Quantity Rationing of Credit

Quantity rationing of credit, when ?firms are denied loans, has greater potential to explain macroeconomics ?fluctuations than borrowing costs. This paper develops a DSGE model with both types of financial frictions. A deterioration in credit market con?fidence leads to a temporary change in the interest rate, but a persistent change in the fraction of ?firms receiving ?financing, which leads to a persistent fall in real activity. Empirical evidence confi?rms that credit market con?fidence, measured by the survey of loan officers, is a signi?cant leading indicator for capacity utilization and output, while borrowing costs, measured by interest rate spreads, is not.Quantity Rationing, Credit, VAR

Quantity Rationing of Credit and the Phillips Curve

Quantity rationing of credit, when some ?firms are denied loans, has macroeconomics effects not fully captured by measures of borrowing costs. This paper develops a monetary DSGE model with quantity rationing and derives a Phillips Curve relation where in?flation dynamics depend on cyclical unemployment, a risk premium and the fraction of fi?rms receiving ?financing. Unemployment arising from disruptions in credit ?flows is defi?ned to be cyclical. GMM estimates using data from a survey of bank managers con?firms the importance of these variables for in?flation dynamics.Quantity Rationing, Phillips Curve, Cyclical Unemployment, GMM

Endogenous Rational Bubbles

Tests on simulated data from an asset pricing model with heterogeneous forecasts show excess variance in the price and ARCH effects in the returns, features not explained by the strong version of the efficient markets hypothesis. An evolutionary game theory dynamic describes how agents switch between a fundamental forecast, a rational bubble forecast and the reflective forecast, which is a weighted average of the former two. Conditions determining the frequency and duration of episodes where a significant fraction of agents adopt the rational bubble forecast leading to large deviations in the price-dividend ratio are discussed.return predictability, excess variance, ARCH, evolutionary game theory, rational bubble

Quantity rationing of credit

Quantity rationing of credit, when firms are denied loans, has greater potential to explain macroeconomic fluctuations than borrowing costs. This paper develops a DSGE model with both types of financial frictions. A deterioration in credit market confidence leads to a temporary change in the interest rate, but a persistent change in the fraction of firms receiving financing, which leads to a persistent fall in real activity. Empirical evidence confirms that credit market confidence, measured by the survey of loan officers, is a significant leading indicator for capacity utilization and output, while borrowing costs, measured by interest rate spreads, is not.quantity rationing; credit; VAR

UML Deficiencies from the perspective of Automatic Performance Model Generation

A discussion surrounding the use of UML for distributed system design

Mental Imagery and Chunks: Empirical and Computational Findings

To investigate experts’ imagery in chess, players were required to recall briefly-presented positions in which the pieces were placed on the intersections between squares (intersection positions). Position types ranged from game positions to positions where both the piece distribution and location were randomized. Simulations were run with the CHREST model (Gobet & Simon, 2000). The simulations assumed that pieces had to be centered back one by one to the middle of the squares in the mind’s eye before chunks could be recognized. Consistent with CHREST’s predictions, chess players (N = 36), ranging from weak amateurs to grandmasters, exhibited much poorer recall on intersection positions than on standard positions (pieces placed on centers of squares). On the intersection positions, the skill difference in recall was larger on game positions than on the randomized positions. Participants recalled bishops better than knights, suggesting that Stroop-like interference impairs recall of the latter. The data supported both the time parameter in CHREST for shifting pieces in the mind’s eye (125 ms per piece) and the seriality assumption. In general, the study reinforces the plausibility of CHREST as a model of cognition

Revised time-of-flight calculations for high-latitude geomagnetic pulsations using a realistic magnetospheric magnetic field model

We present a simple time-of-flight analysis of Alfvén pulsations standing on closed terrestrial magnetic field lines. The technique employed in this study in order to calculate the characteristic period of such oscillations builds upon earlier time-of-flight estimates via the implementation of a more recent magnetospheric magnetic field model. In this case the model employed is the Tsyganenko (1996) field model, which includes realistic magnetospheric currents and the consequences of the partial penetration of the interplanetary magnetic field into the dayside magnetopause. By employing a simple description of magnetospheric plasma density, we are therefore able to estimate the period of standing Alfvén waves on geomagnetic field lines over a significantly wider range of latitudes and magnetic local times than in previous studies. Furthermore, we investigate the influence of changing season and upstream interplanetary conditions upon the period of such pulsations. Finally, the eigenfrequencies of magnetic field lines computed by the time-of-flight technique are compared with corresponding numerical solutions to the wave equation and experimentally observed pulsations on geomagnetic field lines

Wireless recording of the calls of Rousettus aegyptiacus and their reproduction using electrostatic transducers

Bats are capable of imaging their surroundings in great detail using echolocation. To apply similar methods to human engineering systems requires the capability to measure and recreate the signals used, and to understand the processing applied to returning echoes. In this work, the emitted and reflected echolocation signals of Rousettus aegyptiacus are recorded while the bat is in flight, using a wireless sensor mounted on the bat. The sensor is designed to replicate the acoustic gain control which bats are known to use, applying a gain to returning echoes that is dependent on the incurred time delay. Employing this technique allows emitted and reflected echolocation calls, which have a wide dynamic range, to be recorded. The recorded echoes demonstrate the complexity of environment reconstruction using echolocation. The sensor is also used to make accurate recordings of the emitted calls, and these calls are recreated in the laboratory using custom-built wideband electrostatic transducers, allied with a spectral equalization technique. This technique is further demonstrated by recreating multi-harmonic bioinspired FM chirps. The ability to record and accurately synthesize echolocation calls enables the exploitation of biological signals in human engineering systems for sonar, materials characterization and imaging

Computational Modelling of Mental Imagery in Chess: A Sensitivity Analysis

An important aim of cognitive science is to build computational models that account for a large number of phenomena but have few free parameters, and to obtain more veridical values for the models’ parameters by successive approximations. A good example of this approach is the CHREST model (Gobet & Simon, 2000), which has simulated numerous phenomena on chess expertise and in other domains. In this paper, we are interested in the parameter the model uses for shifting chess pieces in its mind’s eye (125 ms per piece), a parameter that had been estimated based on relatively sparse experimental evidence. Recently, Waters and Gobet (2008) tested the validity of this parameter in a memory experiment that required players to recall briefly presented positions in which the pieces were placed on the intersections between squares. Position types ranged from game positions to positions where both the piece distribution and location were randomised. CHREST, which assumed that pieces must be centred back to the middle of the squares in the mind’s eye before chunks can be recognized, simulated the data fairly well using the default parameter for shifting pieces. The sensitivity analysis presented in the current paper shows that the fit was nearly optimal for all groups of players except the grandmaster group for which, counterintuitively, a slower shifting time gave a better fit. The implications for theory development are discussed