702 research outputs found
Digital image correlation (DIC) analysis of the 3 December 2013 Montescaglioso landslide (Basilicata, Southern Italy). Results from a multi-dataset investigation
Image correlation remote sensing monitoring techniques are becoming key tools for
providing effective qualitative and quantitative information suitable for natural hazard assessments,
specifically for landslide investigation and monitoring. In recent years, these techniques have
been successfully integrated and shown to be complementary and competitive with more standard
remote sensing techniques, such as satellite or terrestrial Synthetic Aperture Radar interferometry.
The objective of this article is to apply the proposed in-depth calibration and validation analysis,
referred to as the Digital Image Correlation technique, to measure landslide displacement.
The availability of a multi-dataset for the 3 December 2013 Montescaglioso landslide, characterized
by different types of imagery, such as LANDSAT 8 OLI (Operational Land Imager) and TIRS
(Thermal Infrared Sensor), high-resolution airborne optical orthophotos, Digital Terrain Models
and COSMO-SkyMed Synthetic Aperture Radar, allows for the retrieval of the actual landslide
displacement field at values ranging from a few meters (2–3 m in the north-eastern sector of the
landslide) to 20–21 m (local peaks on the central body of the landslide). Furthermore, comprehensive
sensitivity analyses and statistics-based processing approaches are used to identify the role of the
background noise that affects the whole dataset. This noise has a directly proportional relationship to
the different geometric and temporal resolutions of the processed imagery. Moreover, the accuracy
of the environmental-instrumental background noise evaluation allowed the actual displacement
measurements to be correctly calibrated and validated, thereby leading to a better definition of
the threshold values of the maximum Digital Image Correlation sub-pixel accuracy and reliability
(ranging from 1/10 to 8/10 pixel) for each processed dataset
Discussion to: ‘Guidelines on the use of inverse velocity method as a tool for setting alarm thresholds and forecasting landslides and structure collapses’ by T. Carlà, E. Intrieri, F. Di Traglia, T. Nolesini, G. Gigli and N. Casagli
The paper ‘Guidelines on the use of inverse velocity method as a tool for setting alarm thresholds and forecasting landslides and structure collapses’ by T. Carlà, E. Intrieri, F. Di Traglia, T. Nolesini, G. Gigli and N. Casagli deals with a sensitive topic for landslide risk management. Exploring the pre-failure behaviour of four different case histories, the authors proposed standard procedures for the application of the inverse velocity method (INV, Fukuzono 1985). Specifically, they suggested guidelines for the filtering of velocity data and an original and simple approach to automatically set the first and the second alarm thresholds using the inverse velocity method. The present discussion addresses three different topics: (1) data filter selection according to the features of monitoring instrument; (2) the importance of data sampling frequency for the forecasting analysis and (3) the influence of the starting point (SP in this discussion) for the application of INV analysis. Moreover, based on this matter, a new method is proposed to update the INV analysis on an ongoing basis
Investigating the Behaviour of Natural Slopes and Man Made Structures by Terrestrial SAR Interferometry
Remote sensing techniques for the monitoring of deformation are opening new opportunities in the field of geotechnical engineering and geology. Terrestrial SAR interferometry (TInSAR) is one of the most innovative technique and it promises to be a very effective solution which will be extensively used in the near future. TInSAR is characterized by several interesting features such as: i) high density of information; ii) fully remote capability; iii) long range capability; iv) widespread view; v) spatially continuous efficacy and vi) high accuracy. Thanks to these features TInSAR has been used for investigation and diagnostic purposes (i.e. landslide and structural instability mapping, state of activity evaluation, analysis of triggering factors and modelling of deformational behavior) thus providing very useful results
Outsourcing, Delocalization and Firm Organization: Transaction Costs vs. Industrial Relations in a Local Production System of Emilia-Romagna
The paper aims at investigating how far transaction costs economics (TCE) concurs in the explanation of outsourcing decisions in firms characterized by “thick’ industrial relations, that is where unions and employees are involved in, and are sometimes able to affect, the relative managerial decisions through participatory formal and informal mechanisms. What is more, the paper aims at investigating whether the concurrence of TCE and industrial relationships has different outsourcing implications for firms which are also involved in delocalization strategies. An empirical model, translating a set of theoretical correlations between an original outsourcing extent variable, on the one hand, and a number of proxies related to TCE, industrial relations and delocalization, on the other hand, is applied to a representative sample of manufacturing firms for the local production system of Reggio Emilia (RE) (in Northern Italy). Overall, the empirical application shows that the role of TCE in accounting for outsourcing in the LPS of RE is quite blurred, if not even contradicted, while the role of industrial relations emerges instead quite straightforwardly. Finally, RE firms generally use outsourcing and international delocalization in a complementary way, but the correlation between outsourcing and delocalization turns out to be dependent on the kind of activity and of the nature of the delocalization channel.Outsourcing; firm organization; transaction costs; competences; innovation; local production systems
The General Profile of the Outsourcing Firm Evidence for a Local Production System of Emilia Romagna
The paper aims at ‘embedding’ the outsourcing firm by considering it as a four-fold unit of analysis: i.e. as an organizational, production, industrial and innovation unit. Theoretical correlations between outsourcing decisions and outsourcing variables are formulated and then tested with respect to a representative cross-sectional sample of firms of a local production system in Emilia Romagna (that is, Reggio Emilia). The main result of the paper is that outsourcing decisions are indeed affected by the organizational and industrial relations typical of the context firms are embedded in. Furthermore, the general profile of the Reggio Emilia outsourcing firm is strategic rather than operative. In particular, tapping-into the provider’s resources and competences to eventually promote technological innovation seems more relevant than searching for lower costs by contracting out.Outsourcing; transaction costs; industrial relations; innovation
Thermal response of jointed rock masses inferred from infrared thermographic surveying (Acuto test-site, Italy)
The Mediterranean region is affected by considerable daily and seasonal temperature variations due to intense solar radiation. In mid-seasons, thermal excursions can exceed tens of degrees thus influencing the long-term behaviour of jointed rock masses acting as a preparatory factor for rock slope instabilities. In order to evaluate the thermal response of a densely jointed rock-block, monitoring has been in operation since 2016 by direct and remote sensing techniques in an abandoned quarry in Acuto (central Italy). Monthly InfraRed Thermographic (IRT) surveys were carried out on its exposed faces and along sections of interest across monitored main joints. The results highlight the daily and seasonal cyclical behaviour, constraining amplitudes and rates of heating and cooling phases. The temperature time-series revealed the effect of sun radiation and exposure on thermal response of the rock-block, which mainly depends on the seasonal conditions. The influence of opened joints in the heat propagation is revealed by the differential heating experienced across it, which was verified under 1D and 2D analysis. IRT has proved to be a valid monitoring technique in supporting traditional approaches, for the definition of the surficial temperature distribution on rock masses or stone building materials
Outsourcing and firm productivity: evidence for an Italian local production system
The paper investigates empirically the impact that outsourcing strategies have on the labour productivity of firms embedded in a local production system characterized by idiosyncratic techno-economic and organizational features. A diachronic cross-section econometric model of the productivity impact of outsourcing is applied to a sample of firms based in the local production system (LPS) of Reggio Emilia (RE) (in Emilia Romagna, Italy). The application confirms some of the results the empirical literature reports for other no or less context specific empirical applications, in particular their dependency on the kind of outsourced activities, the internationalization of the outsourcing firm and time horizon of the productivity effects. On the other hand, when the actual extent at which the different kinds of activities are outsourced is retained, important exceptions to these results are obtained: the positive impact of the externalization of manufacturing activities is the most relevant and the most consistent with the district nature of the investigated LPS.outsourcing, productivity, transaction costs, industrial relations, innovation
NEURAL NETWORK DISCRIMINATION OF HEAVY FLAVOR JETS: A SURVEY
A short survey of the use of neural networks and statistical discriminants in high energy physics for recognition of heavy flavor jets is presented. After illustrating the various neural and statistical classifiers currently used, some assessment of their comparative performance for top and bottom jets is made
Imaging multi-age construction settlement behaviour by advanced SAR interferometry
This paper focuses on the application of Advanced Satellite Synthetic Aperture Radar Interferometry (A-DInSAR) to subsidence-related issues, with particular reference to ground settlements due to external loads. Beyond the stratigraphic setting and the geotechnical properties of the subsoil, other relevant boundary conditions strongly influence the reliability of remotely sensed data for quantitative analyses and risk mitigation purposes. Because most of the Persistent Scatterer Interferometry (PSI) measurement points (Persistent Scatterers, PSs) lie on structures and infrastructures, the foundation type and the age of a construction are key factors for a proper interpretation of the time series of ground displacements. To exemplify a methodological approach to evaluate these issues, this paper refers to an analysis carried out in the coastal/deltaic plain west of Rome (Rome and Fiumicino municipalities) affected by subsidence and related damages to structures. This region is characterized by a complex geological setting (alternation of recent deposits with low and high compressibilities) and has been subjected to different urbanisation phases starting in the late 1800s, with a strong acceleration in the last few decades. The results of A-DInSAR analyses conducted from 1992 to 2015 have been interpreted in light of high-resolution geological/geotechnical models, the age of the construction, and the types of foundations of the buildings on which the PSs are located. Collection, interpretation, and processing of geo-thematic data were fundamental to obtain high-resolution models; change detection analyses of the land cover allowed us to classify structures/infrastructures in terms of the construction period. Additional information was collected to define the types of foundations, i.e., shallow versus deep foundations. As a result, we found that only by filtering and partitioning the A-DInSAR datasets on the basis of the above-mentioned boundary conditions can the related time series be considered a proxy of the consolidation process governing the subsidence related to external loads as confirmed by a comparison with results from a physically based back analysis based on Terzaghi's theory. Therefore, if properly managed, the A-DInSAR data represents a powerful tool for capturing the evolutionary stage of the process for a single building and has potential for forecasting the behaviour of the terrain-foundation-structure combination
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