McStas is a neutron ray-trace simulation package that simulates neutron scattering instruments. I... more McStas is a neutron ray-trace simulation package that simulates neutron scattering instruments. Its developers at Riso National Laboratory in Denmark and the Institute Max von Laue-Paul Langevin in France are collaborating with the SNS instrument scientists, the Neutron Science TeraGrid developers, and the DANSE developers to improve the package and make it available to more researchers. Distributed computing on the
... The authors are: Kim Lefmann Materials Research Department, Risø National Laboratory, Roskild... more ... The authors are: Kim Lefmann Materials Research Department, Risø National Laboratory, Roskilde, Denmark email: kim.lefmann@risoe.dk Peter Kjær Willendrup Materials Research Department, Risø National Laboratory, Roskilde, Denmark email: peter.willendrup@risoe.dk ...
We propose a new model of exchange rates, which yields a theory of the forward premium puzzle. Ou... more We propose a new model of exchange rates, which yields a theory of the forward premium puzzle. Our explanation combines two ingredients: the possibility of rare economic disasters, and an asset view of the exchange rate. Our model is frictionless, has complete markets, and works for an arbitrary number of countries. In the model, rare worldwide disasters can occur and
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment, 2008
Long-pulse spallation sources will offer a very high time-integrated neutron flux similar to that... more Long-pulse spallation sources will offer a very high time-integrated neutron flux similar to that of the best steady-state sources. Using Monte Carlo simulations we show that the exceptional source qualities translate directly into strongly enhanced instrument performance for a large class of instruments ranging from high-resolution backscattering to low-resolution small-angle scattering. The relation of the source duty cycle to the
The paper revisits and qualifies existing insights on security design. A rich literature argues t... more The paper revisits and qualifies existing insights on security design. A rich literature argues that tranching creates debt-like instruments that are robust to adverse selection or discourage wasteful information acquisition. Yet, for a given information structure, while tranching confines and liquefies the safe part of a cash flow (the insulation effect), bundling makes the risky part more liquid (the trading adjuvant effect). Moreover, tranching always has adverse welfare effects on information acquisition: It encourages (discourages) information acquisition when it should be deterred (encouraged). The paper provides conditions under which tranching reduces welfare even when the insulation effect dominates the trading adjuvant effect. The paper’s second contribution is to analyze the velocity of assets that are repeatedly traded. The dynamic model can be nested into the static one and insights are shown to be closely related to those on tranching. The central insight is that liqui...
We explore the link between liquidity and investment in a an overlapping generation model with a ... more We explore the link between liquidity and investment in a an overlapping generation model with a standard asynchronicity between firms' access to and need for cash. Imperfect pledgeability hinders the capacity of capital markets to resolve this asynchronicity, resulting in credit rationing and a net demand for stores of value -- liquidity -- by the corporate sector. At the heart of the model is a distinction between inside liquidity -- liquidity created within the private sector -- and outside liquidity -- assets that do not originate in private investment decisions. In the model, outside liquidity comes in two forms: rents and asset bubbles. We make four contributions. First, we show that imperfect pledgeability severs the link between dynamic efficiency and the level of the interest rate. Bubbles are possible even when the economy is dynamically efficient. Second, we demonstrate that the link between outside liquidity and investment is ambiguous: on the one hand, outside liqu...
The Paper highlights one critical difference between Europe and the US regarding the Phillips cur... more The Paper highlights one critical difference between Europe and the US regarding the Phillips curve: the behaviour of prices. While they are quickly restored to an equilibrium level in the US, European prices are driven by highly counter-cyclical mark-ups. In bad times, European firms manage to keep their price high relative to cost, while their US counterparts are pressed into cuts and discounts of various forms. We show that this behaviour is the critical reason why Phillips curve look different across the Atlantic, much more than because of differences arising on the labour markets.
... FEAR OF REJECTION? TIERED CERTIFICATION AND TRANSPARENCY Emmanuel FarhiJosh Lerner Jean Tirol... more ... FEAR OF REJECTION? TIERED CERTIFICATION AND TRANSPARENCY Emmanuel FarhiJosh Lerner Jean Tirole Working Paper 14457 http://www.nber.org/papers/w14457 ... 2008 byEmmanuel Farhi, Josh Lerner, and Jean Tirole. All rights reserved. ...
We present results of a virtual experiment, carried out by means of a McStas simulation of the po... more We present results of a virtual experiment, carried out by means of a McStas simulation of the powder diffractometer DMC at PSI, using the new powder sample component PowderN. This powder component takes tabulated crystallographic input to define realistic powder lines. ...
Monte-Carlo simulations of a focusing supermirror guide after the monochromator on the IN14 cold ... more Monte-Carlo simulations of a focusing supermirror guide after the monochromator on the IN14 cold neutron three-axis spectrometer, I.L.L. were carried out using the instrument simulation programs RESTRAX and McSTAS. The simulations were compared to experiment to check their accuracy. Comparisons of the flux ratios over both a 100 and a 1600mm2 area at the sample position compare well, and there is a very close agreement between simulation and experiment for the energy spread of the incident beam.
... Of course, the RITA-II spectrometer is designed for inelastic measurements rather than powder... more ... Of course, the RITA-II spectrometer is designed for inelastic measurements rather than powder diffraction (although use of energy analysis may be of importance for powder diffraction in special cases ... 8. SN Klausen, K. Lefmann, DF McMorrow, F. Altorfer, S. Janssen and M. Lüthy ...
McStas is a neutron ray-trace simulation package that simulates neutron scattering instruments. I... more McStas is a neutron ray-trace simulation package that simulates neutron scattering instruments. Its developers at Riso National Laboratory in Denmark and the Institute Max von Laue-Paul Langevin in France are collaborating with the SNS instrument scientists, the Neutron Science TeraGrid developers, and the DANSE developers to improve the package and make it available to more researchers. Distributed computing on the
... The authors are: Kim Lefmann Materials Research Department, Risø National Laboratory, Roskild... more ... The authors are: Kim Lefmann Materials Research Department, Risø National Laboratory, Roskilde, Denmark email: kim.lefmann@risoe.dk Peter Kjær Willendrup Materials Research Department, Risø National Laboratory, Roskilde, Denmark email: peter.willendrup@risoe.dk ...
We propose a new model of exchange rates, which yields a theory of the forward premium puzzle. Ou... more We propose a new model of exchange rates, which yields a theory of the forward premium puzzle. Our explanation combines two ingredients: the possibility of rare economic disasters, and an asset view of the exchange rate. Our model is frictionless, has complete markets, and works for an arbitrary number of countries. In the model, rare worldwide disasters can occur and
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment, 2008
Long-pulse spallation sources will offer a very high time-integrated neutron flux similar to that... more Long-pulse spallation sources will offer a very high time-integrated neutron flux similar to that of the best steady-state sources. Using Monte Carlo simulations we show that the exceptional source qualities translate directly into strongly enhanced instrument performance for a large class of instruments ranging from high-resolution backscattering to low-resolution small-angle scattering. The relation of the source duty cycle to the
The paper revisits and qualifies existing insights on security design. A rich literature argues t... more The paper revisits and qualifies existing insights on security design. A rich literature argues that tranching creates debt-like instruments that are robust to adverse selection or discourage wasteful information acquisition. Yet, for a given information structure, while tranching confines and liquefies the safe part of a cash flow (the insulation effect), bundling makes the risky part more liquid (the trading adjuvant effect). Moreover, tranching always has adverse welfare effects on information acquisition: It encourages (discourages) information acquisition when it should be deterred (encouraged). The paper provides conditions under which tranching reduces welfare even when the insulation effect dominates the trading adjuvant effect. The paper’s second contribution is to analyze the velocity of assets that are repeatedly traded. The dynamic model can be nested into the static one and insights are shown to be closely related to those on tranching. The central insight is that liqui...
We explore the link between liquidity and investment in a an overlapping generation model with a ... more We explore the link between liquidity and investment in a an overlapping generation model with a standard asynchronicity between firms' access to and need for cash. Imperfect pledgeability hinders the capacity of capital markets to resolve this asynchronicity, resulting in credit rationing and a net demand for stores of value -- liquidity -- by the corporate sector. At the heart of the model is a distinction between inside liquidity -- liquidity created within the private sector -- and outside liquidity -- assets that do not originate in private investment decisions. In the model, outside liquidity comes in two forms: rents and asset bubbles. We make four contributions. First, we show that imperfect pledgeability severs the link between dynamic efficiency and the level of the interest rate. Bubbles are possible even when the economy is dynamically efficient. Second, we demonstrate that the link between outside liquidity and investment is ambiguous: on the one hand, outside liqu...
The Paper highlights one critical difference between Europe and the US regarding the Phillips cur... more The Paper highlights one critical difference between Europe and the US regarding the Phillips curve: the behaviour of prices. While they are quickly restored to an equilibrium level in the US, European prices are driven by highly counter-cyclical mark-ups. In bad times, European firms manage to keep their price high relative to cost, while their US counterparts are pressed into cuts and discounts of various forms. We show that this behaviour is the critical reason why Phillips curve look different across the Atlantic, much more than because of differences arising on the labour markets.
... FEAR OF REJECTION? TIERED CERTIFICATION AND TRANSPARENCY Emmanuel FarhiJosh Lerner Jean Tirol... more ... FEAR OF REJECTION? TIERED CERTIFICATION AND TRANSPARENCY Emmanuel FarhiJosh Lerner Jean Tirole Working Paper 14457 http://www.nber.org/papers/w14457 ... 2008 byEmmanuel Farhi, Josh Lerner, and Jean Tirole. All rights reserved. ...
We present results of a virtual experiment, carried out by means of a McStas simulation of the po... more We present results of a virtual experiment, carried out by means of a McStas simulation of the powder diffractometer DMC at PSI, using the new powder sample component PowderN. This powder component takes tabulated crystallographic input to define realistic powder lines. ...
Monte-Carlo simulations of a focusing supermirror guide after the monochromator on the IN14 cold ... more Monte-Carlo simulations of a focusing supermirror guide after the monochromator on the IN14 cold neutron three-axis spectrometer, I.L.L. were carried out using the instrument simulation programs RESTRAX and McSTAS. The simulations were compared to experiment to check their accuracy. Comparisons of the flux ratios over both a 100 and a 1600mm2 area at the sample position compare well, and there is a very close agreement between simulation and experiment for the energy spread of the incident beam.
... Of course, the RITA-II spectrometer is designed for inelastic measurements rather than powder... more ... Of course, the RITA-II spectrometer is designed for inelastic measurements rather than powder diffraction (although use of energy analysis may be of importance for powder diffraction in special cases ... 8. SN Klausen, K. Lefmann, DF McMorrow, F. Altorfer, S. Janssen and M. Lüthy ...
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