599 research outputs found

    Recursive exact H-infinity identification from impulse-response measurements

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    We study the H∞-partial realization problem from a behavioral point of view; we give necessary and sufficient conditions for solvability, and a characterization of all solutions. Instrumental in such analysis is the notion of time- and space-symmetrization of the data, which allows to transform the realization problem with metric- and stability constraints into an unconstrained behavioral modeling one

    Totally dissipative systems

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    In a totally dissipative behavior, all non-trivial trajectories dissipate energy. A characterization of such behaviors is given in terms of properties of the one- and two-polynomial matrices associated with the supply rate and with their kernel- and image representation

    Contrasts in Vital Rates: Madras and Punjab in the Colonial Period

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    It is well known that there have been persistent differences in demographic rates between northern and southern areas in post-independence India: in the north marital fertility is higher, infant mortality higher and life expectancy shorter than in the south. As Tim Dyson has shown for infant mortality, this probably has pre-independence origins. In this paper the post-WWII contrasts in demographic performances between north and south India will be traced back to the colonial period. By choosing Madras and Punjab, by selecting districts whose registration statistics are reasonably usable in each province (Madras: Coimbatore, Salem, North Arcot, South Arcot, and Tilnelvelli; Punjab: Gurdaspur, Jallundur, Amritsar, Hoshiarpur, Ferozepore, and Ambala, Karnal and Rohtak), and then by adopting W. Brass's relational Gompertz fertility model, logit life-table system and growth balance method, as exemplified by Dyson's seminal work on Berar, we estimate annual series of e0 and TFR for both provinces. The series clearly show that even in the colonial period both fertility and mortality were higher in the north than in the south, which will have wider implications in historical contexts.

    Characterization of solutions of the discrete-time algebraic Riccati equation based on quadratic difference forms

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    This paper is concerned with a characterization of all symmetric solutions to the discrete-time algebraic Riccati equation (DARE). Dissipation theory and quadratic difference forms from the behavioral approach play a central role in this paper. Along the line of the continuous-time results due to Trentelman and Rapisarda [H.L. Trentelman, P. Rapisarda, Pick matrix conditions for sign-definite solutions of the algebraic Riccati equation, SIAM J. Contr. Optim. 40 (3) (2001) 969–991], we show that the solvability of the DARE is equivalent to a certain dissipativity of the associated discrete-time state space system. As a main result, we characterize all unmixed solutions of the DARE using the Pick matrix obtained from the quadratic difference forms. This characterization leads to a necessary and sufficient condition for the existence of a non-negative definite solution. It should be noted that, when we study the DARE and the dissipativity of the discrete-time system, there exist two difficulties which are not seen in the continuous-time case. One is the existence of a storage function which is not a quadratic function of state. Another is the cancellation between the zero and infinite singularities of the dipolynomial spectral matrix associated with the DARE, due to the infinite generalized eigenvalues of the associated Hamiltonian pencil. One of the main contributions of this paper is to demonstrate how to resolve these difficulties

    Kotenkaisekigaku ni okeru hokanmondai to Most Powerful Unfalsified Model (MPUM)

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    This review article (in Japanese) presents the essentials of exact identification. Particular attention is given to the formalization of interpolation problems involving stability- and metric constraints (e.g. the Nevanlinna and the Takagi interpolation problems) in the framework of exact identification, and the representational issues for the Most powerful Unfalsified Model arising in these applications

    Positive selection on the Plasmodium falciparum clag2 gene encoding a component of the erythrocyte-binding rhoptry protein complex

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    A protein complex of high-molecular-mass proteins (PfRhopH) of the human malaria parasite Plasmodium falciparum induces host protective immunity and therefore is a candidate for vaccine development. Clarification of the level of polymorphism and the evolutionary processes is important both for vaccine design and for a better understanding of the evolution of cell invasion in this parasite. In a previous study on 5 genes encoding RhopH1/Clag proteins, positive diversifying selection was detected in clag8 and clag9 but not in the paralogous clag2, clag3.1 and clag3.2. In this study, to extend the analysis of clag polymorphism, we obtained sequences surrounding the most polymorphic regions of clag2, clag8, and clag9 from parasites collected in Thailand. Using sequence data obtained newly in this study and reported previously, we classified clag2 sequences into 5 groups based on the similarity of the deduced amino acid sequences and number of insertions/deletions. By the sliding window method, an excess of nonsynonymous substitutions over synonymous substitutions was detected in the group 1 and group 2 clag2 and clag8 sequences. Population-based analyses also detected a significant departure from the neutral expectation for group 1 clag2 and clag8. Thus, two independent approaches suggest that clag2 is subject to a positive diversifying selection. The previously suggested positive selection on clag8 was also supported by population-based analyses. However, the positive selection on clag9, which was detected by comparing the 5 sequences, was not detected using the additional 34 sequences obtained in this study

    Coevolutionary GA with schema extraction by machine learning techniques and its application to knapsack problems

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    The authors introduce a novel coevolutionary genetic algorithm with schema extraction by machine learning techniques. Our CGA consists of two GA populations: the first GA (H-GA) searches for the solutions in the given problems and the second GA (P-GA) searches for effective schemata of the H-GA. We aim to improve the search ability of our CGA by extracting more efficiently useful schemata from the H-GA population, and then incorporating those extracted schemata in a natural manner into the P-GA. Several computational simulations on multidimensional knapsack problems confirm the effectiveness of the proposed method</p

    Tryptophan-rich domains of Plasmodium falciparum SURFIN4.2 and Plasmodium vivax PvSTP2 interact with membrane skeleton of red blood cell

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    Additional file 1: Table S1. Primers for PCR amplification and plasmid construction
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