A contour matching approach for accurate NOAA-AVHRR image navigation

Although different methods for NOAA AVHRR image navigation have already been established, the multitemporal and multi-satellite character of most studies requires automatic and accurate methods for navigation of satellite images. In the proposed method, a simple Kepplerian orbital model for the NOAA satellites is considered as reference model, and mean orbital elements are given as input to the model from ephemeris data. In order to correct the errors caused by these simplifications, errors resulting from inaccuracies in the positioning of the satellite and failures in the satellite internal clock, an automatic global contour matching approach has been adopted. First, the sensed image is preprocessed to obtain a gradient energy map of the reliable areas (sea-land contours) using a cloud detection algorithm and a morphological gradient operator. An initial estimation of the reliable contour positions is automatically obtained. The final positions of the contours are obtained by means of an iterative local minimization procedure that allows a contour to converge on an area of high image energy (edge). Global transformation parameters are estimated based on the initial and final positions of all reliable contour points. Finally, the performance of this approach is assessed using NOAA 14 AVHRR images from different geographic areas.Postprint (published version

The Political Economy of Exchange Rate Policies in Argentina

This paper identifies three periods in Argentine exchange rate policy, corresponding with different development strategies and political coalitions. The first, periodic adjustments to a pegged rate until the mid-1970s, accompanied an Import Substitution Industrialization approach and a redistribution of income from agrarian to industrial production during an era of strong labor union influence. A second period, from the mid-1970s, marked by accelerated devaluations, represented efforts by both military and civilian governments to meet the demands of their respective constituencies while maintaining capital flows from abroad; these efforts culminated in hyperinflation. A third period, beginning in the early 1990s, was notable for exchange rate stability, based on the Convertibility Plan, as a broad consensus emerged that the exchange rate should be used for containing inflation rather than engaging in redistribution among domestic interest groups. The authors conclude that additional innovations in Argentina`s monetary and exchange rate policies may eventually be necessary.

Accurate and automatic NOAA-AVHRR image navigation using a global contour matching approach

The problem of precise and automatic AVHRR image navigation is tractable in theory, but has proved to be somewhat difficult in practice. The authors' work has been motivated by the need for a fully automatic and operational navigation system capable of geo-referencing NOAA-AVHRR images with high accuracy and without operator supervision. The proposed method is based on the simultaneous use of an orbital model and a contour matching approach. This last process, relying on an affine transformation model, is used to correct the errors caused by inaccuracies in orbit modeling, nonzero value for the spacecraft's roll, pitch and yaw, errors due to inaccuracies in the satellite positioning and failures in the satellite internal clock. The automatic global contour matching process is summarized as follows: i) Estimation of the gradient energy map (edges) in the sensed image and detection of the cloudless (reliable) areas in this map. ii) Initialization of the affine model parameters by minimizing the Euclidean distance between the reference and sensed images objects. iii) Simultaneous optimization of all reference image contours on the sensed image by energy minimization in the domain of the global transformation parameters. The process is iterated in a hierarchical way, reducing the parameter searching space at each iteration. The proposed image navigation algorithm has proved to be capable of geo-referencing a satellite image within 1 pixel.Peer ReviewedPostprint (published version

The Polyakov loop and the hadron resonance gas model

The Polyakov loop has been used repeatedly as an order parameter in the deconfinement phase transition in QCD. We argue that, in the confined phase, its expectation value can be represented in terms of hadronic states, similarly to the hadron resonance gas model for the pressure. Specifically, L(T) \approx 1/2\sum_\alpha g_\alpha \,e^(-\Delta_\alpha/T), where g_\alpha are the degeneracies and \Delta_\alpha are the masses of hadrons with exactly one heavy quark (the mass of the heavy quark itself being subtracted). We show that this approximate sum rule gives a fair description of available lattice data with N_f=2+1 for temperatures in the range 150MeV<T<190MeV with conventional meson and baryon states from two different models. For temperatures below 150MeV different lattice results disagree. One set of data can be described if exotic hadrons are present in the QCD spectrum while other sets do not require such states.Comment: 5 pages, 4 figures. Error in normalization corrected. Excited states included. Substantially revise

The inter-related roles of the regional and local government in developing local partnerships in Italy

Building partnerships is becoming an important issue at the local level of government in many countries. Different experiences can be traced throughout Europe, as well as in other OECD countries. This is because partnerships, especially when the size of the single local government is small, can help to manage services in a more efficient and effective way.Nevertheless, building a relation is difficult, nor is it always successful, as many scholars emphasise. For a number of reasons, higher levels of government may then play a significant role in supporting partnerships between different stakeholders.Given the shortage of empirical studies on this subject, this chapter combines conceptual and empirical analysis, and is based upon:- the direct observation of a number of partnerships in Italy, with particular reference to those Regions in which the birth and the development of partnerships has been positively influenced by the regional level of government;- surveys of other partnerships which have been formalised in Italy;- literature review and analysis of official documents.The issues analysed most carefully in the chapter are the critical aspects of partnership building, and the role played by higher levels of government in activating or facilitating partnerships. It is in fact clear that higher levels of government may gain considerable benefit from the development of partnerships at the local level.Finally, the chapter deals with comparative aspects, and investigates the existence of common patterns and trends in the different regional experiences examined