351 research outputs found
External and internal knowledge in the KGF
No full textThis chapter implements the notion of s recombinant knowledge generation function, and explores the role of internal and external knowledge in the generation of new technological knowledge. It enables us to appreciate: i) the complementary as opposed to supplementary role of external knowledge; and ii) the role of the size and composition of the internal stock of knowledge. The empirical section is based on a panel of companies listed on the main European financial markets for the period 1995–2006. The econometric analysis is based on simultaneous equations. The results confirm that R & D efforts and external knowledge are indispensable to the generation of new technological knowledge
Peak-Duration magnitude for the Irpinia Seismic Network, Southern Italy
No full textThe estimation of magnitude is a routine task in the seismological observatories and can be obtained through well-established automatic procedures. Several magnitude scales are available, based on amplitude measurements of different seismic phases, and/or on total signal duration. In particular, duration magnitude is adopted in many regional networks since it allows for a rapid determination of earthquake size, for a large number of events, through a fairly simple procedure. The main purposes of this work are two: to derive a duration magnitude relationship for the Irpinia Seismic Network (ISNet, http://isnet.na.infn.it) in Southern Italy and to develop an automatic procedure for discriminating among events occurring inside and outside the network.
To the former aim, we performed a multiple regression analysis to get a duration magnitude relationship of the form
M = a*logτ + b*logR + c
where M is the local magnitude, τ is the signal duration, and R is the epi(hypo) -central distance. Signal duration is evaluated on the vertical component of velocimeter records as the time from the first P-arrival time to the time along the trace at which the wave amplitude has decreased to the noise level. The parameters a, b and c are determined through a linear regression analysis. For events inside the network (R < 100 km) the coefficient c turned out to be negligible, so we adopted a simpler relationship of the form M = a’*logτ + b’. Measuring the distances in kilometers and the durations in seconds, we obtained the following set of parameters: a =-3.83+/-0.12 , b =3.03+/- 0.12, c =0.42+/-0.08, a’ = -1.59+/-0.14, b’ =2.06+/-0.08.
Moreover, for each station we determined a station correction coefficient, comparing theoretical and observed magnitude values, to improve the accuracy on magnitude estimation.
The ISNet data management system is set to automatically detect earthquakes having magnitude greater than 2. A current problem for the automatic detection system is the discrimination of seismic events occurring inside the network from those located outside. Given the dependency of signal duration (τ) and peak-amplitude (P) on source-to-receiver distance, the simultaneous measurement of these two parameters can be effective to identify events inside the seismic network. To this aim, we propose two methodologies, both based on the combined use of τ and P.
The former approach is based on the Peak-Duration Magnitude that is defined as
Mi = a*logτi + b*logPi + c*log Ri + d
where Mi, τ i, and Pi represent the magnitude, the total signal duration, and the peak-amplitude for the i-th station, respectively, and Ri depends on both the i-th station and epicentral coordinates. Parameters a, b, c, and d are determined through a multivariate linear regression analysis. The previous equation can be then used to determine the epicentral coordinates given a set of (τ i, Pi) measurements at the network stations.
A rough, but faster method is based on a the definition of a decision-table according to threshold values for τ and P. The basic idea is that (large) earthquakes far away from the network produce small amplitudes and long durations. We then derive two threshold values for τ and P for earthquakes occurring inside the network and having a maximum magnitude of 3. The τ threshold is derived from a relationship linking the duration and magnitude, such as logτ = A + B*M, while the P threshold is derived from a similar relationship relating the peak-amplitude and magnitude, such as logP = A’ + B’*M. The coefficients are determined through a best-fit procedure obtaining A=1.202+/-0.017, B=0.258+/-0.009, A’=2.28+/-0.12, and B’=0.72+/-0.06.
Some examples of application of both approaches will be shown
Retrospective performance analysis of a ground shaking early warning system for the 2023 Turkey–Syria earthquake
No full textRecently developed earthquake early warning systems rely on the idea of combining the measured ground motion and the source parameter estimate to issue an alert based on the ground shaking prediction at sites where high potential damage is expected. Here we apply a P-wave, shaking-forecast method that can track and alert in real-time the area where peak ground motion is expected to exceed a user-set threshold during the earthquake. The system performance in providing a fast and reliable warning during the Mw 7.8, February 6 Turkey–Syria earthquake is investigated by the real-time simulated playback of the near-source hundred accelerograms. With an instrumental intensity threshold
an alert issued 10–20 s after the event origin, results in 95% of successful warning (positive and negative) and lead-times of 10–60 s within the potential damage zone. Setting a higher intensity threshold requires larger alert times (50–60 s) to achieve 90% of successful warning and overall shorter lead-times. Our simulation shows that the P-wave predicted, strong-shaking zone can be rapidly detected only 20 s after the mainshock nucleation. As the time increases, it well delineates the NE-SW bi-lateral rupture development as inferred by kinematic source models
Far-infrared and ultra-high-speed quantum-cascade lasers
No full textQuantum cascade (QC) lasers, invented and first demonstrated at Bell Labs in 1994, already outperform all other mid-infrared (IR) semiconductor laser technologies in terms of optical power and spectral agility and are now commercially available. They can be designed to cover the entire mid-IR spectrum and part of the far-IR spectrum (3-24 mum) using the same material. They are also the only compact lasers capable of broad continuous single mode tuning in the mid-IR and in particular in the two atmospheric windows (3-5 mum and 8-13 mum). The latter regions can be used advantageously for the detection of many trace gases and vapors, down to parts-per-billion by volume (ppbv), for applications such as pollution detection, atmospheric chemistry and industrial process monitoring and control. QC lasers have already achieved many important milestones in trace gas detection via a large variety of spectroscopic techniques. QC lasers are the first mid-IR semiconductor lasers to operate pulsed at room temperature and above and have also achieved record powers (over 1 W) in both pulsed and CW mode. The above power levels are three orders of magnitude higher than those of commercial lead salt lasers. Using AlInAs/GaInAs heterostructures lattice matched to InP, our group has covered the entire range from 4.3 to 24 mum. Using strained layered AlInAs/GaInAs, this range has been extended to 3.4 mu
Super-short (4-mm) postextractive, immediately provisionalized implant in a minimally invasive rehabilitation approach avoiding extraction of the impacted maxillary canine: A 2-year follow-up case report
No full textThis case report describes an alternative minimally invasive fixed rehabilitation to approach an impacted maxillary canine (IMC) and the residual deciduous teeth. The patient refused any orthodontic treatment or surgical extraction of the IMC, asking for a fixed and fast option. Considering the available bone was about 5 mm in height, an immediately provisionalized postextractive 4-mm super-short implant was placed. Healing was uneventful. Two years after loading, the result was stable and the patient was fully satisfied. Within all the limitations of this case report, this approach could reduce rehabilitative times, possible complications, and costs
Enhanced sensing properties of cobalt bis-porphyrin derivative thin films by a magneto-plasmonic-opto-chemical sensor
No full textOn Firm Growth and Innovation. Some new empirical perspectives using French CIS (1992-2004)
No full textIn the paper we wish to examine if the firms that innovate know a higher growth than the firm that do not. We use diverse waves of CIS for the French industries over the period 1992- 2004 and carry out different models and new econometric methods (quantile regression). Our main findings are that innovative firms produce more growth than non innovative firms. The estimates show that the results are robust to the different types of models that we have implemented. Process innovators are more productive in terms of growth than product innovators when OLS and Random effects models are used. The reverse is true for Fix effect model and quantile regression. In the three growth equations estimated by GMM the coefficients related to innovation product are always higher. Our study does not give definitive results with respect to the magnitude of the effects of the type of innovation on firm growth.Innovation, process and product, firm growth, CIS
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