Stochastic process approximation for recursive estimation with guaranteed bound on the error covariance

An approach, is proposed for the design of approximate, fixed order, discrete time realizations of stochastic processes from the output covariance over a finite time interval, was proposed. No restrictive assumptions are imposed on the process; it can be nonstationary and lead to a high dimension realization. Classes of fixed order models are defined, having the joint covariance matrix of the combined vector of the outputs in the interval of definition greater or equal than the process covariance; (the difference matrix is nonnegative definite). The design is achieved by minimizing, in one of those classes, a measure of the approximation between the model and the process evaluated by the trace of the difference of the respective covariance matrices. Models belonging to these classes have the notable property that, under the same measurement system and estimator structure, the output estimation error covariance matrix computed on the model is an upper bound of the corresponding covariance on the real process. An application of the approach is illustrated by the modeling of random meteorological wind profiles from the statistical analysis of historical data

Reconceptualizing hegemony: the circle of hydro-hegemony

This paper proposes a partial reconceptualization and a redesign of the Framework of Hydro-Hegemony, an analytical tool devised to study how power, hegemony, and power asymmetries can influence transboundary water politics. This is done by presenting the original Circle of Hydro-Hegemony (CHH), an analytical framework that places the neo-Gramscian notion of hegemony at the centre of its structure, to illustrate how various forms of power are connective in the function of hegemony. Following a theoretical discussion on how the concepts of power and hegemony can interact, the case of the Aral Sea basin in Central Asia will provide a practical application of the CHH to transboundary water politics

Bigger is better or how governments learned to stop worrying and love megaprojects

Megaprojects, with their sheer size and their physical and emotional impact, can emerge as central elements around which political elites construct an ideology. Following a comparison of the narratives surrounding the Strait of Messina Bridge in Italy and the Rogun Dam in Tajikistan, I find that similar narratives appear in arguments for mega projects across different regime types, as advocates portray large infrastructure as a panacea for varied problems and thus justify the significant investment such projects require. Politicians in both Italy and Tajikistan have embraced images of heroic progress toward a better future to frame megaprojects as inevitable signs of progress and national well-being

Hydropolis: reinterpreting the polis in water politics

The construction of a large dam is often a contested and controversial matter. Delicate aspects related to the dam construction business such as the resettlement of peoples, environmental impact and financial costs, can trigger popular discontent and hinder the realisation of a particular project. By advancing the notion of the hydropolis, a reinterpretation of Hannah Arendt (1958) definition of the polis, this paper will explore how ruling elites can manipulate the public opinion to politically construct a large dam as a foreign policy matter. This, it will be argued, serves to conceal the negative consequences of a dam so that issues related to its social and environmental impact are removed from the national political debate. Specifically, the case of the Grand Ethiopian Renaissance Dam (GERD) in Ethiopia will be used to illustrate how a large dam can become a geopolitical object grounded on the friend/enemy distinction, in the context of the longstanding geopolitical tensions in the Nile River Basin

Entanglement detection measuring classical correlations

L'entanglement è un fenomeno di natura puramente quantistica ed è considerato la principale risorsa dei protocolli quantistici di manipolazione e trasmissione di informazione. Lo studio e la caratterizzazione dell'entanglement rivestono dunque un ruolo cruciale nello sviluppo della teoria dell'informazione quantistica e nella comprensione delle strutture fondamentali della meccanica quantistica non relativistica. Uno dei principali problemi legati alla teoria dell'entanglement è quello di trovare dei criteri ottimali per la rilevazione, la caratterizzazione e la quantificazione dell'entanglement. Ad oggi, non esiste una soluzione completa per questo problema. In questo lavoro di tesi, abbiamo esaminato e generalizzato un criterio per la rilevazione dell'entanglement basato sulla misura delle correlazioni classiche esistenti tra osservabili locali complementari di un sistema bipartito. In particolare, ci siamo occupati dei criteri che si basano sulla misura dell'informazione mutua, e abbiamo analizzato le prestazioni di questo criterio per una generica coppia di osservabili, non necessariamente complementari. Le prestazioni del nuovo criterio, in termini di efficienza, robustezza ed applicabilità, sono state analizzate in dettaglio per sistemi bipartiti di qubit, poichè in questo caso l'entanglement è completamente caratterizzato e sono a disposizione strumenti di confronto. In particolare, il criterio è stato utilizzato per la rivelazione di entanglement in presenza di rumore esterno e decoerenza. L'analisi condotta in questa tesi ha mostrato che il criterio presentato è robusto, dal momento che la percentuale di stati rivelati non cala in maniera drammatica quando ci si sposta dalla condizione di complementarietà, e inoltre, pur non avendo performance ottimali rispetto ad altri metodi di rilevazione dell'entanglement, è interessante dal punto di vista applicativo poichè si è rivelato affidabile e complessivamente efficiente

The Spherical Inverted Pendulum with Pelvis Width in Polar Coordinates for Humanoid Walking Design

The present communication is a follow up and extension of the paper “The Spherical Inverted Pendulum: Exact Solutions of Gait and Foot Placement Estimation Based on Symbolic Computation” by the same author. The walk design is approached by a 3-D inverted pendulum in a polar coordinate system. The advantage of this model is to easily offer indications of the energy expenditure of an efficient walk. However, the disadvantages that were never recognized by authors previously using this model is that the COG trajectory has to pass through the supporting foot location. This causes an unnecessary and unrealistic waving in the frontal plane during gait. The problem is discussed here and solved by extending the model of the inverted pendulum by introducing the pelvis width and the distance between the hips of the two legs, without adding dynamical complexity

Domestic and international dimensions of transboundary water politics

A considerable amount of research in the field of International Relations (IR) has acknowledged the interplay between domestic politics and foreign policy. Few studies, however, have investigated this phenomenon in the narrower field of transboundary water politics. There is also a general lack of research exploring how the formation of a national identity can overlap with the construction of a large hydraulic infrastructure, and how this can have repercussions at the international level. This paper draws on Robert Putnam’s (1988) two-level game theory to illustrate how the interrelation between the domestic and the international dimensions matters in transboundary water politics. Perspectives from IR, political geography, and water politics serve to present a conceptual framework which is then linked to studies on nationalism. This helps to highlight the analytical relevance of such a perspective to understand the issue of large dams. The paper takes the cases of the Grand Ethiopian Renaissance Dam in Ethiopia and the Rogun Dam in Tajikistan as examples