Distribution by Scientific Domains
Distribution within Mathematics and Statistics

Kinds of Integer

  • nonnegative integer
  • positive integer

  • Terms modified by Integer

  • integer k
  • integer linear programming
  • integer n
  • integer program
  • integer programming
  • integer programming problem
  • integer variable

  • Selected Abstracts

    Hybrid adaptive predictive control for a dynamic pickup and delivery problem including traffic congestion

    Cristián E. Cortés
    Abstract This paper presents a hybrid adaptive predictive control approach to incorporate future information regarding unknown demand and expected traffic conditions, in the context of a dynamic pickup and delivery problem with fixed fleet size. As the routing problem is dynamic, several stochastic effects have to be considered within the analytical expression of the dispatcher assignment decision objective function. This paper is focused on two issues: one is the extra cost associated with potential rerouting arising from unknown requests in the future, and the other is the potential uncertainty in travel time coming from non-recurrent traffic congestion from unexpected incidents. These effects are incorporated explicitly in the objective function of the hybrid predictive controller. In fact, the proposed predictive control strategy is based on a multivariable model that includes both discrete/integer and continuous variables. The vehicle load and the sequence of stops correspond to the discrete/integer variable, adding the vehicle position as an indicator of the traffic congestion conditions. The strategy is analyzed under two scenarios. The first one considers a predictable congestion obtained using historical data (off-line method) requiring a predictive model of velocities distributed over zones. The second scenario that accepts unpredictable congestion events generates a more complex problem that is managed by using both fault detection and isolation and fuzzy fault-tolerant control approaches. Results validating these approaches are presented through a simulated numerical example. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Generalised algorithm of novel space vector modulation: for N -level three-phase voltage source inverter

    Hachemi Chekireb
    Abstract This paper concerns the development of a generalised algorithm of a novel space vector modulation (SVM) for N -level three-phase voltage source inverter. It is considering that the (N,1) DC input voltages of inverter are constant. The proposed method ensures initially the determination of the N3 inverter switching states, the extraction of the redundancies to obtain 3N(N -1),+,1 independent switching states and their organisation by sector in six distinct matrices Wk with k,=,(1,,,,,6). After that, these matrices Wk with k,=,(2,,,,,6) are ordered as the matrix W1 related to the first sector. So, the research of the three closest vectors to the reference vector is carried out only in first sector and for this purpose, the equivalent reference vector is introduced which is resulting from the rotation by ,(k,1),/3 of the reference vector. The on-line choice of the three vectors (three switching states of the inverter) is based on the distances between the equivalent reference vector and some vectors located in its vicinity in the (,,,) plane of the first sector. Moreover, a simple method for the calculation of the duty cycles for these three switching states is proposed which exploits directly the three shortest distances associated to these three selected vectors. The sequence of these three switching states over a sampling period is investigated in view to reduce the harmonic contents of the voltage output. The application is carried out on an N -level three-phase voltage source inverter, where N is an arbitrary odd integer. Finally, the phase voltage and its harmonic spectrum provided by a three-phase N- level inverter with N,=,(3,5,7,9,13,15) are presented to confirm the generalisation of this method. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Price Clustering: Evidence Using Comprehensive Limit-Order Data

    FINANCIAL REVIEW, Issue 1 2009
    Chaoshin Chiao
    G14; G15 Abstract Employing comprehensive limit-order data which identify investor types, this paper examines the clustering pattern of limit-order prices. First, limit orders, particularly those submitted by individual investors (IIs), tend to cluster at integer and even prices. Second, nonmarketable limit-order prices cluster more than marketable limit-order prices, indicating that aggressive limit orders generally embed more information. Third, investors choosing even-priced limit orders are not penalized by lower execution ratios. Fourth, investors (particularly IIs) strategically exhibit front-running behavior. Fifth, price clustering indeed creates price barriers. Finally, the degree of price clustering using trade data is significantly underestimated, compared to that using limit-order data. [source]

    On the existence of non-supersymmetric black hole attractors for two-parameter Calabi-Yau's and attractor equations

    P. Kaura
    We look for possible nonsupersymmetric black hole attractor solutions for type II compactification on (the mirror of) CY3(2,128) expressed as a degree-12 hypersurface in WCP4[1,1,2,2,6]. In the process, (a) for points away from the conifold locus, we show that the existence of a non-supersymmetric attractor along with a consistent choice of fluxes and extremum values of the complex structure moduli, could be connected to the existence of an elliptic curve fibered over C8 which may also be "arithmetic" (in some cases, it is possible to interpret the extremization conditions for the black-hole superpotential as an endomorphism involving complex multiplication of an arithmetic elliptic curve), and (b) for points near the conifold locus, we show that existence of non-supersymmetric black-hole attractors corresponds to a version of A1 -singularity in the space Image(Z6,R2/Z2 (,R3)) fibered over the complex structure moduli space. The (derivatives of the) effective black hole potential can be thought of as a real (integer) projection in a suitable coordinate patch of the Veronese map: CP5,CP20, fibered over the complex structure moduli space. We also discuss application of Kallosh's attractor equations (which are equivalent to the extremization of the effective black-hole potential) for nonsupersymmetric attractors and show that (a) for points away from the conifold locus, the attractor equations demand that the attractor solutions be independent of one of the two complex structure moduli, and (b) for points near the conifold locus, the attractor equations imply switching off of one of the six components of the fluxes. Both these features are more obvious using the attractor equations than the extremization of the black hole potential. [source]

    A mixed integer programming for robust truss topology optimization with stress constraints

    Yoshihiro Kanno
    Abstract This paper presents a mixed integer programming (MIP) formulation for robust topology optimization of trusses subjected to the stress constraints under the uncertain load. A design-dependent uncertainty model of the external load is proposed for dealing with the variation of truss topology in the course of optimization. For a truss with the discrete member cross-sectional areas, it is shown that the robust topology optimization problem can be reduced to an MIP problem, which is solved globally. Numerical examples illustrate that the robust optimal topology of a truss depends on the magnitude of uncertainty. Copyright © 2010 John Wiley & Sons, Ltd. [source]

    Improved genetic algorithm for design optimization of truss structures with sizing, shape and topology variables

    Wenyan Tang
    Abstract This paper presents an improved genetic algorithm (GA) to minimize weight of truss with sizing, shape and topology variables. Because of the nature of discrete and continuous variables, mixed coding schemes are proposed, including binary and float coding, integer and float coding. Surrogate function is applied to unify the constraints into single one; moreover surrogate reproduction is developed to select good individuals to mating pool on the basis of constraint and fitness values, which completely considers the character of constrained optimization. This paper proposes a new strategy of creating next population by competing between parent and offspring population based on constraint and fitness values; so that lifetime of excellent gene is prolonged. Because the initial population is created randomly and three operators of GA are also indeterminable, it is necessary to check whether the structural topology is desirable. An improved restart operator is proposed to introduce new gene and explore new space, so that the reliability of GA is enhanced. Selected examples are solved; the improved numerical results demonstrate that the enhanced GA scheme is feasible and effective. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Free energy and structure of polyproline peptides: An ab initio and classical molecular dynamics investigation

    Mahmoud Moradi
    Abstract Depending on their environment, polyproline peptides form chiral helices that may be either left- (PPII) or right-handed (PPI). Here, we have characterized both the structure and free energy landscapes of Ace-(Pro)n -Nme (n an integer less than 13) peptides, in vacuo and in implicit water environments. Both ab initio and classical molecular dynamics methods were used. In terms of the latter, we used a recently developed Adaptively Biased Molecular Dynamics (ABMD) method in conjunction with three different force fields (ff99, ff99SB, ff03) and two different Generalized Born models for the implicit solvent environment. Specifically, the ABMD method provides for an accurate description of the free energy landscapes in terms of a set of collective variables, which were carefully chosen as to reflect the "slow modes" of the polyproline peptides. These are primarily based on the cis - trans isomerization associated with the prolyl bonds. In agreement with recent experimental results, the peptides form not only the pure PPII or PPI structures but also a large number of stable conformers having more or less similar free energies, whose distributions we have characterized. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source]

    Adaptive output feedback tracking control of spacecraft formation

    Hong Wong
    Abstract In this paper, an adaptive, output feedback control design methodology is presented for a spacecraft formation flying (SFF) system. A Lagrangian derivation of the SFF model is considered to produce position dynamics for follower spacecraft #n relative to follower spacecraft #(n,1), where n is an arbitrary positive integer, assuming that the leader spacecraft in the formation follows a no-thrust, natural, elliptical orbit. Next, a control law is designed to provide a filtered velocity measurement and a desired adaptive compensation with semi-global, asymptotic, relative position tracking. To show the efficacy of the control algorithm, all desired trajectories are generated online by numerically solving the unperturbed nonlinear SFF dynamics with initial conditions satisfying a no-thrust, natural orbit constraint equation. The proposed control law is simulated for the case of two and three spacecraft and is shown to yield semi-global, asymptotic tracking of the relative position in addition to the convergence of disturbance parameter estimates. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    An Integer Linear Programming Problem with Multi-Criteria and Multi-Constraint Levels: a Branch-and-Partition Algorithm

    Jun Li
    In this paper, we propose a branch-and-partition algorithm to solve the integer linear programming problem with multi-criteria and multi-constraint levels (MC-ILP). The procedure begins with the relaxation problem that is formed by ignoring the integer restrictions. In this branch-and-partition procedure, an MC linear programming problem is adopted by adding a restriction according to a basic decision variable that is not integer. Then the MC-simplex method is applied to locate the set of all potential solutions over possible changes of the objective coefficient parameter and the constraint parameter for a regular MC linear programming problem. We use parameter partition to divide the (,, ,) space for integer solutions of MC problem. The branch-and-partition procedure terminates when every potential basis for the relaxation problem is a potential basis for the MC-ILP problem. A numerical example is used to demonstrate the proposed algorithm in solving the MC-ILP problems. The comparison study and discussion on the applicability of the proposed method are also provided. [source]

    The Scaling of Mixed-Item-Format Tests With the One-Parameter and Two-Parameter Partial Credit Models

    Robert C. Sykes
    Item response theory scalings were conducted for six tests with mixed item formats. These tests differed in their proportions of constructed response (c.r.) and multiple choice (m.c.) items and in overall difficulty. The scalings included those based on scores for the c.r. items that had maintained the number of levels as the item rubrics, either produced from single ratings or multiple ratings that were averaged and rounded to the nearest integer, as well as scalings for a single form of c.r. items obtained by summing multiple ratings. A one-parameter (IPPC) or two-parameter (2PPC) partial credit model was used for the c.r. items and the one-parameter logistic (IPL) or three-parameter logistic (3PL) model for the m.c. items, ltem fit was substantially worse with the combination IPL/IPPC model than the 3PL/2PPC model due to the former's restrictive assumptions that there would be no guessing on the m.c. items and equal item discrimination across items and item types. The presence of varying item discriminations resulted in the IPL/IPPC model producing estimates of item information that could be spuriously inflated for c.r. items that had three or more score levels. Information for some items with summed ratings were usually overestimated by 300% or more for the IPL/IPPC model. These inflated information values resulted in under-estbnated standard errors of ability estimates. The constraints posed by the restricted model suggests limitations on the testing contexts in which the IPL/IPPC model can be accurately applied. [source]

    On totally multicolored stars

    Juan José Montellano-Ballesteros
    Abstract Given an edge-coloring of a graph G, a subgraph M of G will be called totally multicolored if no two edges of M receive the same color. Let h(G, K1,q) be the minimum integer such that every edge-coloring of G using exactly h(G, K1,q) colors produces at least one totally multicolored copy of K1,q (the q -star) in G. In this article, an upper bound of h(G, K1,q) is presented, as well as some applications of this upper bound. © 2005 Wiley Periodicals, Inc. [source]

    On the number of colorings of a snark minus an edge

    Richard C. Bradley
    Abstract For a given snark G and a given edge e of G, let ,(G, e) denote the nonnegative integer such that for a cubic graph conformal to G , {e}, the number of Tait colorings with three given colors is 18,·,,(G, e). If two snarks G1 and G2 are combined in certain well-known simple ways to form a snark G, there are some connections between , (G1, e1), , (G2, e2), and ,(G, e) for appropriate edges e1, e2, and e of G1, G2, and G. As a consequence, if j and k are each a nonnegative integer, then there exists a snark G with an edge e such that ,(G, e),=,2j,·,3k. © 2005 Wiley Periodicals, Inc. [source]

    Fan-type theorem for path-connectivity

    Zhiquan Hu
    Abstract For a connected noncomplete graph G, let ,(G):=min{max {dG(u), dG(v)}:dG(u, v)=2}. A well-known theorem of Fan says that every 2-connected noncomplete graph has a cycle of length at least min{|V(G)|, 2,(G)}. In this paper, we prove the following Fan-type theorem: if G is a 3-connected noncomplete graph, then each pair of distinct vertices of G is joined by a path of length at least min{|V(G)|,1, 2,(G),2}. As consequences, we have: (i) if G is a 3-connected noncomplete graph with , then G is Hamilton-connected; (ii) if G is a (s+2)-connected noncomplete graph, where s,1 is an integer, then through each path of length s of G there passes a cycle of length,min{|V(G)|, 2,(G),s}. Several results known before are generalized and a conjecture of Enomoto, Hirohata, and Ota is proved. © 2002 Wiley Periodicals, Inc. J Graph Theory 39: 265,282, 2002 DOI 10.1002/jgt.10028 [source]

    Positive solutions of a higher order neutral differential equation

    John R. Graef
    Abstract In this paper, we consider the higher order neutral delay differential equation where p : [0, ,) , (0, ,) is a continuous function, r > 0 and , > 0 are constants, and n > 0 is an odd integer. A positive solution x(t) of Eq. (*) is called a Class,I solution if y(t) > 0 and y,(t) < 0 eventually, where y(t) = x(t) , x(t , r). We divide Class,I solutions of Eq. (*) into four types. We first show that every positive solution of Eq. (*) must be of one of these four types. For three of these types, a necessary and sufficient condition is obtained for the existence of such solutions. A necessary condition for the existence of a solution of the fourth type is also obtained. The results are illustrated with examples. [source]

    Capacitated lot-sizing and scheduling with parallel machines, back-orders, and setup carry-over

    Daniel Quadt
    Abstract We address the capacitated lot-sizing and scheduling problem with setup times, setup carry-over, back-orders, and parallel machines as it appears in a semiconductor assembly facility. The problem can be formulated as an extension of the capacitated lot-sizing problem with linked lot-sizes (CLSPL). We present a mixed integer (MIP) formulation of the problem and a new solution procedure. The solution procedure is based on a novel "aggregate model," which uses integer instead of binary variables. The model is embedded in a period-by-period heuristic and is solved to optimality or near-optimality in each iteration using standard procedures (CPLEX). A subsequent scheduling routine loads and sequences the products on the parallel machines. Six variants of the heuristic are presented and tested in an extensive computational study. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009 [source]

    Rainbow trees in graphs and generalized connectivity

    Gary Chartrand
    Abstract An edge-colored tree T is a rainbow tree if no two edges of T are assigned the same color. Let G be a nontrivial connected graph of order n and let k be an integer with 2 , k , n. A k -rainbow coloring of G is an edge coloring of G having the property that for every set S of k vertices of G, there exists a rainbow tree T in G such that S , V(T). The minimum number of colors needed in a k -rainbow coloring of G is the k -rainbow index of G. For every two integers k and n , 3 with 3 , k , n, the k -rainbow index of a unicyclic graph of order n is determined. For a set S of vertices in a connected graph G of order n, a collection {T1,T2,,,T,} of trees in G is said to be internally disjoint connecting S if these trees are pairwise edge-disjoint and V(Ti) , V(Tj) = S for every pair i,j of distinct integers with 1 , i,j , ,. For an integer k with 2 , k , n, the k -connectivity ,k(G) of G is the greatest positive integer , for which G contains at least , internally disjoint trees connecting S for every set S of k vertices of G. It is shown that ,k(Kn)=n,,k/2, for every pair k,n of integers with 2 , k , n. For a nontrivial connected graph G of order n and for integers k and , with 2 , k , n and 1 , , , ,k(G), the (k,,)-rainbow index rxk,,(G) of G is the minimum number of colors needed in an edge coloring of G such that G contains at least , internally disjoint rainbow trees connecting S for every set S of k vertices of G. The numbers rxk,,(Kn) are determined for all possible values k and , when n , 6. It is also shown that for , , {1, 2}, rx3,,(Kn) = 3 for all n , 6. © 2009 Wiley Periodicals, Inc. NETWORKS, 2010 [source]

    On the L(h, k)-labeling of co-comparability graphs and circular-arc graphs

    Tiziana Calamoneri
    Abstract Given two nonnegative integers h and k, an L(h, k)- labeling of a graph G = (V, E) is a map from V to a set of integer labels such that adjacent vertices receive labels at least h apart, while vertices at distance at most 2 receive labels at least k apart. The goal of the L(h, k)-labeling problem is to produce a legal labeling that minimizes the largest label used. Since the decision version of the L(h, k)-labeling problem is NP-complete, it is important to investigate classes of graphs for which the problem can be solved efficiently. Along this line of thought, in this article we deal with co-comparability graphs, its subclass of interval graphs, and circular-arc graphs. To the best of our knowledge, ours is the first reported result concerning the L(h, k)-labeling of co-comparability and circular-arc graphs. In particular, we provide the first algorithm to L(h, k)-label co-comparability, interval, and circular-arc graphs with a bounded number of colors. Finally, in the special case where k = 1 and G is an interval graph, our algorithm improves on the best previously-known ones using a number of colors that is at most twice the optimum. © 2008 Wiley Periodicals, Inc. NETWORKS, 2009 [source]

    Extreme point characterizations for infinite network flow problems

    H. Edwin Romeijn
    Abstract We study capacitated network flow problems with demands defined on a countably infinite collection of nodes having finite degree. This class of network flow models includes, for example, all infinite horizon deterministic dynamic programs with finite action sets, because these are equivalent to the problem of finding a shortest path in an infinite directed network. We derive necessary and sufficient conditions for flows to be extreme points of the set of feasible flows. Under an additional regularity condition met by all such problems with integer data, we show that a feasible solution is an extreme point if and only if it contains neither a cycle nor a doubly-infinite path consisting of free arcs (an arc is free if its flow is strictly between its upper and lower bounds). We employ this result to show that the extreme points can be characterized by specifying a basis. Moreover, we establish the integrality of extreme point flows whenever node demands and arc capacities are integer valued. We illustrate our results with an application to an infinite horizon economic lot-sizing problem. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 48(4), 209,222 2006 [source]

    Connectedness of digraphs and graphs under constraints on the conditional diameter

    X. Marcote
    Abstract Given a digraph G with minimum degree , and an integer 0, , , ,, consider every pair of vertex subsets V1 and V2 such that both the minimum out-degree of the induced subdigraph G[V1] and the minimum in-degree of G[V2] are at least ,. The conditional diameter D, of G is defined as the maximum of the distances d(V1, V2) between any two such vertex subsets. Clearly, D0 is the standard diameter and D0 , D1 , ··· , D, holds. In this article, we guarantee appropriate lower bounds for the connectivities and superconnectivities of a digraph G when D, , h(,,), h(,,) being a function of the parameter ,,,which is related to the shortest paths in G. As a corollary of these results, we give some constraints of the kind D, , h(,,), which assure that the digraph is maximally connected, maximally edge-connected, superconnected, or edge-superconnected, extending other previous results of the same kind. Similar statements can be obtained for a graph as a direct consequence of those for its associated symmetric digraph. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 45(2), 80,87 2005 [source]

    Solving the minimum-weighted coloring problem

    Massimiliano Caramia
    Abstract Weighted coloring is a generalization of the well-known vertex (unweighted) coloring for which a number of exact algorithms have been presented in the literature. We are not aware of any optimal method specifically designed for the minimum-weighted coloring problem on arbitrary graphs. Only a few heuristics have been developed with the goal of finding tighter upper bounds for the maximum-weighted clique problem. Moreover, as shown in the paper, a straightforward reduction of a weighted instance into an unweighted one permits us to solve only very small instances. In this paper, we present a branch-and-bound algorithm for the weighted case capable of solving random graphs of up to 90 vertices for any edge density with integer weights uniformly drawn from the range [1, ,,10]. Likewise, we have used properly modified benchmark instances borrowed from vertex coloring as a further test bed for our algorithm. © 2001 John Wiley & Sons, Inc. [source]

    Matrix rounding with respect to small submatrices

    Benjamin Doerr
    We show that any real valued matrix A can be rounded to an integer one B such that the error in all 2 × 2 (geometric) submatrices is less than 1.5, that is, we have |aij , bij| < 1 and for all i,j. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006 [source]

    Analysis of oligomeric peroxides in synthetic triacetone triperoxide samples by tandem mass spectrometry

    Michael E. Sigman
    Oligomeric peroxides formed in the synthesis of triacetone triperoxide (TATP) have been analyzed by mass spectrometry utilizing both electrospray ionization (ESI) and chemical ionization (CI) to form sodiated adducts (by ESI) and ammonium adducts (by CI and ESI). Tandem mass spectrometry and deuterium isotopic labeling experiments have been used to elucidate the collision-induced dissociation (CID) mechanisms for the adducts. The CID mechanisms differ for the sodium and ammonium adducts and vary with the size of the oligoperoxide. The sodium adducts of the oligoperoxides, H[OOC(CH3)2]nOOH, do not cyclize under CID, whereas the ammonium adducts of the smaller oligoperoides (n,<,6) do form the cyclic peroxides under CID. Larger oligoperoxide adducts with both sodium and ammonium undergo dissociation through cleavage of the backbone under CID to form acyl- and hydroperoxy-terminated oligomers of the general form CH3C(O)[OOC(CH3)2]xOOH, where x is an integer less than the original oligoperoxide degree of oligomerization. The oligoperoxide distribution is shown to vary batch-to-batch in the synthesis of TATP and the post-blast distribution differs slightly from the distribution in the uninitiated material. The oligoperoxides are shown to be decomposed under gentle heating. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Structural investigation of GeSb6Te10 and GeBi6Te10 intermetallic compounds in the chalcogenide homologous series

    Toshiyuki Matsunaga
    The crystal structures of GeSb6Te10 and GeBi6Te10 were scrutinized using an X-ray powder diffraction method, which revealed that these compounds crystallize in trigonally distorted cubic close-packed structures with a 51-layer period (). Each layer consists of a triangular atomic net; Te atoms occupy their own specific layers, whereas Ge, Sb and Bi atoms are located in the other layers. In these pseudobinary compounds, random atomic occupations of Ge and Sb/Bi are observed and the layers form two kinds of elemental structural blocks by their successive stacking along the c axis. These compounds can be presumed to be isostructural. It is known that the chemical formula of the chalcogenide compounds with the homologous structures found in these pseudobinary systems can be written as (GeTe)n(Sb2Te3)m or (GeTe)n(Bi2Te3)m (n, m: integer); the GeSb6Te10 and GeBi6Te10 investigated in this study, which correspond to the case in which n = 1 and m = 3, naturally have 3,×,l = 51-layer structures according to a formation rule l = 2n + 5m commonly found in the compounds of these chalcogenide systems (l represents the number of layers in the basic structural unit). Calculations based on the density functional theory revealed that these materials are compound semiconductors with very narrow band gaps. [source]

    The distinction of integer and fractional Quantum Hall Effect is a mathematical artifact without physical merit

    ANNALEN DER PHYSIK, Issue 5 2003
    E.J. Post
    Abstract Many body wave function assessments of the quantum Hall effect are compared with a global assessment using Aharonov-Bohm and Gauss-Ampère period-integrals as counters of flux and charge quanta. Experiment pleads in favor of a two quanta unified description in terms of flux and charge numbers. [source]


    Xiefu Jiang
    ABSTRACT This paper is concerned with the problem of robust H, controller design for a class of uncertain networked control systems (NCSs). The network-induced delay is of an interval-like time-varying type integer, which means that both lower and upper bounds for such a kind of delay are available. The parameter uncertainties are assumed to be normbounded and possibly time-varying. Based on Lyapunov-Krasovskii functional approach, a robust H, controller for uncertain NCSs is designed by using a sum inequality which is first introduced and plays an important role in deriving the controller. A delay-dependent condition for the existence of a state feedback controller, which ensures internal asymptotic stability and a prescribed H, performance level of the closed-loop system for all admissible uncertainties, is proposed in terms of a nonlinear matrix inequality which can be solved by a linearization algorithm, and no parameters need to be adjusted. A numerical example about a balancing problem of an inverted pendulum on a cart is given to show the effectiveness of the proposed design method. [source]

    Crystallization and initial X-ray diffraction analysis of a mannose-binding lectin from champedak

    Mads Gabrielsen
    Mannose-binding lectin from champedak (Artocarpus integer) is a homotetramer with a single-monomer molecular weight of 16,800,Da. Previous work has shown it to bind IgE and IgM, as well as being a mitogen of T cells in humans. Champedak mannose-binding lectin has successfully been used to detect altered glycosylation states of serum proteins. The protein was crystallized at 293,K in space group P212121 (unit-cell parameters a = 76.89, b = 86.22, c = 95.37,Å) and the crystals diffracted to 2.0,Å resolution. [source]

    Long-distance signals influence assessment of close range mating displays in the field cricket, Gryllus integer

    Male sexual displays often include components detected across long distances, and those perceived only at close range. Understanding what information females gain from each component of a complex display and how they use these signals to make decisions are questions of major interest in sexual selection research. We evaluated content-based hypotheses (,redundant signals' and ,multiple messages') for the courtship displays of field crickets (Gryllus integer) by measuring female responses to males' long-distance calling song (calls) and close-range chemical cues. Females' responses to a male's calls and chemical cues were uncorrelated, supporting the ,multiple messages' hypothesis. We also tested the ,inter-signal interaction' hypothesis by investigating how long-distance calls influence evaluation of close-range courtship. The relationship between long- and close-range signals was complex and conditional: females accepted close-range courtship more quickly after exposure to attractive calling song than they did after exposure to either unattractive calling song or silence, and unattractive calls were no more or less effective than silence. This inter-signal interaction could affect our understanding of mate choice in species with multiple mating signals because it implies that females may save time and energy by not assessing the close-range signals of attractive long-distance signalers. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 856,865. [source]

    A behavioural syndrome in the field cricket Gryllus integer: intrasexual aggression is correlated with activity in a novel environment

    Behavioural syndromes, or suites of correlated behaviours across different contexts and situations, have recently drawn attention from evolutionary biologists. In the field cricket Gryllus integer, males are aggressive with one another and fight vigorously over females and territories. We examined whether aggressiveness with other males was correlated with activity in a potentially dangerous context (a novel environment) in laboratory-raised virgin males. Aggressiveness was measured as fighting ability against a weight-matched opponent. First, we measured each cricket's latency to become active in a novel environment and latency to emerge from a refuge within a novel environment. Next, we determined which of two weight-matched males was more aggressive, by pitting the males together in an agonistic contest and counting the number of fights won by each male. More aggressive males, who won more fights, had shorter latencies to become active when placed in a novel environment and shorter latencies to emerge from a safe refuge. These results suggest that a behavioural syndrome exists in G. integer, in which more aggressive males are also more active in general, and possibly less cautious towards predation risk. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 475,482. [source]

    Crystallization and preliminary structural studies of champedak galactose-binding lectin

    Mads Gabrielsen
    Galactose-binding lectin from champedak (Artocarpus integer) consists of two chains: , and , (133 and 21 amino acids, respectively). It has been shown to recognize and bind to carbohydrates involved in IgA and C1 inhibitor molecules. The protein was purified and crystallized at 293,K. Crystals were observed in two space groups, P21 and P21212, and diffracted to 1.65 and 2.6,Å, respectively. [source]

    Drawbacks to Noninteger Scoring for Ordered Categorical Data

    BIOMETRICS, Issue 1 2007
    Stephen Senn
    Summary A proposal to improve trend tests by using noninteger scores is examined. It is concluded that despite improved power such tests are usually inferior to the simpler integer scored approach. [source]