1,721,022 research outputs found
Development of an asymmetric re-centering dissipative device
No full textThe seismic retrofit design of structures in which the bracings are compressed due to the presence of significant vertical loads shall take into account the strong asymmetric working conditions of the bracings induced by the seismic action. The initial compression and the consequent asymmetric cyclic loading lead, indeed, to poor global performances and drawbacks in the case of seismic retrofitting through the substitution of the existing bracings with dissipative ones. In order to overcome such issues, this paper presents the development of an asymmetric re-centering dissipative device characterized by a different behavior in tension and in compression and by a strong re-centering capacity, making it suitable to resist and dissipate the energy generated by asymmetric cyclic loadings. The paper firstly analyzes the specific issues of structures in which the bracings work in strong asymmetric loading conditions due to the presence of significant vertical loads, highlighting the main problems that can arise adopting traditional dissipative bracings. Then the proposed device is conceptually described and its behavior experimentally assessed. Finally, the structural behavior of a sub-system equipped with the proposed device is assessed through numerical analyses. The experimental and numerical results show the effectiveness of the proposed device in reducing the residual displacements and protecting the other structural elements demanded to resist to the vertical loads
Experimental behavior of laser cut I-beam-to-CHS-column steel-concrete composite joints under vertical loads
No full textThis paper presents the results of an extensive experimental campaign on I beam to Circular Hollow Section column joints obtained cutting a dedicated slot on the column through precision laser technology and letting the beam or connection plates pass through the column itself. The application of this technology minimizes the welding necessary to complete the connection, the number and dimensions of the plates, and it assures the continuity of the beam within the column leading to a more favorable mechanical behavior of the joint under vertical loads. Even if the passing-through beam idea was already tested in the past, only recently the laser cutting technology made it really feasible and competitive from a technical and economic point of view. However, several issues about this structural solution needs further clarifications, especially when considering the interaction of the bare steel node with the reinforced concrete slab or the influence of the infill concrete in the column. For this reason, within this research, different joint configurations were designed extrapolating them from realistic case study buildings and testing them under monotonic vertical loads. To deeply understand their behavior, the specimens were designed and realized as four-way joint, differentiating the structural scheme of the joint connecting the main beams and the joints connecting the secondary beams, obtaining a representation of the most common solutions currently adopted in the real practice
The Italian Remote Sensing Data Archive: from DBRMS to Web Distribution
No full textDuring the Antarctic campaign 1989-1990, a NOAA-HRPT receiving station was installed at the Italian Base, Mario Zucchelli Station, at Terra Nova Bay. The receiving station is operational when the base is open, usually from mid-October to mid-February. Three NOAA polar orbiting satellites are normally in operation at the same time, at the present they are NOAA-15, NOAA-17, NOAA-18. During the campaign 1998-1990 was installed a new dual-receiving HRPT station to get also DMSP (Defence Meteorological Satellites Program of USA) satellites and currently we receive three DMSP satellites f-13, f-14 and f-15. At the present about fifty passes per day are acquired and processed each day reaching a total of around 4500 passes per expedition.
All data acquired during campaigns are stored on DDS tape, which format is changed during years. Up to now more than 7 TB of data are stored on different media (from 8mm tapes to DDS4 tapes), regarding a period of time from V to XXII expedition.
In order to achieve a more flexible and reliable system to access all the above data, in 2005, a process to copy to Hard-Disk storage in RAID mode, has been started. The activity is a work in progress, in the meantime the opportunity to realize a web application to process and distribute data to scientific community has been planned. We created a working prototype system based on a LAMP open source architecture (Linux, Apache, MySQL, PHP) and the TERASCAN software (from SeaSpace Corp.) to process and archive remote sensing data. The demo provides a web form to query the relational database containing all data related to each raw acquired satellite pass and as final result a quicklook of the requested pass is showed.
This demo is just a first step of an application that in the future will be able to supply to the user a valid tool to navigate in entire data archive and eventually getting products such AVHRR images, TOVS profile, ARGOS data or extracting the complete satellite pass.UnpublishedConsiglio Nazionale delle Ricerche, Roma, Italyope
The Italian Remote Sensing Data Archive: from DBRMS to Web Distribution
No full textDuring the Antarctic campaign 1989-1990, a NOAA-HRPT receiving station was installed at the Italian Base, Mario Zucchelli Station, at Terra Nova Bay. The receiving station is operational when the base is open, usually from mid-October to mid-February. Three NOAA polar orbiting satellites are normally in operation at the same time, at the present they are NOAA-15, NOAA-17, NOAA-18. During the campaign 1998-1990 was installed a new dual-receiving HRPT station to get also DMSP (Defence Meteorological Satellites Program of USA) satellites and currently we receive three DMSP satellites f-13, f-14 and f-15. At the present about fifty passes per day are acquired and processed each day reaching a total of around 4500 passes per expedition.
All data acquired during campaigns are stored on DDS tape, which format is changed during years. Up to now more than 7 TB of data are stored on different media (from 8mm tapes to DDS4 tapes), regarding a period of time from V to XXII expedition.
In order to achieve a more flexible and reliable system to access all the above data, in 2005, a process to copy to Hard-Disk storage in RAID mode, has been started. The activity is a work in progress, in the meantime the opportunity to realize a web application to process and distribute data to scientific community has been planned. We created a working prototype system based on a LAMP open source architecture (Linux, Apache, MySQL, PHP) and the TERASCAN software (from SeaSpace Corp.) to process and archive remote sensing data. The demo provides a web form to query the relational database containing all data related to each raw acquired satellite pass and as final result a quicklook of the requested pass is showed.
This demo is just a first step of an application that in the future will be able to supply to the user a valid tool to navigate in entire data archive and eventually getting products such AVHRR images, TOVS profile, ARGOS data or extracting the complete satellite pass.UnpublishedConsiglio Nazionale delle Ricerche, Roma, Italyope
Weather Forecast Activity at MZS, Terra Nova Bay:Automated Antarctic ECMWF Data Processing and Distribution Management
No full textThe Weather Forecast at the Italian base in Antarctica “Mario Zucchelli Station”, is a service conducted by personnel from Aeronautica Militare Italiana (Italian Air Force) and is very important for operational activity during the summer expedition. It allows to manage the base activities in order to use resources in a very safe mode.
Currently, weather forecasts, are based on the Global Model of European Centre for Medium Weather Forecast (ECMWF, Reading, UK) data, and on the AMPS forecasts provided by NCAR. Concerning ECMWF data, PNRA staff manages the system architecture from data acquisition directly from Centro Nazionale Meteorologia e Climatologia of Aeronautica Militare (CNMCA, Pratica di Mare, Italy), the italian meteorological service, to data processing and distribution. The final result is the GRADS maps production, utilized by base staff for forecasting activity.
During the XXI Antartic expedition the system architecture was changed. It was migrated on Linux-Red Hat platform with the aid of open-source software and it was improved in order to: 1. to supply a more reliable system in term of data distribution and 2. to upgrade the product in the respect of the technical requirements suggested by the meteorological staff.UnpublishedConsiglio Nazionale delle Ricerche, Roma , Italyope
Estimation of Signal to Noise Ratio for Unsupervised Hyperspectral Images
No full textHyperspectral sensors have become a standard technology used in the techniques of observation by
satellite and aerial platform for observing the terrestrial ecosystem with particular interest in the
detection and identification of minerals, vegetation, materials and artificial environments. The detection
of real materials depends on the coverage spectral resolution and signal to noise ratio of the spectrometer itself,
as well as the density of the material and the absorption characteristics for the material in the region of
wavelength measured. The signal to noise ratio in particular is one of the parameters that need to be estimated
to establish the quality of images acquired by these systems.
In this contribution a method to estimate the Signal to Noise Ratio (SNR) for unsupervised hyperspectral images
has been investigated.
The method uses the computation of local means and local standard deviations of small homogeneous blocks
in order to define respectively the average signal and the mean noise of the images. If the noise may be
considered mainly addictive the local standard deviation may be considered as the mean noise of image. This
method uses all the spatial information contained in the image scene giving a representative SNR of entire image.
The technique has been engineered in IDL environment and applied to hyperspectral data of HYPER-SIMGA
sensor, developed in the frame of AIRFIRE Project for wildfire detection by airborne remote sensing data.
The SNR results point out that HYPER-SIMGA SWIR images are quite noisy and the spectral range that has to
be taken into account for data analysis is from 1000 to 1700 nm.Published1-181.10. TTC - TelerilevamentoN/A or not JCRope
Estimation of Signal to Noise Ratio for Unsupervised Hyperspectral Images
No full textHyperspectral sensors have become a standard technology used in the techniques of observation by
satellite and aerial platform for observing the terrestrial ecosystem with particular interest in the
detection and identification of minerals, vegetation, materials and artificial environments. The detection
of real materials depends on the coverage spectral resolution and signal to noise ratio of the spectrometer itself,
as well as the density of the material and the absorption characteristics for the material in the region of
wavelength measured. The signal to noise ratio in particular is one of the parameters that need to be estimated
to establish the quality of images acquired by these systems.
In this contribution a method to estimate the Signal to Noise Ratio (SNR) for unsupervised hyperspectral images
has been investigated.
The method uses the computation of local means and local standard deviations of small homogeneous blocks
in order to define respectively the average signal and the mean noise of the images. If the noise may be
considered mainly addictive the local standard deviation may be considered as the mean noise of image. This
method uses all the spatial information contained in the image scene giving a representative SNR of entire image.
The technique has been engineered in IDL environment and applied to hyperspectral data of HYPER-SIMGA
sensor, developed in the frame of AIRFIRE Project for wildfire detection by airborne remote sensing data.
The SNR results point out that HYPER-SIMGA SWIR images are quite noisy and the spectral range that has to
be taken into account for data analysis is from 1000 to 1700 nm.Published1-181.10. TTC - TelerilevamentoN/A or not JCRope
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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