The space activities in almost every orbital regime are now jeopardized by the continuous growth of the space debris populations. To prevent the proliferation of the space debris in Earth orbit it is necessary to tackle the problem from dierent perspectives, exploiting the latest theoretical and experimental knowledge in dierent elds, such as astrodynamics, spacecraft engineering and legal studies, to address four main pillars: prevention, protection, mitigation and regulation. In this respect the European Community nanced a large H2020 project named ReDSHIFT whose goal is to nd passive means to mitigate the proliferation of space debris. A short summary of the project and of its main ndings is given in the paper, with particular emphasis on the more theoretical part, related to the simulation of long term evolutionary scenarios of the whole space debris environment and to the mapping of the Low Earth Orbit phase space, looking for passive dynamical de-orbiting solutions.
In the framework of remote sensing, infrared (IR) cameras allow the user to sense IR radiation, similar to common cameras that sense visible light. The radiation acquired from IR cameras is related to the temperature of the observed scene through the Planck's law, in fact IR cameras are also known as "thermal cameras" for their capability of detecting information concerning the heat of the observed scene. Thermal cameras were originally developed for military purposes to detect and track targets on complex scenarios as an alternative to radar systems, in that optical systems - due to their passive nature - are more robust to countermeasures for interception. Nevertheless, over the years IR cameras have been employed also in several civilian fields. In a military context, the images acquired from IR devices are processed to reveal the presence of targets that typically cannot be easily distinguished from both clutter, spatial and temporal noise sources. The aim of automatic target detection (ATD) techniques is to furnish detections to consider reliable in a statistical approach, i.e. in terms of probability of false-alarm and probability of detection. In order to improve ATD performance, appropriate de-noising techniques and clutter removal algorithms have to be developed as a pre-processing step, since the mitigation of both noise sources (spatial and temporal) and the accurate estimation of background clutter improve the performance of ATD. In this framework, this PhD thesis is focused on pre-processing techniques developed to improve the performance of ATD techniques. The first part of the thesis is focused on a de-noising problem known in the literature as non-uniformity correction (NUC) for last generation focal-plane arrays (FPAs) IR devices. Particular emphasis has been posed on scene-based techniques since NUC is operated with the only employment of the sensed radiation. A detailed overview of scene-based NUC techniques presented in the literature is carried out highlighting advantages and drawbacks. Focusing on the performance of the NUC scene-based techniques, the Scribner's algorithm has been deeply analyzed revealing high NUC performance combined with small computational load. In relation to this NUC technique, it has been introduced the problem of ghosting artifacts which is considered as a collateral effect emerging from scene-based NUC techniques based on a statistical approach. Novel methods to mitigate ghosting artifacts are presented in this PhD thesis: (i) Bilateral filter (BF)- based de-ghosting. The bilateral filter has been employed to operate accurate spatial estimates of the FPN; (ii) Temporal statistics (TS)-based de-ghosting. Temporal statistics are computed to predict the trend of an accurate estimate of the NUC parameters. The proposed techniques have been tested and evaluated in terms of de-ghosting capability and global NUC effectiveness by means of IR experimental data sets with simulated FPN. The second part of the PhD thesis concerns a complementary topic of data processing for ATD applications: background estimation and removal in IR images. It has been adopted a well-established scheme for target detection in IR surveillance systems, that is the cascade of background clutter removal plus a strategy of target detection. In such an ATD scheme, the overall detection performance is strongly influenced by the effectiveness of the employed BEA. Particularly, the BEA and its design parameters should be chosen so as to get an accurate estimate of the background signal and to avoid biases caused by the possible presence of targets (target leakage). In this framework, it is proposed a novel method for the choice and setting of the best performing BEA in its best performing configuration for the detection of dim point targets in IR images. The proposed procedure relies on a simulation-based off-line approach. The effectiveness of the proposed BEA selection procedure is evaluated in two case studies typical of IR video-surveillance: maritime and airborne surveillance scenarios. Experimental image sequences have been acquired by MWIR cameras in order to test the proposed BEA selection criterion (BEA-SC).
Space debris are all man made objects including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non functional. This widely accepted official definition was adopted by the Inter-Agency Space Debris Coordination Committee (IADC), an international governmental forum for the worldwide coordination of activities related to the issues of man-made and natural debris in space.
Background: Given the well-documented acute increase in psychopathology after disasters as well as the greater likelihood of suicide among persons with psychopathology, it may be expected that suicide rates also rise after such events. Aim: To investigate the suicide rate 1 year after the April 2009 earthquake that struck L'Aquila (Italy). Methods: Suicide rates were collected from administrative data sets of the Italian National Institute of Statistics for the years 2004 through 2009. Results: The number and rate of suicides during 2009 are the lowest since 2004 – and significantly lower than the two prequake years. Conclusions: The findings suggest that an investigation of resilience and posttraumatic personal growth might be useful in guiding public health efforts on suicidal prevention in the aftermath of disasters.
PurposeThis paper contributes to the debate on the relationship between IT‐artefacts and organisational structuration by describing the dynamics surrounding the collaborative development of an innovative electronic metering system. The aim of the paper is to address a clear gap in the current literature on collaborative IT‐artefacts design, as cooperation at early design stages has barely been analysed. This work tries to understand whether and to what extent the design of an IT‐artefact is driven by the interests of a number of heterogeneous actors and how these are able to affect the artefact's evolution.Design/methodology/approachThe research relies on a case study analysis, which focuses on a consortium of heterogeneous actors (firms, the public sector, research institutes) working within the green energy industry. The research focuses on a workgroup attempting to develop an innovative IT‐artefact: an electronic metering system.FindingsThe main results emerging from the field study are: the relevance of each actor's interests as a prevalent rationale for explaining the technical features of the IT‐artefact; the role of negotiation and consensus in determining the final shape of the IT‐artefact in terms of its features; and the bundling/unbundling of IT‐artefact features as a result of changes in the alignment of actors.Research limitations/implicationsThe research presents two clear limitations. First, the activities of the workgroup are still ongoing thus limiting some of the insights one may draw from the case study. Second, the analysis is carried out on a single case study. Further analysis should be done to increase consistency and validity of the findings.Practical implicationsFindings indicate that in an open and collaborative environment, the conceptualisation and evolution of an IT‐artefact are influenced more by the political agendas of the various actors rather than by pure technical problems and concerns. The practical implications thus are that every attempt to manage such a collaborative effort must seriously take into consideration these aspects.Originality/valueStarting from the recognition that little research has been conducted on the factors influencing cooperative IT‐artefact design, this paper sheds new light on how these factors influence such cooperative activity. The authors believe that this kind of work helps lay some foundations for general models attempting to explain cooperative innovation processes such as the open innovation model.
AbstractThis study's first aim was to explore whether stigma's facets differ between internalizing and externalizing disorders in adolescence. The second aim was to compare the relationships among stigma's facets toward these disorders. Two vignettes depicting a peer with Major Depressive Disorder (MDD) or Attention‐Deficit Hyperactivity Disorder (ADHD) were used with 616 adolescents in Italy. A Repeated measure MANOVA showed biogenetic causes, social distancing, and discomfort were more attributed to depression, while dangerousness to ADHD. Furthermore, a Psychometric Network Analysis showed no differences between these disorders in the relations among stigma's components. However, dangerousness seemed to be among the nodes with the highest levels of "strength," confirming previous literature that shows that dangerousness plays a major role in stigma.
The underlying thesis of this study is that the biomass for energy purposes, coming from farms, forestry, timber industry and Short Rotation Forestry (SRF) for energy, can provide various environmental and socio-economic benefits. First of all, the production of forest biomass for energy involves the reduction of CO2 emissions and the improvement of forest functions, such as hydrogeological and biodiversity conservation. Moreover, forest biomass consumption could contribute to the socio-economic development of rural areas, through the restoration of agro-forest activities and technological advances in the bio-energy field. In the last ten years in Italy several companies of the bioenergy industry, attracted by Government subsidies planned to build dedicated power that use biomass as their main fuel. The primary goal of this study is to analyse the local forest wood supply chain. Therefore, field surveys have been done in order to classify the management and the characteristics of the woodchips supply chain (wood sub-product availability, forest enterprises, working systems, forest woodchips quality). DOI: http://dx.medra.org/10.19254/LaborEst.15.09
