Flight research capabilities of the NASA/Army rotor systems research aircraft

A description is given of the capabilities and limitations of the Rotor Systems Research Aircraft (RSRA) that was demonstrated during the development contract, and assesses the expected research capabilities of the RSRA on delivery to the government

Everyday Haunting

This document outlines a journey of self-exploration, discovery, construction and destruction. It is a story of learning, a testament to impermanence, and a proposal for possibility. The words and work contained in this document are exclusive to the thoughts and actions of one man that hopes to share with others

Decidability Results for Multi-objective Stochastic Games

We study stochastic two-player turn-based games in which the objective of one player is to ensure several infinite-horizon total reward objectives, while the other player attempts to spoil at least one of the objectives. The games have previously been shown not to be determined, and an approximation algorithm for computing a Pareto curve has been given. The major drawback of the existing algorithm is that it needs to compute Pareto curves for finite horizon objectives (for increasing length of the horizon), and the size of these Pareto curves can grow unboundedly, even when the infinite-horizon Pareto curve is small. By adapting existing results, we first give an algorithm that computes the Pareto curve for determined games. Then, as the main result of the paper, we show that for the natural class of stopping games and when there are two reward objectives, the problem of deciding whether a player can ensure satisfaction of the objectives with given thresholds is decidable. The result relies on intricate and novel proof which shows that the Pareto curves contain only finitely many points. As a consequence, we get that the two-objective discounted-reward problem for unrestricted class of stochastic games is decidable.Comment: 35 page

Probing Density Fluctuations using the FIRST Radio Survey

We use results of angular clustering measurements in 3000 sq. deg's of the FIRST radio survey to infer information on spatial clustering. Measurements are compared with CDM-model predictions. Clustering of FIRST sources with optical ID's in the APM catalog are also investigated. Finally, we outline a preliminary search for a weak lensing signal in the survey.Comment: 6 pages latex, 2 figures, to appear in Cosmology with the New Radio Surveys (Kluwer

Clinical evaluation of glucagon by continuous infusion in the treatment of low cardiac output states

A continuous infusion of glucagon in an average dose of 4 mg. per hour over several days produced distinct improvement in the clinical state of 12 of 16 patients. Improvement was noted by an increase in blood pressure and urinary output and decrease in dyspnea, pulmonary rales, diaphoresis, and peripheral edema when present. Serum potassium must be carefully monitored. The rise in blood glucose has not been a clinical problem. No cardiac arrhythmias were induced by glucagon, and as cardiac function improved, the heart rate usually decreased. Nausea was the most frequent side effect, but no toxic effects or tachyphylaxis were observed. Long-term therapy with glucagon infusion is both safe and highly efficacious in selected patients with severe cardiovascular disease states and is the treatment of choice in cardiac decompensation secondary to beta-blocking agents.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32778/1/0000151.pd

The Complexity of Nash Equilibria in Simple Stochastic Multiplayer Games

We analyse the computational complexity of finding Nash equilibria in simple stochastic multiplayer games. We show that restricting the search space to equilibria whose payoffs fall into a certain interval may lead to undecidability. In particular, we prove that the following problem is undecidable: Given a game G, does there exist a pure-strategy Nash equilibrium of G where player 0 wins with probability 1. Moreover, this problem remains undecidable if it is restricted to strategies with (unbounded) finite memory. However, if mixed strategies are allowed, decidability remains an open problem. One way to obtain a provably decidable variant of the problem is restricting the strategies to be positional or stationary. For the complexity of these two problems, we obtain a common lower bound of NP and upper bounds of NP and PSPACE respectively.Comment: 23 pages; revised versio

Decision Problems for Nash Equilibria in Stochastic Games

We analyse the computational complexity of finding Nash equilibria in stochastic multiplayer games with $\omega$-regular objectives. While the existence of an equilibrium whose payoff falls into a certain interval may be undecidable, we single out several decidable restrictions of the problem. First, restricting the search space to stationary, or pure stationary, equilibria results in problems that are typically contained in PSPACE and NP, respectively. Second, we show that the existence of an equilibrium with a binary payoff (i.e. an equilibrium where each player either wins or loses with probability 1) is decidable. We also establish that the existence of a Nash equilibrium with a certain binary payoff entails the existence of an equilibrium with the same payoff in pure, finite-state strategies.Comment: 22 pages, revised versio

Practical solution to the Monte Carlo sign problem: Realistic calculations of 54Fe

We present a practical solution to the "sign problem" in the auxiliary field Monte Carlo approach to the nuclear shell model. The method is based on extrapolation from a continuous family of problem-free Hamiltonians. To demonstrate the resultant ability to treat large shell-model problems, we present results for 54Fe in the full fp-shell basis using the Brown-Richter interaction. We find the Gamow-Teller beta^+ strength to be quenched by 58% relative to the single-particle estimate, in better agreement with experiment than previous estimates based on truncated bases.Comment: 11 pages + 2 figures (not included