is a homogenious Riemannian metric, the first gap is given. The examples of different dimensions of Killing vetor space in low dimensisional case can be determined. It shows the gap phenomenon almost disappear in the (α,β)-space.%本文证明了非Riemannian(α,β)-空间中的Killing向量场最大维数是n(n-1)/2+1.并且给出了具有最大维数Killing向量场的非Riemannian (α,β)-空间的度量形式.最后,若进一步假定α是一个齐性Riemannian度量,则可确定(α,β)-空间的第二空隙.最后给出几个低维流形上Killing场空间维数的例子,这表明在(α,β)情形下Killing场空间维数的空隙被压缩.
Solving the Poisson partial differential equation using vector space projection methods
Marendic, Boris
This research presents a new approach at solving the Poisson partial differential equation using Vector Space Projection (VSP) methods. The work attacks the Poisson equation as encountered in two-dimensional phase unwrapping problems, and in two-dimensional electrostatic problems. Algorithms are developed by first considering simple one-dimensional cases, and then extending them to two-dimensional problems. In the context of phase unwrapping of two-dimensional phase functions, we explore an approach to the unwrapping using a robust extrapolation-projection algorithm. The unwrapping is done iteratively by modification of the Gerchberg-Papoulis (GP) extrapolation algorithm, and the solution is refined by projecting onto the available global data. An important contribution to the extrapolation algorithm is the formulation of the algorithm with the relaxed bandwidth constraint, and the proof that such modified GP extrapolation algorithm still converges. It is also shown that the unwrapping problem is ill-posed in the VSP setting, and that the modified GP algorithm is the missing link to pushing the iterative algorithm out of the trap solution under certain conditions. Robustness of the algorithm is demonstrated through its performance in a noisy environment. Performance is demonstrated by applying it to phantom phase functions, as well as to the real phase functions. Results are compared to well known algorithms in literature. Unlike many existing unwrapping methods which perform unwrapping locally, this work approaches the unwrapping problem from a globally, and eliminates the need for guiding instruments, like quality maps. VSP algorithm also very effectively battles problems of shadowing and holes, where data is not available or is heavily corrupted. In solving the classical Poisson problems in electrostatics, we demonstrate the effectiveness and ease of implementation of the VSP methodology to solving the equation, as well as imposing of the boundary conditions
Voltage space vector's computation for current control in three phase converters
Directory of Open Access Journals (Sweden)
Alberto Berzoy
2012-01-01
Full Text Available Este trabajo presenta dos técnicas de control de corriente para convertidores trifásicos de voltaje trabajando como rectificadores controlados, operando con factor de potencia unitario. El primer algoritmo está basado en la escogencia del mejor vector natural, entre los 7 vectores espaciales naturales del convertidor de dos niveles de voltaje trifásico, mediante una función de costo. El segundo está basado en el cómputo y síntesis del vector espacial óptimo de convertidores trifásicos tal que el se obtiene el vector que proporciona un mínimo absoluto de la función de costo. El primer algoritmo es un método sencillo que controla muy bien el factor de potencia y presenta una considerable compensación del contenido armónico. El segundo algoritmo provee una nueva formula cerrada para calcular el vector de voltaje óptimo aplicado al convertidor. Para este segundo método se necesita generar la señal de control con un modulador de ancho de pulso para así controlar directamente la corriente de línea permitiendo seguir la referencia de corriente. Las simulaciones y resultados experimentales muestran las ventajas del algoritmo propuesto.
Brief Communication: Breeding vectors in the phase space reconstructed from time series data
Lynch, Erin; Kaufman, Daniel; Surjalal Sharma, A.; Kalnay, Eugenia; Ide, Kayo
2016-06-01
Bred vectors characterize the nonlinear instability of dynamical systems and so far have been computed only for systems with known evolution equations. In this article, bred vectors are computed from a single time series data using time-delay embedding, with a new technique, nearest-neighbor breeding. Since the dynamical properties of the standard and nearest-neighbor breeding are shown to be similar, this provides a new and novel way to model and predict sudden transitions in systems represented by time series data alone.
Sliding Mode Control of Three Levels Back-To-Back VSC-HVDC System Using Space Vector Modulation
Directory of Open Access Journals (Sweden)
Bouafia Saber
2014-03-01
Full Text Available In this study, a sliding mode strategy proposed to control a three levels Back-to-Back High Voltage Direct Current (HVDC system based on the three-level voltage source converter (VSC. The voltage-balancing control of two split DC capacitors of the VSC-HVDC system is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. Finally, a complete simulation of the VSC-HVDC system validates the efficiency of the proposed strategy law. Compared to the conventional control, Sliding Mode Control scheme for the VSC-HVDC system shows the attractive advantages such as offering high tracking accuracy, fast dynamic response and good robustness.
Directory of Open Access Journals (Sweden)
Mehdi Manoochehri
2012-07-01
Full Text Available Applying the direct thrust force control (DFC method in permanent magnet linear synchronous motor (PMLSM leads to some important problems. The most important disadvantages of applying this method are electromagnetic force and linkage flux big ripple and variable switching frequency. In this paper space vector modulation (SVM technique is applied for removing the disadvantages of classic DFC method. SVM technique makes the switching frequency constant and provides continues Voltage space compared with discrete space in classic method. Simulation results confirmed the theory. They show that combining the DFC method with SVM technique removes lots of the disadvantages of classic DFC method like big ripples and variable switching and remains the benefits of this method.
基于FPGA的空间矢量PWM的实现%A Realization of FPGA-based Space-vector PWM
Institute of Scientific and Technical Information of China (English)
孙文焕; 程善美; 秦忆
2000-01-01
本文详述了空间矢量SVPWM的算法，并提出用FPGA实现SVPWM的方法，最后分析了使用FPGA的优点。%This paper reviews an arithmetic of the space-vector PWM in detail,and advances a realization of FPGA-based space-vector PWM ,finally analyses the merit of FPGA-based strategy.
Chetyrkin, K. G.; Maier, A
2010-01-01
We present analytical results both in momentum and position space for the massless correlators of the vector and scalar currents to order alpha_s^4 as well as for the tensor currents to order alpha_s^3. The evolution equations for the correlators together with all relevant anomalous dimensions are discussed in detail. As an application we present explicit conversion formulas relating the MSbar-renormalized vector, scalar and tensor currents to their counterparts renormalized in the X-space re...
Weak Precompactness in the Space of Vector-Valued Measures of Bounded Variation
Directory of Open Access Journals (Sweden)
Ioana Ghenciu
2015-01-01
Full Text Available For a Banach space X and a measure space (Ω,Σ, let M(Ω,X be the space of all X-valued countably additive measures on (Ω,Σ of bounded variation, with the total variation norm. In this paper we give a characterization of weakly precompact subsets of M(Ω,X.
Institute of Scientific and Technical Information of China (English)
Xiang Zheng; Zhang Taiyi; Sun Jiancheng
2006-01-01
A new strategy for noise reduction of fast fading channel is presented. Firstly, more information is acquired utilizing the reconstructed embedding phase space. Then, based on the Recurrent Least Squares Support Vector Machines (RLS-SVM), noise reduction of the fast fading channel is realized. This filtering technique does not make use of the spectral contents of the signal. Based on the stability and the fractal of the chaotic attractor, the RLS-SVM algorithm is a better candidate for the nonlinear time series noise-reduction. The simulation results shows that better noise-reduction performance is acquired when the signal to noise ratio is 12dB.
Torres-Valencia, Cristian A; Álvarez, Mauricio A; Orozco-Gutiérrez, Alvaro A
2014-01-01
Human emotion recognition (HER) allows the assessment of an affective state of a subject. Until recently, such emotional states were described in terms of discrete emotions, like happiness or contempt. In order to cover a high range of emotions, researchers in the field have introduced different dimensional spaces for emotion description that allow the characterization of affective states in terms of several variables or dimensions that measure distinct aspects of the emotion. One of the most common of such dimensional spaces is the bidimensional Arousal/Valence space. To the best of our knowledge, all HER systems so far have modelled independently, the dimensions in these dimensional spaces. In this paper, we study the effect of modelling the output dimensions simultaneously and show experimentally the advantages in modeling them in this way. We consider a multimodal approach by including features from the Electroencephalogram and a few physiological signals. For modelling the multiple outputs, we employ a multiple output regressor based on support vector machines. We also include an stage of feature selection that is developed within an embedded approach known as Recursive Feature Elimination (RFE), proposed initially for SVM. The results show that several features can be eliminated using the multiple output support vector regressor with RFE without affecting the performance of the regressor. From the analysis of the features selected in smaller subsets via RFE, it can be observed that the signals that are more informative into the arousal and valence space discrimination are the EEG, Electrooculogram/Electromiogram (EOG/EMG) and the Galvanic Skin Response (GSR).
Modeling Interferometric Structures with Birefringent Elements: A Linear Vector-Space Formalism
2013-11-12
the conventional representation, state |si〉 is repre- sented by the 3D vector ~si as well as a “fiducial paddle ” which permits an overall phase to be...which is represented by a fiducial paddle attached to ~s. Thus, in rotating through angle φ, the orientation of the initial fiducial paddle at ~si is...changed to the grey shaded paddle at ~sf . The overall phase change is represented by a rotation of the fiducial paddle by an additional Modeling
2017-04-07
simultane-225 ously provide loop and dipole modes [ King , 1959; Robey et al., 2016]. A perimeter loop226 provides the third loop antenna along with mechanical... Stephen White, Kamen Kozarev, Sarah Klein, Sara Seager, Fash Azad, Will287 Rogers, Tom Brown.288 Generous support for the development of the vector...20th National Solar Physics Meeting, held 31 May - 4 June, 2010 in310 Papradno, Slovakia, p. 108-130, pp. 108–130, 2010.311 King , R. The rectangular
An explicit Ricci potential for the Universal Moduli Space of Vector Bundles
DEFF Research Database (Denmark)
Andersen, Jørgen Ellegaard; Poulsen, Niccolo Skovgård
In this paper we modify the coordinate construction in [5] on the universal moduli space of pair consisting of a Riemann Surfaces and a stable holomorphic bundles on the Riemann Surface, so as to produce a new set of coordinates, which are in fact Kähler coordinates on this universal moduli space....... Further, we give a functional determinant formula for the Ricci potential of the universal moduli space....
Vector-Valued almost Convergence and Classical Properties in Normed Spaces
Indian Academy of Sciences (India)
A Aizpuru; R Armario; F J Garcia-Pacheco; F J Perez-Fernandez
2014-02-01
In this paper we study the almost convergence and the almost summability in normed spaces. Among other things, spaces of sequences defined by the almost convergence and the almost summability are proved to be complete if the basis normed space is so. Finally, some classical properties such as completeness, reflexivity, Schur property, Grothendieck property, and the property of containing a copy of 0 are characterized in terms of the almost convergence.
The approximation property of some vector valued Sobolev-Slobodeckij spaces
Directory of Open Access Journals (Sweden)
Carlos Bosch
1992-01-01
Full Text Available In this paper we consider the Sobolev-Slobodeckij spaces Wm,p(ℜn,E where E is a strict (LF-space, m∈(0,∞\\ℕ and p∈[1,∞. We prove that Wm,p(ℜn,E has the approximation property provided E has it, furthermore if E is a Banach space with the strict approximation property then Wm,p(ℜn,E has this property.
新型SVPWM调制方法研究%Research on a Novel Space Vector PWM Modulation Method
Institute of Scientific and Technical Information of China (English)
徐传芳; 张可畏; 王英; 李东辉
2012-01-01
在阐述传统SVPWM调制方式的基础上,推导出了SVPWM的一种新型调制方法.该方法直接利用三相相电压的大小进行简单的大小判断即可得到空间矢量所在扇区,同时利用三相相电压的简单加减运算就可以得到非零矢量的导通时间,避免了传统SVPWM算法中三相到两相的Clark坐标变换、三角函数计算等过程,简化了SVPWM算法步骤,实现方式简单快速,实时性强.最后利用该算法对一台三相异步电动机进行了仿真,仿真结果验证了该算法的正确性.%A novel modulation algorithm of space vector pulse-width modulation (SVPWM) was proposed based on the conventional SVPWM. In the algorithm, the sector of space vector was determined by simple comparison of the value of three-phase voltage and the duty cycle of non-zero vector was calculated simply by addition and subtraction to the phase voltage. The complexity was reduced by avoiding the Clark coordinate transformations and trigonometric function calculation in the conventional SVPWM. The simulation of a three-phase asynchronous motor was built by using the novel SVPWM. The results verify the validity of the algorithm.
Energy Technology Data Exchange (ETDEWEB)
Ghennam, Tarak [Laboratoire d' Electronique de Puissance (LEP), UER: Electrotechnique, Ecole Militaire Polytechnique d' Alger, BP 17, Bordj EL Bahri, Alger (Algeria); Berkouk, El-Madjid [Laboratoire de Commande des Processus (LCP), Ecole Nationale Polytechnique d' Alger, BP 182, 10 avenue Hassen Badi, 16200 el Harrach (Algeria)
2010-04-15
In this paper, a novel space-vector hysteresis current control (SVHCC) is proposed for a back-to-back three-level converter which is used as an electronic interface in a wind conversion system. The proposed SVHCC controls the active and reactive powers delivered to the grid by the doubly fed induction machine (DFIM) through the control of its rotor currents. In addition, it controls the neutral point voltage by using the redundant inverter switching states. The three rotor current errors are gathered into a single space-vector quantity. The magnitude of the error vector is limited within boundary areas of a square shape. The control scheme is based firstly on the detection of the area and sector in which the vector tip of the current error can be located. Then, an appropriate voltage vector among the 27 voltage vectors of the three-level voltage source inverter (VSI) is applied to push the error vector towards the hysteresis boundaries. Simple look-up tables are required for the area and sector detection, and also for vector selection. The performance of the proposed control technique has been verified by simulations. (author)
Directory of Open Access Journals (Sweden)
Sandra Maria Scheffer
2014-10-01
Full Text Available The paper presents preliminary results of the research of doctorate on urban space production in relation to housing in Ponta Grossa, Brazil, regarding the support to families in socio-environmental risk. The soil use and occupation are historically produced and reveal the dynamics of each society and the interaction between several social segments. Public policies foster the production of urban space, more specifically the housing policy, through the implementation of programs that define characteristics of space concentration and determine the population profile. In March 2009, the Program “My House My Life” was launched, this is a Federal Program that in one of its income groups aims to prioritize the support to families living in risky or unhealthy areas or that have become homeless, therefore, are exposed to socio-environmental risk. This study presents preliminary results regarding the analysis of urban space production, under the perspective of sustainability and considering the implementation of the Housing Program in the city of Ponta Grossa, State of Paraná, Brazil, from 2010 to 2013. This city is relevant for the study as it received high investment of Federal resources to build housing units. The city also presents a large number of precarious settlements with families living in socio-environmental risk and who demand housing. The methodology adopted is the Henri Lefebvre Method, called regressive-progressive, which helps to reflect on the historicity of the space production. Research preliminary data was gathered from governmental organizations documents. The housing policy is shown as a vector of space production in which some distancing of the individuals involved might occur regarding the moments of the policy conception and its implementation.Key words: Families in socio-environmental risk, housing policy, space production
Institute of Scientific and Technical Information of China (English)
Jiaqi Wang; Ping Yu; Changxiang Yan; Jianyue Ren; Bin He
2005-01-01
@@ For space optical remote sensor (SORS) with either film or time delay and integrate charge coupled device (TDI-CCD) imaging, in order to achieve higher resolution it requires more accurate real-time image motion compensation.
Embracing the convenient care concept.
Ferris, Allison H; McAndrew, Thomas M; Shearer, Debra; Donnelly, Gloria F; Miller, Howard A
2010-01-01
The landscape of primary care medicine is rapidly changing. The decline in interest, both in primary care fields and students choosing these career paths, has left a vacuum in the health care system that must be filled. One of the recent developments has been the birth of "convenient care centers," also known as "retail clinics." This form of health care delivery has mostly been entrepreneurial and based in retail organizations, such as drug stores. These walk-in clinics provide basic medical care for minor common medical conditions, such as sore throat, urinary tract infection, the common cold, and ear infections. Much of this care is provided not by physicians, but by nurse practitioners or physician assistants. After seeing the success of the earliest of these clinics, MinuteClinic by CVS, many other businesses joined the venture, and retail clinics popped up in Wal-Mart, Target, and many local grocery stores. Gradually, hospital systems, physician groups, and managed care companies have also entered the market, sometimes partnering with retail outlets, such as the local grocery store or Wal-Mart, and less often, starting a stand-alone facility. Only 12% of retail clinics are owned by hospital systems or physician groups, while 73% are owned by CVS, Walgreens, or Target. There is even a national nonprofit organization called the Convenient Care Association, started in 2006, and based in Philadelphia, PA. This new trend in delivering health care has been mostly, if not totally, ignored by the medical school practice plans, with the exception of the Mayo Clinic in Minnesota, which has developed several "express care" clinics as stand-alone facilities. As a medical school practice plan and a division of general internal medicine, we could continue to keep a blind eye toward this new trend in primary care medicine or embrace the concept. We aim to develop a new convenient care model integrating our College of Medicine practice plan in partnership with our College of
Positioning doctors for convenience medicine.
Haley, M
1984-01-01
Faced with an increasingly competitive environment, physicians must learn to organize themselves into group practices positioned to perform as the customer expects. To be successful, these new group practices must recruit the kind of physician who will meet the consumer's demands for quality care: convenience, continuity of care, and confidence in the doctor's competence. This article describes how doctors can become more competitive based on my observations as a former consultant with such healthcare companies as Cigna Healthplan, the largest for-profit HMO, and as the current vice president of Operations Planning and Development with Republic Health Corporation, a Dallas-based hospital management company. These observations should help hospital managers learn how to organize their medical staffs to better serve the patient's needs. By repositioning their physician services, hospitals should become better positioned to compete for new patients.
Colorings of simplicial complexes and vector bundles over Davis-Januszkiewicz spaces
Notbohm, D.R.A.W.
2009-01-01
We show that coloring properties of a simplicial complex K are reflected by splitting properties of a bundle over the associated Davis-Januszkiewicz space whose Chern classes are given by the elementary symmetric polynomials in the generators of the Stanley-Reisner algebra of K.
Directory of Open Access Journals (Sweden)
M. Shankar
2014-01-01
Full Text Available This study proposes a novel control design of Unified Power Quality Conditioner (UPQC. This design is enabled by a control framework that employs Genetic Algorithm which determines optimum points and angle for filtering and Space Vector Pulse Width Modulation Technique (SVPWM to offer significant flexibility to optimize waveform. In addition the same framework integrates the major functions of the UPQC with ease to unify the treatments of several power quality problems including system harmonics in the supply voltage and load current, sags/swells in the supply voltage, variations in the load demands and poor power factor at the supply side. Simulation studies on a three phase power distribution system are used to verify the performance and implementation of this control design with the UPQC.
Directory of Open Access Journals (Sweden)
S. Radha Krishna Reddy
2012-06-01
Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulse width modulation (SVPWM is widely used. This paper deals with the three-phase three-level inverter fed induction motor drive. The proposed scheme deals with the development and implementation of three phase three level inverter to improve the efficiency and reliability of the inverter. Simulation tests have been carried out to examine the operating characteristics of the completed three-phase three-level inverter driving induction motor and an RL load with different switching devices and are compared
Indian Academy of Sciences (India)
A. Izadi; A. Shojai; M. Nouradini
2013-03-01
We consider tensor–vector theories by varying the space-time–matter coupling constant (varying Einstein velocity) in a spatially flat FRW universe.We examine the dynamics of this model by dynamical system method assuming a CDM background and we find some exact solutions by considering the character of critical points of the theory and their stability conditions. Then we reconstruct the potential (2) and the coupling (2) by demanding a background CDM cosmology. Also we set restrictions on the varying Einstein velocity to solve the horizon problem. This gives a selection rule for choosing the appropriate stable solution. We will see that it is possible to produce the background expansion history () indicated by observations. Finally we will discuss the behavior of the speed of light (E) for those solutions.
Martins, F V C; Carrano, E G; Wanner, E F; Takahashi, R H C; Mateus, G R; Nakamura, F G
2014-01-01
Recent works raised the hypothesis that the assignment of a geometry to the decision variable space of a combinatorial problem could be useful both for providing meaningful descriptions of the fitness landscape and for supporting the systematic construction of evolutionary operators (the geometric operators) that make a consistent usage of the space geometric properties in the search for problem optima. This paper introduces some new geometric operators that constitute the realization of searches along the combinatorial space versions of the geometric entities descent directions and subspaces. The new geometric operators are stated in the specific context of the wireless sensor network dynamic coverage and connectivity problem (WSN-DCCP). A genetic algorithm (GA) is developed for the WSN-DCCP using the proposed operators, being compared with a formulation based on integer linear programming (ILP) which is solved with exact methods. That ILP formulation adopts a proxy objective function based on the minimization of energy consumption in the network, in order to approximate the objective of network lifetime maximization, and a greedy approach for dealing with the system's dynamics. To the authors' knowledge, the proposed GA is the first algorithm to outperform the lifetime of networks as synthesized by the ILP formulation, also running in much smaller computational times for large instances.
Cochrane, Corey J.; Blacksberg, Jordana; Anders, Mark A.; Lenahan, Patrick M.
2016-11-01
Magnetometers are essential for scientific investigation of planetary bodies and are therefore ubiquitous on missions in space. Fluxgate and optically pumped atomic gas based magnetometers are typically flown because of their proven performance, reliability, and ability to adhere to the strict requirements associated with space missions. However, their complexity, size, and cost prevent their applicability in smaller missions involving cubesats. Conventional solid-state based magnetometers pose a viable solution, though many are prone to radiation damage and plagued with temperature instabilities. In this work, we report on the development of a new self-calibrating, solid-state based magnetometer which measures magnetic field induced changes in current within a SiC pn junction caused by the interaction of external magnetic fields with the atomic scale defects intrinsic to the semiconductor. Unlike heritage designs, the magnetometer does not require inductive sensing elements, high frequency radio, and/or optical circuitry and can be made significantly more compact and lightweight, thus enabling missions leveraging swarms of cubesats capable of science returns not possible with a single large-scale satellite. Additionally, the robustness of the SiC semiconductor allows for operation in extreme conditions such as the hot Venusian surface and the high radiation environment of the Jovian system.
Cochrane, Corey J; Blacksberg, Jordana; Anders, Mark A; Lenahan, Patrick M
2016-11-28
Magnetometers are essential for scientific investigation of planetary bodies and are therefore ubiquitous on missions in space. Fluxgate and optically pumped atomic gas based magnetometers are typically flown because of their proven performance, reliability, and ability to adhere to the strict requirements associated with space missions. However, their complexity, size, and cost prevent their applicability in smaller missions involving cubesats. Conventional solid-state based magnetometers pose a viable solution, though many are prone to radiation damage and plagued with temperature instabilities. In this work, we report on the development of a new self-calibrating, solid-state based magnetometer which measures magnetic field induced changes in current within a SiC pn junction caused by the interaction of external magnetic fields with the atomic scale defects intrinsic to the semiconductor. Unlike heritage designs, the magnetometer does not require inductive sensing elements, high frequency radio, and/or optical circuitry and can be made significantly more compact and lightweight, thus enabling missions leveraging swarms of cubesats capable of science returns not possible with a single large-scale satellite. Additionally, the robustness of the SiC semiconductor allows for operation in extreme conditions such as the hot Venusian surface and the high radiation environment of the Jovian system.
Separdar, L.; Davatolhagh, S.
2016-12-01
Molecular dynamics simulations at constant (N , V , T) are used to study the mutual effects of gold nanoparticles on the structure and dynamics of Kob-Andersen binary Lennard-Jones (BLJ) liquid within the framework of mode coupling theory of dynamic glass transition in the reciprocal space. The results show the 'softening' effect of the gold nanoparticles on the liquid dynamics in terms of (i) reducing the mode coupling crossover temperature Tc with respect to that of the bulk BLJ (i.e. BLJ without nanoparticles), (ii) decreasing the time interval of β-relaxation, and (iii) decreasing the exponent γ characterizing the power-law behavior of the α-relaxation time. This softening effect is explained in terms of the van der Waals attraction between the gold atoms comprising the nanoparticle and the BLJ host atoms, such that adsorption of host atoms onto the nanoparticle surface creates more space or free-volume for the other atoms to diffuse. By the same token interactions of purely excluded-volume-type are expected to result in the opposite effect. It is also noted that, much unlike BLJ host particles, the dynamics of gold nanoparticles is much less dependent on the wave-vector and that it exhibits a nearly exponential behavior in the α-relaxation regime.
The Momentum 4-Vector in Bulk Viscous Bianchi Type-V Space-time
Aydogdu, O; Aydogdu, Oktay; Salti, Mustafa
2006-01-01
Using the Einstein and Bergmann-Thomson prescriptions, the energy and momentum distributions for the Bianchi type-V bulk viscous space-time are evaluated in both general relativity and the teleparallel gravity (the tetrad theory of gravity). It is shown that for the Bianchi type-V bulk viscous solution, the energy and momentum due to matter and fields including gravity are the same in both the methods used. This paper indicates an important point that these energy-momentum definitions agree with each other not only in general relativity but also in teleparallel gravity and sustains the results obtained by some physicist who show that the energy-momentum definitions of Einstein, Landau-Lifshitz, Papapetrou, Weinberg, Penrose and Bergmann-Thomson complexes give the same energy expression in general relativity.
The generalized vector convex-like mappings on real linear spaces%实线性空间中的广义向量类凸性
Institute of Scientific and Technical Information of China (English)
余国林; 刘三阳
2008-01-01
By using the concept of vector closure,a property of the generalized vector convexlike maps on real linear spaces is presented and it is showed that the Slater constraint qualification for vector optimization holds if the constraint mapping is the generalized vector convexlike. Furthermore, characterization of proper effi-ciency is established in terms of saddle-point criterion.%作者利用向量闭包给出了实线性空间上广义向量类凸映射的一个性质,并依此说明在向量优化问题中,如果约束映射是广义向量类凸的则Slater约束品性成立.另外,作者利用鞍点准则刻画了实线性空问中的真有效性.
Energy Technology Data Exchange (ETDEWEB)
Garcia Lopez, Manuel
2001-10-15
This work describes the design and implementation of an open loop speed controller for an induction motor. This controller is based on a DSP TMS320F240 chip from Texas Instruments. Speed control is achieved by maintaining the magnetic flux constant through the regularization of stator voltage/frequency relationship. Voltage and frequency variation are achieved using the strategy of pulse width modulation with space vectors. Hardware design is presented (current source and the printed circuit for the intelligent power module) and the software (control algorithms and the modulation strategy using space vectors). The algorithms given were implement using the TMS320F240 language. [Spanish] Este trabajo describe el diseno y la implementacion de un control de la velocidad en lazo abierto de un motor de induccion, basado en el DSP TMS320F240 de Texas Instruments. El control de la velocidad se logra manteniendo el flujo en el entre hierro constante, lo cual es realizado al regular el valor de la relacion voltaje/frecuencia en el estator. La variacion del voltaje y la frecuencia se realiza utilizando la estrategia de modulacion del ancho de los pulsos con vectores espaciales. Se presenta el diseno de los circuitos (fuente de corriente continua y circuito impreso para el modulo inteligente de potencia) y de los programas (algoritmos de control y de la estrategia de modulacion con vectores espaciales) necesarios que se utilizaron durante la implementacion del accionamiento del motor. Los algoritmos dados fueron implementados en el lenguaje ensamblador del TMS320F240.
On the stability of the first order linear recurrence in topological vector spaces
Moslehian, Mohammad Sal
2010-01-01
Suppose that $\\mathcal{X}$ is a sequentially complete Hausdorff locally convex space over a scalar field $\\mathbb{K}$, $V$ is a bounded subset of $\\mathcal{X}$, $(a_n)_{n\\ge 0}$ is a sequence in $\\mathbb{K}\\setminus\\{0\\}$ with the property\\ $\\ds\\liminf_{n\\to\\infty} |a_n|>1$ and $(b_n)_{n\\ge 0}$ is a sequence in $\\mathcal{X}$. We show that for every sequence $(x_n)_{n\\ge 0}$ in $\\mathcal{X}$ satisfying \\begin{eqnarray*} x_{n+1}-a_nx_n-b_n\\in V\\q(n\\geq 0) \\end{eqnarray*} there exists a unique sequence $(y_n)_{n\\ge 0}$ satisfying the recurrence $y_{n+1}=a_ny_n+b_n\\,\\,(n\\geq 0)$ and for every $q$ with $1
Research and Realization of Space Vector Information Progressive Transmission%空间矢量信息渐进传输研究与实现
Institute of Scientific and Technical Information of China (English)
杨素悦
2012-01-01
In order to solve the problem of transfering a great deal of space vector data, this paper puts forward a solution of space vector information progressive transmission. It expounds the basic idea of space vector information progressive transmission which includes space vector information of integration, selection, summarization, simplification, and designs the saving mode of database. From the progressive transmission realization of Guangdong administrative map, it proves that the method can make the user have no network delay feeling, when it disposes the processing of data transmission, and reduces the occupied network bandwidth.%为解决大量空间矢量数据的传输问题,提出一种空间矢量信息渐进传输解决方法.阐述空间矢量信息渐进传输的基本思想,包括空间矢量信息的综合、选取、概括、简化,设计数据库存储模式.以广东省行政区域图渐进传输的实现,证明该方法在处理大数据量传输时能使用户无网络延时感,且减少占用的网络带宽.
Directory of Open Access Journals (Sweden)
Ehab Malkawi
2014-01-01
Full Text Available The classical free Lagrangian admitting a constant of motion, in one- and two-dimensional space, is generalized using the Caputo derivative of fractional calculus. The corresponding metric is obtained and the fractional Christoffel symbols, Killing vectors, and Killing-Yano tensors are derived. Some exact solutions of these quantities are reported.
基于向量空间的中文概念检索技术研究%Research on the Vector Space- based Chinese Concept Retrieval Technology
Institute of Scientific and Technical Information of China (English)
罗威
2003-01-01
Concept retrieval can achieve better results as it deals with the user's request on the concept level. This article introduces the vector space-based concept retrieval technology. Firstly, it explains why this technology is adopted. Then, it describes how to implement this technology. Finally, the article puts forward some measures to improve retrieval performance.
Al-Naseem, Osama Abdulrahman
A novel multilevel matrix converter is developed to efficiently transfer energy between a three-phase variable-speed generator of a wind turbine and a three-phase ac utility network. Optimizing the energy transfer efficiency at light load is critical in variable-speed wind generators. Laboratory experiment suggests that converter efficiency at light load may be increased via soft-switching and multilevel switching techniques. The new converter includes the advantages of multilevel converters, such as reduced harmonic content, increased power handling capability without additional switching loss, and high efficiency at low machine voltages. It also features the characteristics of conventional matrix converters, such as space vector control and improved efficiency via auxiliary resonant commutation soft-switching techniques. Similar to a conventional matrix converter, the novel multilevel matrix converter uses a nine-switch matrix with four-quadrant switches to connect input phases at one side of the converter with output phases at the other side of the converter. However, the switches of the new converter are configured differently from those used in the conventional matrix converter. Each switch of the new converter is a cell that resembles a full-bridge inverter topology and can assume three voltage levels while used. Semiconductor devices in a switch cell are always clamped to a known constant do voltage of a capacitor. This is a typical characteristic of multilevel converters where device voltage stresses are reduced by clamping the main transistor voltages to low levels. With reduced voltage stresses, switching frequency can be increased to allow for reduced size of filter magnetics. Unlike conventional matrix converter, the multilevel matrix converter uses inductors on both input and output sides of the converter. This symmetry allows for both step up and step down operations. Each switch cell features double the power handling capability compared to the four
Robinson, Gilbert de B
2011-01-01
This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom
Directory of Open Access Journals (Sweden)
Lesyani Teresa León Viltre
2015-04-01
Full Text Available El gran desarrollo de la automatización industrial, como resultado de la modernización y el progreso de los equipos con microprocesador y electrónica de potencia, ha hecho que las cargas en la actualidad sean más sensibles a las caídas de tensión de corta duración. Estos trastornos, incluso en tiempos muy cortos, pueden detener procesos enteros causando enormes pérdidas. Por esta razón en el presente trabajo se propone un Restaurador Dinámico de Tensión (dynamic voltaje restorer- DVR, para mantener la operación ininterrumpida de una carga industrial, sensible a huecos de tensión. El control propuesto para el DVR está basado en la transformada de Fourier del vector espacial (space vector Fourier transform- SVFT. El vector controlado es implementado en los ejes de referencia estacionarios alfa y beta. Se obtienen resultados satisfactorios ante señales distorsionadas. Se realizan simulaciones en el Matlab del sistema propuesto para huecos de tensión balanceados y desbalanceados. The great development of industrial automation, as a result of modernization and progress of equipment with microprocessor and power electronics has made loads now more sensitive to voltage drops. These disorders, even in very short time, can stop the whole process causing huge losses. For this reason a dynamic voltage restorer (DVR is proposed in this paper for keeping uninterrupted operation of sensitive industrial load during voltages sags. The proposed DVR controller is based on the Space Vector Fourier Transform (SVFT. The vector controller is implemented in the stationary reference frames. Satisfactory results are obtained for distorted signals.The proposed system is simulated in Matlab for voltage dips balanced and unbalanced.
Forecasting Exchange Rates with Commodity Convenience Yields
Beutler, Toni
2012-01-01
This paper investigates whether commodity convenience yields - the yields that accrue to the holders of physical commodities - can predict the exchange rate of commodity-exporters' currencies. Predictability is a consequence of the fact that i) convenience yields are useful predictors for commodity prices and ii) commodity currencies have a strong relationship with commodity prices. The empirical evidence indicates that there is a significant relationship between aggregate measures of conveni...
Energy Technology Data Exchange (ETDEWEB)
Wu, Fengjun, E-mail: wufengjun@impcas.ac.cn [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Cui, Yuan [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yan, Hongbin [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Zhang, Huajian [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Bin [University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohui [Institute of Modern Physics, CAS, Lanzhou 730000 (China)
2016-08-01
To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply. - Highlights: • Applying SVPWM rectification technology in an accelerator power supply improves its grid-side performance. • New Topology and its control strategies make an accelerator power supply have bidirectional power flow ability. • Hardware and software of controller provide a good reference for design of this new type of power supply.
Wu, Fengjun; Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen; Cui, Yuan; Yan, Hongbin; Zhang, Huajian; Wang, Bin; Li, Xiaohui
2016-08-01
To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply.
Directory of Open Access Journals (Sweden)
Hassan Farhan Rashag
2013-04-01
Full Text Available Various aspects related to controlling induction motor are investigated. Direct torque control is an original high performance control strategy in the field of AC drive. In this proposed method, the control system is based on Space Vector Modulation (SVM, amplitude of voltage in direct- quadrature reference frame (d-q reference and angle of stator flux. Amplitude of stator voltage is controlled by PI torque and PI flux controller. The stator flux angle is adjusted by rotor angular frequency and slip angular frequency. Then, the reference torque and the estimated torque is applied to the input of PI torque controller and the control quadrature axis voltage is determined. The control d-axis voltage is determined from the flux calculator. These q and d axis voltage are converted into amplitude voltage. By applying polar to Cartesian on amplitude voltage and stator flux angle, direct voltage and quadratures voltage are generated. The reference stator voltages in d-q are calculated based on forcing the stator voltage error to zero at next sampling period. By applying inverse park transformation on d-q voltages, the stator voltages in &alpha and &beta frame are generated and apply to SVM. From the output of SVM, the motor control signal is generated and the speed of the induction motor regulated toward the rated speed. The simulation Results have demonstrated exceptional performance in steady and transient states and shows that decrease of torque and flux ripples is achieved in a complete speed range.
Indian Academy of Sciences (India)
Gopalakrishnan K S; G Narayanan
2015-08-01
The voltage ripple and power loss in the DC-capacitor of a voltage source inverter depend on the harmonic currents flowing through the capacitor. This paper presents a double Fourier series based analysis of the harmonic contents of the DC capacitor current in a three-level neutral-point clamped (NPC) inverter, modulated with sine-triangle pulse-width modulation (SPWM) or conventional space vector pulse-width modulation (CSVPWM) schemes. The analytical results are validated experimentally on a 3-kVA three-level inverter prototype. The capacitor current in an NPC inverter has a periodicity of 120º at the fundamental or modulation frequency. Hence, this current contains third-harmonic and triplen-frequency components, apart from switching frequency components. The harmonic components vary with modulation index and power factor for both PWM schemes. The third harmonic current decreases with increase in modulation index and also decreases with increase in power factor in case of both PWM methods. In general, the third harmonic content is higher with SPWM than with CSVPWM at a given operating condition. Also, power loss and voltage ripple in the DC capacitor are estimated for both the schemes using the current harmonic spectrum and equivalent series resistance (ESR) of the capacitor.
Khan, Mansoor; Yong, Wang; Mustafa, Ehtasham
2017-07-01
After the rapid advancement in the field of power electronics devices and drives for last few decades, there are different kinds of Pulse Width Modulation techniques which have been brought to the market. The applications ranging from industrial appliances to military equipment including the home appliances. The vey common application for the PWM is three phase voltage source inverter, which is used to convert DC to AC in the homes to supply the power to the house in case electricity failure, usually named as Un-interrupted Power Supply. In this paper Space Vector Pulse Width Modulation techniques is discussed and analysed under the control technique named as Field Oriented Control. The working and implementation of this technique has been studied by implementing on the three phase bridge inverter. The technique is used to control the Permanente Magnet Synchronous Motor. The drive system is successfully implemented in MATLAB/Simulink using the mathematical equation and algorithm to achieve the satisfactory results. PI type of controller is used to tuned ers of the motothe parametr i.e. torque and current.
Research on Space Vector PWM Based on RBF Neural Network%基于RBF神经网络的SVPWM研究
Institute of Scientific and Technical Information of China (English)
宣光银; 胡丹; 车畅
2011-01-01
论述了电压空间矢量脉宽调制( SVPWM)的基本原理,提出利用径向基(RBF)网络实现SVPWM的方法；并在Matlab下结合神经网络工具箱进了仿真研究.仿真结果表明,RBF-SVPWM收敛速度快、误差精度高,使用该方法建立的异步电动机控制系统具有更小的定子电流谐波和转矩脉动.%The basic principle of space voltage vector PWM was discussed,and a new algorithm for SVPWM based on radial basis function neural network( RBF-SVPWM) was proposed. The emulation of RBF-SVPWM was carried out in Mat-lab together with Nntoolbox. The results indicate that RBF-SVPWM has a fast convergence and high accurate error,and the induction motor control system using RBF-SVPWM also has less stator current harmonics and torque pulsation.
Convenience food products. Drivers for consumption.
Brunner, Thomas A; van der Horst, Klazine; Siegrist, Michael
2010-12-01
Convenience is one of the big trends in the food business. The demand for convenience food products is steadily increasing; therefore, understanding convenience food consumption is an important issue. Despite being vital properties of convenience food, saving time and effort have not been very successful constructs for predicting convenience food consumption. To examine a wide range of possible drivers for convenience food consumption, the present study uses a convenience food frequency questionnaire that asks about consumption behavior. A paper-and-pencil questionnaire was sent out to a representative sample of people in German-speaking Switzerland and yielded N = 918 complete datasets from persons mainly responsible for buying and preparing food in the household. The various convenience food products could be categorized into four groups, which we labeled as highly processed food items, moderately processed food items, single components, and salads. Fifteen drivers were found to have a significant impact either on total convenience consumption or on one of the identified categories. Strong predictors were age, concern about naturalness, nutrition knowledge, and cooking skills.
More than Just Convenient: The Scientific Merits of Homogeneous Convenience Samples
Jager, Justin; Putnick, Diane L.; Bornstein, Marc H.
2017-01-01
Despite their disadvantaged generalizability relative to probability samples, non-probability convenience samples are the standard within developmental science, and likely will remain so because probability samples are cost-prohibitive and most available probability samples are ill-suited to examine developmental questions. In lieu of focusing on how to eliminate or sharply reduce reliance on convenience samples within developmental science, here we propose how to augment their advantages when it comes to understanding population effects as well as subpopulation differences. Although all convenience samples have less clear generalizability than probability samples, we argue that homogeneous convenience samples have clearer generalizability relative to conventional convenience samples. Therefore, when researchers are limited to convenience samples, they should consider homogeneous convenience samples as a positive alternative to conventional or heterogeneous) convenience samples. We discuss future directions as well as potential obstacles to expanding the use of homogeneous convenience samples in developmental science. PMID:28475254
Bouhali, O.; Francois, B.; Berkouk, E. M.; Saudemont, C.
2005-07-01
This paper presents a simple and general direct modulation strategy that enables to copy directly modulated waveforms onto output voltages of a multilevel three-phase Diode Clamped Inverter (DCI). A general modelling of this converter is presented. A space vector scheme is developed without using Park transforms. Based on this algorithm, the location of the reference voltage vector is determined and the voltage vectors for the modulation are deduced. Simultaneously, their durations are calculated. The proposed algorithm is general and can be directly applied to a (n+1) levels inverter independently on its topology (Diode Clamped Inverter, Neutral Point Clamped, Flying Capacitor Inverter...). To verify this algorithm, both control algorithms of a 5-level DCI and a 11-level DCI are considered and simulation results are given.
Tsang, Leung; Ding, Kung-Hau
1991-01-01
Complete polarimetric signatures of a layer of random, nonspherical discrete scatterers overlying a homogeneous half space are studied with the first- and second-order solutions of the vector radiative transfer theory. Some of the salient features of the numerical results are as follows: (1) the inclusion of the nondiagonal extinction matrix in the vector radiative transfer theory accounts for an appreciable phase difference between vv and hh polarizations, particularly for aligned scatterers; (2) the ensemble-averaged scattered Stokes vector is generally partially polarized, with the degree of polarization less than unity; (3) there generally exists a pedestal in the copolarization return when plotted as a function of ellipticity and orientation angles, which may be due to heterogeneity of scattering objects and/or multiple scattering effects; and (4) multiple scattering effects generally enhance the pedestal in copolarization return, decrease the degree of polarization, affect phase difference, and also enhance the depolarization return.
Thrall, Robert M
2011-01-01
This volume is suitable as a primary or supplementary text for college-level courses in linear algebra. It possesses the distinct advantage of approaching the subject simultaneously at two levels, the concrete and the axiomatic. Students thus receive the benefits of axiom-based mathematical reasoning as well as a grasp of concrete formulations. 1957 edition.
Convenience foods. What, why, and when.
Scholliers, Peter
2015-11-01
An attempt is made to assess the academic interest in convenience foods in the past decades in order to introduce this special section on historical dimensions of convenience foods, prepared by FOST, a unit that investigates the history and culture of food (up to today). First, the rise of academic interest is trailed since the appearance of the concept in the 1920s and, next, themes in connection to this interest are considered (e.g., time, health, or gender). Then, definitions of convenience foods are tracked since the 1950s, which leads to suggesting a clear focus (linking convenience foods to home cooking of meals and industrially produced foods). The conclusion stresses the changing definition of the concept, as well as the need to gain historical insight in present-day issues related to convenience foods.
基于空间矢量调制的直接转矩控制%Direct torque control based on space vector modulation
Institute of Scientific and Technical Information of China (English)
景晓东; 高赟; 李燕涛; 王坤
2013-01-01
针对传统的直接转矩控制存在较大的转矩和磁链脉动问题,提出了一种基于空间矢量调制的直接转矩控制策略.该控制策略采用磁链、转矩PI控制器代替传统直接转矩控制系统中的滞环比较器,以空间矢量脉宽调制代替电压矢量开关表合成电压矢量,来补偿磁链误差和转矩误差,达到消除滞环脉动的目的.Matlab/Simulink仿真结果表明,基于空间矢量调制的电动机控制系统相对于传统的直接转矩控制系统,磁链轨迹更接近圆形,转矩、磁链和电流响应脉动更小.%In view of problems of big ripple of torque and flux linkage of traditional direct torque control,the paper proposed a control strategy of direct torque control based on space vector modulation.The control strategy uses flux and torque PI controller to instead of hysteresis comparator of traditional direct torque control system,and adopts space vector pulse width modulation to instead of voltage vector switch to synthetic voltage vector which can compensate for flux error and torque error to avoid hysteresis ripple.The Matlab/Simulink simulation result shows that the flux truck of control system of motor based on space vector pulse width modulation is more closed to round,and its torque and flux and current ripple is smaller compared with the traditional direct torque control system.
Milione, Giovanni; Huang, Hao; Ren, Yongxiong; Xie, Guodong; Nguyen, Thien An; Karimi, Ebrahim; Marrucci, Lorenzo; Nolan, Daniel A; Alfano, Robert R; Willner, Alan E
2014-01-01
Vector modes are spatial modes that have spatially inhomogeneous states of polarization, such as, radial and azimuthal polarization. They can produce smaller spot sizes and stronger longitudinal polarization components upon focusing. As a result, they are used for many applications, including optical trapping and nanoscale imaging. In this work, vector modes are used to increase the information capacity of free space optical communication via the method of optical communication referred to as mode division multiplexing. A mode (de)multiplexer for vector modes based on a liquid crystal technology referred to as a q-plate is introduced. As a proof of principle, using the mode (de)multiplexer four vector modes each carrying a 20 Gbit/s quadrature phase shift keying signal on a single wavelength channel (~1550nm), comprising an aggregate 80 Gbit/s, were transmitted ~1m over the lab table with <-16.4 dB (<2%) mode crosstalk. Bit error rates for all vector modes were measured at the forward error correction t...
Directory of Open Access Journals (Sweden)
P. Saravanan
2014-05-01
Full Text Available This research study mainly focuses on using an efficient control strategy for extracting reference currents of shunt active filters under non linear load conditions. In recent decades, the utilization of highly automatic electric equipments has resulted in enormous economic loss. Thus, the power suppliers as well as the power consumers are very much concerned about the power quality issues and compensation approaches. In order to deal with this issue, Active Power Filter (APF has been considered as an attractive solution due to its significant harmonic compensation. But, the performance of APF is not consistent and is varies based on the output of the controller techniques. An efficient (id-id control strategy is used in this approach for attaining utmost profit from grid-interfacing inverters installed in transmission systems. The voltages are controlled through the PI controller which is further tuned by an optimization approach. Bacterial Forge Optimization (BFO is used in this approach for tuning the PI controller for the optimal value. The inverter used in this approach can be considered as a Shunt Active Power Filter (SAPF to compensate non linear load current harmonics. In order to improve the overall performance of the system, Space Vector Pulse Width Modulation (SVPWM is used in this proposed approach which regulates power frequency and produces good circularity through DC-AC part. SVPWM also eliminates the 3rd order harmonics and minimizes the 5th order harmonics effectively. The integration of (id-id control strategy and SVPWM has been proposed in this research study. Simulation results are carried out in MATLAB/Simulink and the performance of the proposed approach is compared with other control strategies. This research studies shows unique approach for attaining maximum benefits from RES with suppression of current harmonics.
Institute of Scientific and Technical Information of China (English)
JIANG Jingfei; ZHANG Jianqiu
2012-01-01
In this paper,the source localization by utilizing the measurements of a single electromagnetic (EM) vector-sensor is investigated in the framework of the geometric algebra of Euclidean 3-space.In order to describe the orthogonality among the electric and magnetic measurements,two multivectors of the geometric algebra of Euclidean 3-space (G3) are used to model the outputs of a spatially collocated EM vector-sensor.Two estimators for the wave propagation vector estimation are then formulated by the inner product between a vector and a bivector in the G3.Since the information used by the two estimators is different,a weighted inner product estimator is then proposed to fuse the two estimators together in the sense of the minimum mean square error (MMSE).Analytical results show that the statistical performances of the weighted inner product estimator are always better than its traditional cross product counterpart.The efficacy of the weighted inner product estimator and the correctness of the analytical predictions are demonstrated by simulation results.
Mück, W
1998-01-01
We use the AdS/CFT correspondence to calculate CFT correlation functions of vector and spinor fields. The connection between the AdS and boundary fields is properly treated via a Dirichlet boundary value problem.
Notification: Purchase Card and Convenience Check Audit
Project #OA-FY13-0116, April 11, 2013. The U.S. Environmental Protection Agency, Office of Inspector General, is beginning the fieldwork phase of its audit of the agency’s purchase card and convenience check programs.
Measuring consumer perceptions of online shopping convenience
Ferreira, Margarida Bernardo
2016-01-01
The aim of this master thesis is to identify which dimensions of convenience affect consumers’ intention of using online shopping. Also it explores a conceptual model to measuring consumer perceptions of online shopping convenience. This paper contains prospects about online consumer behavior, and the results have important implications for retailers, managers and marketers, related to online shopping strategies. An empirical investigation was carried out to test the hypotheses. In order t...
Extended Mixed Vector Equilibrium Problems
Directory of Open Access Journals (Sweden)
Mijanur Rahaman
2014-01-01
Full Text Available We study extended mixed vector equilibrium problems, namely, extended weak mixed vector equilibrium problem and extended strong mixed vector equilibrium problem in Hausdorff topological vector spaces. Using generalized KKM-Fan theorem (Ben-El-Mechaiekh et al.; 2005, some existence results for both problems are proved in noncompact domain.
Kojima, Kaname; Imoto, Seiya; Yamaguchi, Rui; Fujita, André; Yamauchi, Mai; Gotoh, Noriko; Miyano, Satoru
2012-01-01
In the analysis of effects by cell treatment such as drug dosing, identifying changes on gene network structures between normal and treated cells is a key task. A possible way for identifying the changes is to compare structures of networks estimated from data on normal and treated cells separately. However, this approach usually fails to estimate accurate gene networks due to the limited length of time series data and measurement noise. Thus, approaches that identify changes on regulations by using time series data on both conditions in an efficient manner are demanded. We propose a new statistical approach that is based on the state space representation of the vector autoregressive model and estimates gene networks on two different conditions in order to identify changes on regulations between the conditions. In the mathematical model of our approach, hidden binary variables are newly introduced to indicate the presence of regulations on each condition. The use of the hidden binary variables enables an efficient data usage; data on both conditions are used for commonly existing regulations, while for condition specific regulations corresponding data are only applied. Also, the similarity of networks on two conditions is automatically considered from the design of the potential function for the hidden binary variables. For the estimation of the hidden binary variables, we derive a new variational annealing method that searches the configuration of the binary variables maximizing the marginal likelihood. For the performance evaluation, we use time series data from two topologically similar synthetic networks, and confirm that our proposed approach estimates commonly existing regulations as well as changes on regulations with higher coverage and precision than other existing approaches in almost all the experimental settings. For a real data application, our proposed approach is applied to time series data from normal Human lung cells and Human lung cells treated by
The convenience food market in Great Britain: convenience food lifestyle (CFL) segments.
Buckley, Marie; Cowan, Cathal; McCarthy, Mary
2007-11-01
Convenience foods enable the consumer to save time and effort in food activities, related to shopping, meal preparation and cooking, consumption and post-meal activities. The objective of this paper is to report on the attitudes and reported behaviour of food consumers in Great Britain based on a review of their convenience food lifestyle (CFLs). The paper also reports the development and application of a segmentation technique that can supply information on consumer attitudes towards convenience foods. The convenience food market in Great Britain is examined and the key drivers of growth in this market are highlighted. A survey was applied to a nationally representative sample of 1000 consumers (defined as the persons primarily responsible for food shopping and cooking in the household) in Great Britain in 2002. Segmentation analysis, based on the identification of 20 convenience lifestyle factors, identified four CFL segments of consumers: the 'food connoisseurs' (26%), the 'home meal preparers' (25%), the 'kitchen evaders' (16%) and the 'convenience-seeking grazers' (33%). In particular, the 'kitchen evaders' and the 'convenience-seeking grazers' are identified as convenience-seeking segments. Implications for food producers, in particular, convenience food manufacturers are discussed. The study provides an understanding of the lifestyles of food consumers in Great Britain, and provides food manufacturers with an insight into what motivates individuals to purchase convenience foods.
Papanyan, Valeri; Oshle, Edward; Adamo, Daniel
2008-01-01
Measurement of the jettisoned object departure trajectory and velocity vector in the International Space Station (ISS) reference frame is vitally important for prompt evaluation of the object s imminent orbit. We report on the first successful application of photogrammetric analysis of the ISS imagery for the prompt computation of the jettisoned object s position and velocity vectors. As post-EVA analyses examples, we present the Floating Potential Probe (FPP) and the Russian "Orlan" Space Suit jettisons, as well as the near-real-time (provided in several hours after the separation) computations of the Video Stanchion Support Assembly Flight Support Assembly (VSSA-FSA) and Early Ammonia Servicer (EAS) jettisons during the US astronauts space-walk. Standard close-range photogrammetry analysis was used during this EVA to analyze two on-board camera image sequences down-linked from the ISS. In this approach the ISS camera orientations were computed from known coordinates of several reference points on the ISS hardware. Then the position of the jettisoned object for each time-frame was computed from its image in each frame of the video-clips. In another, "quick-look" approach used in near-real time, orientation of the cameras was computed from their position (from the ISS CAD model) and operational data (pan and tilt) then location of the jettisoned object was calculated only for several frames of the two synchronized movies. Keywords: Photogrammetry, International Space Station, jettisons, image analysis.
Roche, John
1997-01-01
Suggests an approach to teaching vectors that promotes active learning through challenging questions addressed to the class, as opposed to subtle explanations. Promotes introducing vector graphics with concrete examples, beginning with an explanation of the displacement vector. Also discusses artificial vectors, vector algebra, and unit vectors.…
Tiled vector data model for the geographical features of symbolized maps
Zhu, Haihong; Li, You; Zhang, Hang
2017-01-01
Electronic maps (E-maps) provide people with convenience in real-world space. Although web map services can display maps on screens, a more important function is their ability to access geographical features. An E-map that is based on raster tiles is inferior to vector tiles in terms of interactive ability because vector maps provide a convenient and effective method to access and manipulate web map features. However, the critical issue regarding rendering tiled vector maps is that geographical features that are rendered in the form of map symbols via vector tiles may cause visual discontinuities, such as graphic conflicts and losses of data around the borders of tiles, which likely represent the main obstacles to exploring vector map tiles on the web. This paper proposes a tiled vector data model for geographical features in symbolized maps that considers the relationships among geographical features, symbol representations and map renderings. This model presents a method to tailor geographical features in terms of map symbols and ‘addition’ (join) operations on the following two levels: geographical features and map features. Thus, these maps can resolve the visual discontinuity problem based on the proposed model without weakening the interactivity of vector maps. The proposed model is validated by two map data sets, and the results demonstrate that the rendered (symbolized) web maps present smooth visual continuity. PMID:28475578
Revealing the values behind convenience food consumption.
Botonaki, Anna; Mattas, Konstadinos
2010-12-01
The increasing importance of convenience in consumer food choices has attracted researchers' interest. In the effort to understand how convenience affects consumers' food preferences, values are believed to play an important role. The present study attempts to examine the way personal values suggested by Schwartz (1992) are associated with behaviour and attitudes regarding convenience food. A number of constructs describing food related attitudes and behaviours were developed and their relationship with personal values was analyzed following the methodology proposed by Brunsø, Scholderer, and Grunert (2004). Data were collected through a questionnaire survey from a random sample of consumers in Thessaloniki city, Greece. The results reveal that convenience food consumption and convenience orientation in the food domain are mainly connected with values that motivate people to seek new experiences, act independently and enhance their own personal interests, while are in conflict with values of conservation and self-transcendence. The opposite holds for other food related attitudes and behaviours like involvement with cooking and variety in diet. The findings seem to be of particular interest not only for marketers of food products, but also for food policy makers.
Directory of Open Access Journals (Sweden)
Weiran Wang
2013-06-01
Full Text Available In order to improve the performance of bearingless brushless DC motor, a closed-loop suspended force controller combining the discrete space voltage vector modulation is applied and the direct torque control is presented in this paper. Firstly, we increase the number of the control vector to reduce the torque ripple. Then, the suspending equation is constructed which is spired by the direct torque control algorithm. As a result, the closed-loop suspended force controller is built. The simulated and experimental results evaluate the performance of the proposed method. The more advantage is that the proposed algorithm can achieve the fast torque response, reduce the torque ripple, and follow ideal stator flux track. Furthermore, the motor which implants the closed-loop suspended force controller cannot onlyobtain the dynamic response rapidly and displacement control accurately, but also has the characteristics of bearingless brushless DC motor (such as simple structure, high energy efficiency, small volume and low failure rate.
Vector-space-model text categorization method based on quotient space theory%基于商空间的向量空间模型文本分类方法
Institute of Scientific and Technical Information of China (English)
黄剑韬
2011-01-01
为了降低基于向量空间模型(VSM)的文本分类方法的向量维数,并减少噪声对分类的影响,现利用商空间的粒度理论对基于VSM的分类模型进行改进,提出了一种基于商空间的新的VSM分类方法,该方法降低了基于VSM文本分类的向量维数,提高了不同文本之间的辨别能力.%To reduce the vector dimension of Text Categorization (TC) based on Vector Space Model (VSM) and the impact of noise on classification, by using granularity computing based on quotient space theory, the authors provided a new method text categorization based on quotient space theory. The experimental results show the method reduces the vector dimension of text categorization based on VSM and increases the discriminating ability among different texts.
On Generalized Vector Equilibrium Problems
Institute of Scientific and Technical Information of China (English)
An-hua Wan; Jun-yi Fu; Wei-hua Mao
2006-01-01
A new generalized vector equilibrium problem involving set-valued mappings and the proper quasi-concavity of set-valued mappings in topological vector spaces are introduced; its existence theorems and the convexity of the solution sets are established.
Influence of convenience on healthy food choice
DEFF Research Database (Denmark)
Mueller Loose, Simone; Peschel, Anne; Grebitus, Carola
Although seafood is considered to be a healthy food choice, the recommended consumption level of two servings per week is still not reached in most countries. Previous research has identified potential barriers of seafood consumption, including purchase and consumption convenience, but it is still...... for policy makers as well as seafood marketers and are in line with the presented literature in that convenience seems to be an important driver which can be manipulated in order to increase seafood consumption. Consumers strongly prefer the ‘ready to eat’ half shell open oysters over closed oysters...
Yang, Fengping; Xiao, Fangfei
2017-03-01
Current control methods include hardware control and software control corresponding to the inherent unbalance problem of neutral point voltage in three level NPC inverter. The hardware control is rarely used due to its high cost. In this paper, a new compound control method has been presented based on the vector method of virtual space and traditional hysteresis control of neutral point voltage, which can make up the shortcoming of the virtual control without the feedback control system of neutral point voltage and the blind area of hysteresis control and control the deviation and wave of neutral point voltage. The accuracy of this method has been demonstrated by simulation.
efficient and convenient synthesis of symmetrical carboxylic ...
African Journals Online (AJOL)
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An efficient and convenient procedure for the synthesis of symmetrical .... solution was stirred for 16 h at 35 °C followed by filtration and washing with ... obtained hydrous zirconia sample was ground to fine powder and immersed in 1 M H2SO4 ..... Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH: Weinheim; 2002.
A convenient synthesis of 6-demethoxycapillarisin
Institute of Scientific and Technical Information of China (English)
Yuan Feng Tong; Shuai Chen; Yong Hao Cheng; Song Wu
2007-01-01
A convenient and effective method for the synthesis of 6-demethoxycapillarisin was described. The highlight was involved in a simple access to the key intermediate 2-ethylthio-5,7-dimethoxy-4H-chromen-4-one from the inexpensive 2,4,6-trihydroxyace-tophenone, using AlCl3 as the demethylation reagent.
Tondu, Bertrand
2003-05-01
The mathematical modelling of industrial robots is based on the vectorial nature of the n-dimensional joint space of the robot, defined as a kinematic chain with n degrees of freedom. However, in our opinion, the vectorial nature of the joint space has been insufficiently discussed in the literature. We establish the vectorial nature of the joint space of an industrial robot from the fundamental studies of B. Roth on screws. To cite this article: B. Tondu, C. R. Mecanique 331 (2003).
Karunaratne, S H P P; Weeraratne, T C; Perera, M D B; Surendran, S N
2013-09-01
Unprecedented incidence of dengue has been recorded in Sri Lanka in recent times. Source reduction and use of insecticides in space spraying/fogging and larviciding, are the primary means of controlling the vector mosquitoes Aedes aegypti and Ae. albopictus in the island nation. A study was carried out to understand insecticide cross-resistance spectra and mechanisms of insecticide resistance of both these vectors from six administrative districts, i.e. Kandy, Kurunegala, Puttalam, Gampaha, Ratnapura and Jaffna, of Sri Lanka. Efficacy of the recommended dosages of frequently used insecticides in space spraying and larviciding in dengue vector control programmes was also tested. Insecticide bioassay results revealed that, in general, both mosquito species were highly resistant to DDT but susceptible to propoxur and malathion except Jaffna Ae. aegypti population. Moderate resistance to malathion shown by Jaffna Ae. aegypti population correlated with esterase and malathion carboxylesterase activities of the population. High levels of acetylcholinesterase (AChE) insensitivity in the absence of malathion and propoxur resistance may be due to non-synaptic forms of AChE proteins. Moderate pyrethroid resistance in the absence of high monooxygenase levels indicated the possible involvement of 'kdr' type resistance mechanism in Sri Lankan dengue vectors. Results of the space spraying experiments revealed that 100% mortality at a 10 m distance and >50% mortality at a 50 m distance can be achieved with malathion, pesguard and deltacide even in a ground with dense vegetation. Pesguard and deltacide spraying gave 100% mortality up to 50 m distance in open area and areas with little vegetation. Both species gave >50% mortalities for deltacide at a distance of 75 m in a dense vegetation area. Larval bioassays conducted in the laboratory showed that a 1 ppm temephos solution can maintain a larval mortality rate of 100% for ten months, and the mortality rate declined to 0% in the
LMMSE Image Denoising Algorithm on Vector Space Model Context%矢量空间上下文模型的LMMSE图像去噪算法研究
Institute of Scientific and Technical Information of China (English)
蔡银珊
2011-01-01
Linear minimum mean square error estimation-LMMSE（wavelet-based multiscale linear minimum mean square-error estimation） is currently a hot topic of wavelet denoising field.Vector space discussed below is the minimum mean square error estimation of the new algorithm.Considering the image more the relationship between layers and the linear MMSE applied to the vector space,blurring the edges of the image denoising have been greatly improved.%线性最小均方误差估计LMMSE（wavelet-based multiscale linear minimum mean squareerror estimation）目前是小波去噪领域的热门课题,讨论了矢量空间的最小均方误差估计的新算法,主要考虑图像各层间的关系,将线性MMSE运用到矢量空间,对去噪图像边缘模糊问题有较大改善。
Vectors and their applications
Pettofrezzo, Anthony J
2005-01-01
Geared toward undergraduate students, this text illustrates the use of vectors as a mathematical tool in plane synthetic geometry, plane and spherical trigonometry, and analytic geometry of two- and three-dimensional space. Its rigorous development includes a complete treatment of the algebra of vectors in the first two chapters.Among the text's outstanding features are numbered definitions and theorems in the development of vector algebra, which appear in italics for easy reference. Most of the theorems include proofs, and coordinate position vectors receive an in-depth treatment. Key concept
Convenience: Så tag på gourmetrestaurant
DEFF Research Database (Denmark)
Grunert, Klaus G.
2006-01-01
Vil De have en særlig oplevelse med convenience food? Så vil jeg anbefale, at De booker et bord på en gourmet-restaurant og bestiller en menu surprise med en tilsvarende vinmenu. Så behøver man slet ikke at lave mad. Man behøver ikke engang at tænke over, hvad man ønsker at spise eller drikke....... Maden bliver serveret for en. Drikkevarerne bliver skænket op. De snavsede tallerkner bliver ryddet væk. Selv servietten bliver foldet ud og lagt på ens skød. Er det ikke det, De forbinder med convenience food? Hvad er det så - pulverkaffe, kagemiks, lørdagskylling? Eller pølsevogn og burgere, når det...
Contract Terminations for Default and Convenience.
1981-06-01
terminations that were converted to convenience ter- minations. Howdyshell’s method (15) was to survey all ASBCA decisions in the selected time period, 1 October...on its own work load. The original research plan also included inquiry of data reported to HQ USAF ( AACC ), Con- tract Finance Office, Comptroller (28...duplicated and mailed for study from Sacramento Air Logistics Center, McClellan AFB. Data Analysis Methods Answers to the two research questions were
VECTOR BUNDLE, KILLING VECTOR FIELD AND PONTRYAGIN NUMBERS
Institute of Scientific and Technical Information of China (English)
周建伟
1991-01-01
Let E be a vector bundle over a compact Riemannian manifold M. We construct a natural metric on the bundle space E and discuss the relationship between the killing vector fields of E and M. Then we give a proof of the Bott-Baum-Cheeger Theorem for vector bundle E.
仅根据Proximity数据构建向量空间模型的方法%An Approach to Constructing Vector Space Models from Proximity Data Alone
Institute of Scientific and Technical Information of China (English)
徐硕; 乔晓东; 朱礼军; 郭怀恩
2011-01-01
In real-world applications, there are lots and lots of abstract research objects that cannot be represented asfeature vectors, therefore many mature data mining and machine learning methods cannot be utilized directly. Nevertheless, it is often not difficult to obtain a proximity matrix, which indicates some "comparison" relationship between objects. To overcome this problem, this study puts forward to obtain corresponding feature vectors for objects only from proximity data matrix by multidimensional scaling (MDS) , that is, to construct a vector space model. Finally, the clustering analysis is conducted on words from Chinese Scientific & Technical Vocabulary System. Experimental results show that the clustering performance from vector space model construction is obviously better than that from clustering analysis directly on proximity data, which verifies the feasibility and efficiency of our approach.%在实际应用中,许多研究对象都是抽象的,难以用某种特征向量的形式表示,这使得许多成熟的数据挖掘和机器学习方法难以被采用.不过,通常可将其转化成一个Proximity数据矩阵,使得矩阵中的元素表示两个对象间某种"比较"关系.针对该问题,本文提出仅根据Proximity数据矩阵利用多维尺度分析法(MDS)将研究对象进行向量化表示,即构建了一种向量空间模型.最后,对汉语科技词系统中的词语进行了聚类分析,结果表明,向量空间模型构建后再聚类的结果明显优于直接针对Proximity数据进行聚类分析的结果,从而验证了该方法的可行性和有效性.
基于模糊滞环空间矢量的变换器控制策略%Fuzzy hysteresis space vector based control scheme for converters
Institute of Scientific and Technical Information of China (English)
孙元岗; 李宏; 石文龙
2015-01-01
采用滞环空间矢量控制的三相电压型变换器电压外环调节主要依赖于传统比例积分(PI)调节器，所以当系统状态或者自身参数变化时，将难以使系统获得满意的动态性能。针对该问题，在电压外环引入模糊PI调节器，根据工程经验在线调整P、I参数，以应对系统变化。同时给出电流内环滞环空间矢量控制中开关状态的选择原则。仿真和实验结果表明，所提控制策略能够有效保证系统稳态性。此外，与采用传统PI调节器的滞环空间矢量控制策略的对比结果表明，所提控制策略可以将变换器的暂态响应时间减少55%以上，使系统获得更为出色的暂态性能。%It is difficult for the classical proportional-integral (PI) regulator employed in the outer voltage loop to satisfy the system performance requirement, when the system states or its parameters are changed in the three-phase voltage source converter using the hysteresis space vector control. The fuzzy based PI regulator is therefore introduced. The coefficients of P and I are adjusted online based on the engineering experience to deal with the system change. A hysteresis space vector control is adopted in the inner current loop. Its principle for selecting the switching states is provided. Finally, the simulation and experiment results show that, the proposed control method can guarantee the system stability effectively. Moreover, compared with the hysteresis space vector control with the classical PI regulator, the proposed control method can reduce the transient setting time more than 55% and ensure the better transient performance.
At-Home Convenience Food Consumption and BMI
Lee, Jonq-Ying; Kilmer, Richard L.
2010-01-01
A variation of the household production theory was used to select relevant explanatory variables for the demand for convenience foods. A convenience food index was used to measure the convenience in food preparation. Because of the nature of the measure of convenience, the tobit regression technique was used to examine the importance of these explanatory variables to the demand for convenience foods. Results show that the presence of children in a household increases the demand for convenienc...
Institute of Scientific and Technical Information of China (English)
Napadol; Sudsom; Kuaanan; Techato; Suwich; Thammapalo; Virasakdi; Chongsuvivatwong; Theerakamol; Pengsakul
2015-01-01
Objective: To examine the resurgence rate, house density index(HDI) and parous rate of the Aedes aegypti vector after space spraying carried out by the routine spraying team,and compare with the rates after standard indoor ultra low volume(SID-ULV) spraying carried out by the trained research spraying team.Methods: Between March and September 2014, a cluster randomized controlled trial including 12 clusters(6 regular ULV, 6 SID-ULV) with totally 4 341 households was conducted, and around 20–31 houses in each cluster were selected for assessment. The parous rate and HDI of collected mosquitoes 2 days before and 1, 2 and 6 days after spraying were obtained and compared.Results: The HDI dropped significantly from the baseline 1 and 2 days after spraying to a non-zero value in the SID-ULV treated locations but not in the regular ULV group locations. However, by 6 days after spraying, the HDI of both groups had returned to the base value measured 2 days before spraying. There were no statistically significant differences in the parous rate between groups.Conclusions: SID-ULV is more effective in reducing Aedes aegypti populations.However, rapid resurgence of dengue vector after spraying in urban areas was observed in both groups.
Institute of Scientific and Technical Information of China (English)
Napadol Sudsom; Kuaanan Techato; Suwich Thammapalo; Virasakdi Chongsuvivatwong; Theerakamol Pengsakul
2015-01-01
Objective:To examine the resurgence rate, house density index (HDI) and parous rate of the Aedes aegypti vector after space spraying carried out by the routine spraying team, and compare with the rates after standard indoor ultra low volume (SID-ULV) spraying carried out by the trained research spraying team. Methods:Between March and September 2014, a cluster randomized controlled trial including 12 clusters (6 regular ULV, 6 SID-ULV) with totally 4 341 households was conducted, and around 20–31 houses in each cluster were selected for assessment. The parous rate and HDI of collected mosquitoes 2 days before and 1, 2 and 6 days after spraying were obtained and compared. Results:The HDI dropped significantly from the baseline 1 and 2 days after spraying to a non-zero value in the SID-ULV treated locations but not in the regular ULV group locations. However, by 6 days after spraying, the HDI of both groups had returned to the base value measured 2 days before spraying. There were no statistically significant differences in the parous rate between groups. Conclusions: SID-ULV is more effective in reducing Aedes aegypti populations. However, rapid resurgence of dengue vector after spraying in urban areas was observed in both groups.
基于SVPWM的VIENNA整流器研究%Study on the VIENNA Rectifier Based on Space Vector Pulse Width Modulation
Institute of Scientific and Technical Information of China (English)
王正; 谭国俊; 曾维俊; 柳萌
2011-01-01
分析了三相三开关三电平(VIENNA)整流器的工作原理,研究了其空间矢量脉宽调制(SVPWM)的实现方法,提出了此整流器的矢量控制策略.采用电压外环和电流内环的双闭环控制,实现了VIENNA整流器的高性能特性.基于Matlab仿真平台,搭建了VIENNA整流器的仿真模型,仿真结果表明,该整流器能实现良好的动态性能和稳态性能.%The working principle of three-phase three-switch three-level (VIENNA) rectifier was analyzed, and its implement method of space vector pulse width modulation (SVPWM) was researched. On that basis, the vector control strategy of VIENNA was proposed. It achieved the high performance characteristics of VIENNA rectifier by using dual closed loop with voltage outer loop and current inner loop. Furthermore, based on the platform of Matlab simulation,the simulation model of VIENNA rectifier was built. The simulation results show that the rectifier can achieve both good dynamic performance and good static performance.
DEFF Research Database (Denmark)
Xiao, Lei; Huang, Shoudao; Lu, Kaiyuan
2013-01-01
Unbalanced grid voltage will cause large dc-bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid-connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load. In this......Unbalanced grid voltage will cause large dc-bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid-connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load....... In this study, a new proportional-integral-resonant (PI-RES) controller-based, space vector modulated direct power control topology is proposed to suppress the dc-bus voltage ripple and in the same time, controlling effectively the instantaneous power of the VSC. A special ac reactive power reference component...
Directory of Open Access Journals (Sweden)
Xing Liu
2016-11-01
Full Text Available A method is proposed for reducing speed ripple of permanent magnet synchronous motors (PMSMs controlled by space vector pulse width modulation (SVPWM. A flux graph and mathematics are used to analyze the speed ripple characteristics of the PMSM. Analysis indicates that the 6P (P refers to pole pairs of the PMSM time harmonic of rotor mechanical speed is the main harmonic component in the SVPWM control PMSM system. To reduce PMSM speed ripple, harmonics are superposed on a SVPWM reference signal. A particle swarm optimization (PSO algorithm is proposed to determine the optimal phase and multiplier coefficient of the superposed harmonics. The results of a Fourier decomposition and an optimized simulation model verified the accuracy of the analysis as well as the effectiveness of the speed ripple reduction methods, respectively.
Ahmed, Waheed; Usman Ali, Syed M.
2013-12-01
We have performed comparative studies of Space Vector Pulse Width Modulation (SVPWM) and Sinusoidal Pulse Width Modulation (SPWM) techniques utilizing MATLAB tools. During these investigations, we carried out intensive simulations, comprehensively analyzed the obtained results and compared the harmonic density, power factor (PF), & switching losses of SVPWM and SPWM. It has been observed during investigations that if the switching frequency is high then losses due to harmonics are negligible, thus based on obtained results we suggested that the SVPWM technique is a more reliable solution. Because SVPWM utilizes DC bus voltage more efficiently, generates less Total Harmonic Distortion (THD) and has higher output quality it provides flexible control of output voltage and output frequency for Variable Speed Drive (VSD).
Sourdough products for convenient use in baking.
Brandt, Markus J
2007-04-01
Sourdough fermentations require a specific knowledge on the effects of process parameters, raw materials and micro-organisms in order to obtain a specific, reproducible sourdough and bread quality. This knowledge is not necessarily available in bakeries. Sourdough starter cultures, either active sourdoughs (Reinzuchtsauerteig) or freeze-dried micro-organisms are used to start sourdough fermentation with the required micro-flora. As sourdough fermentation is a labour-intensive and a time-consuming process, a growing demand for convenient products arised early. First organic acids (lactic acid, acetic acid, citric acid) and mixtures thereof came in use. These agents were used directly without or in combination with a sourdough; however, flavour and taste of the resulting breads were unsatisfactory. Based on modified and optimized traditional sourdough processes, dried, pasty and liquid sourdoughs were developed. Companies which produce such ready-to-use products, claim for a convenient, direct production of baked goods in constant quality, in combination with all advantages of a biological sourdough fermentation, e.g. flavour and taste, fresh keeping and prolonged microbial shelf-life. Currently, a broad variety of sourdough products with different fermented cereals is available on the market. In order to obtain a stable product, it is a necessity to inactivate the sourdough micro-biota by e.g. pasteurization, drying or autosterilization.
电压空间矢量脉宽调制的简单算法%A Simple Algorithm of Voltage Space Vector PWM
Institute of Scientific and Technical Information of China (English)
袁帆
2015-01-01
在电压空间矢量脉宽调制(SVPWM)控制技术原理的基础上，提出了一种简单快速算法，该算法只有普通的四则运算，计算变得非常简单，消除了常规的空间矢量控制算法中由于三角函数和无理数的近似计算而带来的计算误差及影响计算精度和速度的缺点，使结果更加准确。因而更适合应用于基于DSP 的数字化控制。理论分析和大量的MATLAB仿真结果表明，该算法具有谐波含量低、直流电压利用率高的优点。%Based on the the principle of space vector pulse width modulation technology. A novel algorithm of space vector PWM was put forward. The algorithm has only normal arithmetic operations. The algorithm needs only four arith-metic operations ,so that the algorithm may become very easy and it eliminates the calculation errors resulted from the ap-proximate calculation of trigonometric functions and irrational numbers and the defects impacting calculation accuracy and speed ,thus the result would be more precise and be more applicable to the digital control based on DSP,theoretical analy-ses and large numbers of MATLAB simulations have proved that the algorithm has the advantages of little harmonic content and high utilization coefficient of DC voltage.
Institute of Scientific and Technical Information of China (English)
张佩炯
2011-01-01
空间矢量脉宽调制在多电平逆变器的控制中应用广泛,但是随着电平数增加,控制算法渐趋复杂化。提出了三电平空间矢量脉宽调制控制方法,将三电平电压矢量区变换为由两电平空间矢量区构成,从而通过使用两电平空间矢量脉宽调制方法简化了控制算法。该方法理论上可应用于更高电平逆变器的控制中,仿真验证了方法的可行性。%Space vector pulse width modulation is widely applied in control of multi-level inverters, but following increasing of level number, the control algorithm becomes more and more complicated. Three-level space vector pulse width modulation control method was raised to transfer three-level voltage vector zone to two-level space vector zones, so as to simplify the control algorithm with two-level space vector pulse modulation method. The method on the theory can be used to control much higher level inverters and simulation has verified feasibility of the method.
Şenyiğit, M.
2016-09-01
The half-space albedo problem has been solved for a combination of Rayleigh and isotropic scattering using HN method which is developed for the neutron transport studies. The numerical results are compared with exact values obtained using variational method and Chandrasekhar's equation for the {H}-matrix. The analytical solutions of HN method are easy to handle in comparison with the other methods. The numerical results are in good agreement with previous works in literature.
Hoffmann, Banesh
1975-01-01
From his unusual beginning in ""Defining a vector"" to his final comments on ""What then is a vector?"" author Banesh Hoffmann has written a book that is provocative and unconventional. In his emphasis on the unresolved issue of defining a vector, Hoffmann mixes pure and applied mathematics without using calculus. The result is a treatment that can serve as a supplement and corrective to textbooks, as well as collateral reading in all courses that deal with vectors. Major topics include vectors and the parallelogram law; algebraic notation and basic ideas; vector algebra; scalars and scalar p
Newell, Homer E
2006-01-01
When employed with skill and understanding, vector analysis can be a practical and powerful tool. This text develops the algebra and calculus of vectors in a manner useful to physicists and engineers. Numerous exercises (with answers) not only provide practice in manipulation but also help establish students' physical and geometric intuition in regard to vectors and vector concepts.Part I, the basic portion of the text, consists of a thorough treatment of vector algebra and the vector calculus. Part II presents the illustrative matter, demonstrating applications to kinematics, mechanics, and e
DEFF Research Database (Denmark)
Costa, Ana I.A.; Ruijschop, R. M. A. J.
2006-01-01
and the types of meals they eat are surprisingly hard to find. One explanation for this could be that perceived convenience finds little support on the technological attributes of products like ready meals. This study's aim was to uncover significant relations between perceived convenience, meal preparation...... activities and technological attributes of frozen pizzas. Ninety-eight Dutch meal preparers, 18-29 years old, were asked to rate expected convenience attributes of frozen pizzas; (2) prepare and consume these pizzas in a home-like setting; (3) rate experienced convenience after consumption. Pizzas were also...... evaluated on their technological degree of convenience. Two main factors of experienced convenience were uncovered - ease of preparation and speed of preparation. However, only ease of preparation was significantly correlated with technologically-defined and expected convenience. Actual speed of preparation...
Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
Dias, Kealey
or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields....
Complex Polynomial Vector Fields
DEFF Research Database (Denmark)
The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields....
Yan, Limei; Zhang, Lei; Tu, Chuanyi; Marsch, Eckart; Chen, Christopher H K; Wang, Xin; Wang, Linghua; Wicks, Robert T
2016-01-01
Intensive studies have been conducted to understand the anisotropy of solar wind turbulence. However, the anisotropy of Els\\"asser variables ($\\textbf{Z}^\\pm$) in 2D wave-vector space has yet to be investigated. Here we first verify the transformation based on the projection-slice theorem between the power spectral density PSD$_{2D}(k_\\parallel,k_\\perp )$ and the spatial correlation function CF$_{2D} (r_\\parallel,r_\\perp )$. Based on the application of the transformation to the magnetic field and the particle measurements from the WIND spacecraft, we investigate the spectral anisotropy of Els\\"asser variables ($\\textbf{Z}^\\pm$), and the distribution of residual energy E$_{R}$, Alfv\\'en ratio R$_{A}$ and Els\\"asser ratio R$_{E}$ in the $(k_\\parallel,k_\\perp)$ space. The spectra PSD$_{2D}(k_\\parallel,k_\\perp )$ of $\\textbf{B}$, $\\textbf{V}$, and $\\textbf{Z}_{major}$ (the larger of $\\textbf{Z}^\\pm$) show a similar pattern that PSD$_{2D}(k_\\parallel,k_\\perp )$ is mainly distributed along a ridge inclined toward t...
基于向量空间模型的信息检索技术研究%Information retrieval technology based on vector space model
Institute of Scientific and Technical Information of China (English)
刘敏娜
2012-01-01
In order to realize the text classification in information retrieval, the space model algorithm is adopted in this paper. The weight document search results were obtained by means of the documentation testing in the lab, In a retrieval process, the vector space model is used according to the similarity between documents to calculate which one conforms to user's input key words. It has the characteristics of text similarity display according to the weight classification in the information retrieval.%为了能够实现对信息检索中的文本分类策略,采用了空间模型算法,做了实验文档测试,获得了各自的权重文档搜索结果,得到在检索过程中,向量空间模型根据文档之间的相似度,计算哪个文档最符合用户输入的关键字的结论,具有信息检索中文本相似度根据权值大小分类显示的特点.
A dissimilarity based kernel space for support vector machines%基于相异度核空间的支持向量机算法
Institute of Scientific and Technical Information of China (English)
王萌; 孙树栋
2013-01-01
提出基于相异度核空间的混合流形学习与支持向量机(SVMs)算法用于解决高维数据分类问题.该算法使用SVMs对流形学习降维后的低维嵌入做分类.通过加常数方法构造了衡量数据点相异度的特征空间.证明了该特征空间不仅能够衡量数据点之间的相异度,还满足Mercer条件对于支持向量机分类核空间的半正定性的要求.在仿真实验中,采用UCI机器学习数据库上标准分类数据集为样本.对比构造的相异度核空间与常用核函数如线性核、多项式核、高斯核在支持向量机分类时的分类精度来验证有效性和优越性.%A dissimilarity based kernel space for hybrid manifold learning and support vector machines (SVMs) classification algorithm is proposed to solve the high-dimensional data classification problem.The SVMs classify the low-dimensional embedding of the manifold learning method in the algorithm.The dissimilarity based kernel space is constructed by using a constant additive method for SVMs.The constructed kernel space is guaranteed to be positive semi-definite in dissimilarity description and meet the Mercer condition.The simulation compares the kernel space with several common kernel including linear,polynomial and Gaussian kernel on data sets selected from UCI benchmark repository to validate its effectiveness and the dissimilarity based kernel space is an optimized kernel space for hybrid manifold learning and SVMs classification problem.
How convenient!? Adolescents’ vistas on food competences in a convenience context
Wahlen, S.; Horst, van der Hilje; Pothoff, Roosje
2016-01-01
Purpose – Adolescents are at a stage in their life course in which they increasingly become choosers, buyers and preparers of food. Hence, they develop and employ required competences. Current food-related competences of adolescents are shaped in an environment with an abundance of convenience foods
Interpolation of Vector Measures
Institute of Scientific and Technical Information of China (English)
Ricardo del CAMPO; Antonio FERN(A)NDEZ; Fernando MAYORAL; Francisco NARANJO; Enrique A. S(A)NCHEZ-P(E)REZ
2011-01-01
Let (Ω, ∑) be a measurable space and m0: ∑→ X0 and m1: ∑ -→ X1 be positive vector measures with values in the Banach K(o)the function spaces X0 and X1. If 0 < α < 1, we define a X10-αXα1 and we analyze the space of integrable functions with respect to measure [m0, m1]α in order to prove suitable extensions of the classical Stein-Weiss formulas that hold for the complex interpolation of Lp-spaces.Since each p-convex order continuous K(o)the function space with weak order unit can be represented as a space of p-integrable functions with respect to a vector measure, we provide in this way a technique to obtain representations of the corresponding complex interpolation spaces. As applications, we provide a Riesz-Thorin theorem for spaces of p-integrable functions with respect to vector measures and a formula for representing the interpolation of the injective tensor product of such spaces.
Extended vector-tensor theories
Kimura, Rampei; Naruko, Atsushi; Yoshida, Daisuke
2017-01-01
Recently, several extensions of massive vector theory in curved space-time have been proposed in many literatures. In this paper, we consider the most general vector-tensor theories that contain up to two derivatives with respect to metric and vector field. By imposing a degeneracy condition of the Lagrangian in the context of ADM decomposition of space-time to eliminate an unwanted mode, we construct a new class of massive vector theories where five degrees of freedom can propagate, corresponding to three for massive vector modes and two for massless tensor modes. We find that the generalized Proca and the beyond generalized Proca theories up to the quartic Lagrangian, which should be included in this formulation, are degenerate theories even in curved space-time. Finally, introducing new metric and vector field transformations, we investigate the properties of thus obtained theories under such transformations.
Wolstenholme, E Œ
1978-01-01
Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and appl
The Duality on Vector Optimization Problems
Institute of Scientific and Technical Information of China (English)
HUANG Long-guang
2012-01-01
Duality framework on vector optimization problems in a locally convex topological vector space are established by using scalarization with a cone-strongly increasing function.The dualities for the scalar convex composed optimization problems and for general vector optimization problems are studied.A general approach for studying duality in vector optimization problems is presented.
基于向量空间模型的维吾尔文文本过滤方法%Uyghur Text Filtering Based on Vector Space Model
Institute of Scientific and Technical Information of China (English)
亚力青·阿里玛斯; 哈力旦·阿布都热依木; 陈洋
2015-01-01
Under the background of large-scale text information retrieval technology, presented Uyghur text filtering model and implementation method. On the basis of vector space model (VSM), using three methods of similarity measure to calculate the similarity of input text with user templates as decision-making tools for Uyghur text filtering experiments. As to the problem of high dimensionality feature space of Uyghur texts, by stemming, stop words filtering, feature selection methods to reduce the dimension of feature space. Finally, analysis the text filtering results by value of F1 presented by Precision and Recall.%在大规模的文本信息检索技术背景下，提出了维吾尔文本过滤模型及实现方法。文本表示模型在向量空间模型（VSM）的基础上，采用三种相似度度量方法计算输入文本与用户模板相似度作为决策手段，对维吾尔文本进行了过滤实验。对于维吾尔文特征空间的高维性问题，通过词干提取，停用词过滤，特征选择等方法降低了特征空间维数。最后利用准确率（Precision）和召回率（Recall）综合函数F1值作为评价指标分析了维吾尔文文本过滤实验结果。
Institute of Scientific and Technical Information of China (English)
陈雪; 马建文
2007-01-01
The Householder transformation-norm structure function in L2 vector space of linear algebra is introduced, and the edge enhancement for remote sensing images is realized. The experiment result is compared with traditional Laplacian and Sobel edge enhancements and it shows that the effect of the new method is better than that of the traditional algorithms.
40 CFR 35.6760 - Enforcement and termination for convenience.
2010-07-01
... convenience. 35.6760 Section 35.6760 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND... Enforcement and termination for convenience. The recipient must comply with all terms and conditions in the... termination for convenience described in 40 CFR 31.43 and 31.44....
Comparison of Two Fast Space Vector Pulse Width Modulation Algorithms%两种快速的空间矢量脉宽调制算法比较
Institute of Scientific and Technical Information of China (English)
范必双; 谭冠政; 樊绍胜; 王玉凤
2014-01-01
A comparison is made between two fast space vector pulse width modulation (SVPWM) algorithms: the 60° non-orthogonal coordinate SVPWM and the 45° rotating coordinate SVPWM. New general methods of the 60° and 45° algorithms for any level SVPWM are also provided, which need only the angle and the modulation depth to generate and arrange the final vector sequence. The analysis shows the latter offers better flexibility with fewer calculations and is well suited for digital implementation. Both methods are implemented in a field programmable gate array (FPGA) with very high speed integrated circuit hardware description language (VHDL) and compared on the basis of implementation complexity and logic resources required. Simulation results show the overwhelm in advantages of the 45° rotating coordinate SVPWM in brevity and efficiency. Finally, the experimental test results for a three-level neutral-point-clamped (NPC) inverter are presented.%对60°非正交坐标系和45°旋转坐标系这两种快速空间矢量脉宽调制算法(space vector pulse width modulation， SVPWM)进行比较，目的是为工程技术人员在这两种SVPWM算法之间选择时提供一个理论和实践的参考。提出了一种新的针对这两种方法的任意多电平调制通用算法，只需角度和调制比两个信号就能够决定最终的矢量开关顺序。理论分析结果表明，45°旋转坐标系 SVPWM 比60°非正交坐标系SVPWM更简单，计算量小，更适合于数字实现。两种算法都以硬件的方式在FPGA上用VHDL语言编程实现，并对实现的复杂度和逻辑资源占用这两方面进行比较。仿真结果表明，45°旋转坐标系下的SVPWM算法比60°坐标系下的SVPWM算法在简洁性和资源占用方面具有明显的优势。最后，在一个三电平中点箝位型逆变器上对所提的两种通用算法进行了实验验证。
Brand, Louis
2006-01-01
The use of vectors not only simplifies treatments of differential geometry, mechanics, hydrodynamics, and electrodynamics, but also makes mathematical and physical concepts more tangible and easy to grasp. This text for undergraduates was designed as a short introductory course to give students the tools of vector algebra and calculus, as well as a brief glimpse into these subjects' manifold applications. The applications are developed to the extent that the uses of the potential function, both scalar and vector, are fully illustrated. Moreover, the basic postulates of vector analysis are brou
Directory of Open Access Journals (Sweden)
Jordi Palacín
2012-06-01
Full Text Available This work proposes the detection of red peaches in orchard images based on the definition of different linear color models in the RGB vector color space. The classification and segmentation of the pixels of the image is then performed by comparing the color distance from each pixel to the different previously defined linear color models. The methodology proposed has been tested with images obtained in a real orchard under natural light. The peach variety in the orchard was the paraguayo (Prunus persica var. platycarpa peach with red skin. The segmentation results showed that the area of the red peaches in the images was detected with an average error of 11.6%; 19.7% in the case of bright illumination; 8.2% in the case of low illumination; 8.6% for occlusion up to 33%; 12.2% in the case of occlusion between 34 and 66%; and 23% for occlusion above 66%. Finally, a methodology was proposed to estimate the diameter of the fruits based on an ellipsoidal fitting. A first diameter was obtained by using all the contour pixels and a second diameter was obtained by rejecting some pixels of the contour. This approach enables a rough estimate of the fruit occlusion percentage range by comparing the two diameter estimates.
Fast Twin Support Vector Regression Algorithm in Primal Space%快速原空间孪生支持向量回归算法
Institute of Scientific and Technical Information of China (English)
彭新俊; 王翼飞
2011-01-01
Twin support vector regression (TSVR) efficiently determines its objective regression function by optimizing a pair of smaller sized SVM-type problems. The objective functions of TSVR in the primal space are directly optimized by introducing the well-known Newton algorithm. This method effectively overcomes the shortcoming of TSVR that its regressor is aplroximated by the dual quadratic programming problems. Numerical studies show that the proposed method provides good performance and obtains less learning time compared with TSVR.%孪生支持向量回归(TSVR)通过快速优化--对较小规模的支持向量机问题获得回归函数.文中提出在原始输入空间中采用Newton法直接优化TSVR的目标函数,从而有效克服TSVR通过对偶二次规划问题求得近似最优解导致性能上的损失.数值模拟实验表明该方法不仅能提高TSVR的性能,并且可降低学习时间.
College Student Internet Use: Convenience and Amusement
Directory of Open Access Journals (Sweden)
Genevieve M. Johnson
2007-02-01
Full Text Available Four hundred five college students completed a questionnaire that assessed patterns of Internet use. Results describe college students, with rare exception, as Internet users. The vast majority of college students frequently communicate online and access websites. While an Internet game experience is typical, relatively few college students are heavy online gamers. Overwhelmingly (i.e., 77.8%, college students conceptualized the Internet as a convenience, although 17.8% considered the Internet a source of amusement. Approximately 5% of college students reported negative perceptions of the Internet (frustrating or a waste of time. Principal component analysis revealed three patterns of online behaviour; integrated-Internet-use, games-only use, and dating-only use. Implications for online instructional practice are presented. Résumé : Quatre cent cinq étudiants du niveau collégial ont répondu à un questionnaire mesurant leurs tendances de l’utilisation d’Internet. Les résultats présentent ces étudiants comme des usagers d’Internet, à quelques exceptions près. La grande majorité de ces étudiants utilisent fréquemment les outils de communication en ligne et naviguent sur Internet. Alors qu’une expérience de jeu en ligne s’avère commune, peu d’étudiants du collège s’avèrent être des joueurs en ligne excessifs. Essentiellement (c.à-d. 77,8 %, ces étudiants perçoivent Internet comme une commodité, même si 17,8 % d’entre eux le considère comme une source d’amusement. Environ 5 % ont indiqué des perceptions négatives d’Internet (frustrations ou pertes de temps. L’analyse en composantes principales a révélé 3 tendances de comportements en ligne, l’utilisation intégrée d’Internet, l’utilisation seule de jeux et l’utilisation à des fins de rencontre seulement. On présente des conséquences pour la pratique de l’enseignement en ligne.
A construct analysis of meal convenience applied to military foods.
Jaeger, Sara R; Cardello, Armand V
2007-07-01
The present research investigates the concept of food convenience within the institutional framework of military feeding. The approach views food-related convenience in terms of two broad dimensions: "type of convenience" and "timing of convenience." A discrete choice experiment was conducted with US military personnel (n=179) regarding their perceptions of the (in)convenience associated with the use and consumption of low-preparation, all-in-one, military meals (MREs-meals, ready-to-eat). The obtained data strongly suggest that perceived (in)convenience, time and effort are separate constructs. A food provisioning process perspective was captured in the "timing of convenience" dimension, and the contribution of different stages in the consumption process to the perceived convenience of the meal situation was empirically demonstrated. The latter result has important implications for the study of food convenience outside this specific population and context. As opposed to the product perspective that is currently predominant in the literature, it demonstrates the necessity of adopting a meal perspective in analysing food-related convenience.
Dean, Richard A.
1971-01-01
The author shows that the set of all sequences in which each term is the sum of the two previous terms forms a vector space of dimension two. He uses this result to obtain the formula for the Fibonacci sequence and applies the same technique to other linear recursive relations. (MM)
Convenience samples and caregiving research: how generalizable are the findings?
Pruchno, Rachel A; Brill, Jonathan E; Shands, Yvonne; Gordon, Judith R; Genderson, Maureen Wilson; Rose, Miriam; Cartwright, Francine
2008-12-01
We contrast characteristics of respondents recruited using convenience strategies with those of respondents recruited by random digit dial (RDD) methods. We compare sample variances, means, and interrelationships among variables generated from the convenience and RDD samples. Women aged 50 to 64 who work full time and provide care to a community-dwelling older person were recruited using either RDD (N = 55) or convenience methods (N = 87). Telephone interviews were conducted using reliable, valid measures of demographics, characteristics of the care recipient, help provided to the care recipient, evaluations of caregiver-care recipient relationship, and outcomes common to caregiving research. Convenience and RDD samples had similar variances on 68.4% of the examined variables. We found significant mean differences for 63% of the variables examined. Bivariate correlations suggest that one would reach different conclusions using the convenience and RDD sample data sets. Researchers should use convenience samples cautiously, as they may have limited generalizability.
Consumers' convenience orientation towards meal preparation: conceptualization and measurement.
Candel, M
2001-02-01
Consumer researchers consider convenience orientation towards meal preparation to be a relevant construct for understanding consumer behavior towards foods. This study set out to conceptualize this construct and to develop a scale that measures it. As examined in two different samples of meal preparers, the resulting scale is reliable, satisfies a unifactorial structure and has satisfactory convergent validity. The scale's nomological validity is supported in that it conforms to expectations regarding various psychographic constructs and various food-related behaviors. Convenience orientation was found to be negatively related to cooking enjoyment, involvement with food products and variety seeking, and to be positively related to role overload. The analyses also suggest that the lack of relation between the meal preparer's working status and convenience food consumption, as found in many studies, is due to convenience food not offering enough preparation convenience. Consuming take-away meals and eating in restaurants appear to satisfy the consumer's need for convenience more adequately.
Construction of Yeast Vectors with Resistance to Geneticin
Institute of Scientific and Technical Information of China (English)
林会兰; 张广; 周全; 陈国强
2002-01-01
Two Escherichia coli-Saccharomyces cerevisiae shuttle vectors containing a resistance marker to geneticin (G418) are constructed. Both vectors contain a kanamycin-resistant marker (KanMX4) module coding aminoglycoside 3'-phosphotransferase (APH) that renders E. coli resistant to kanamycin and S. cerevisiae to geneticin. These vectors overcome the shortage of the conventional yeast vectors bearing HIS3, TRP1, LEU2, and URA3 modules as selection markers, which require hosts to be auxotrophic. Green fluorescent protein (GFP) is used as the reporter to examine the functions of the vectors. The vectors are powerful tools for the convenient cloning and controlled expression of genes in most S. cerevisiae strains.
Institute of Scientific and Technical Information of China (English)
周熙炜; 梅芳; 陈金平; 林海
2016-01-01
深入分析基本空间矢量SV与特定谐波消去SHEPWM之间的内在联系，提出三电平NPC逆变器的一种基于空间分区矢量提取的SHEPWM调制策略,推导出空间电压矢量PWM的三相等效调制波规则采样的开关角矩阵，得出基本空间矢量SV的选用与规则采样的运算关系以及SHEPWM的脉冲状态由基本SV组成的矢量序列特殊解。在此基础上，在三电平NPC逆变器的矢量空间六边形所分区的两电平六边形中，研究SHEPWM脉冲序列的空间电压矢量组成的扇区分布，并提取相应的基本SV，求解作用时间。 SHEPWM的脉冲状态由空间分区提取的基本SV矢量序列运算合成而实现，避开了其开关角非线性超越方程组的求解，并具有同样的消谐效果且便于实现。%According to the studies of internal relation for the basic space vector(SV) and the selective harmonic elimination PWM (SHEPWM), this paper puts forward a kind of SHEPWM implementation strategy based on the space partition vector SV extraction to the three-level NPC inverter, deduces the space voltage vector switch angle matrix of the three-phase equivalent modulation wave regulation sampling and the operation relationship. So, on the basis of the switch angle trajectory characteristics of SHEPWM and its realization by regulation sampling, the SHEPWM waveform pulse state can be gained by the vectors sequence special solution which composed of basic SV vector. To the three-level inverter, on the Two level small hexagon which be partitioned from space vector hexagon, the work sector allocation of SHEPWM pulse state be researched, and the corresponding basic SV vector and its action time also be achieved by the experiment and FFT analysis. This method avoid the solution of SHEPWM switch angle nonlinear transcendental equations, and it has the same effect of harmonic elimination and to facilitate online implementation.
Huchard, Elise; Canale, Cindy I; Le Gros, Chloé; Perret, Martine; Henry, Pierre-Yves; Kappeler, Peter M
2012-04-07
Classic sex roles depict females as choosy, but polyandry is widespread. Empirical attempts to understand the evolution of polyandry have often focused on its adaptive value to females, whereas 'convenience polyandry' might simply decrease the costs of sexual harassment. We tested whether constraint-free female strategies favour promiscuity over mating selectivity through an original experimental design. We investigated variation in mating behaviour in response to a reversible alteration of sexual dimorphism in body mass in the grey mouse lemur, a small primate where female brief sexual receptivity allows quantifying polyandry. We manipulated body condition in captive females, predicting that convenience polyandry would increase when females are weaker than males, thus less likely to resist their solicitations. Our results rather support the alternative hypothesis of 'adaptive polyandry': females in better condition are more polyandrous. Furthermore, we reveal that multiple mating incurs significant energetic costs, which are strikingly symmetrical between the sexes. Our study shows that mouse lemur females exert tight control over mating and actively seek multiple mates. The benefits of remating are nevertheless not offset by its costs in low-condition females, suggesting that polyandry is a flexible strategy yielding moderate fitness benefits in this small mammal.
All optical vector magnetometer Project
National Aeronautics and Space Administration — This Phase I research project will investigate a novel method of operating an atomic magnetometer to simultaneously measure total magnetic fields and vector magnetic...
Guilfoyle, R.A.; Smith, L.M.
1994-12-27
A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.
Guilfoyle, Richard A.; Smith, Lloyd M.
1994-01-01
A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.
Direct Torque Control for Induction Motor Based on Space Vector Modulation%异步电动机的SVM-DTC控制
Institute of Scientific and Technical Information of China (English)
蒋建虎; 姬宣德
2011-01-01
针对基本直接转矩控制(BASIC-DTC)转矩和磁链脉动大的缺点,采用空间电压矢量调制与直接转矩控制相结合(SVM-DTC)的方法,以减小转矩和磁链脉动；为了提高定子磁链的观测精度,利用全阶磁链观测器观测定子磁链,并提出一种单自由度极点配置方法实现磁链观测器的极点配置.仿真结果表明,系统不但实现了转矩和磁链的定量控制,降低了转矩脉动和磁链脉动,提高了定子磁链的观测精度,而且同时使得逆变器开关周期恒定,更易于数字化实现.%For the disadvantage of the basic direct torque control (BASIC-DTC) 's torque and flux ripple when it runs, the direct torque control combined with space vector modulation (SVM-DTC) was used to reduce the torque and flux ripple. To improve the accuracy of the stator flux observation,the full order flux observer was used to achieve the stator flux observation. The new method of pole placement was proposed to achieve the configuration of the flux full order observer gain matrix parameters. The simulation results show that the torque ripple and flux ripple is reduced and the accuracy of the stator flux observation is improved,and in this method the invertor has constant switching period and is easy to realizing digital.
Institute of Scientific and Technical Information of China (English)
丁协平
2009-01-01
Some new systems of generalized vector quasi-equilibrium problems and simultaneous generalized vector quasi-equihbrium problems are introduced and studied in locally FC-uniform spaces. By using a KKM type theorem and a Himmelberg type fixed point theorem in locally FC-uniform spaces due to author, a new coincidence point theorem for two families of set-valuod mappings is first proved in locally FC-uniform spaces. As applications,some new existence theorems of solutions for the systems of generalized vector quasi-equilibrium problems and the systems of simultaneous generalized vector quasi-equilibrium problems are obtained in locally FC-unfform spaces.These results generalize some known results in literature.%在局部FC-一致空间内引入和研究了某些新的广义矢量拟平衡问题组和联立广义矢量拟平衡问题组.应用KKM型定理和作者在局部FC-一致空间得到的Himmelberg型不动点定理,首先在局部FC-一致空间内对两族集值映象证明了一个新的重合点定理.作为应用,在局部FC-一致空间内得到了广义矢量拟平衡问题组和联立广义矢量拟平衡问题组的解的某些新的存在性定理.这些结果推广了文献中某些已知结果.
Public Attitudes toward Stuttering in Turkey: Probability versus Convenience Sampling
Ozdemir, R. Sertan; St. Louis, Kenneth O.; Topbas, Seyhun
2011-01-01
Purpose: A Turkish translation of the "Public Opinion Survey of Human Attributes-Stuttering" ("POSHA-S") was used to compare probability versus convenience sampling to measure public attitudes toward stuttering. Method: A convenience sample of adults in Eskisehir, Turkey was compared with two replicates of a school-based,…
43 CFR 12.84 - Termination for convenience.
2010-10-01
... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Termination for convenience. 12.84 Section 12.84 Public Lands: Interior Office of the Secretary of the Interior ADMINISTRATIVE AND AUDIT... Termination for convenience. Except as provided in § 12.83 awards may be terminated in whole or in part...
45 CFR 1183.44 - Termination for convenience.
2010-10-01
... 45 Public Welfare 3 2010-10-01 2010-10-01 false Termination for convenience. 1183.44 Section 1183.44 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL FOUNDATION ON THE ARTS..., Retention, and Enforcement § 1183.44 Termination for convenience. Except as provided in § 1183.43 awards...
10 CFR 600.244 - Termination for convenience.
2010-01-01
... 10 Energy 4 2010-01-01 2010-01-01 false Termination for convenience. 600.244 Section 600.244 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS FINANCIAL ASSISTANCE RULES Uniform... Requirements § 600.244 Termination for convenience. Except as provided in § 600.443 awards may be terminated...
32 CFR 33.44 - Termination for convenience.
2010-07-01
... 32 National Defense 1 2010-07-01 2010-07-01 false Termination for convenience. 33.44 Section 33.44 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... convenience. Except as provided in § 33.43 awards may be terminated in whole or in part only as follows:...
29 CFR 97.44 - Termination for convenience.
2010-07-01
... 29 Labor 1 2010-07-01 2010-07-01 true Termination for convenience. 97.44 Section 97.44 Labor Office of the Secretary of Labor UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND COOPERATIVE... § 97.44 Termination for convenience. Except as provided in § 97.43 awards may be terminated in whole...
28 CFR 66.44 - Termination for convenience.
2010-07-01
... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Termination for convenience. 66.44 Section 66.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) UNIFORM ADMINISTRATIVE... Reports, Records, Retention, and Enforcement § 66.44 Termination for convenience. Except as provided...
40 CFR 51.355 - Test frequency and convenience.
2010-07-01
... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Test frequency and convenience. 51.355 Section 51.355 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Requirements § 51.355 Test frequency and convenience. (a) The performance standards for I/M programs assume...
22 CFR 135.44 - Termination for convenience.
2010-04-01
... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Termination for convenience. 135.44 Section 135.44 Foreign Relations DEPARTMENT OF STATE MISCELLANEOUS UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS..., Retention, and Enforcement § 135.44 Termination for convenience. Except as provided in § 135.43 awards...
34 CFR 303.423 - Convenience of proceedings; timelines.
2010-07-01
... 34 Education 2 2010-07-01 2010-07-01 false Convenience of proceedings; timelines. 303.423 Section 303.423 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF... Parents and Children § 303.423 Convenience of proceedings; timelines. (a) Any proceeding for...
45 CFR 602.44 - Termination for convenience.
2010-10-01
... 45 Public Welfare 3 2010-10-01 2010-10-01 false Termination for convenience. 602.44 Section 602.44 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION UNIFORM... Requirements § 602.44 Termination for convenience. Except as provided in § 602.43 awards may be terminated...
21 CFR 1403.44 - Termination for convenience.
2010-04-01
... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Termination for convenience. 1403.44 Section 1403.44 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY UNIFORM ADMINISTRATIVE REQUIREMENTS FOR..., Retention, and Enforcement § 1403.44 Termination for convenience. Except as provided in § 1403.43 awards...
45 CFR 1174.44 - Termination for convenience.
2010-10-01
... 45 Public Welfare 3 2010-10-01 2010-10-01 false Termination for convenience. 1174.44 Section 1174.44 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL FOUNDATION ON THE ARTS..., Retention, and Enforcement § 1174.44 Termination for convenience. Except as provided in § 1174.43 awards...
45 CFR 92.44 - Termination for convenience.
2010-10-01
... 45 Public Welfare 1 2010-10-01 2010-10-01 false Termination for convenience. 92.44 Section 92.44 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION UNIFORM ADMINISTRATIVE... Requirements Reports, Records Retention, and Enforcement § 92.44 Termination for convenience. Except...
29 CFR 1470.44 - Termination for convenience.
2010-07-01
... 29 Labor 4 2010-07-01 2010-07-01 false Termination for convenience. 1470.44 Section 1470.44 Labor Regulations Relating to Labor (Continued) FEDERAL MEDIATION AND CONCILIATION SERVICE UNIFORM ADMINISTRATIVE... Reports, Records Retention, and Enforcement § 1470.44 Termination for convenience. Except as provided...
38 CFR 43.44 - Termination for convenience.
2010-07-01
... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Termination for convenience. 43.44 Section 43.44 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... convenience. Except as provided in § 43.43 awards may be terminated in whole or in part only as follows:...
45 CFR 1157.44 - Termination for convenience.
2010-10-01
... 45 Public Welfare 3 2010-10-01 2010-10-01 false Termination for convenience. 1157.44 Section 1157.44 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL FOUNDATION ON THE ARTS... Enforcement § 1157.44 Termination for convenience. Except as provided in § 1157.43 awards may be terminated...
34 CFR 80.44 - Termination for convenience.
2010-07-01
... 34 Education 1 2010-07-01 2010-07-01 false Termination for convenience. 80.44 Section 80.44 Education Office of the Secretary, Department of Education UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS... Retention, and Enforcement § 80.44 Termination for convenience. Except as provided in § 80.43 awards may...
13 CFR 143.44 - Termination for convenience.
2010-01-01
... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Termination for convenience. 143.44 Section 143.44 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION UNIFORM ADMINISTRATIVE... Reports, Records, Retention, and Enforcement § 143.44 Termination for convenience. Except as provided...
20 CFR 437.44 - Termination for convenience.
2010-04-01
... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Termination for convenience. 437.44 Section 437.44 Employees' Benefits SOCIAL SECURITY ADMINISTRATION UNIFORM ADMINISTRATIVE REQUIREMENTS FOR..., Retention, and Enforcement § 437.44 Termination for convenience. Except as provided in § 437.43, awards...
Public Attitudes toward Stuttering in Turkey: Probability versus Convenience Sampling
Ozdemir, R. Sertan; St. Louis, Kenneth O.; Topbas, Seyhun
2011-01-01
Purpose: A Turkish translation of the "Public Opinion Survey of Human Attributes-Stuttering" ("POSHA-S") was used to compare probability versus convenience sampling to measure public attitudes toward stuttering. Method: A convenience sample of adults in Eskisehir, Turkey was compared with two replicates of a school-based,…
15 CFR 24.44 - Termination for convenience.
2010-01-01
... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Termination for convenience. 24.44 Section 24.44 Commerce and Foreign Trade Office of the Secretary of Commerce UNIFORM ADMINISTRATIVE... Reports, Records, Retention, and Enforcement § 24.44 Termination for convenience. Except as provided...
Efficient and Convenient Preparation of Water-Soluble Fullerenol
Institute of Scientific and Technical Information of China (English)
ZHANG Jian-Min章建民; YANG Wen杨文; HE Ping何萍; ZHU Shi-Zheng朱士正
2004-01-01
An efficient and convenient preparation of fullerenols was described. With polyethylene glycol (PEG) 400 as catalyst, fullerenols were conveniently synthesized via the direct reaction of fullerene with aqueous NaOH. By control of reaction conditions, either water-soluble C60 fullerenol or water-insoluble C60 fullerenol could be obtained selectively.
Convenience Samples and Caregiving Research: How Generalizable Are the Findings?
Pruchno, Rachel A.; Brill, Jonathan E.; Shands, Yvonne; Gordon, Judith R.; Genderson, Maureen Wilson; Rose, Miriam; Cartwright, Francine
2008-01-01
Purpose: We contrast characteristics of respondents recruited using convenience strategies with those of respondents recruited by random digit dial (RDD) methods. We compare sample variances, means, and interrelationships among variables generated from the convenience and RDD samples. Design and Methods: Women aged 50 to 64 who work full time and…
36 CFR 1207.44 - Termination for convenience.
2010-07-01
... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Termination for convenience. 1207.44 Section 1207.44 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS... Termination for convenience. Except as provided in § 1207.43 awards may be terminated in whole or in part...
7 CFR 3016.44 - Termination for convenience.
2010-01-01
... 7 Agriculture 15 2010-01-01 2010-01-01 false Termination for convenience. 3016.44 Section 3016.44 Agriculture Regulations of the Department of Agriculture (Continued) OFFICE OF THE CHIEF FINANCIAL OFFICER... Termination for convenience. Except as provided in § 3016.43 awards may be terminated in whole or in part...
40 CFR 31.44 - Termination for convenience.
2010-07-01
... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Termination for convenience. 31.44 Section 31.44 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL... convenience. Except as provided in § 31.43 awards may be terminated in whole or in part only as follows:...
41 CFR 105-71.144 - Termination for convenience.
2010-07-01
... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Termination for convenience. 105-71.144 Section 105-71.144 Public Contracts and Property Management Federal Property... Termination for convenience. Except as provided in § 105-71.143 awards may be terminated in whole or in...
24 CFR 85.44 - Termination for convenience.
2010-04-01
... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Termination for convenience. 85.44 Section 85.44 Housing and Urban Development Office of the Secretary, Department of Housing and Urban... § 85.44 Termination for convenience. Except as provided in § 85.43 awards may be terminated in whole...
44 CFR 13.44 - Termination for convenience.
2010-10-01
... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Termination for convenience. 13.44 Section 13.44 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY... § 13.44 Termination for convenience. Except as provided in § 13.43 awards may be terminated in whole...
48 CFR 49.601 - Notice of termination for convenience.
2010-10-01
... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Notice of termination for convenience. 49.601 Section 49.601 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... termination for convenience. (See 49.402-3(g) for notice of termination for default.)...
49 CFR 18.44 - Termination for convenience.
2010-10-01
... 49 Transportation 1 2010-10-01 2010-10-01 false Termination for convenience. 18.44 Section 18.44 Transportation Office of the Secretary of Transportation UNIFORM ADMINISTRATIVE REQUIREMENTS FOR GRANTS AND... Enforcement § 18.44 Termination for convenience. Except as provided in § 18.43 awards may be terminated...
Public Attitudes toward Stuttering in Turkey: Probability versus Convenience Sampling
Ozdemir, R. Sertan; St. Louis, Kenneth O.; Topbas, Seyhun
2011-01-01
Purpose: A Turkish translation of the "Public Opinion Survey of Human Attributes-Stuttering" ("POSHA-S") was used to compare probability versus convenience sampling to measure public attitudes toward stuttering. Method: A convenience sample of adults in Eskisehir, Turkey was compared with two replicates of a school-based, probability cluster…
Vector fields on nonorientable surfaces
Directory of Open Access Journals (Sweden)
Dorin Ghisa
2003-01-01
Full Text Available A one-to-one correspondence is established between the germs of functions and tangent vectors on a NOS X and the bi-germs of functions, respectively, elementary fields of tangent vectors (EFTV on the orientable double cover of X. Some representation theorems for the algebra of germs of functions, the tangent space at an arbitrary point of X, and the space of vector fields on X are proved by using a symmetrisation process. An example related to the normal derivative on the border of the MÃƒÂ¶bius strip supports the nontriviality of the concepts introduced in this paper.
Institute of Scientific and Technical Information of China (English)
林强
2001-01-01
在Hausdorff局部凸线性拓扑空间中讨论集值系统x∈F(x,y),y∈G(x,y)解的存在性，推广了Rzepechi B在一致凸Banach空间中相应的结论。%This paper deals with existence of solutions for set-valued system x∈F(x,y)，y∈G(x,y) in local convex Hausdorff topological vector space. The results obtained are generalization of Rzepechi theorem in uniform convex Banach space.
Food availability/convenience and obesity.
Gordon-Larsen, Penny
2014-11-01
Neighborhood environments have received considerable attention in recent local, state, and national obesity prevention initiatives, with a particular focus on food deserts, or areas with poor access to healthy foods. Yet, there are inconsistencies in the evidence base, suggesting a nuanced association between neighborhood environment, food availability, diet behaviors, and obesity. There is heterogeneity in associations between environmental exposures and health outcomes across race/ethnicity, gender, region, and urbanicity, which results in complexity in the interpretation of findings. There are several limitations in the literature, including a predominance of cross-sectional studies, reliance on commercial business listings, lack of attention to the process by which diet resources are established and expanded within neighborhoods and the potential for individuals to selectively migrate to locate near such facilities, a predominant focus on residential neighborhoods, and lack of information about the decision-making process underlying purchasing patterns. More research is needed to address the complexity of individual-level residential decision making as well as the purposeful placement of food environment resources across social and geographic space using longitudinal data and complex statistical approaches. In addition, improvements in data quality and depth related to food access and availability are needed, including behavioral data on purchase patterns and interactions with the food environment, and greater attention to heterogeneity across subpopulations. As policy changes to the food environment move forward, it is critical that there is rigorous and scientific evaluation of environmental changes and their impact on individual-level diet choices and behaviors, and their further influence on body weight. © 2014 American Society for Nutrition.
Institute of Scientific and Technical Information of China (English)
Hua WANG; ALATANCANG; Junjie HUANG
2011-01-01
The authors investigate the completeness of the system of eigen or root vectors of the 2 x 2 upper triangular infinite-dimensional Hamiltonian operator H0.First,the geometrical multiplicity and the algebraic index of the eigenvalue of H0 are considered.Next,some necessary and sufficient conditions for the completeness of the system of eigen or root vectors of H0 are obtained. Finally,the obtained results are tested in several examples.
Continuous representations of scalar products of Bethe vectors
Galleas, W
2016-01-01
We present families of single determinantal representations of on-shell scalar products of Bethe vectors. Our families of representations are parameterized by a continuous complex variable which can be fixed at convenience. Here we consider Bethe vectors in two versions of the six-vertex model: the case with boundary twists and the case with open boundaries.
Vector and tensor analysis with applications
Borisenko, A I; Silverman, Richard A
1979-01-01
Concise and readable, this text ranges from definition of vectors and discussion of algebraic operations on vectors to the concept of tensor and algebraic operations on tensors. It also includes a systematic study of the differential and integral calculus of vector and tensor functions of space and time. Worked-out problems and solutions. 1968 edition.
Institute of Scientific and Technical Information of China (English)
胡应宏; 王建赜; 申科; 佘禄平; 纪延超
2012-01-01
In allusion to such defects in traditional voltage space vector pulse width modulation algorithm as complex calculation and weak expansibility when it is applied in multilevel converter, based on sampling time staggered space vector modulation theory a simplified one-dimensional space vector modulation algorithm for single-phase cascaded multilever inverter is proposed. Through simple operation the selection of one-dimensional voltage vector can be chosen and corrsponding action time can be obtained, and the optimized firing sequence of the valves can be reasonably selected; redundant switch status is utlized to implement the dead zone is achieved to effectively avoid the danger of short-circuit "of bridge arms. Simulation results show that the proposed modulation method is correct and feasible.%电压空间矢量脉宽调制算法在应用于多电平变换器场合时存在计算复杂、扩展性差的缺点.针对单相级联型多电平逆变器,结合错时采样原理,提出一种简化一维空间矢量调制算法.通过简单运算可以得到一维电压矢量的选取和相应的作用时间,并合理选择优化的开关导通序列,同时利用冗余开关状态实现死区,有效地避免了桥臂直通的危险.仿真和实验结果证明了本文提出调制方法的正确性和可行性.
Hertz, Frej Daniel; Halkier, Bente
2017-03-15
The term convenience food is subject to diversification, lack of clarity and moral ambiguity. In this paper we address these issues and critically discuss convenience food by using empirical findings from a Danish study that deals with practitioners' uses of meal box schemes. The methodological design consists of thirteen individual interviews, four focus groups and some observations of cooking practices. We combine the empirical findings with a particular definition of convenience food by Brunner et al. (2010) and selected practice theoretical concepts. This particular combination enables us to categorize meal box schemes as a new form of convenience food called convenient food. In addition, results suggest that meal box schemes reduce leftovers from dinner. Meal boxes also influence dinner related activities such as planning ahead in time and grocery shopping, which require less physical and mental effort.
Directory of Open Access Journals (Sweden)
Imtihan Hanum
2016-12-01
experiment for this study 43 respondents were used to evaluate a stimulus set consisting of simulated images of a convenience store interior. The response data were analyzed using ANOVA. The experiment results showed that a cashier location far from the exit with a cool color combination is deemed secure by the respondents, while the location of a counter away from the exit has a positive effect on client behavior. However, the façade variable did not contribute significantly to improving security perception and client behavior. The experimental results can be used in convenience store design guidelines and for developing design knowledge. In the future, other types of shops or public spaces with similar problems can be studied.Keywords: convenience store; crime prevention; consumer behavior; security perception.
Current progress of polymeric gene vectors
Institute of Scientific and Technical Information of China (English)
ZENG Xuan; SUN YunXia; ZHUO RenXi; ZHANG XianZheng
2011-01-01
After over 40 years ot progress,gene therapy provides great opportunities for treating diseases from various genetic disorders,infections and cancers.The success of gene therapy largely depends on the availability of suitable gene vectors.As an attractive alternative to virus-based gene therapy,non-viral gene delivery system has been developed and investigated due to their merits including low immunogenecity,convenient operability,and large-scale manufacturability [1].Because polycations can condense with DNA as a result of electrostatic interactions,form nanosize polyplexes,and protect DNA from degradation by DNase,cationic polymer becomes a major type of non-viral gene delivery vectors (Figure 1) [2].A wide range of polymeric vectors have been developed and investigated in the past decade,such as polyethylenimine (PEI)-based vectors,poly(L-lysine) (PLL)-based vectors,dendrimer-based vectors,polypeptide-based vectors,and chitosan-based vectors [3].However,unlike viral vectors that have the ability to infect host cells and overcome cellular barriers through the course of evolution,nonviral gene vectors exhibit Significantly reduced transfection efficiency as they are obstructed by various extra- and intracellular barriers,including serum proteins in blood stream,cell membrane,endosomal compartment and nuclear membrane [4].
Multipartite State Representations in Multi-mode Fock Space and Their Squeezing Transformations
Institute of Scientific and Technical Information of China (English)
YUAN Hong-Chun; LI Heng-Mei; QI Kai-Guo
2007-01-01
We present the continuous state vector of the total coordinate of multi-particle and the state vector of their total momentum, respectively, which possess completeness relation in multi-mode Fock space by virtue of the integration within an order product (IWOP) technique. We also calculate the transition from classical transformation of variables in the states to quantum unitary operator, deduce a new multi-mode squeezing operator, and discuss its squeezing effect. In progress, it indicates that the IWOP technique provides a convenient way to construct new representation in quantum mechanics.
Wang, Wenyu; Xiong, Zhao-Hua; Zhao, Xin-Yan
2016-09-01
In models with vector-like quark doublets, the mass matrices of up and down type quarks are related. Precise diagonalization of the mass matrices has become an obstacle in numerical studies. In this work we first propose a diagonalization method. As its application, in the Standard Model with one vector-like quark doublet we present the quark mass spectrum and Feynman rules for the calculation of B → Xsγ. We find that i) under the constraints of the CKM matrix measurements, the mass parameters in the bilinear term are constrained to a small value by the small deviation from unitarity; ii) compared with the fourth generation extension of the Standard Model, there is an enhancement to the B → Xsγ process in the contribution of vector-like quarks, resulting in a non-decoupling effect in such models. Supported by Natural Science Foundation of China (11375001) and Talents Foundation of Education Department of Beijing
Wang, Wenyu; Zhao, Xin-Yan
2016-01-01
In the models with vector like quark doublets, the mass matrices of up and down type quarks are related. Precise diagonalization for the mass matrices became an obstacle in the numerical studies. In this work we propose a diagonalization method at first. As its application, in the standard model with one vector like quark doublet we present quark mass spectrum, Feynman rules for the calculation of $B\\to X_s\\gamma$. We find that i) under the constraints of the CKM matrix measurements, the mass parameters in the bilinear term are constrained to a small value by the small deviation from unitarity; ii) compared with the fourth generation extension of the standard model, there is an enhancement to $B\\to X_s\\gamma$ process in the contribution of vector like quark, resulting a non-decoupling effect in such models.
A new convenient access to highly functionalized ()-2-arylvinyl bromides
Indian Academy of Sciences (India)
Yubo Jiang; Chunxiang Kuang
2009-11-01
Highly functionalized ()-2-arylvinyl bromides were prepared in high yields through a new convenient access by acylation of ()-4-(2-bromovinyl)phenol with fatty and aromatic acids at room temperature using dicyclohexyl carbodiimide (DCC) and dimethylaminopyridine (DMAP).
A Convenient Synthetic Method of Metal Dendritic Porphyrins
Institute of Scientific and Technical Information of China (English)
Wen Bin CUI; Jie ZHOU; Lei CHEN; Xiao Bin DENG; Chun GUO
2006-01-01
A convenient synthetic method of metal dendritic porphyrins through the convergent synthetic strategy is described. The porphyrin core were linked with the synthetic fragments by forming ether or ester bonds to give five target compounds were prepared.
Kordyum, Elizabeth; Sarnatska, Veresa; Ovcharenko, Yulia
A root graviperceptive apparatus is known to form in microgravity but does not function in the absence of a gravitational vector, that has been shown in many spaceflight experiments with seedlings of different plant species. In statocytes, which are differentiated in microgravity, a nucleus is localized in the proximal part of a cell as at 1 g. Unlike control, amyloplastsstatoliths do not sedimented in the distal part of a cell in microgravity, they group in the cell center more often, sometimes they localized in the different part of a cell. In all these experiments, the objects of investigations were embryonal roots formed in seeds at 1 g. There is only single report that columella cells in roots, which developed de novo from callus in space flight, did not differentiate in statocytes. Therefore, we call to attention to rhizogenesis in vitro as a convenient model for studying the influence of microgravity on differentiation of a root graviperceptive apparatus. Two methods for obtaining of Arabidopsis thaliana roots in vitro are proposed: the first-from the primary callus of leaf origin and the second - from leaf fragments. Callus initiation and growth are successful on MS medium supplemented with vitamin B5, glycine, inositol, 2,4-D, kinetin, glucose and agar. For induction of rhizogenesis calli were transferred to medium without hormones or medium which contained one to ten of MS mineral salts and microelements, without vitamins and hormones. Rhyzogenesis was obtained without added growth substances, but considerably higher number of calli with roots and number of roots per callus are on MS medium diluted tenfold. Rhizogenesis in A. thaliana leaf segments should present no problem, but the most intensive root formation is obtained when culturing them for three day on diluted MS medium supplemented with salycilic acid and then on diluted MS medium only. The low temperature treatment for three days increases the number of roots formed. A role of both plasticity
Health Indicators: Eliminating bias from convenience sampling estimators
Hedt, Bethany L.; Pagano, Marcello
2011-01-01
Public health practitioners are often called upon to make inference about a health indicator for a population at large when the sole available information are data gathered from a convenience sample, such as data gathered on visitors to a clinic. These data may be of the highest quality and quite extensive, but the biases inherent in a convenience sample preclude the legitimate use of powerful inferential tools that are usually associated with a random sample. In general, we know nothing abou...
Customer service of convenience stores / by K. Kleynhans
Kleynhans, Karin Belinda Margerete
2008-01-01
This study researches the topic customer service of convenience sores. Two objectives are set, namely to measure the customer service levels of convenience stores, and then to determine if any differences exist between customer perceptions and customer expectations. The literature review covers two models of service quality, namely the Kano model and the SERVQUAL model. Both the Kano model and the SERVQUAL model are client service models that currently exist in practice. The Kano model pro...
Institute of Scientific and Technical Information of China (English)
郑建勇; 王杰; 梅军; 王磊
2011-01-01
A hysteresis current control based on voltage space vector is proposed,which obtains three groups of current error vector by importing the phase current error to the hysteresis comparator and outputs the optimal voltage space by determining the distribution of current error vector and reference voltage vector. Therefore,the current error is limited in the hysteresis width. It can efficiently eliminate the interference and restrict the current error under a lower switching frequency. A fully digital control system based on DSP-FPGA is designed,with quicker current response,better current tracking performance and enhanced system stability. Simulative and experimental results verify the correctness of the given control strategy.%提出了一种基于电压空间矢量的滞环电流控制方法.该方法将相电流误差通过滞环比较器得到3组电流误差矢量,并通过对电流误差矢量和参考电压矢量扇区的判别输出最优电压矢量,从而使电流误差控制在滞环宽度内.该方法能有效地消除相间影响,并且能够在较低的开关频率下有效地限制电流误差,既有较好的电流响应速度,又有较好的电流跟踪性能.设计了基于DSP-FPGA的全数字控制系统,极大提高整个系统的稳定性.仿真和实验结果验证了控制策略的正确性.
DEFF Research Database (Denmark)
Kildegaard, Kanchana Rueksomtawin; Jensen, Niels Bjerg; Maury, Jerome
2013-01-01
auxotrophic and dominant markers for convenience of use. Our vector set also contains both integrating and multicopy vectors for stability of protein expression and high expression level. We will make the new vector system available to the yeast community and provide a comprehensive protocol for cloning...
DEFF Research Database (Denmark)
2012-01-01
The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...... assembly for emission of a measurement beam for illumination of an object in a measurement volume with coherent light whereby a signal beam emanating from the object in the measurement volume is formed in response to illumination of the object by the measurement beam, a reference beam generator...... detector element signal when the fringe pattern formed by the interfering signal beam and reference beam moves across the first detector array; and a signal processor that is adapted for generation of a velocity signal corresponding to a first velocity component of movement of the object in the measurement...
DEFF Research Database (Denmark)
2012-01-01
for generation of a reference beam, a detector system comprising a first detector arrangement arranged in such a way that the signal beam and the reference beam are incident upon the first detector arrangement with the reference beam propagating at an angle relative to a signal beam, and wherein the first......The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...... assembly for emission of a measurement beam for illumination of an object in a measurement volume with coherent light whereby a signal beam emanating from the object in the measurement volume is formed in response to illumination of the object by the measurement beam, a reference beam generator...
空间矢量脉宽调制( SVPWM)技术的仿真与分析%Simulation and Analysis of Space Vector Pulse Width Modulation Technique
Institute of Scientific and Technical Information of China (English)
张成; 王心坚; 李良璋; 孙泽昌
2012-01-01
By analyzing the basic principle of flux tracking and voltage space vector synthesis , the DC voltage utilization ratio of space vector pulse width modulation (SVPWM) was analyzed theoretically.The PMSM speed regulating system model adopting SVPWM technique was built in Matlab /Simulink environment.And the simulation results show that SVPWM yields a circular magnetic field in motor space .The harmonics of output voltage distribute mainly around integer multiples of carrier frequency , and higher modulation index yields a low-er voltage total harmonic distortion.% 基于SVPWM的磁链跟踪和电压矢量合成原理，理论分析了SVPWM的直流电压利用率，在Matlab/Simulink中建立SVPWM及永磁同步电机调速系统的仿真模型。仿真结果表明， SVPWM可在电机空间实现圆形磁场，输出电压谐波集中在载波频率整数倍附近，较高的调制比可获得较小的电压谐波畸变。
Zhang, Xiaofei; Cao, Renzheng; Zhou, Ming
2013-12-01
In this paper, we propose a noncircular-parallel factor (NC-PARAFAC) algorithm for two-dimensional direction of arrival (DOA) estimation of noncircular signals for acoustic vector-sensor array. The proposed algorithm enhances the angle estimation performance via utilizing the noncircularity of the signals, and it can be suitable for arbitrary array subjected to unknown locations and achieve automatically paired two-dimensional angle estimation. The proposed algorithm has better angle estimation performance than estimation of signal parameters via rotational invariance technique, PARAFAC algorithm, and propagator method. Furthermore, the proposed algorithm has a lower computational complexity than the PARAFAC algorithm. We also derive the Crámer-Rao bound of DOA estimation of noncircular signal in acoustic vector-sensor array. The simulation results verify the effectiveness of the algorithm.
First come, First served: Enhancing the Convenience Store Service Experience
Directory of Open Access Journals (Sweden)
Yuan-Ling Chiao
2012-09-01
Full Text Available One distinctive characteristic of Taiwanese city streets is the omnipresence of convenience stores. These clean, brightly lit stores are in operation 24 hours a day, seven days a week, and offer a wide range of constantly updated lifestyle products and services. Past research in convenience stores have often overlooked the work experiences of convenience store employees, and their contribution to the overall service experience. Thus, the goal of this exploratory study is to explore the convenience store work environment, and to provide some suggestions for in-store technological enhancements. Data was collected through in-depth interviewing, field study observations and Living Lab methodologies. Our research reveals that convenience store employees experience several types of physical, mental and emotional strains throughout their shifts. These strains are often derived from excessive physical exertion and unpleasant interactions with customers. We suggest that certain in-store technological enhancements, such as seamless sensing and seamful actuating, can serve to alleviate employee sense of pressure and anxiety during customer interactions.
[A comparison of convenience sampling and purposive sampling].
Suen, Lee-Jen Wu; Huang, Hui-Man; Lee, Hao-Hsien
2014-06-01
Convenience sampling and purposive sampling are two different sampling methods. This article first explains sampling terms such as target population, accessible population, simple random sampling, intended sample, actual sample, and statistical power analysis. These terms are then used to explain the difference between "convenience sampling" and purposive sampling." Convenience sampling is a non-probabilistic sampling technique applicable to qualitative or quantitative studies, although it is most frequently used in quantitative studies. In convenience samples, subjects more readily accessible to the researcher are more likely to be included. Thus, in quantitative studies, opportunity to participate is not equal for all qualified individuals in the target population and study results are not necessarily generalizable to this population. As in all quantitative studies, increasing the sample size increases the statistical power of the convenience sample. In contrast, purposive sampling is typically used in qualitative studies. Researchers who use this technique carefully select subjects based on study purpose with the expectation that each participant will provide unique and rich information of value to the study. As a result, members of the accessible population are not interchangeable and sample size is determined by data saturation not by statistical power analysis.
Directory of Open Access Journals (Sweden)
Maziar Nekovee
2010-01-01
Full Text Available Cognitive radio is being intensively researched as the enabling technology for license-exempt access to the so-called TV White Spaces (TVWS, large portions of spectrum in the UHF/VHF bands which become available on a geographical basis after digital switchover. Both in the US, and more recently, in the UK the regulators have given conditional endorsement to this new mode of access. This paper reviews the state-of-the-art in technology, regulation, and standardisation of cognitive access to TVWS. It examines the spectrum opportunity and commercial use cases associated with this form of secondary access.
基于脉冲跳变的空间矢量脉冲宽度调制策略%Novel space vector pulse width modulation based on pulse-shifting
Institute of Scientific and Technical Information of China (English)
林城美; 王公宝; 汪光森; 李卫超; 崔小鹏
2016-01-01
针对二极管钳位型单相九电平逆变器,分析其工作原理,提取了逆变器工作的有效开关状态。根据伏秒平衡原理和两矢量三段式调制规律,提出了一种基于脉冲跳变的空间矢量脉冲宽度调制( space vector pulse width modulation,SVPWM)策略。通过分析所有开关周期脉冲的跳变情况,给出了脉冲类型的判断条件,并根据脉冲类型计算起始和终止电压矢量及其作用时间；同时,应用FPGA设计了模块化SVPWM控制系统,并对该控制系统进行了时钟与资源消耗评估。性能分析结果表明,该调制策略计算速度快、资源消耗小。最后,仿真与实验结果验证了所提调制策略的正确性和有效性,而且能够有效地均衡电容电压。%The operating principle of diode-clamped single phase 9-level inverter was analyzed firstly, and its useful switching vectors of the inverter were obtained. A novel space vector pulse width modulation ( SVPWM) was presented based on pulse-shifting, according to volt-second balance principle and two-vector modulation rule. By analyzing the pulse-shifting condition within one normal switching period, the criterion for judging pulse type was also proposed. Based on different pulse type, the computing method of the start and end voltage vector were different, and their dwell time were also different. The SVPWM control system was implemented using a field programmable gate array ( FPGA) circuit as the hardware simulation platform, whose clock and resource utilization are evaluated. The simulation and experimental results demonstrate that the presented control strategy has good control effect, and balances the capacitor voltages better.
Conveniently assembled multiple-electrode-pair CO2 laser
Ye, Lihua; Li, Xiangyen; He, Anzhi
2000-04-01
A conveniently assembled multiple-electrode-pair (MEP) transversely excited amplify (TEA) CO2 laser is introduced in this paper. The laser is described from the view of device configuration, power supply, control circuit, and etc. The laser output is variable from single pulse to double pulse and multiple pulse with different assembly. We adopt a new alignment method for cavity. The pulse time interval given by control system is continuously adjustable from 0 to 150 microseconds. Experiments prove that the pulse series property is stable and that the pulse parameters are perfect. The conveniently assembled laser lay a foundation for the industry application of multiple-electrode-pair CO2 laser.
Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F
2016-07-01
In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK.
Triangle Lattice Green Functions for Vector Fields
Moritz, Brian; Schwalm, William
2000-03-01
The triangle lattice is convenient for modeling fields and fluid flows in two dimensions. Discrete vector field equations are defined through the analogy between differential forms and simplicial homology theory. The basic vector difference operators on the lattice correspond to the graph adjacency matricies of the triangle, honeycomb, and Kagomé lattices. The scalar Green functions for nearest neighbor interactions on the triangle lattice are known in closed form in terms of the complete elliptic integrals. Green functions for vector field operators are obtained explicitly in terms of the known scalar Green functions. The scalar Green functions for the Kagomé lattice are thus written in terms of the Green functions for the triangle lattice and ultimately in closed form. Thus, Green functions for a wide range of vector difference models are reduced to closed form in terms of the complete elliptic integrals.
Killen, R.
1977-01-01
There are six cases considered: (1) no updates made during the flight, (2) one ground update in the vertical components only at the first practice separation minus 15 minutes, (3) one ground update in all components at the first practice separation minus 5 minutes, (4) updates 2 and 3 applied successively, (5) Case 4 plus an update in all components at the second separation attempt minus 3 minutes, and (6) one ground update at first separation attempt minus 5 minutes and a second update at second separation minus two minutes. The mission control simulation program, GROPER, was run using as radar input a tape containing radar derived state vectors for the trajectory.
Less Expensive and More Convenient Gaucher's Disease Treatment
King, Angela G.
2006-01-01
A new research finding related to a less costly and more convenient treatment for Gaucher's disease, the most common lysosomal storage disorder and genetic disorder affecting Jewish people of Eastern European ancestry is reported. The reports suggest that chemical chaperons could partially correct the genetic defect responsible for most cases of…
Convenient meat and meat products. Societal and technological issues.
Leroy, Frédéric; Degreef, Filip
2015-11-01
In past and contemporary foodscapes, meat and meat products have not only been following convenience trends, they have been at the heart of them. Historically, the first substantial demands for meat convenience must have been for the outsourcing of hunting or domestication, as well as slaughtering activities. In its turn, this prompted concerns for shelf-life stabilisation and the development of preservation strategies, such as meat fermentation. Demands for ease of preparation and consumption can be traced back to Antiquity but have gained in importance over the centuries, especially with the emergence of novel socio-cultural expectations and (perceived) time scarcity. Amongst other trends, this has led to the creation of ready meals and meat snacks and the expansion of urban fast food cultures. Additionally, contemporary requirements focus on the reduction of mental investments, via the "convenient" concealment of slaughtering, the optimisation of nutritional qualities, and the instant incorporation of more intangible matters, such as variety, hedonistic qualities, reassurance, and identity. An overview is given of the technological issues related to the creation of meat convenience, in its broadest sense, along with their societal implications. Copyright © 2015 Elsevier Ltd. All rights reserved.
Simple and convenient method for culturing anaerobic bacteria.
Behbehani, M J; Jordan, H. V.; Santoro, D L
1982-01-01
A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.
Analisis Industri pada Ritel Convenience Store: Kasus 7-Eleven (Sevel
Directory of Open Access Journals (Sweden)
Son Wandrial
2013-05-01
Full Text Available 7-Eleven, a Japanese retailer is very popular and loved in Jakarta. 7-Eleven or commonly abbreviated to Sevel is now reaping a lot of fans because of the concept of 7-Eleven Indonesia, found only in Indonesia. With the rising middle classes in Indonesia, 7-Eleven becomes a luxurious place for hanging-out but affordable. Consequently, it is attracting the interest of investors to make such a kind of convenience store like Sevel, and it is likely the competition in this sector will be increasingly fierce. PT. Modern’s initial plans are to focus onopening stores in Jakarta, targeting densely-populated commercial and office areas, to offer Indonesian workersa convenient place to shop for lunch, snacks, and emergency items. The company’s goal is to focus on opening stores in Jakarta in its first years of operation. Other major cities, such as Bandung, Semarang, and Surabaya offer for future expansion opportunities. The objective of this article is to describe the competitive condition in convenience store industries using Porter’s Five Forces model. Although the competition is fierce andunfavorable industry condition, Sevel is still leading and dominating the convenience store market in Indonesia.
45 CFR 2541.440 - Termination for convenience.
2010-10-01
... 45 Public Welfare 4 2010-10-01 2010-10-01 false Termination for convenience. 2541.440 Section 2541.440 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND... LOCAL GOVERNMENTS Reports, Records, Retention and Enforcement § 2541.440 Termination for...
Power Law of Customers’ Expenditures in Convenience Stores
Mizuno, Takayuki
2008-03-01
In a convenience store chain, a tail of the cumulative density function of the expenditure of a person during a single shopping trip follows a power law with an exponent of -2.5. The exponent is independent of the location of the store, the shopper's age, the day of week, and the time of day.
Convenient Synthesis of Bis(oxazoline) Dicarboxylate Derivatives
Institute of Scientific and Technical Information of China (English)
Bin FU; Da Ming DU; Qing XIA
2004-01-01
The synthesis of bis(oxazoline) dicarboxylate derivatives was investigated.Diethyl-aminosulfur trifluoride(DAST)was used as a convenient cyclization reagent in the synthesis of bis(oxazoline)dicarboxylate derivatives,which can not be obtained by the general method using MsCl and Et3N as dehydrating cyclization reagent.
Zhao, Jinlong; Sun, Wenye; Liang, Jing; Jiang, Jing; Wu, Zhao
2016-09-01
Transcription activator-like effector nucleases (TALENs) are powerful tools for targeted genome editing in diverse cell types and organisms. However, the highly identical TALE repeat sequences make it challenging to assemble TALEs using conventional cloning approaches, and multiple repeats in one plasmid are easily catalyzed for homologous recombination in bacteria. Although the methods for TALE assembly are constantly improving, these methods are not convenient because of laborious assembly steps or large module libraries, limiting their broad utility. To overcome the barrier of multiple assembly steps, we report a one-step system for the convenient and flexible assembly of a 180 TALE module library. This study is the first demonstration to ligate 9 mono-/dimer modules and one circular TALEN backbone vector in a one step process, generating 9.5 to 18.5 repeat sequences with an overall assembly rate higher than 50%. This system makes TALEN assembly much simpler than the conventional cloning of two DNA fragments because this strategy combines digestion and ligation into one step using circular vectors and different modules to avoid gel extraction. Therefore, this system provides a convenient tool for the application of TALEN-mediated genome editing in scientific studies and clinical trials.
电压空间矢量PWM控制技术的探讨%Discussion of Space Voltage Vector PWM Technology
Institute of Scientific and Technical Information of China (English)
赵利
2011-01-01
In this paper, SVPWM control technology is utilized method is employed by inserting zero voltage vectors between SVPWM w＇aves and the basic knowledge of Fourier series, the the fundamental frequency, which the inverter output U/f is a to produce hexagonal rotating magnetic field, and a the basic voltage vectors skillfully. Using the above proof is given when adjusting motor＇s speed under constant. It is important for students to understand and master the knowledge of SVPWM technology and AC drive system accurately and comprehensively.%本文利用SVPWM控制技术产生的正六边形旋转磁场，在基本电压矢量之间插入零电压矢量。利用得到的SVPWM波及傅立叶级数基本知识，证明了基频以下调速时，逆变器输出电压一频率比为恒值这一结论。这对准确而全面理解SVPWM控制技术、深刻掌握交流调速系统有关内容具有重要意义。
Horikis, Theodoros P
2016-01-01
Families of soliton pairs, namely vector solitons, are found within the context of a coupled nonlocal nonlinear Schrodinger system of equations, as appropriate for modeling beam propagation in nematic liquid crystals. In the focusing case, bright soliton pairs have been found to exist provided their amplitudes satisfy a specific condition. In our analytical approach, focused on the defocusing regime, we rely on a multiscale expansion methods, which reveals the existence of dark-dark and antidark-antidark solitons, obeying an effective Korteweg-de Vries equation, as well as dark-bright solitons, obeying an effective Mel'nikov system. These pairs are discriminated by the sign of a constant that links all physical parameters of the system to the amplitude of the stable continuous wave solutions, and, much like the focusing case, the solitons' amplitudes are linked leading to mutual guiding.
DEFF Research Database (Denmark)
Frandsen, Rasmus John Normand; Andersson, Jens A.; Kristensen, Matilde Bylov;
2008-01-01
technique that allows single step cloning of the two required homologous recombination sequences into different sites of a recipient vector. The advantages are: A simple experimental design, free choice of target sequence, few procedures and user convenience. The vectors are intented for Agrobacterium...... with an average efficiency of 84% for gene replacement and 80% for targeted overexpression. Conclusion: The new vectors designed for USER Friendly cloning provided a fast reliable method to construct vectors for targeted gene manipulations in fungi....
2012-04-09
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and..., 2012 The following Applications for Certificates of Public Convenience and Necessity and Foreign Air..., Inc. (``People Express'') requesting a certificate of public convenience and necessity...
2011-09-01
... TRANSPORTATION Office of the Secretary Notice of Applications for Certificates of Public Convenience and... August 20, 2011 The following Applications for Certificates of Public Convenience and Necessity and..., Inc. (``Universal'') requesting a certificate of public convenience and necessity...
2011-02-24
... TRANSPORTATION Office of the Secretary Notice of Applications for Certificates of Public Convenience and... February 12, 2011 The following Applications for Certificates of Public Convenience and Necessity and... certificate of public convenience and necessity authorizing interstate charter air transportation....
五相电压源逆变器的空间矢量脉宽调制方法研究%Research of Space Vector PWM Techniques for Five-phase Voltage Source Inverter
Institute of Scientific and Technical Information of China (English)
高宏伟; 杨贵杰; 刘剑
2014-01-01
To improve the DC bus voltage utilization of five-phase voltage source inverter (VSI) and reduce the harmonic component of output phase voltages, a space vector pulse width modulation (SVPWM) algorithm of five-phase VSI based on adjacent four voltage vectors was proposed. According to the value of modulation index, the modulation range could be divided into sine modulation region and non-sine modulation region. In sine modulation region, the output phase voltages are standard sine waves without any harmonic component through allocating the action time of space vector appropriately. In non-sine modulation region, through optimizing the voltage vector in harmonic subspace, not only the DC bus voltage utilization is improved effectively, but also the harmonic component of output phase voltages is minimized. Simulation and experimental results verify the correctness and feasibility of the proposed algorithm.%为提高五相电压源逆变器(voltage source inverter，VSI)的直流母线电压利用率，减少输出相电压中所含的谐波分量，提出一种改进的基于最近四矢量的五相 VSI 空间矢量脉宽调制算法。根据调制系数的不同，将整个调制范围分为正弦调制区和非正弦调制区。在正弦调制区，通过合理分配空间矢量的作用时间，使得输出相电压为标准正弦波形，不含有任何谐波成分；在非正弦调制区，通过对谐波子空间内的电压矢量进行优化控制，在进一步提高直流母线电压利用率的同时，保证输出相电压中所含谐波分量更少，使逆变器工作在最优状态。仿真和实验结果验证了所提算法的正确性和可行性。
Higgs Decays and Brane Gravi-vectors
Clark, T. E.; Liu, B. Y.; Love, S. T.; Xiong, C.; ter Veldhuis, T.
2008-01-01
Higgs boson decays in flexible brane world models with stable, massive gravi-vectors are considered. Such vectors couple bilinearly to the Standard Model fields through either the Standard Model energy-momentum tensor, the weak hypercharge field strength or the Higgs scalar. The role of the coupling involving the extrinsic curvature is highlighted. It is found that within the presently allowed parameter space, the decay rate of the Higgs into two gravi-vectors (which would appear as an invisi...
The vector algebra war: A historical perspective
Chappell, James M; Hartnett, John G; Abbott, Derek
2015-01-01
There are a wide variety of different vector formalisms currently utilized in science. For example, Gibbs three-vectors, spacetime four-vectors, complex spinors for quantum mechanics, quaternions used for rigid body rotations and Clifford multivectors. With such a range of vector formalisms in use, it thus appears that there is as yet no general agreement on a vector formalism suitable for the whole of science. This surprising situation exists today, despite the fact that one of the main goals of nineteenth century science was to correctly describe vectors and the algebra of three-dimensional space. This situation has also had the unfortunate consequence of fragmenting knowledge across many disciplines and requiring a very significant amount of time and effort in learning the different formalisms. We thus review historically the development of our various vector systems and conclude that the Clifford algebra multivector fulfills the goal of correctly describing vectorial quantities in three dimensions.
Bifurcations of optimal vector fields
Kiseleva, T.; Wagener, F.
2015-01-01
We study the structure of the solution set of a class of infinite-horizon dynamic programming problems with one-dimensional state spaces, as well as their bifurcations, as problem parameters are varied. The solutions are represented as the integral curves of a multivalued optimal vector field on sta
Sentiment Vector Space Model Based Music Emotion Tag Prediction%基于情感向量空间模型的歌曲情感标签预测模型
Institute of Scientific and Technical Information of China (English)
李静; 林鸿飞; 李瑞敏
2012-01-01
Music emotion tag prediction algorithm plays an important role in music sentiment analysis. This paper presents a sentiment vector space model (s-VSM) based music emotion tag prediction algorithm. Firstly, we extract the emotion words to build the sentiment vector space model. Then, we use SVM classifier to generate training samples, and to get the collection which shares the same main emotion category with the predicted music. Finally, by finding the nearest k songs, we can get the emotion tag for recommendation. Experimental results show that s-VSM and the "emotional words-emotional label" co-occurrence based feature reduction method perform better than traditionally word-based vector space model in mood classification. Meanwhile, the emotion tag prediction based on the result of classification can effectively prevent the music "main mood drift", thus achieving better tag predict accuracy than k-nearest neighbors method.%音乐的情感标签预测对音乐的情感分析有着重要的意义.该文提出了一种基于情感向量空间模型的歌曲情感标签预测算法,首先,提取歌词中的情感特征词构建情感空间向量模型,然后利用SVM分类器对已知情感标签的音乐进行训练,通过分类技术找到与待预测歌曲情感主类一致的歌曲集合,最后,通过歌词的情感相似度计算找到最邻近的k首歌曲,将其标签推荐给待预测歌曲.实验发现本文提出的情感向量空间模型和“情感词—情感标签”共现的特征降维方法比传统的文本特征向量模型能够更好地提高歌曲情感分类准确率.同时,在分类基础上进行的情感标签预测方法可以有效地防止音乐“主类情感漂移”,比最近邻居方法达到更好的标签预测准确率.
Unsupervised learning of binary vectors
Copelli Lopes da Silva, Mauro
In this thesis, unsupervised learning of binary vectors from data is studied using methods from Statistical Mechanics of disordered systems. In the model, data vectors are distributed according to a single symmetry-breaking direction. The aim of unsupervised learning is to provide a good approximation to this direction. The difference with respect to previous studies is the knowledge that this preferential direction has binary components. It is shown that sampling from the posterior distribution (Gibbs learning) leads, for general smooth distributions, to an exponentially fast approach to perfect learning in the asymptotic limit of large number of examples. If the distribution is non-smooth, then first order phase transitions to perfect learning are expected. In the limit of poor performance, a second order phase transition ("retarded learning") is predicted to occur if the data distribution is not biased. Using concepts from Bayesian inference, the center of mass of the Gibbs ensemble is shown to have maximal average (Bayes-optimal) performance. This upper bound for continuous vectors is extended to a discrete space, resulting in the clipped center of mass of the Gibbs ensemble having maximal average performance among the binary vectors. To calculate the performance of this best binary vector, the geometric properties of the center of mass of binary vectors are studied. The surprising result is found that the center of mass of infinite binary vectors which obey some simple constraints, is again a binary vector. When disorder is taken into account in the calculation, however, a vector with continuous components is obtained. The performance of the best binary vector is calculated and shown to always lie above that of Gibbs learning and below the Bayes-optimal performance. Making use of a variational approach under the replica symmetric ansatz, an optimal potential is constructed in the limits of zero temperature and mutual overlap 1. Minimization of this potential
Cerba Diaconescu, Oxana; Schlomiuk, Dana; Vulpe, Nicolae
In this article, we consider the class QSL4{u +vc+w^c, ∞ } of all real quadratic differential systems (dx)/(dt) = p(x, y), (dy)/(dt) = q(x, y) with gcd(p, q) = 1, having invariant lines of total multiplicity four and two complex and one real infinite singularities. We first construct compactified canonical forms for the class QSL4{u +vc+w^c, ∞ } so as to include limit points in the 12-dimensional parameter space of this class. We next construct the bifurcation diagrams for these compactified canonical forms. These diagrams contain many repetitions of phase portraits and we show that these are due to many symmetries under the group action. To retain the essence of the dynamics we finally construct the quotient spaces under the action of the group G = Aff(2, ℝ) × ℝ* of affine transformations and time homotheties and we place the phase portraits in these quotient spaces. The final diagrams retain only the necessary information to capture the dynamics under the motion in the parameter space as well as under this group action. We also present here necessary and sufficient conditions for an affine line to be invariant of multiplicity k for a quadratic system.
Valuation of commodity derivatives with an unobservable convenience yield
Lai, Anh Ngoc; Mellios, Constantin
2016-01-01
International audience; This paper extends the existing literature on commodity derivatives to account for an unobservable stochastic convenience yield. Investors operate in an economy with incomplete information. In contrast to other incomplete information models, analytical formulas for forward and futures prices, as well as for European options on forward and futures contracts are obtained. These formulas reveal the important role played by the initial values of the estimator of the conven...
Creating convenience food based on human nutritional requirements
2010-01-01
International audience; Nanoscale science and technology are now enabling us to understand many natural and unnatural processes. Studying nanostructures at the cell and DNA level, gives us insight in to the working of these processes and how to manipulate, prevent and/or enhance them for the benefit of mankind. Emergent technologies can and must help correct the food system by creating modern convenience foods on a mass scale that mimic and improve on the nutritional value of the most nutriti...
Health indicators: eliminating bias from convenience sampling estimators.
Hedt, Bethany L; Pagano, Marcello
2011-02-28
Public health practitioners are often called upon to make inference about a health indicator for a population at large when the sole available information are data gathered from a convenience sample, such as data gathered on visitors to a clinic. These data may be of the highest quality and quite extensive, but the biases inherent in a convenience sample preclude the legitimate use of powerful inferential tools that are usually associated with a random sample. In general, we know nothing about those who do not visit the clinic beyond the fact that they do not visit the clinic. An alternative is to take a random sample of the population. However, we show that this solution would be wasteful if it excluded the use of available information. Hence, we present a simple annealing methodology that combines a relatively small, and presumably far less expensive, random sample with the convenience sample. This allows us to not only take advantage of powerful inferential tools, but also provides more accurate information than that available from just using data from the random sample alone. Copyright © 2011 John Wiley & Sons, Ltd.
Research of Hysteresis Current Control Method Based on Voltage Space Vector%基于空间矢量的滞环电流跟踪控制策略仿真研究
Institute of Scientific and Technical Information of China (English)
陈志华; 曹以龙; 张海
2013-01-01
研究了一种基于电压空间矢量脉宽调制(SVPWM)的不定频滞环电流控制方法.设计了基于该控制策略的PWM整流器和有源电力滤波器的Simulink仿真模型,仿真结果表明了该控制策略的可行性.%A variable-frequency hysteresis current control method based on voltage space vector pulse width modulation ( SVPWM) was proposed, and the Simulink model for PWM rectifier and active power filter was designed based on this control strategy. The simulation results prove the feasibility of this controlling strategy.
Low Power, Self Calibrated Vector Magnetometer Project
National Aeronautics and Space Administration — This Phase I SBIR project investigates a novel approach to vector magnetometry based on high precision measurements of the total magnetic field. The calibration is...
Twisted Vector Bundles on Pointed Nodal Curves
Indian Academy of Sciences (India)
Ivan Kausz
2005-05-01
Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich’s and Vistoli’s twisted bundles and Gieseker vector bundles.
Institute of Scientific and Technical Information of China (English)
谢松山; 唐雁
2015-01-01
提出一种基于左归词频向量空间模型的抄袭检测算法 .通过左归处理将抄袭文本的指代还原 ,借助同义词链对所有同义词统一左对齐于同义词链首词 ,然后以直接统计词频构造文本词频特征 ,抛弃词频统计抄袭检测算法中以TF-IDF多步计算相对词频的处理 ,最后以词频特征构造向量空间模型 ,用余弦相似计算文本相似度 .实验表明 ,算法在各种抄袭类型的数据集上综合性能更优、稳定性更好、效率更高 .%In this paper ,an algorithm for plagiarism detection based on left align word frequency vector space model is proposed .First ,left align treatment is made to recover the reference in the copied text . Next ,all synonyms are unified with the synonym chain by left-justifying them with the first word at their synonym chain .Then ,a text word frequency features are constructed directly with statistical method ,a-bandoning the multi-step process of TF-IDF to calculate the relative word frequency in other word frequen-cy plagiarism detection algorithms .Finally ,a vector space model is constructed ,using the word frequency features ,and the text similarity is calculated using the cosine similarity .Experimental results show that this algorithm on various types of plagiarism data sets has better overall performance ,better stability and greater efficiency .
Red'kov, V M
2011-01-01
In the work some relations between three techniques, Hopf's bundle, Kustaanheimo-Stiefel's bundle, 3-space with spinor structure have been examined. The spinor space is viewed as a real space that is minimally (twice as much) extended in comparison with an ordinary vector 3-space: at this instead of 2\\pi-rotation now only 4\\pi-rotation is taken to be the identity transformation in the geometrical space. With respect to a given P-orientation of an initial unextended manyfold, vector or pseudovector one, there may be constructed two different spatial spinors, $\\xi$ and $\\eta$, respectively. By definition, those spinors provide us with points of the extended space odels, each spinor is in the correspondence $2 \\longrightarrow 1 with points of a vector space. For both models an explicit parametrization of the spinors \\xi and \\eta by spherical and parabolic coordinates is given, the parabolic system turns out to be the most convenient for simple defining spacial spinors. Fours of real-valued coordinates by Kustaan...
Vectors a Fortran 90 module for 3-dimensional vector and dyadic arithmetic
Energy Technology Data Exchange (ETDEWEB)
Brock, B.C.
1998-02-01
A major advance contained in the new Fortran 90 language standard is the ability to define new data types and the operators associated with them. Writing computer code to implement computations with real and complex three-dimensional vectors and dyadics is greatly simplified if the equations can be implemented directly, without the need to code the vector arithmetic explicitly. The Fortran 90 module described here defines new data types for real and complex 3-dimensional vectors and dyadics, along with the common operations needed to work with these objects. Routines to allow convenient initialization and output of the new types are also included. In keeping with the philosophy of data abstraction, the details of the implementation of the data types are maintained private, and the functions and operators are made generic to simplify the combining of real, complex, single- and double-precision vectors and dyadics.
48 CFR 8.406-5 - Termination for the Government's convenience.
2010-10-01
... Government's convenience. 8.406-5 Section 8.406-5 Federal Acquisition Regulations System FEDERAL ACQUISITION... Termination for the Government's convenience. (a) An ordering activity contracting officer may terminate individual orders for the Government's convenience. Terminations for the Government's convenience...
Convenience food with environmentally-sustainable attributes: A consumer perspective.
Stranieri, Stefanella; Ricci, Elena Claire; Banterle, Alessandro
2017-09-01
The use of chemicals in agriculture poses risks on both human health and the environment. Regulatory measures, both mandatory and voluntary, have been introduced to promote a reduction in the use of pesticides. The proliferation of such standards is related to the gradual shift of consumer preferences towards food with reduced negative health and environmental impacts. Beside consumer demand for sustainable food products, convenience food is also assuming an increasingly important role in developed countries. Among such products, minimally-processed vegetables are showing a growing positive trend, but their production has also negative effects on the environment. The goal of this study is to investigate the interaction between environmentally-friendly and healthy convenience food, and to investigate the determinants behind the purchase of healthy convenience food products with environmentally-sustainable attributes, focusing on minimally-processed vegetables labelled with voluntary standards related to integrated agriculture. To do so, we started from the Theory of Planned Behaviour and tested the efficacy of an extended model by considering also other variables which were found to affect significantly food choices. Data were collected by means of face-to-face interviews with 550 consumers in charge of grocery shopping in the metropolitan area of Milan, in northern Italy. Structural equation modelling was performed to analyse the relative importance of the constructs on consumer behaviour. Results confirm the relations of Ajzen's theory and reveal positive relations with consumer food shopping habits, food-related environmental behaviour, gender, income and knowledge. A negative relation with agricultural practices concern also emerges, highlighting that the most concerned consumers may prefer other more stringent environmental certifications. Copyright © 2017 Elsevier Ltd. All rights reserved.
Essays in petroleum futures market, convenience yield, and long memory
Mazaheri, Ataollah
This thesis is a collection of three essays which address some empirical applications of long memory processes with specific interest in financial economics of energy futures market. The first essay 'Evidence of Long Memory in the Petroleum Market' studies evidence of long memory in the energy market using daily and weekly futures data. This essay concentrates on the question of interdependence between crude oil futures and the corresponding products. The empirical results provide strong support for long memory in the energy futures market. The cointegrating relations between crude oil and heating oil futures as well as crude oil and unleaded gasoline futures exhibit long memory, whereas the individual series are unit-root. The second essay 'Convenience Yield, Mean Reversion and Long Memory in the Petroleum Market' analyzes convenience yields in the petroleum market. The focus of this essay is the behavior of the spot and futures prices over the long run. The implied convenience yield for petroleum and petroleum products is found to be driven by a nonstationary and mean reverting long memory process. The theoretical implication of this finding is established. It is discussed that this might be attributed to the fact that the market is expecting mean reversion in the spot prices. Furthermore, the volatility process and its relation with the mean process and the corresponding direction of causality have been studied in detail. The third essay 'Long Memory and Conditional Heteroskedasticity, A Monte Carlo Investigation', unlike the first two, looks at the econometrics of the estimators of the long memory process. It evaluates performance of three methods of estimating the parameter of fractionally integrated noise: the exact maximum likelihood estimator (MLE), the quasi maximum likelihood estimator (QMLE), and the GPH under different realizations for variance.
Accessibility of antiretroviral therapy in Ghana: convenience of access.
Addo-Atuah, Joyce; Gourley, Dick; Gourley, Greta; White-Means, Shelley I; Womeodu, Robin J; Faris, Richard J; Addo, Nii Akwei
2012-01-01
The convenience of accessing antiretroviral therapy (ART) is important for initial access to care and subsequent adherence to ART. We conducted a qualitative study of people living with HIV/AIDS (PLWHA) and ART healthcare providers in Ghana in 2005. The objective of this study was to explore the participants' perceived convenience of accessing ART by PLWHA in Ghana. The convenience of accessing ART was evaluated from the reported travel and waiting times to receive care, the availability, or otherwise, of special considerations, with respect to the waiting time to receive care, for those PLWHA who were in active employment in the formal sector, the frequency of clinic visits before and after initiating ART, and whether the PLWHA saw the same or different providers at each clinic visit (continuity of care). This qualitative study used in-depth interviews based on Yin's case-study research design to collect data from 20 PLWHA and 24 ART healthcare providers as study participants. • Reported travel time to receive ART services ranged from 2 to 12 h for 30% of the PLWHA. • Waiting time to receive care was from 4 to 9 h. • While known government workers, such as teachers, were attended to earlier in some of the centres, this was not a consistent practice in all the four ART centres studied. • The PLWHA corroborated the providers' description of the procedure for initiating and monitoring ART in Ghana. • PLWHA did not see the same provider every time, but they were assured that this did not compromise the continuity of their care. Our study suggests that convenience of accessing ART is important to both PLWHA and ART healthcare providers, but the participants alluded to other factors, including open provider-patient communication, which might explain the PLWHA's understanding of the constraints under which they were receiving care. The current nation-wide coverage of the ART programme in Ghana, however, calls for the replication of this study to identify
Rotations with Rodrigues' Vector
Pina, E.
2011-01-01
The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…
Convenient Airports: Point of View of the Passengers
Magri, Adival Aparecido, Jr.; Alves, Claudio Jorge Pinto
2003-01-01
The competition among airlines or among airports aiming at to increase the demand for its services has been more and more incited. Knowledge the perception of the users for the offered services means to meet the customer's needs and expectations in order either to keep the customer, and therefore keep a significant advantage over competitors. The passenger of the air transportation wants rapidity, security and convenience. Convenience can be translated by comfort that the passenger wants for the price that he can pay. In this paper had been identified. as a result of a survey achieved in six Brazilian airports during 2002, the best indicators in the passenger's perception. These indicators among any others were listed m the handbook of Airports Council International (ACI). Distinctive perceptions were observed among passengers with different travel motivations. This survey had been carried through in the airports of Brasilia, Porto Alegre, Salvador. Fortaleza, Curitiba and Bel6m. Considering this survey we can identified the most attractive airport among them. This work is a way to help improve quality of service, in particular, m these six airports of the Brazilian network. The results should be published and made available to all the parties concerned (airport authority, airlines and service providers) and should lead to corrective action when the passenger is not satisfied with the service.
Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization
Liu, Xiao-Pan; Wang, Hao-Yang; Zhang, Jun-Ting; Wu, Meng-Xi; Qi, Wan-Shu; Zhu, Hui; Guo, Yin-Long
2015-11-01
Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray gases, but just using small size of n-butane flame (height approximately 1 cm, about 500 oC) to accomplish the rapid desorption and ionization for direct analysis of gaseous-, liquid- and solid-phase organic compounds, as well as real-world samples. This method has high sensitivity with a limit of detection of 1 picogram for propyphenazone, which allows consuming trace amount of samples. Compared to previous ionization methods, this ion source device is extremely simple, maintain-free, low-cost, user-friendly so that even an ordinary lighter (with n-butane as fuel) can achieve efficient ionization. A new orientation to mass spectrometry ion source exploitation might emerge from such a convenient, easy and inexpensive AFI ion source.
Robbery characteristics and employee injuries in convenience stores.
Faulkner, K A; Landsittel, D P; Hendricks, S A
2001-12-01
Each year approximately 30,000 convenience store employees are at risk for injuries related to robberies and many are fatal. A prospective cohort study of 460 convenience store robberies from 1 February 1995 to 30 September 1996 was conducted to uncover possible associations between injury and pertinent robbery circumstances and work environments. Data collection sources included police reports, employee interviews, store evaluations, and relevant Census data. Rate ratios and correlation statistics were calculated to identify associations with injury and relationships between variables. Injury risk was strongly associated with the following characteristics: employee resistance, robberies without firearms or money taken, daytime and merchandise robberies, stores with limited escape routes and no cash policy or drop safe, older clerks, and surrounding areas with lower valued buildings, less expensive rent, more vacant structures, and younger residents. Numerous intercorrelations between these characteristics were identified. Training opportunities, store procedures, and environmental designs are important factors to consider in reducing robbery-related injuries. Published 2001 Wiley-Liss, Inc
Household food waste separation behavior and the importance of convenience.
Bernstad, Anna
2014-07-01
Two different strategies aiming at increasing household source-separation of food waste were assessed through a case-study in a Swedish residential area (a) use of written information, distributed as leaflets amongst households and (b) installation of equipment for source-segregation of waste with the aim of increasing convenience food waste sorting in kitchens. Weightings of separately collected food waste before and after distribution of written information suggest that this resulted in neither a significant increased amount of separately collected food waste, nor an increased source-separation ratio. After installation of sorting equipment in households, both the amount of separately collected food waste as well as the source-separation ratio increased vastly. Long-term monitoring shows that results where longstanding. Results emphasize the importance of convenience and existence of infrastructure necessary for source-segregation of waste as important factors for household waste recycling, but also highlight the need of addressing these aspects where waste is generated, i.e. already inside the household.
Hyperorthogonal family of vectors and the associated Gram matrix
DEFF Research Database (Denmark)
Fuglede, Bent
2014-01-01
A family of non-zero vectors in Euclidean n -space is termed hyperorthogonal if the angle between any two distinct vectors of the family is at least π/2 . Any hyperorthogonal family is finite and contains at most 2n vectors. It decomposes uniquely into the union of mutually orthogonal irreducible...
Institute of Scientific and Technical Information of China (English)
李武云
2014-01-01
The improved space vector hysteresis control was introduced for the disadvantage of poor current tracking caused by the traditional control strategy in the three-phase voltage source PWM rectifier. The improved strategy choose the hysteresis loop width and the switch state through the judgment of the AC error current vector modulus, and the selection principle of the switch state was provided in order to reduce the switching losses. Final y, the simulation model was established under matlab/simulink to compare AC current quality between the traditional and the improved control strategies, the simulation results further demonstrated the superiority of the improved control scheme.%提出了一种改进的滞环空间矢量控制，用于解决三相电压型PWM整流器采用传统滞环空间矢量控制时，电流跟踪效果不佳的问题。改进后的控制策略通过对交流侧误差电流矢量模值大小判断后，选择滞环环宽和对应的开关状态，同时总结出最佳的开关状态选择原则，以最大限度地低开关损耗，提高系统响应速度。最后在matlab/simulink下建立系统的仿真模型，通过对改进前后两种控制策略下交流侧电流质量的对比，进一步验证了改进后控制策略的优越性。
Fan, Zhong-Ying
2016-09-01
In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.
Causality of spacetimes admitting a parallel null vector and weak KAM theory
Minguzzi, E
2012-01-01
The causal spacetimes admitting a covariantly constant null vector provide a connection between relativistic and non-relativistic physics. We explore this relationship in several directions. We start proving a formula which relates the Lorentzian distance in the full spacetime with the least action of a mechanical system living in a quotient classical space time. The timelike eikonal equation satisfied by the Lorentzian distance is proved to be equivalent to the Hamilton-Jacobi equation for the least action. We also prove that the Legendre transform on the classical base corresponds to the musical isomorphism on the light cone, and the Young-Fenchel inequality is nothing but a well known geometric inequality in Lorentzian geometry. A strategy to simplify the dynamics passing to a reference frame moving with the E.-L. flow is explained. It is then proved that the causality properties can be conveniently expressed in terms of the least action. In particular, strong causality coincides with stable causality and ...
Exploring the relationship between convenience and fish consumption: a cross-cultural study.
Olsen, Svein Ottar; Scholderer, Joachim; Brunsø, Karen; Verbeke, Wim
2007-07-01
The purpose of the present study is to explore cultural differences in the meaning of convenience and the relationships between convenience, attitudes and fish consumption in five European countries. The results suggest that the meaning of meal convenience is not culture specific, whilst the absolute levels of convenience orientation and the perceived inconvenience of fish differ between cultures. Convenience orientation was highest in Poland, followed by Spain, and was lowest in the Netherlands. The relationships between convenience orientation and attitudes towards fish, and convenience orientation and fish consumption, were insignificant in most countries. However, convenience orientation was positively related to the perceived inconvenience of fish. Perceived inconvenience of fish was negatively related to both attitudes towards fish and to fish consumption. Together, these results confirm some earlier findings that fish is generally perceived as a relatively inconvenient type of food. This study suggests that convenience orientation can be crucial to understanding food choice or behaviour only when critical mediating constructs are explored.
一种带约束的电压空间矢量脉宽调制方法%A Novel Method of Space Vector Pulse Width Modulation With Constraints
Institute of Scientific and Technical Information of China (English)
吴德会; 夏晓昊; 李钷
2013-01-01
为解决传统调制方法中的最小脉宽问题，提出了一种带约束的电压空间矢量脉宽调制(space vector pulse width modulation，SVPWM)方法。首先，建立新的三相桥臂坐标，取消了扇区的划分和判断；其次，将基本电压空间矢量由8个减小为3个，并将其作用时间与三相桥臂的导通时间一一对应；再次，通过增加约束条件，将传统 SVPWM 方法的调制过程及其结果离散化，从而避免了窄脉宽的出现；最后，给出了一种快速的计算策略，其计算量仅与 SVPWM方法一个扇区的计算量基本相同。相对于 SVPWM 方法，所提方法调制的基波与杂波在频谱上的分布更清晰，低次谐波较少，有利于进行低通滤波处理，更适合较高电压和较大电流的逆变要求。仿真及实验结果均验证了该方法的可行性。%To solve the problem of the minimum pulse width in traditional modulation methods, a space vector pulse width modulation (SVPWM) method with constraints is proposed. Firstly, a three-phase bridge-arm coordinate is established to cancel the traditional sector division and the judgment;secondly, the number of basic voltage space vectors is reduced from 8 to 3, and their actuation durations correspond to the on-times of three-phase bridge-arms respectively;thirdly, by means of adding constraint conditions the modulation process of traditional SVPWM and modulation results are discretized to prevent the appearance of narrow pulse width;finally a fast computational strategy is given and its calculated amount is basically same as to the calculated amount for one sector by SVPWM method. Relative to SVPWM method, the distribution of the fundamental wave and clutters modulated by the proposed method on the frequency spectrum is more clear and there are less low-order harmonics, so it is favorable to implement low-pass filtering, thus the proposed method is more suitable for PV inverters with higher voltage and
Combinatorial vector fields and the valley structure of fitness landscapes.
Stadler, Bärbel M R; Stadler, Peter F
2010-12-01
Adaptive (downhill) walks are a computationally convenient way of analyzing the geometric structure of fitness landscapes. Their inherently stochastic nature has limited their mathematical analysis, however. Here we develop a framework that interprets adaptive walks as deterministic trajectories in combinatorial vector fields and in return associate these combinatorial vector fields with weights that measure their steepness across the landscape. We show that the combinatorial vector fields and their weights have a product structure that is governed by the neutrality of the landscape. This product structure makes practical computations feasible. The framework presented here also provides an alternative, and mathematically more convenient, way of defining notions of valleys, saddle points, and barriers in landscape. As an application, we propose a refined approximation for transition rates between macrostates that are associated with the valleys of the landscape.
Clifford Fourier transform on vector fields.
Ebling, Julia; Scheuermann, Gerik
2005-01-01
Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space.
Ethics of infant relinquishment, cultural considerations, and obstetric conveniences.
Callister, Lynn Clark
2011-01-01
Ethical issues relating to infant relinquishment, caring for culturally diverse women, the importance of shared power between women and their caregivers, and the provision of evidence-based practice versus reliance on obstetric conveniences are addressed in this article. Respectful care of women relinquishing their infants including use of appropriate language demonstrates moral and ethical nursing practice; providing cultural competent care of multilinguistic, multicultural, and multiethnic childbearing women and their families is an ethical imperative. Nurses practicing ethically will foster adoption of best practices on perinatal and neonatal units, and generate a clearly articulated vision of woman and family centered organizational culture. In ethical terms, this demonstrates respect for others as well as beneficence. Promoting the use of ethical nursing practice and evidence-based practice requires that nurses identify change agents, those who are champions and facilitators of evidence-based practice, and then reward such innovators and make sure that clinical guidelines be developed based on best practices.
Institute of Scientific and Technical Information of China (English)
邓文浪; 齐庭庭; 李辉; 龙美志; 崔贵平; 毛勇; 郭有贵
2013-01-01
高频链矩阵整流器是一种新型的电力电子变换器，具有体积小、重量轻、转换级数少和可靠性高等特点。分析了高频链矩阵整流器的双极性空间矢量调制策略，提出了基于参考输入电流空间矢量的预测控制算法，建立了基于该预测控制算法的高频链矩阵整流器系统仿真模型。该预测控制算法具有计算量小，开关频率固定，可靠性高等特点，能实现高频链矩阵整流器输入侧电流正弦、单位输入功率因数和稳定的输出直流电流。仿真结果验证了所提控制策略的有效性。%High frequency link matrix rectifier is a new type power electronic converter with smaller size, lighter weight, less stages of conversion and high reliability, etc. The high frequency link matrix rectifier’s bipolar space vector modulation strategy is analyzed at first, and then a predictive control algorithm based on the referenced input current space vector is proposed. Based on the predictive control algorithm, the system simulation model of high frequency link matrix rectifier is established. The proposed predictive control algorithm shows the advantages of small computation, fixed switch frequency and high reliability, what’s more, it can realize sine waveform of input currents, unity input power factor and stable output DC current. Simulation results verify the effectiveness of the proposed control strategy. This work is supported by National Natural Science Foundation of China (No. 51277156 and No. 50977080).
Institute of Scientific and Technical Information of China (English)
耿俊利; 梁晖; 金渊
2015-01-01
The working modes of hybrid cascaded 7-level inverter with dead zone are analyzed and analysis results show that there are different jumping situations of inverter voltage under different working modes. On this basis, based on space vector pulse width modulation (SVPWM) strategy an optimal control method is proposed. In the premise that the supporting capacitor voltage is under the control, through analyzing the jumping of output voltage level and the valve action times corresponding to the charging/discharging process of supporting capacity voltage switching in each interval an optimal control strategy to reduce the jumping of output voltage is put forward; besides, the output voltage loss due to the existence of dead zone time is analyzed and calculated according to the principle of volt-second balance, and the dead zone compensation for its modulation wave is performed. The effectiveness of the proposed control strategy is validated by results of simulation and experiments.%分析混合级联七电平逆变器带死区时的工作模式，不同工作模式下其逆变器电压的跳变情况不同。在此基础上，提出了基于空间矢量脉冲调制(space vector pulse width modulation，SVPWM)策略的优化控制方法。以控制支撑电容电压为前提，通过对每个区间支撑电容充放电切换过程所对应的开关动作次数、输出电压电平跳变情况的分析，提出了一种减小输出电压跳变的优化控制策略；此外，分析了死区时间的存在所带来的输出电压损失，根据伏秒平衡原理进行计算，并对其调制波进行死区补偿。仿真及实验结果验证了该控制策略的有效性。
Eliezer, C J; Maxwell, E A; Sneddon, I N
1963-01-01
Concise Vector Analysis is a five-chapter introductory account of the methods and techniques of vector analysis. These methods are indispensable tools in mathematics, physics, and engineering. The book is based on lectures given by the author in the University of Ceylon.The first two chapters deal with vector algebra. These chapters particularly present the addition, representation, and resolution of vectors. The next two chapters examine the various aspects and specificities of vector calculus. The last chapter looks into some standard applications of vector algebra and calculus.This book wil
Chen, Kan; Liu, Xiang; Matsuki, Takayuki
2015-01-01
Inspired by the abundant experimental observation of axial vector states, we study whether the observed axial vector states can be categorized into the conventional axial vector meson family. In this paper we carry out analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial vector mesons, which are valuable to further experimental exploration of the observed and predicted axial vector mesons.
2011-06-08
... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF TRANSPORTATION Office of the Secretary Notice of Applications for Certificates of Public Convenience and... May 14, 2011 The following Applications for Certificates of Public Convenience and Necessity...
2011-07-19
... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF TRANSPORTATION Office of the Secretary Notice of Applications for Certificates of Public Convenience and... June 25, 2011 The following Applications for Certificates of Public Convenience and Necessity...
2011-11-03
... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under Subpart B... of Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart...
2012-05-25
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and... The following Applications for Certificates of Public Convenience and Necessity and Foreign...
2012-06-22
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and... The following Applications for Certificates of Public Convenience and Necessity and Foreign...
2012-09-26
... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF TRANSPORTATION Office of the Secretary Notice of Applications for Certificates of Public Convenience and... September 1, 2012 The following Applications for Certificates of Public Convenience and Necessity...
2011-06-20
... for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart...
Exploring the relationship between convenience and fish consumption: A cross-cultural study
DEFF Research Database (Denmark)
Olsen, Svein Ottar; Scholderer, Joachim; Brunsø, Karen
2007-01-01
The purpose of the present study is to explore cultural differences in the meaning of convenience and the relationships between convenience, attitudes and fish consumption in five European countries. The results suggest that the meaning of meal convenience is not culture specific, whilst...... the absolute levels of convenience orientation and the perceived inconvenience of fish differ between cultures. Convenience orientation was highest in Poland, followed by Spain, and was lowest in the Netherlands. The relationships between convenience orientation and attitudes towards fish, and convenience...... orientation and fish consumption, were insignificant in most countries. However, convenience orientation was positively related to the perceived inconvenience of fish. Perceived inconvenience of fish was negatively related to both attitudes towards fish and to fish consumption. Together, these results confirm...
2012-08-02
... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under Subpart B... Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart B...
2012-07-05
... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under Subpart B... Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart B...
2011-06-20
... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under Subpart B... Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart B...
Overview of Space Vector Pulse Width Algorithm of Dual Three-phase Motor%双三相感应电机空间矢量脉冲宽度调制算法综述
Institute of Scientific and Technical Information of China (English)
李洪亮; 贺诚; 田明; 许奔
2013-01-01
空间矢量脉冲宽度(SVPWM)调制算法将逆变器和电动机视为一个整体，着眼于使电动机获得幅值恒定的旋转磁场。与正弦脉冲宽度(SPWM)算法相比，SVPWM 可使功率开关器件的开关次数减少1/3，直流电压利用率提高15%，能获得较好的谐波抑制效果。本文分析了双三相感应电机常用的SVPWM调制算法，讨论了它们各自的优缺点，并给出了仿真和实验验证。%The algorithm of space vector pulse width modulation (SVPWM) regards the inverter and motor as a whole model to make the motor acquire a rotating magnetic field with constant amplitude. Comparing with the algorithm of sine pulse width modulation (SPWM), SVPWM can achieve a good harmonic control effect with less than 30 percent action times of the power switching devices and more than 15 percent DC voltage utilization. This paper analyzes the SVPWM’s common modulation algorithm of the three-phase motor and discusses their advantages and disadvantages. Simulation and experimental verification are given in the last.
Institute of Scientific and Technical Information of China (English)
高中臣; 张爱玲; 陈晨
2009-01-01
To reduce the low speed torque ripple of induction motor and keep constant switch frequency, this paper proposed a new control strategy on the basis of direct torque control (DTC),which uses Space Vector Pulse Width Modulation instead of switch table.The experiment and simulation results show that it can reduce the torque ripple,and improve the waveform of stator flux and current.%针对传统直接转矩控制开关频率不恒定及低速时的转矩脉动大的缺点,采用了基于SVPWM的直接转矩控制方法.根据转矩和定子磁链的误差确定应该施加的参考电压矢量,然后利用电压空间矢量脉宽调制(SVPWM)的方法合成该矢量.仿真和实验结果表明,基于SVPWM的直接转矩控制(SVPWM-DTC)能够有效减小转矩脉动,改善磁链和电流波形.
Study of Single-phase Three-level NPC Rectifier Based on Space Vector PWM%基于SVPWM的单相三电平NPC整流器研究
Institute of Scientific and Technical Information of China (English)
黄嘉鹏; 丛林; 许建平; 张斐; 陈章勇
2012-01-01
介绍了单相三电平中点箝位(Neutral Point Clamped,NPC)整流器的工作原理,推导了空间矢量脉宽调制(Space Vector Pulse Width Modulation,SVPWM)与正弦脉宽调制(Sinusoidal Pulse Width Modulation,SPWM)之间的关系,并在此基础上把基于SPWM的中点电压平衡算法推广至SVPWM.计算机仿真和试验结果表明,在支撑电容参数不相等的恶劣情况下,基于SVPWM的中点电压平衡方法仍能有效地抑制单相三电平中点箝位整流器的中点电压不平衡问题.%Working principle of single-phase three-level neutral-point-clamped (NPC) rectifier was discussed, and the relation between SVPWM and carrier-based PWM was established, thereby, balance control method based on SPWM for single phase three-level NPC rectifier was presented. Computer simulation and experiment results demonstrated that the proposed neutral-point voltage balance control method could solve the neutral-point voltage unbalance problem effectively even if the parameiers of the two capacitors were different.
Space vector control strategy fixed-frequency hysteresis loop APF%有源电力滤波器的定频滞环空间矢量控制策略研究
Institute of Scientific and Technical Information of China (English)
薛博文
2015-01-01
本文通过基于空间电压矢量（SVPWM）滞环电流控制策略，搭建了以DSP2407控制芯片为控制核心、定频滞环SVPWM为控制策略的有源电力滤波器控制系统，针对两种负载做了无功补偿实验，同时分析了在该控制策略下有源电力滤波器的补偿效果。实验结果验证了定频滞环SVPWM控制策略理论的正确性及可行性。%In this paper, based on space voltage vector (SVPWM) hysteresis current control strategy, built to DSP2407 control chip to control the core, fixed-frequency hysteresis SVPWM control strategy for active power filter control system, made for two kinds of load reactive power compensation experiments, and analyzes the compensation effect of the control strategy under APF. The experimental results demonstrate the fixed-frequency hysteresis SVPWM control strategy correctness and feasibility of the theory.
HE CONTROL OF HYSTERESIS SPACE VECTOR OF PARALLEL ACTIVE POWER FILTER%并联型有源电力滤波器的滞环空间矢量控制
Institute of Scientific and Technical Information of China (English)
张润和; 武海涛; 杜超; 张丽荣
2009-01-01
本文分析了与滞环相结合的空间矢量PWM的基本控制原理,并将该方法应用到并联型有源电力滤波器的控制中.利用Matlab进行了仿真研究,结果表明有源滤波器在任一时刻输出的补偿电流均能实时地跟踪指令电流,有效减小电流补偿误差,达到消除非线性负载所引起的谐波电流对电网污染的目的.%An analysis on the basic control principle of space vector PWM combined with hysteresis is made and a method is devised for implementing the control over the parallel active power filter (APF).Results of simulation by means of Matlab show that the output compensation current given at any time can track the instruction current of the APF at real-time.Thus,the current compensation error can be reduced effectively.Consequently,the harmonic current pollution on the grid caused by nonlinear load is eliminated.
U.S. Department of Health & Human Services — VectorBase is a Bioinformatics Resource Center for invertebrate vectors. It is one of four Bioinformatics Resource Centers funded by NIAID to provide web-based...
Vector Diffusion Maps and the Connection Laplacian
Singer, Amit
2011-01-01
We introduce {\\em vector diffusion maps} (VDM), a new mathematical framework for organizing and analyzing massive high dimensional data sets, images and shapes. VDM is a mathematical and algorithmic generalization of diffusion maps and other non-linear dimensionality reduction methods, such as LLE, ISOMAP and Laplacian eigenmaps. While existing methods are either directly or indirectly related to the heat kernel for functions over the data, VDM is based on the heat kernel for vector fields. VDM provides tools for organizing complex data sets, embedding them in a low dimensional space, and interpolating and regressing vector fields over the data. In particular, it equips the data with a metric, which we refer to as the {\\em vector diffusion distance}. In the manifold learning setup, where the data set is distributed on (or near) a low dimensional manifold $\\MM^d$ embedded in $\\RR^{p}$, we prove the relation between VDM and the connection-Laplacian operator for vector fields over the manifold.
Axial Vector $Z'$ and Anomaly Cancellation
Ismail, Ahmed; Tsao, Kuo-Hsing; Unwin, James
2016-01-01
Whilst the prospect of new $Z'$ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that the masses of these new states must generally be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.
Axial vector Z‧ and anomaly cancellation
Ismail, Ahmed; Keung, Wai-Yee; Tsao, Kuo-Hsing; Unwin, James
2017-05-01
Whilst the prospect of new Z‧ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that in a large class of models masses of these new states are expected to be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.
Are Bred Vectors The Same As Lyapunov Vectors?
Kalnay, E.; Corazza, M.; Cai, M.
Regional loss of predictability is an indication of the instability of the underlying flow, where small errors in the initial conditions (or imperfections in the model) grow to large amplitudes in finite times. The stability properties of evolving flows have been studied using Lyapunov vectors (e.g., Alligood et al, 1996, Ott, 1993, Kalnay, 2002), singular vectors (e.g., Lorenz, 1965, Farrell, 1988, Molteni and Palmer, 1993), and, more recently, with bred vectors (e.g., Szunyogh et al, 1997, Cai et al, 2001). Bred vectors (BVs) are, by construction, closely related to Lyapunov vectors (LVs). In fact, after an infinitely long breeding time, and with the use of infinitesimal ampli- tudes, bred vectors are identical to leading Lyapunov vectors. In practical applications, however, bred vectors are different from Lyapunov vectors in two important ways: a) bred vectors are never globally orthogonalized and are intrinsically local in space and time, and b) they are finite-amplitude, finite-time vectors. These two differences are very significant in a dynamical system whose size is very large. For example, the at- mosphere is large enough to have "room" for several synoptic scale instabilities (e.g., storms) to develop independently in different regions (say, North America and Aus- tralia), and it is complex enough to have several different possible types of instabilities (such as barotropic, baroclinic, convective, and even Brownian motion). Bred vectors share some of their properties with leading LVs (Corazza et al, 2001a, 2001b, Toth and Kalnay, 1993, 1997, Cai et al, 2001). For example, 1) Bred vectors are independent of the norm used to define the size of the perturba- tion. Corazza et al. (2001) showed that bred vectors obtained using a potential enstro- phy norm were indistinguishable from bred vectors obtained using a streamfunction squared norm, in contrast with singular vectors. 2) Bred vectors are independent of the length of the rescaling period as long as the
Institute of Scientific and Technical Information of China (English)
Zhuo CHEN; Zhang Ju LIU; Yun He SHENG
2014-01-01
In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.
Chen, Zhuo; Liu, Zhangju; Sheng, Yunhe
2011-01-01
In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.
A 4-vector formalism for classical mechanics
Güémez, Julio
2014-01-01
We present a matrix formalism, inspired by the Minkowski four-vectors of special relativity, useful to solve classical physics problems related to both mechanics and thermodynamics. The formalism turns out to be convenient to deal with exercises involving non-conservative forces and production or destruction of mechanical energy. On the other hand, it provides a framework to treat straightforwardly changes of inertial reference frames, since it embodies the Principle of Relativity. We apply the formalism to a few cases to better show how it works.
2012-09-06
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and..., 2012 The following Applications for Certificates of Public Convenience and Necessity and Foreign Air.... (``KaiserAir'') requesting an amended certificate of public convenience and necessity authorizing it...
48 CFR 809.270 - Qualified products for convenience/labor-saving foods.
2010-10-01
... convenience/labor-saving foods. 809.270 Section 809.270 Federal Acquisition Regulations System DEPARTMENT OF... 809.270 Qualified products for convenience/labor-saving foods. (a) Each VISN Nutrition and Food Service representative is authorized to establish a common VISN QPL for convenience and labor-saving...
2013-04-04
... Office of the Secretary Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits; Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier... Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits were...
49 CFR 1150.23 - Modified certificate of public convenience and necessity.
2010-10-01
... 49 Transportation 8 2010-10-01 2010-10-01 false Modified certificate of public convenience and..., ACQUIRE, OR OPERATE RAILROAD LINES Modified Certificate of Public Convenience and Necessity § 1150.23 Modified certificate of public convenience and necessity. (a) The operator must file a notice with...
2011-02-23
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and..., 2011 The following Applications for Certificates of Public Convenience and Necessity and Foreign Air... Airlines, Inc., d/b/a Alpha Cargo, and for reissuance of its certificate of public convenience...
48 CFR 49.603 - Formats for termination for convenience settlement agreements.
2010-10-01
... for convenience settlement agreements. 49.603 Section 49.603 Federal Acquisition Regulations System... Formats 49.603 Formats for termination for convenience settlement agreements. The formats to be used for termination for convenience settlement agreements should be substantially as shown in this section (see...
41 CFR 101-26.103-2 - Restriction on personal convenience items.
2010-07-01
... convenience items. 101-26.103-2 Section 101-26.103-2 Public Contracts and Property Management Federal Property... SOURCES AND PROGRAM 26.1-General § 101-26.103-2 Restriction on personal convenience items. Government... type items intended solely for the personal convenience or to satisfy the personal desire of...
2010-05-26
... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under Subpart B... Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart B...
78 FR 75441 - Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits
2013-12-11
... Office of the Secretary Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier... following Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier...
78 FR 76701 - Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits
2013-12-18
... Office of the Secretary Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier... following Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier...
2010-07-16
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and... The following Applications for Certificates of Public Convenience and Necessity and Foreign Air.... requesting a certificate of public convenience and necessity to engage in foreign scheduled...
78 FR 25782 - Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits
2013-05-02
... Office of the Secretary Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier... Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits were...
2013-07-25
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and..., 2013 The following Applications for Certificates of Public Convenience and Necessity and Foreign Air... convenience and necessity in the name of ``ENDEAVOR AIR, INC.''. Barbara J. Hairston, Acting Program...
30 CFR 885.22 - When and how can my grant be terminated for convenience?
2010-07-01
... convenience? 885.22 Section 885.22 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... § 885.22 When and how can my grant be terminated for convenience? Either you or we may terminate the grant for convenience following the procedures in 43 CFR part 12....
2011-04-12
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Notice of Applications for Certificates of Public Convenience and Necessity... March 5, 2011. The following Applications for Certificates of Public Convenience and Necessity...
78 FR 68134 - Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits
2013-11-13
... Office of the Secretary Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier... Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits were...
30 CFR 886.26 - When and how can my grant be terminated for convenience?
2010-07-01
... convenience? 886.26 Section 886.26 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... INDIAN TRIBES § 886.26 When and how can my grant be terminated for convenience? Either you or we may... worth the additional costs. We will handle a termination for convenience as an amendment to the grant...
78 FR 19354 - Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits
2013-03-29
... Office of the Secretary Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Notice of Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier... Applications for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits were...
2013-10-23
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under Subpart B... of Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart...
2011-11-03
... for Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits Filed Under... Certificates of Public Convenience and Necessity and Foreign Air Carrier Permits were filed under Subpart B... Corporation (``JetBlue'') requesting a certificate of public convenience and necessity and requests...
2012-09-06
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and..., 2012 The following Applications for Certificates of Public Convenience and Necessity and Foreign Air... transfer of its certificates of public convenience and necessity to facilitate the reorganization of...
48 CFR 52.249-4 - Termination for Convenience of the Government (Services) (Short Form).
2010-10-01
... Convenience of the Government (Services) (Short Form). 52.249-4 Section 52.249-4 Federal Acquisition... CONTRACT CLAUSES Text of Provisions and Clauses 52.249-4 Termination for Convenience of the Government... convenience of the Government, limit termination settlement charges to services rendered before the date...
2012-08-16
... Office of the Secretary Notice of Applications for Certificates of Public Convenience and Necessity and..., 2012 The following Applications for Certificates of Public Convenience and Necessity and Foreign Air.../a Transair requesting a certificate of public convenience and necessity authorizing it to engage...
48 CFR 52.249-2 - Termination for Convenience of the Government (Fixed-Price).
2010-10-01
... Convenience of the Government (Fixed-Price). 52.249-2 Section 52.249-2 Federal Acquisition Regulations System... Text of Provisions and Clauses 52.249-2 Termination for Convenience of the Government (Fixed-Price). As prescribed in 49.502(b)(1)(i), insert the following clause: Termination for Convenience of the...