8,937 research outputs found
Measuring Social Capital: Culture as an Explanation of Italy's Economic Dualism.
The paper presents a quantitative test of the oft-repeated view that Italy's backward and poor South suffered from low "social capital", a tendency to defect from co-operative engagements. The problem with such assertions is that they run the risk of taking as evidence in favour of the hypothesis the very observations that need to be explained. The analysis carried out in this work tries to break out of this impasse by analyzing the conditions under which it was ex ante welfare-improving for farmers in early 20th century Italy to join an unlimited liability rural co-operative bank which would give them access to cheaper credit but also exposed them to the risk of their neighbours' defection.POVERTY ; CULTURE ; SOCIAL CAPITAL
Design and development of a smart panel with five decentralised control units for the reduction of vibration and sound radiation
This Technical Report discusses the design and the construction of a smart panel with five decentralised direct velocity feedback control units in order to reduce the vibration of the panel dominated by well separated low frequency resonances. Each control unit consists of an accelerometer sensor and a piezoelectric patch strain actuator. The integrated accelerometer signal is fed back to the actuator via a fixed negative control gain. In this way the actuator generates a control excitation proportional and opposite to the measured transverse velocity of the panel so that it produces active damping on the panel. First the open loop frequency response function between the sensor and the actuator of a single channel has been studied and an analogue controller has been designed and tested in order to improve the stability of this control system. Following the stability of all five control units has been assessed using the generalised Nyquist criterion. Finally the performances of the smart panel have been tested with reference to the reduction of the vibrations at the error positions and with reference to the reduction of the radiated sound. Finally in appendix to this Report, a parametric study is presented on the properties of sensor-actuator FRFs measured with different types of piezoelectric patch actuators. The results of this parametric study have been used in order to choose the actuators to be used for the construction of the smart pane
Modeling sea level changes and geodetic variations by glacial isostasy: the improved SELEN code
We describe the basic features of SELEN, an open source Fortran 90 program
for the numerical solution of the so-called "Sea Level Equation" for a
spherical, layered, non-rotating Earth with Maxwell viscoelastic rheology. The
Sea Level Equation was introduced in the 70s to model the sea level variations
in response to the melting of late-Pleistocene ice-sheets, but it can be also
employed for predictions of geodetic quantities such as vertical and horizontal
surface displacements and gravity variations on a global and a regional scale.
SELEN (acronym of SEa Level EquatioN solver) is particularly oriented to
scientists at their first approach to the glacial isostatic adjustment problem
and, according to our experience, it can be successfully used in teaching. The
current release (2.9) considerably improves the previous versions of the code
in terms of computational efficiency, portability and versatility. In this
paper we describe the essentials of the theory behind the Sea Level Equation,
the purposes of SELEN and its implementation, and we provide practical
guidelines for the use of the program. Various examples showing how SELEN can
be configured to solve geodynamical problems involving past and present sea
level changes and current geodetic variations are also presented and discussed
A Fast Chi-squared Technique For Period Search of Irregularly Sampled Data
A new, computationally- and statistically-efficient algorithm, the Fast
algorithm, can find a periodic signal with harmonic content in
irregularly-sampled data with non-uniform errors. The algorithm calculates the
minimized as a function of frequency at the desired number of
harmonics, using Fast Fourier Transforms to provide performance.
The code for a reference implementation is provided.Comment: Source code for the reference implementation is available at
http://public.lanl.gov/palmer/fastchi.html . Accepted by ApJ. 24 pages, 4
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