7,927 research outputs found

    Game-theoretic approach to risk-sensitive benchmarked asset management

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    In this article we consider a game theoretic approach to the Risk-Sensitive Benchmarked Asset Management problem (RSBAM) of Davis and Lleo \cite{DL}. In particular, we consider a stochastic differential game between two players, namely, the investor who has a power utility while the second player represents the market which tries to minimize the expected payoff of the investor. The market does this by modulating a stochastic benchmark that the investor needs to outperform. We obtain an explicit expression for the optimal pair of strategies as for both the players.Comment: Forthcoming in Risk and Decision Analysis. arXiv admin note: text overlap with arXiv:0905.4740 by other author

    Evaluation of ADAM/1 model for advanced coal extraction concepts

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    Several existing computer programs for estimating life cycle cost of mining systems were evaluated. A commercially available program, ADAM/1 was found to be satisfactory in relation to the needs of the advanced coal extraction project. Two test cases were run to confirm the ability of the program to handle nonconventional mining equipment and procedures. The results were satisfactory. The model, therefore, is recommended to the project team for evaluation of their conceptual designs

    Characteristic impedance of microstrip lines

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    The dyadic Green's function for a current embedded in a grounded dielectric slab is used to analyze microstrip lines at millimeter wave frequencies. The dyadic Green's function accounts accurately for fringing fields and dielectric cover over the microstrip line. Using Rumsey's reaction concept, an expression for the characteristic impedance is obtained. The numerical results are compared with other reported results

    Ionospheric Disturbances Accompanying Noncrochet and Crochet Associated Flares

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    BRIGE: Translating Robotic Technology for Inclusive Fitness: An Innovative Robotic Rowing Exoskeleton (RRE) Development Project

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    Intellectual Merit: The opportunities for inclusion in fitness activity for disabled individuals, particularly those with severe disabilities, are extremely limited due to intrinsic, environmental, and social factors. This BRIGE project focuses on advancing robotic technology as a strategy to promote fitness opportunities for a range of individuals with disabilities. This project will 1) design, test, and build a prototype robotic device called Robotic Rowing Exoskeleton (RRE) that will augment movement, coordination, and strength in the activity of rowing; 2) yield a complete dynamics model of rowing biomechanics and parameter determination via human subject data; 3) provide a model system through which biomechanics and parameter determination using human subject data can be translated into precise robotic-assisted movement; 4) integrate electromyography and robotics to create a prototype that will be responsive to individual user needs; and 5) advance the development of an ongoing research program in robotic devices for improved quality of life. Broader Impacts: This project will be used as the foundation for the CIDER (Creating Investigator Diversity in Engineering Research) model with five major components. First, diverse students for whom the research agenda is personally relevant and compelling will be recruited to participate in all phases of the program. Second, each of the student researchers will engage in outreach in schools and a summer camp program for middle and high school students to perpetuate ongoing recruitment of diverse students into engineering research careers. Third, a video of RRE, its development, and its use will be made for on-site and virtual dissemination nationwide. Fourth, we will continue an ongoing program which hosts robotics demos for middle school and high school students, especially, women, to encourage them to pursue a career in Engineering. Finally, the model will be formalized and evaluated so that it can be expanded to encourage the involvement of other underrepresented groups in engineering

    UNDERSTANDING AND IMPROVING LITHIUM ION BATTERIES THROUGH MATHEMATICAL MODELING AND EXPERIMENTS

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    There is an intense, worldwide effort to develop durable lithium ion batteries with high energy and power densities for a wide range of applications, including electric and hybrid electric vehicles. For improvement of battery technology understanding the capacity fading mechanism in batteries is of utmost importance. Novel electrode material and improved electrode designs are needed for high energy- high power batteries with less capacity fading. Furthermore, for applications such as automotive applications, precise cycle-life prediction of batteries is necessary. One of the critical challenges in advancing lithium ion battery technologies is fracture and decrepitation of the electrodes as a result of lithium diffusion during charging and discharging operations. When lithium is inserted in either the positive or negative electrode, there is a volume change associated with insertion or de-insertion. Diffusion-induced stresses (DISs) can therefore cause the nucleation and growth of cracks, leading to mechanical degradation of the batteries. With different mathematical models we studied the behavior of diffusion induces stresses and effects of electrode shape, size, concentration dependent material properties, pre-existing cracks, phase transformations, operating conditions etc. on the diffusion induced stresses. Thus we develop tools to guide the design of the electrode material with better mechanical stability for durable batteries. Along with mechanical degradation, chemical degradation of batteries also plays an important role in deciding battery cycle life. The instability of commonly employed electrolytes results in solid electrolyte interphase (SEI) formation. Although SEI formation contributes to irreversible capacity loss, the SEI layer is necessary, as it passivates the electrode-electrolyte interface from further solvent decomposition. SEI layer and diffusion induced stresses are inter-dependent and affect each-other. We study coupled chemical-mechanical degradation of electrode materials to understand the capacity fading of the battery with cycling. With the understanding of chemical and mechanical degradation, we develop a simple phenomenological model to predict battery life. On the experimental part we come up with a novel concept of using liquid metal alloy as a self-healing battery electrode. We develop a method to prepare thin film liquid gallium electrode on a conductive substrate. This enabled us to perform a series of electrochemical and characterization experiments which certify that liquid electrode undergo liquid-solid-liquid transition and thus self-heals the cracks formed during de-insertion. Thus the mechanical degradation can be avoided. We also perform ab-initio calculations to understand the equilibrium potential of various lithium-gallium phases

    A method for determining CP violating phase γ\gamma

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    A new way of determining the phases of weak amplitudes in charged BB decays based on SU(3) symmetry is proposed. The CP violating phase γ\gamma can now be determined without the previous difficulty associated with electroweak penguins.Comment: 9 pages plus one figure, Revte

    Electroweak Model Independent Tests for SU(3) Symmetry in Hadronic B Decays

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    We study effects of new physics beyond the Standard Model on SU(3) symmetry in charmless hadronic two body B decays. It is found that several equalities for some of the decay amplitudes, such as A(Bd(Bu)π+π,π+K(πKˉ0))=A(BsK+π,KK+(K0Kˉ0))A(B_d (B_u) \to \pi^+\pi^-,\pi^+ K^- (\pi^- \bar K^0)) =A(B_s \to K^+ \pi^-, K^- K^+ (K^0 \bar K^0)), A(Bdπ+ρ,πρ+,Kρ+,π+K)=A(BsK+ρ,πK+,KK+,K+K)A(B_d \to \pi^+\rho^-, \pi^- \rho^+, K^-\rho^+, \pi^+ K^{*-}) = A(B_s \to K^+ \rho^-, \pi^- K^{*+}, K^- K^{*+}, K^+ K^{*-}), A(Bd(Bu)ρ+ρ,ρ+K(ρKˉ0))=A(BsK+ρ,KK+(K0Kˉ0))A(B_d (B_u) \to \rho^+\rho^-, \rho^+ K^{*-}(\rho^- \bar K^{*0})) =A(B_s \to K^{*+} \rho^-, K^{*-} K^{*+} (K^{*0} \bar K^{*0})), predicted by SU(3) symmetry in the SM are not affected by new physics. These relations provide important electroweak model independent tests for SU(3) symmetry in B decays.Comment: 4 pages, revte
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