Unpleasant surprises : sovereign default determinants and prospects

This paper uses model averaging techniques to identify robust predictors of sovereign default episodes on a pooled database for 46 emerging economies over the period 1980-2004. Sovereign default episodes are defined according to Standard&Poor’s or by non-concessional International Monetary Fund loans in excess of 100 percent of the country’s quota. The authors find that, in addition to the level of indebtedness, the quality of policies and institutions is the best predictor of default episodes in emerging market countries with relatively low levels of external debt. For emerging market countries with a higher level of debt, macroeconomic stability plays a robust role in explaining differences in default probabilities. The paper provides evidence that model averaging can improve out-of-sample prediction of sovereign defaults, and draws policy conclusions for the current crisis based on the results.Debt Markets,External Debt,Bankruptcy and Resolution of Financial Distress,Economic Theory&Research,Currencies and Exchange Rates

Laser Scanner 3D per lo studio e la catalogazione dell’archeologia medievale: la chiesa di Santa Croce in Bergamo

The improvement of new active optical sensors has revolutionized the methods for documenting cultural heritage. The conservation and appreciation of our cultural legacy re¬quire an extensive documentation both in terms of shape, color and geometry as well as the more traditional art-historical features. The incessant development of scientific research today provides new possibilities and tools which are essential to know and use in a responsible and scientific way. In the field of archaeology, the automatic 3D survey is now recognized as an added value compared to traditional practices and the active contribution that this technology can provide to the interpretative phase, cataloguing and promotion of archaeological assets, even through the web, is becoming increasingly clear. On the other hand, even considering the speed of the procedure and the accuracy of measurement, there have been calls for reflection on the role that laser scanning can play in the field of archaeology; this role needs to be clarified and consolidated by conducting new studies and experiments, such as the one presented here that concerns the Church of Santa Croce in Bergamo, a small octagonal Romanesque chapel built in the first half of the 11th century

Progressive contour coding in the wavelet domain

This paper presents a new wavelet-based image contour coding technique, suitable for representing either shapes or generic contour maps. Starting from a contour map (e.g. a segmentation map or the result of a contour extraction operator), this is first converted in a one-dimensional signal. Coordinate jumps among different contour extremities are converted, if under a suitable threshold, into signal discontinuities which can be compactly represented in the wavelet domain. Otherwise, the exceeding discontinuities are coded as side information. This side information is minimized by an optimized contour segment sequencing. The obtained 1D signal is decomposed and coded in the wavelet domain by using a 1D version of an improved implementation of the SPIHT algorithm. This technique can efficiently code every kind of 2D contour map, from one to many unconnected contour segments. It guarantees a fully embedded progressive coding, state-of-art coding performance, good approximation capabilities for both open and closed contours, and visually graceful degradation at low bit-rates

Fatigue damage modelling of PEEK short fibre composites

Abstract In the present research the fatigue damage evolution of a PEEK based composite was studied. Examined material consisted of a PEEK matrix reinforced by carbon micro-fibres with addition of fillers such as graphite and PTFE. Fatigue tests in load control were carried out up to 106 cycles at different stress level, with cycle ratio R = 0 and frequency 10 Hz. The damage evolution was evaluated by defining damage parameter based on elastic modulus reduction observed under cyclic loading. The cyclic damage evolution of PEEK based composite, which is a function of applied stress level, presented significantly different damage stages. In order to reproduce fatigue damage kinetic observed experimentally a phenomenological modelling approach was then implemented into a finite element code, based on fatigue damage model recently proposed for short fibre reinforced thermoplastic composites

A modular cable robot for inspection and light manipulation on celestial bodies

Planetary exploration has been carried out with solitary probes since the nineteen-sixties; on the other hand, the newly emerging paradigm for robotic exploration shows multi-expertize, complex modular systems as necessary for efficient and thorough activities. In this paper we propose a modular Cable Driven Parallel Robot (CDPR) that is deployed by a rover, which can take advantage of its large workspace for tasks as inspection or light manipulation. While the general deployment procedure is described, focus is given on the CDPR; a model for the pseudostatics of the robot is formulated, as well as an analysis on its modules stability. The workspace is then characterized using appropriate metrics. Results show that a 1 Kg payload for the end-effector is effectively feasible with substantial margin for an equilateral triangular workspace of 10 m side. Finally, several possible practical applications are illustrated

Unpleasant Surprises: Sovereign Default Determinants and Prospects, Policy Research Working Papers, 5401

This paper uses model averaging techniques to identify robust predictors of sovereign default episodes on a pooled database for 46 emerging economies over the period 1980-2004. Sovereign default episodes are defined according to Standard & Poor s or by non-concessional International Monetary Fund loans in excess of 100 percent of the country s quota. The authors find that, in addition to the level of indebtedness, the quality of policies and institutions is the best predictor of default episodes in emerging market countries with relatively low levels of external debt. For emerging market countries with a higher level of debt, macroeconomic stability plays a robust role in explaining differences in default probabilities. The paper provides evidence that model averaging can improve out-of-sample prediction of sovereign defaults, and draws policy conclusions for the current crisis based on the results

Software Development in the Post-PC Era: Towards Software Development as a Service

Abstract. Software systems affect all aspects of our modern life andare revolutionizing the way we live. Over the years, software developmenthas evolved to meet the needs of new types of applications and toembrace new technological disruptions. Today, we witness the rise of mobilitywhere the role of the conventional high-specification PC is declining.Some refer to this era as the Post-PC era. This technological shift,powered by a key enabling technology - cloud computing, has opened new opportunities for human advancement (e.g. the Internet of Things).Consequently, the evolving landscape of software systems drives the need for new methods for conceiving them. Such methods need to a) address the challenges and requirements of this era and b) embrace the benefitsof new technological breakthroughs. In this paper, we list the characteristics of the Post-PC era from the software development perspective. In addition, we describe three motivating trends of software development processes. Then, we derive a list of requirements for the future software development approach from the characteristics of the Post-PC era and from the motivating trends. Finally, we propose a reference architecturefor cloud-based software process enactment as an enabler for Software Development as a Service (SDaaS). The architecture is thefirst step to address the needs that we have identified

A New Mechanism for the Deployment of Modular Solar Arrays: Kinematic and Static Analysis

This paper presents a new solar arrays deployment mechanism for space applications. It consists of a modular kinematic structure, which is operated by a single cable (1 DoF). Compared to traditional methods, this mechanism has the advantage of being reversible in the movement. Kinematic analysis of the mechanism is carried out in this work, as well as static analysis. They allow to define the main actuation parameters such as cable pull tension and spring stiffness. Moreover, suitable values for the mechanism parameters are computed by means of a dedicated algorithm