234 research outputs found

    Calculating effective resistances on underlying networks of association schemes

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    Recently, in Refs. \cite{jsj} and \cite{res2}, calculation of effective resistances on distance-regular networks was investigated, where in the first paper, the calculation was based on stratification and Stieltjes function associated with the network, whereas in the latter one a recursive formula for effective resistances was given based on the Christoffel-Darboux identity. In this paper, evaluation of effective resistances on more general networks which are underlying networks of association schemes is considered, where by using the algebraic combinatoric structures of association schemes such as stratification and Bose-Mesner algebras, an explicit formula for effective resistances on these networks is given in terms of the parameters of corresponding association schemes. Moreover, we show that for particular underlying networks of association schemes with diameter dd such that the adjacency matrix AA possesses d+1d+1 distinct eigenvalues, all of the other adjacency matrices AiA_i, i0,1i\neq 0,1 can be written as polynomials of AA, i.e., Ai=Pi(A)A_i=P_i(A), where PiP_i is not necessarily of degree ii. Then, we use this property for these particular networks and assume that all of the conductances except for one of them, say cc1=1c\equiv c_1=1, are zero to give a procedure for evaluating effective resistances on these networks. The preference of this procedure is that one can evaluate effective resistances by using the structure of their Bose-Mesner algebra without any need to know the spectrum of the adjacency matrices.Comment: 41 page

    On an Improved Diagnosis Program

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    Coordinated Science Laboratory was formerly known as Control Systems LaboratoryContract DA-28-043-AMC-00073(E

    Generations of Trees without Duplications

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    Coordinated Science Laboratory was formerly known as Control Systems LaboratoryDepartment of the Army / DA-28-043-AMC-00073(E)Department of the Air Force (Office of Scientific Research) / AF 49(638) - 138

    Comparison of methods to determine point-to-point resistance in nearly rectangular networks with application to a ‘hammock’ network

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    Considerable progress has recently been made in the development of techniques to exactly determine two-point resistances in networks of various topologies. In particular, two types of method have emerged. One is based on potentials and the evaluation of eigenvalues and eigenvectors of the Laplacian matrix associated with the network or its minors. The second method is based on a recurrence relation associated with the distribution of currents in the network. Here, these methods are compared and used to determine the resistance distances between any two nodes of a network with topology of a hammock

    Current Control Technique For Grid Connected Distributed Generation (DG) Resources Using ANN controller

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    — This paper deals with the current controlling method based on Artificial Neural Network technique. In this proposed controlling strategy compensation for active, reactive powers will be done and harmonic load current components compensation will be done during connection of DG link to the grid. So that this paper is a multi objective control technique. With this strategy the integration of distributed generation (DG) resources to the electrical power network will get much importance. This proposed control method does not need a phase-locked loop in control circuit and has fast dynamic response in providing active and reactive power components of the grid-connected loads. The transformed variables are used in control of the voltage source converter as the heart of the interfacing system between DG resources and utility grid. Using the compensation current references from the sensed load currents of DG, the active, reactive, and harmonic load current components will be compensated with fast dynamic response, thereby achieving sinusoidal grid currents in phase with load voltages, while required power of the load is more than the maximum injected power of the DG to the grid.  The effectiveness of the proposed control technique with ANN controller in DG application are presented using through matlab / simulink software under steady-state and dynamic operating conditions

    Modeling 3D Magma Dynamics Using a Discontinuous Galerkin Method

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    Discontinuous Galerkin (DG) and matrix-free finite element methods with a novel projective pressure estimation are combined to enable the numerical model- ing of magma dynamics in 2D and 3D using the library deal.II . The physical model is an advection-reaction type system consisting of two hyperbolic equations to evolve porosity and soluble mineral abundance and one elliptic equation to recover global pressure. A combination of a discontinuous Galerkin method for the advection equa- tions and a finite element method for the elliptic equation provide a robust and efficient solution to the channel regime problems of the physical system in 3D. A projective and adaptively applied pressure estimation is employed to significantly reduce the compu- tational wall time without impacting the overall physical reliability in the modeling of important features of melt and segregation, such as melt channel bifurcation in 2D and 3D time dependent simulations

    Multilevel and Local Timestepping Discontinuous Galerkin Methods for Magma Dynamics

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    Discontinuous Galerkin (DG) method is presented for numerical modeling of melt migration in a chemically reactive and viscously deforming upwelling mantle column. DG methods for both advection and elliptic equations provide a robust and efficient solution to the problems of melt migration in the asthenospheric upper mantle. Assembling and solving the elliptic equation is the major bottleneck in these computations. To address this issue, adaptive mesh refinement and local timestepping methods have been proposed to significantly improve the computational wall time. The robustness of DG methods is demonstrated through two benchmark problems by modeling detailed structure of high-porosity dissolution channels and compaction-dissolution waves

    Microbial Co-Infection Alters Macrophage Polarization, Phagosomal Escape, and Microbial Killing

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    Macrophages are important innate immune cells that respond to microbial insults. In response to multi-bacterial infection, the macrophage activation state may change upon exposure to nascent mediators, which results in different bacterial killing mechanism(s). In this study, we utilized two respiratory bacterial pathogens, Mycobacterium bovis (Bacillus Calmette Guẻrin, BCG) and Francisella tularensis live vaccine strain (LVS) with different phagocyte evasion mechanisms, as model microbes to assess the influence of initial bacterial infection on the macrophage response to secondary infection. Non-activated (M0) macrophages or activated M2-polarized cells (J774 cells transfected with the mouse IL-4 gene) were first infected with BCG for 24–48 h, subsequently challenged with LVS, and the results of inhibition of LVS replication in the macrophages was assessed. BCG infection in M0 macrophages activated TLR2-MyD88 and Mincle-CARD9 signaling pathways, stimulating nitric oxide (NO) production and enhanced killing of LVS. BCG infection had little effect on LVS escape from phagosomes into the cytosol in M0 macrophages. In contrast, M2-polarized macrophages exhibited enhanced endosomal acidification, as well as inhibiting LVS replication. Pre-infection with BCG did not induce NO production and thus did not further reduce LVS replication. This study provides a model for studies of the complexity of macrophage activation in response to multi-bacterial infection

    Components of the sex pheromone of the female spotted stalk borer,Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae): Identification and preliminary field trials

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    FemaleChilo partellus (Swinhoe) abdominal tip extracts were examined by gas-liquid chromatography (GLC) combined with simultaneous electroantennographic (EAG) recording from the male moth. Two olfactory stimulants were detected and identified as (Z)-11-hexadecenal (I) and (Z)-11-hexadecen-1-ol (II) by their GLC behavior, microchemical reactions, and comparison with synthetic materials. Both compounds were detected in volatiles emitted by the “calling” female moth. Synthetic (Z)-9-tetradecenyl formate, a structural analog of aldehyde (I), also elicited a significant EAG response from the male moth. Field trials carried out in India using synthetic (I) and (II) as bait in water traps showed that compound (I) was highly attractive to maleC. partellus; compound (II) was not attractive, and its addition to (I) significantly reduced trap catches
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