30,507 research outputs found

    Meaning, moral realism, and the importance of morality

    Get PDF
    Many philosophers have suspected that the normative importance of morality depends on moral realism. In this paper, I defend a version of this suspicion: I argue that if teleological forms of moral realism, those that posit an objective purpose to human life, are true, then we gain a distinctive kind of reason to do what is morally required. I argue for this by showing that if these forms of realism are true, then doing what is morally required can provide a life with meaning, which is a widespread human need. I also argue that rival meta-ethical views, like anti-realism or non-naturalist realism, cannot make morality meaning-conferring in this way

    Optimal Sizing of Voltage Control Devices for Distribution Circuit with Intermittent Load

    Full text link
    We consider joint control of a switchable capacitor and a D-STATCOM for voltage regulation in a distribution circuit with intermittent load. The control problem is formulated as a two-timescale optimal power flow problem with chance constraints, which minimizes power loss while limiting the probability of voltage violations due to fast changes in load. The control problem forms the basis of an optimization problem which determines the sizes of the control devices by minimizing sum of the expected power loss cost and the capital cost. We develop computationally efficient heuristics to solve the optimal sizing problem and implement real-time control. Numerical experiments on a circuit with high-performance computing (HPC) load show that the proposed sizing and control schemes significantly improve the reliability of voltage regulation on the expense of only a moderate increase in cost.Comment: 10 pages, 7 figures, submitted to HICSS'1

    On martingale approximations

    Full text link
    Consider additive functionals of a Markov chain WkW_k, with stationary (marginal) distribution and transition function denoted by π\pi and QQ, say Sn=g(W1)+...+g(Wn)S_n=g(W_1)+...+g(W_n), where gg is square integrable and has mean 0 with respect to π\pi. If SnS_n has the form Sn=Mn+RnS_n=M_n+R_n, where MnM_n is a square integrable martingale with stationary increments and E(Rn2)=o(n)E(R_n^2)=o(n), then gg is said to admit a martingale approximation. Necessary and sufficient conditions for such an approximation are developed. Two obvious necessary conditions are E[E(SnW1)2]=o(n)E[E(S_n|W_1)^2]=o(n) and limnE(Sn2)/n<\lim_{n\to \infty}E(S_n^2)/n<\infty. Assuming the first of these, let g+2=lim supnE(Sn2)/n\Vert g\Vert^2_+=\limsup_{n\to \infty}E(S_n^2)/n; then +\Vert\cdot\Vert_+ defines a pseudo norm on the subspace of L2(π)L^2(\pi) where it is finite. In one main result, a simple necessary and sufficient condition for a martingale approximation is developed in terms of +\Vert\cdot\Vert_+. Let QQ^* denote the adjoint operator to QQ, regarded as a linear operator from L2(π)L^2(\pi) into itself, and consider co-isometries (QQ=IQQ^*=I), an important special case that includes shift processes. In another main result a convenient orthonormal basis for L02(π)L_0^2(\pi) is identified along with a simple necessary and sufficient condition for the existence of a martingale approximation in terms of the coefficients of the expansion of gg with respect to this basis.Comment: Published in at http://dx.doi.org/10.1214/07-AAP505 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org
    corecore