New procedure for determining minimum time orbit transfers

Computer program includes time minimizing function required for propellant constrained minimum time impulsive transfer between coplanar circular orbits or unrestricted orbits. Basic formulation is extended to include inclined circular or inclined elliptic orbits

Odd-primary homotopy exponents of compact simple Lie groups

We note that a recent result of the second author yields upper bounds for odd-primary homotopy exponents of compact simple Lie groups which are often quite close to the lower bounds obtained from v_1-periodic homotopy theory.Comment: This is the version published by Geometry & Topology Monographs on 22 February 200

Computer program for interplanetary conic patching

Computer program enables study of one-way transfers, single and double planet flybys, single and double planet stopovers, or mixed flyby and stopover trajectories. In each operation it first computes the heliocentric conic which connects the centers of the launch and target planets and requires a given trip time

EXPLORING THE SHORT- AND LONG-RUN LINKS FROM BANK COMPETITION TO RISK – RECONCILING CONFLICTING HYPOTHESES?

Using a dataset for the EU-27 covering 1998-2012, this is one of the first studies of banking competition and risk to look at the dynamics of the relation between these variables, to take account of a full 6 year period since the onset of the crisis in 2007, as well as a comparable period before it; and to compare and contrast results using two competition indicators, the H statistic and the Lerner index. Using the H statistics, we find that in the crucial pre crisis period, the change in competition has a positive effect on risk (measured by the Z Score), while there is a overall negative effect of the level of competition on risk. The Lerner index provides results supportive of the hypothesis that there are dynamic relations between competition and risk, in that the change in the Lerner index again correlates positively with risk (i.e. narrower margins when competition increases make banks weaker) while the long run effect of heightened competition is also to increase risk. Testing for the reason for differences in long run effects we find that the H and Lerner differ in their impact on the volatility of profits, a key input to the Z Score risk indicator. There are important implications for the interpretation of results in the literature based on these different indicators

Could early warning systems have helped to predict the sub prime crisis?

One of the features of the sub-prime crisis, that began in August 2007, was its unexpected nature. It came as a surprise not only to most financial market participants but also in some degree to the policy community. In this context, we seek to assess whether early warning systems based on the logit and binomial tree approaches on the UK and US economies could have helped to warn about the crisis. We also consider a “check list approach” of indicators based on history. Although not all of the complementary approaches are successful, we contend that our work suggests that a broadening of approaches of macroprudential analysis is appropriate

Comparing early warning systems for banking crises

Despite the extensive literature on prediction of banking crises by Early Warning Systems (EWS), their practical use by policy makers is limited, even in the international financial institutions. This is a paradox since the changing nature of banking risks as more economies liberalise and develop their financial systems, as well as ongoing innovation, makes the use of EWS for crisis prevention more necessary than ever. In this context, we assess the logit and signal extraction EWS for banking crises on a comprehensive common dataset. We suggest that logit is the most appropriate approach for global EWS and signal extraction for country specific EWS. Furthermore it is important to consider the policy maker s objectives when designing predictive models and setting related thresholds since there is a sharp trade-off between correctly calling crises and false alarms