Design, Development, and Testing of Near-Optimal Satellite Attitude Control Strategies

Advances in space technology and interest toward remote sensing mission have grown in the recent years, requiring the attitude control subsystems of observation satellites to increase their performances in terms of pointing accuracy and on-board implementability. Moreover, an increased interest in small satellite missions and the recent technological developments related to the CubeSats standard have drastically reduced the cost of producing and flying a satellite mission. In this context, the proposed research aims to improve the state of the art for satellite attitude control methodologies by proposing a near-optimal attitude control strategy, simulated in a high-fidelity environment. Two strategies are presented, both are based on the implementation of a direct method, the Inverse Dynamics in the Virtual Domain (IDVD), and a nonlinear programming solver, the Sequential Gradient-Restoration Algorithm (SGRA). The IDVD allows the transcription of the original optimal control problem into an equivalent nonlinear programming problem. SGRA is adopted for the quick determination of near-optimal attitude trajectories. The two optimization criteria considered are the target acquisition time and the maneuver energy associated to the actuation torques. In addition, the development and initial testing of a satellite attitude simulator testbed for on-ground experimentation of attitude, determination, and control methodologies is proposed. The Suspended Satellite Three-Axis Rotation Testbed (START) is a novel low-cost satellite three-axis attitude simulator testbed, it is located at the Aerospace Robotics Testbed Laboratory (ARTLAB). START is mainly composed by a 3D printed base, a single-board computer, a set of actuators, and an electric battery. The suspension system is based on three thin high tensile strength wires allowing a three degrees-of freedom rotation range comparable to the one of air bearing-based floating testbeds, and minimal resistive torque in all the rotations axis. This set up will enable the hardware in-the-loop experimentation of attitude guidance navigation and control strategies. Finally, a set of guidelines to select a solver for the solution of nonlinear programming problems is proposed. With this in mind, a comparison of the convergence performances of commonly used solvers for both unconstrained and constrained nonlinear programming problems is presented. The terms of comparison involve accuracy, convergence rate, and convergence speed. Because of its popularity among research teams in academia and industry, MATLAB is used as common implementation platform for the solvers

SHOOTING DOWN THE PRICE: EVIDENCE FROM MAFIA HOMICIDES AND HOUSING MARKET VOLATILITY

In this work, we assess the role of a specific type of organized crime in influencing choices on where living within the city territory, and consequently, volatility in house prices. More specifically, we test how organized crime killing may influence house pricing behaviors. Firstly, we show evidences about how organized crime is associated with higher inequality of housing prices for Italian cities in 2011. Then, by collecting and geo referencing data on the city of Naples for the period 2002-2016, we test for the direct influence of homicides on the relevant territory, as on the neighboring districts. Results show a negative and significant impact of killing on the house prices either for sales or for rents and a positive effect in neighboring district, driving increases in within-city inequality

Organized Crime, Corruption and Economic Growth

In this paper we study the relationship between organized crime, corruption and economic growth. To shed light on this nexus, we propose a growth model in which organized crime can embezzle public spending by corrupting and threatening public officers. Then we bring the empirical implications of the model to data from Italian regions, as stylized facts show that less developed regions are characterized by the highest levels of corruption and of presence of criminal organizations of Mafia-type. Our main findings are: i) the per capita GDP dynamics of Italian regions in the period considered is characterized by multiple regimes identified by the initial level of organized crime, a finding consistent with a multiple steady state growth dynamics (e.g. Durlauf and Johnson, 1995); ii) in the regions with the higher levels of organized crime the estimated share of embezzled public expenditure is higher and, moreover, public expenditure has a negative effect on per capita GDP. Differently, in the regions with lower levels of organized crime the estimated share of embezzled public expenditure is lower and the effect of public expenditure on per capita income is positive

Shooting Down the Price: Evidence from Mafia Homicides and Housing Market Volatility

In this paper we estimate the effect of the homicides by the Camorra, the Neapolitan Mafia, on housing prices in Naples. The study develops on a unique panel dataset at the administrative district level for the period 2002-2018 of geo-localized homicides involving innocent victims (denoted as IVH ), which are treated as exogenous shocks that negatively affect housing demand. We find that the occurrence of such homicides causes a decrease in housing prices in the range of 2.5 − 3.8 percentage points. This effect decreases with the distance from an IVH and over time. These results are robust to the utilization of different econometric specifications and to the considerations of possible confounding factors such as other types of textitCamorra homicides

Shooting down the price: Evidence from Mafia homicides and housing prices

In this paper, we estimate the effect of the homicides by the Camorra, the Neapolitan Mafia, on housing prices in Naples. The study develops on a unique panel data set at the administrative district level for the period 2002–2018 of geo-localized homicides involving innocent victims (denoted as IVH), which are treated as exogenous shocks that negatively affect housing demand. We find that the occurrence of such homicides causes a decrease in housing prices in the range of 2.5–3.8 percentage points. This effect decreases with the distance from an IVH and over time. These results are robust to the utilization of different econometric specifications and to the considerations of possible confounding factors such as other types of Camorra homicides

Socio-Economic Inequalities and Organized Crime: an Empirical Analysis

In this chapter we contribute to the recent literature (e.g., Istat, 2010, Acciari et al., 2016, Guell et al., 2017) that provides evidence that inequality is high and social mobility is low in the Italian regions and prov-inces where organized crime is widespread such as those of Southern Italy. We complement this line of work in two respects. First, using a novel pan-el dataset at the regional level for the period 1985-2014 we investigate the relationship between inequality and organized crime at the regional level, exploiting both time and cross-sectional variation. Second, we assess the role of social mobility in organized crime. Our main finding is that higher inequality leads to higher organized crime development. The results are robust for different organized crime measures and inequality indices. For all measures the ratio of 90th quintile over the 10th in the distribution is a strong predictor of organized crime, even if we control for other covariates that capture economic development, education, etc. We also find that consumption inequality performs better that income inequality as the relevant inequality measure. Finally, we conduct a provincial level analysis to study the effect of socio-economic mobility on organized crime. We consider three alternative measures of social mobility. We find that lower socio-economic mobility displays a robust association with organized crime developmen

START: A Satellite Three Axis Rotation Testbed

The main goal of this paper is to illustrate the development of a satellite attitude simulator testbed for on-ground experimentation of attitude, determination, and control methodologies. This setup aims to be a low-cost alternative to testbeds based on air-bearing couplings. Our system is mainly composed of a suspended base, a single-board processor, a set of reaction wheels, and a battery. The suspension system entails a set of thin high-tensile strength wires converging on a single wire, which is in turn connected to the base. This configuration allows a three degrees-of-freedom rotation range and minimal resistive torque in all the rotations axis. The adjustability of the hanging point at the base, and a set of sliding masses, allow us to achieve a quite accurate superposition of rotation point and center of mass for a quasi-neutral equilibrium. The testbed is completed by a PC workstation, to generate and stream the desired angular rates of the wheels, and a motion capture system for attitude determination

Comparative Analysis of Nonlinear Programming Solvers: Performance Evaluation, Benchmarking, and Multi-UAV Optimal Path Planning

In this paper, we propose a set of guidelines to select a solver for the solution of nonlinear programming problems. We conduct a comparative analysis of the convergence performances of commonly used solvers for both unconstrained and constrained nonlinear programming problems. The comparison metrics involve accuracy, convergence rate, and computational time. MATLAB is chosen as the implementation platform due to its widespread adoption in academia and industry. Our study includes solvers which are either freely available or require a license, or are extensively documented in the literature. Moreover, we differentiate solvers if they allow the selection of different optimal search methods. We assess the performance of 24 algorithms on a set of 60 benchmark problems. We also evaluate the capability of each solver to tackle two large-scale UAV optimal path planning scenarios, specifically the 3D minimum time problem for UAV landing and the 3D minimum time problem for UAV formation flying. To enrich our analysis, we discuss the effects of each solver’s inner settings on accuracy, convergence rate, and computational time

Shooting down the price: evidence from mafia homicides and housing market

In this paper we estimate the effect of the homicides by the Camorra, the Neapolitan Mafia, on housing prices in Naples. The study develops on a unique panel dataset at the administrative district level for the period 2002-2018 of geo-localized homicides involving innocent victims (denoted as IVH ), which are treated as exogenous shocks that negatively affect housing demand. We find that the occurrence of such homicides causes a decrease in housing prices in the range of 2.5 − 3.8 percentage points. This effect decreases with the distance from an IVH and over time. These results are robust to the utilization of different econometric specifications and to the considerations of possible confounding factors such as other types of textitCamorra homicides