Topography of (exo)planets

Current technology is not able to map the topography of rocky exoplanets, simply because the objects are too faint and far away to resolve them. Nevertheless, indirect effect of topography should be soon observable thanks to photometry techniques, and the possibility of detecting specular reflections. In addition, topography may have a strong effect on Earth-like exoplanet climates because oceans and mountains affect the distribution of clouds \citep{Houze2012}. Also topography is critical for evaluating surface habitability \citep{Dohm2015}. We propose here a general statistical theory to describe and generate realistic synthetic topographies of rocky exoplanetary bodies. In the solar system, we have examined the best-known bodies: the Earth, Moon, Mars and Mercury. It turns out that despite their differences, they all can be described by multifractral statistics, although with different parameters. Assuming that this property is universal, we propose here a model to simulate 2D spherical random field that mimics a rocky planetary body in a stellar system. We also propose to apply this model to estimate the statistics of oceans and continents to help to better assess the habitability of distant worlds

Does Inflation Targeting Make a Difference?

Yes, as inferred from panel evidence for inflation-targeting countries and a control group of high-achieving industrial countries that do not target inflation. Our evidence suggests that inflation targeting helps countries achieve lower inflation in the long run, have smaller inflation response to oil-price and exchange-rate shocks, strengthen monetary policy independence, improve monetary policy efficiency, and obtain inflation outcomes closer to target levels. Some benefits of inflation targeting are larger when inflation targeters have achieved disinflation and are able to make their inflation targets stationary. Despite these favorable results for inflation targeting, our evidence generally does not suggest that countries that adopt inflation targeting have attained better monetary policy performance relative to our control group of highly successful non-inflation targeters. However, inflation targeting does seem to help all country groups to move toward performance of the control group. The performance attained by industrial-country inflation targeters generally dominates performance of emerging-economy inflation targeters and is similar to that of industrial non-inflation targeting countries

One decade of inflation targeting in the world : What do we know and what do we need to know?

One decade of inflation targeting in the world offers lessons on the design and implementation of inflation targeting, the conduct of monetary policy, and country performance under inflation targeting. This paper reviews briefly the main design features of 18 inflation targeting experiences, analyzes statistically if countries under inflation targeting are structurally different from non-inflation targeting industrial countries, and reviews existing evidence about the success of inflation targeting. The interaction of inflation targeting design features and the conduct of monetary policy during transition to low inflation are tackled next. The paper ends by focusing on unresolved issues on design and implementation of inflation targeting and their relation to the conduct of monetary policy – open issues that have to be addressed in the next decade of inflation targeting.

Does Inflation Targeting Make a Difference?

Yes, as inferred from panel evidence for inflation-targeting countries and a control group of high-achieving industrial countries that do not target inflation. Our evidence suggests that inflation targeting helps countries achieve lower inflation in the long run, have a smaller inflation response to oil-price and exchange-rate shocks, strengthen monetary policy independence, improve monetary policy efficiency, and obtain inflation outcomes closer to target levels. Some benefits of inflation targeting are larger when inflation targeters have achieved disinflation and are able to make their inflation targets stationary. Despite these favorable results for inflation targeting, our evidence generally does not suggest that countries that adopt inflation targeting have attained better monetary policy performance relative to our control group of highly successful non-inflation targeters. However, inflation targeting does seem to help all country groups to move toward the performance of the control group. The performance attained by industrial-country inflation targeters generally dominates the performance of emerging-economy inflation targeters and is similar to that of industrial non-inflation targeting countries.Inflation targeting, monetary policy.

One Decade of Inflation Targeting in the World: What Do We Know and What Do We Need to Know?

One decade of inflation targeting in the world offers lessons on the design and implementation of inflation targeting, the conduct of monetary policy, and country performance under inflation targeting. This paper reviews briefly the main design features of 18 inflation targeting experiences, analyzes statistically if countries under inflation targeting are structurally different from non-inflation targeting industrial countries, and reviews existing evidence about the success of inflation targeting. The interaction of inflation targeting design features and the conduct of monetary policy during transition to low inflation are tackled next. The paper ends by focusing on unresolved issues on design and implementation of inflation targeting and their relation to the conduct of monetary policy open issues that have to be addressed in the next decade of inflation targeting.

Implementation strategies for hyperspectral unmixing using Bayesian source separation

Bayesian Positive Source Separation (BPSS) is a useful unsupervised approach for hyperspectral data unmixing, where numerical non-negativity of spectra and abundances has to be ensured, such in remote sensing. Moreover, it is sensible to impose a sum-to-one (full additivity) constraint to the estimated source abundances in each pixel. Even though non-negativity and full additivity are two necessary properties to get physically interpretable results, the use of BPSS algorithms has been so far limited by high computation time and large memory requirements due to the Markov chain Monte Carlo calculations. An implementation strategy which allows one to apply these algorithms on a full hyperspectral image, as typical in Earth and Planetary Science, is introduced. Effects of pixel selection, the impact of such sampling on the relevance of the estimated component spectra and abundance maps, as well as on the computation times, are discussed. For that purpose, two different dataset have been used: a synthetic one and a real hyperspectral image from Mars.Comment: 10 pages, 6 figures, submitted to IEEE Transactions on Geoscience and Remote Sensing in the special issue on Hyperspectral Image and Signal Processing (WHISPERS