Lunar Ascent and Orbit Injection via Neighboring Optimal Guidance and Constrained Attitude Control

Future human or robotic missions to the Moon will require efficient ascent path and accurate orbit injection maneuvers, because the dynamical conditions at injection affect the subsequent phases of spaceflight. This research focuses on the original combination of two techniques applied to lunar ascent modules, i.e., (1) the recently introduced variable-time-domain neighboring optimal guidance (VTD-NOG), and (2) a constrained proportional-derivative (CPD) attitude control algorithm. VTD-NOG belongs to the class of feedback implicit guidance approaches aimed at finding the corrective control actions capable of maintaining the spacecraft sufficiently close to the reference trajectory. CPD pursues the desired attitude using thrust vector control while constraining the rate of the thrust deflection angle. The numerical results unequivocally demonstrate that the joint use of VTD-NOG and CPD represents an accurate and effective methodology for guidance and control of lunar ascent path and orbit injection in the presence of nonnominal flight conditions

Power Law Tails in the Italian Personal Income Distribution

We investigate the shape of the Italian personal income distribution using microdata from the Survey on Household Income and Wealth, made publicly available by the Bank of Italy for the years 1977-2002. We find that the upper tail of the distribution is consistent with a Pareto power-law type distribution, while the rest follows a two-parameter lognormal distribution. The results of our analysis show a shift of the distribution and a change of the indexes specifying it over time. As regards the first issue, we test the hypothesis that the evolution of both gross domestic product and personal income is governed by similar mechanisms, pointing to the existence of correlation between these quantities. The fluctuations of the shape of income distribution are instead quantified by establishing some links with the business cycle phases experienced by the Italian economy over the years covered by our dataset.Personal income; Pareto law; Lognormal distribution; Income growth rate; Business cycle

Mapping the spatial variation of soil moisture at the large scale using GPR for pavement applications

The characterization of shallow soil moisture spatial variability at the large scale is a crucial issue in many research studies and fields of application ranging from agriculture and geology to civil and environmental engineering. In this framework, this work contributes to the research in the area of pavement engineering for preventing damages and planning effective management. High spatial variations of subsurface water content can lead to unexpected damage of the load-bearing layers; accordingly, both safety and operability of roads become lower, thereby affecting an increase in expected accidents. A pulsed ground-penetrating radar system with ground-coupled antennas, i.e., 600-MHz and 1600-MHz center frequencies of investigation, was used to collect data in a 16 m × 16 m study site in the Po Valley area in northern Italy. Two ground-penetrating radar techniques were employed to non-destructively retrieve the subsurface moisture spatial profile. The first technique is based on the evalu¬ation of the dielectric permittivity from the attenuation of signal amplitudes. Therefore, dielectrics were converted into moisture values using soil-specific coefficients from Topp’s relationship. Ground-penetrating-radar-derived values of soil moisture were then compared with measurements from eight capacitance probes. The second technique is based on the Rayleigh scattering of the signal from the Fresnel theory, wherein the shifts of the peaks of frequency spectra are assumed comprehensive indi¬cators for characterizing the spatial variability of moisture. Both ground-penetrating radar methods have shown great promise for mapping the spatial variability of soil moisture at the large scale

The Solaria Syndrome: Social Capital in a Growing Hyper-technological Economy

We develop a dynamic model to analyze the sources and the evolution of social participation and social capital in a growing economy characterized by exogenous technical progress. Starting from the assumption that the well-being of agents basically depends on material and relational goods, we show that the best-case scenarios hold when technology and social capital both support just one of the two productions at the expenses of the other. However, trajectories are possible where technology and social interaction balance one another in fostering the growth of both the social and the private sector of the economy. Along such tracks, technology may play a crucial role in supporting a “socially sustainable” economic growth.technology, economic growth, relational goods, social participation, social capital

The Solaria Syndrome: Social Capital in a Growing Hyper-technological Economy

We develop a dynamic model to analyze the sources and the evolution of social participation and social capital in a growing economy characterized by exogenous technical progress. Starting from the assumption that the well-being of agents basically depends on material and relational goods, we show that the best-case scenarios hold when technology and social capital both support just one of the two productions at the expenses of the other. However, trajectories are possible where technology and social interaction balance one another in fostering the growth of both the social and the private sector of the economy. Along such tracks, technology may play a crucial role in supporting a “socially sustainable” economic growth.Technology, Economic Growth, Relational Goods, Social Participation, Social Capital

Economic Growth, Technological Progress, and Social Capital: The Inverted U Hypothesis

We set up a theoretical framework to analyze the possible role of economic growth and technological progress in the erosion of social capital. Under certain parameters, the relationship between technological progress and social capital can take the shape of an inverted U curve. We show the circumstances allowing the economy to follow trajectories where the stock of social capital grows endogenously and unboundedly.Economic growth; social capital; social norms; technological progress.

Will growth and technology destroy social interaction? The inverted U-shape hypothesis

This paper addresses two hot topics of the contemporary debate, social capital and economic growth. Our theoretical analysis sheds light on decisive but so far neglected issues: how does social capital accumulate over time? Which is the relationship between social capital, technical progress and economic growth in the long run? The analysis shows that the economy may be attracted by alternative steady states, depending on the initial social capital endowments and cultural exogenous parameters representing the relevance of social interaction and trust in well-being and production. When material consumption and relational goods are substitutable, the choice to devote more and more time to private activities may lead the economy to a “social poverty trap”, where the cooling of human relations causes a progressive destruction of the entire stock of social capital. In this case, the relationship of social capital with technical progress is described by an inverted U-shaped curve. However, the possibility exists for the economy to follow a virtuous trajectory where the stock of social capital endogenously and unboundedly grows.Relational goods, social capital, economic growth, technical change

The fragility of social capital

This paper addresses two hot topics of the contemporary debate, social capital and economic growth. Our theoretical analysis sheds light on decisive but so far neglected issues: how does social capital accumulate over time? Which is the relationship between social capital, technical progress and economic growth in the long run? The analysis shows that the economy may be attracted by alternative steady states, depending on the initial social capital endowments and cultural exogenous parameters representing the relevance of social interaction and trust in well-being and production. When material consumption and relational goods are substitutable, the choice to devote more and more time to private activities may lead the economy to a "social poverty trap", where the cooling of human relations causes a progressive destruction of the entire stock of social capital. In this case, the relationship of social capital with technical progress is described by an inverted U-shaped curve. However, the possibility exists for the economy to follow a virtuous trajectory where the stock of social capital endogenously and unboundedly grows. Such result may follow from a range of particular conditions, under which the economy behaves as if there was no substitutability between relational activities and material consumption.Social capital; Technical progress; Social sphere; Economic action; Well-being; Social poverty trap

See you on Facebook: the effect of social networking on human interaction

This paper proposes an evolutionary framework to explore the dynamics of social interaction in an environment characterized by online networking and increasing pressure on time. The model shows how time pressure encourages the choice to develop social interactions also through online networking instead of relying exclusively on face to face encounters. Our findings suggest that the joint influence exerted by the reduction in leisure time and the new opportunities of participation offered by web-mediated communication may progressively lead a growing share of the population to adopt networking sites as an indispensable environment for the development of interpersonal relationships.internet, computer-mediated communication, social networking, online networks, Facebook, human interaction, social capital