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Innovative inversion approaches for buried objects detection and imaging
No full textThe study, development, and analysis of innovative inversion techniques for the detection and imaging of buried objects is addressed in this thesis. The proposed methodologies are based on the use of microwave radiations and radar techniques for subsurface prospecting, such as, for example, the Ground Penetrating Radar (GPR). More precisely, the reconstruction of shallow buried objects is firstly addressed by an electromagnetic inverse scattering method based on the integration of the inexact Newton (IN) method with an iterative multiscaling approach.
The performances of such an inversion approach are analyzed both when considering the use of a second-order Born approximation (SOBA) and when exploiting the full set of non-linear equations governing the scattering phenomena for the buried scenario. The presented methodologies are particularly suitable for applications such as demining (e.g., for the detection of unexploded ordnances, UXOs, and improvised explosive devices, IEDs), for civil engineering applications (e.g., for the investigation of possible structural damages, voids, cracks or water infiltrations in walls, pillars, bridges) as well as for biomedical imaging (e.g., for early cancer detection)
A novel high-efficiency SiPM-based system for Ps-TOF
No full textA novel set up for Positronium Time Of Flight is proposed, using Silicon Photomultipliers (SiPMs) instead of Photomultiplier Tubes.
The solution allows us to dramatically increase the compactness of the set up, thus improving the efficiency of 240%.
Different configurations of SiPM+scintillators are characterized in order to find the best solution. Also, simulations are provided, together with preliminary tests in the particular application. A compact read-out board for the processing of up to 44 channels has been designed and tested.Further tests, expected in the near future, are needed in order to confirm the simulations and to build the final set up
Development of drug screening assays for identification of new molecules against pancreatic ductal adenocarcinoma
No full textThe yes-associated protein, YAP, is a transcriptional co-activator, able to regulate the expression level of a wide range of target genes. Despite deregulation of YAP has been associated with cancer etiology, no compounds are known to specifically modulate its functions. Here we identified an inhibitor of YAP functionality, called GF 10923X, and we proposed it as a potential lead molecule to be used against disease where YAP is found deregulated, pancreatic ductal adenocarcinoma (PDAC) included. GF 109203X is an already known kinase inhibitor, preferentially targeting PKCα. We developed a high throughput approach by which we identified this compound able to reduce YAP-induced proliferation and clonogenicity of PDAC cellsin vitro, despite it leads to increased YAP nuclear levels. The Hippo pathway is the main inhibitor of YAP. One component of this signaling cascade,Lats1/2, phosphorylates YAP at Serine 127, thereby promoting its cytosolic retention and degradation.In line with YAP nuclear retention after the treatment, we observed that GF 109203X caused an increase of both acetylations and phosphorylations on YAP protein, with the exception of P-S127, suggesting a Hippo pathway-independent mechanism of action of the identified compound. TEAD is the major transcriptional factor partner in the functional activity of YAP and CTGF is considered one of the main representative target genes whose expression is regulated by this couple of transcriptional regulators.Chromatin immunoprecipitation experiments allowed us to demonstrate that GF 109203X interferes with YAP binding to CTGF promoter, without affecting the presence of TEAD at the same region. This inhibition is responsible of CTGF downregulation during GF 109203X administration and it can explain the phenotypic effects we observed. These effects, associated with the observed toxicity in pancreatic cancer cells but not in immortalized HPNE cell lines, make GF 109203X a potential lead compound to be used in drug development for PDAC treatment
Algebraic methods for the distance of cyclic codes
No full textIn this thesis we provide known and new results which explain the relationship between the actual minimum distance of cyclic codes, bounds that use only information on the defining sets of cyclic codes to lower bound the distance (root bounds) and bounds that also need the knowledge of the defining sets of all cyclic subcodes (border bounds).
We propose a new bound which is provably better of many known bounds and that can be computed in polynomial time with respect to the length of the code.
We sketch how to use the generalized Newton identities to give alternative proofs of known bounds.
Finally, we use Groebner bases to prove that the optimal root bound can be computed in finite time
Optimization Modulo Theories with Linear Rational Costs
No full textIn the contexts of automated reasoning (AR) and formal verification (FV),important { decision} problems are effectively encoded into Satisfiability Modulo Theories (SMT). In the last decade efficient SMT solvers have been developed for several theories of practical interest (e.g., linear arithmetic, arrays, bit-vectors).
Surprisingly, little work has been done to extend SMT
to deal with optimization problems; in particular,
concerning the development of SMT solvers able to produce solutions which minimize cost functions over arithmetical variables (we are aware of only one very-recent work [Li et al., POPL-14]). In the work described in this thesis we start filling this gap. We present and discuss two general procedures for leveraging SMT to handle the minimization of linear rational cost functions, combining SMT with standard minimization techniques. We have implemented the procedures within the MathSAT SMT solver.
Due to the absence of competitors in AR and FV, we have experimentally evaluated our implementation against state-of-the-art tools for the domain of linear generalized disjunctive programming (LGDP), which is closest in
spirit to our domain, and a very-recent SMT-based optimizer [Li et al., POPL-14]. Our benchmark set consists of problems which have been previously proposed for our competitors. The results show that our tool is very competitive, and often outperforms these tools (especially LGDP ones)on their problems, clearly demonstrating the potential of the approach. Stochastic Local-Search (SLS) procedures are sometimes very competitive in pure SAT
on both satisfiable instances and optimization problems.
As a side work, in this thesis we investigate the possibility to exploit SLS inside SMT tools which are commonly based on the lazy approach (it combines a Conflict-Driven-Clause-Learning(CDCL)SAT solver with theory-specific decision procedures, called T-solvers). We first introduce a general procedure for integrating a SLS solver of the WalkSAT family with a T-solver. Then we present a group of techniques aimed at improving the synergy between these two components. Finally we implement all these techniques into a novel SLS-based SMT solver for the theory of linear arithmetic over the rationals, and perform an empirical evaluation on satisfiable instances. Although the results are encouraging, we concluded that the efficiency of proposed SLS-based SMT techniques is still far from being comparable to that of standard SMT solvers
«Give me a break! I'm from Brooklyn, we're not fancy». Institutions, Housing and Lifestyles in Super-gentrification process. A Field and Historical research in Park Slope, New York City
Get PDFIn an attempt to make concrete linkages between neighborhood change and the boundary-making paradigm, this field and historical study of a New York City's neighborhood, addresses the influences of displacement, housing- abandonment and resettlement in Super-gentrification processes on 1) the types of institutions that emerged to represent different class interests; 2) the types of social groups that came to inhabit the neighborhood; 3) the pattern of that evolution over time; 4) the particular goals, values, and morals that such community organizations evolved; and 5) the social status displays carried out in cultured consumption in housing and leisure.
Employing a multi-methodological and theoretical approach, the study follows the evolution and development of neighborhood change over forty years through the analysis of social groups and their community organizations (looking at archival documents for the past and by in-depth interviews, shadowing and ethnographic observation for the present time), census data analysis, archival/documental research, and visual data.
Community organizations emerged, on the one hand, to represent different class interests - improvement, mandated, ideological - and to emphasize liberal progressive values, on the other. This emergence followed historical and geographical patterns of accelerating gentrification. The study argues that four waves of gentrification showed up across the time and tended to concentrate in four different neighborhood areas, where the incoming groups formed parallel boundary shifts.
Accordingly, I found that different waves of gentrification were associated with the emergence of different types of Gentrifiers over time, and this had to do with the changing role of post-industrial cities within the American economy, the processes of government/local institution interventions in the neighborhood housing market, the changes in class interests, morals and ideologies, and the increased aestheticized re-scriptings of neighborhood housing choices and lifestyles. Such aesthetic appreciation operated for gentrifiers as a visible marker of social status.
As residential displacement, the disappearance of "old" local stores, and their replacement of upscale shops entailed forms of social inequality that enhanced the lifestyle of new waves of gentrifiers (raising housing values and rents) while, at the same time, forced out morally (by alienation) or practically (by displacement) long-term residents, who helped produce the neighborhood socio-cultural fabric.
Diversity and aesthetic appeal seemed to underlie the motives of wealthier, well-educated newcomers to move into the neighborhood. Interestingly, those have not been changing throughout the different waves of gentrifiers who came to inhabit the community in the last 40 years. However - during the process of Super-gentrification - I found that the more they populate the neighborhood, the more it becomes homogenized and less richly diverse, still quite progressive but in a different way. I would say, in a privileged progressive way.
Despite the fact that the moral order of these institutions has always been the one of community solidarity, culture, education, and growth, I observed at the same time the playing out of the most common paradox of gentrifiers. The desire of diversity and the producing of difference. This is, I believe, the central problem of gentrification: the balance between, or the combination of, pleasure and power. Balancing pleasure and power is a social, political, and moral problem. It brings together many of the concerns about gentrification, the desire for (and the loss of) diversity, and expresses the central thesis of this study
CMOS Terahertz Sensors and Circuits for Imaging Applications
No full textA low-cost THz sensor, with a broadband high responsivity, low noise equivalent power, and capable of working at room temperature is still a challenge. Moreover, sensor integration with signal processing electronics is required in order to realize compact systems to be used in commercial imaging applications.
In this thesis, CMOS FET-based THz detectors and with integrated noise-efficient readout circuits are presented as a solution. In an attempt to improve the THz focal plane arrays state of the art, the use of an imager architecture is proposed, where each sensing element of an array can be addressed individually. This architecture provides better system performance in terms of sensitivity, resolution or speed.
A first chip was fabricated in the LFoundry 0.15-µm standard CMOS technology containing a 16 x 16 staring imaging array for terahertz detection in the range of 0.8 THz to 1.5 THz. Each pixel is composed of an antenna, a FET detector, and its readout electronics (a current integrator) so as the whole matrix can be integrated simultaneously. The current integrator employs an amplifier with two offset compensation techniques (chopper and current injection) and an output saturation control by adding and subtracting voltages.
A second chip composed of 15 test structures was fabricated in the STMicrolectronics 0.13 µm standard CMOS technology for terahertz detection at 600 GHz, 850 GHz and 1.5 THz. This chip contains different FET detectors (transistor and antenna) and switched-capacitor readout circuits that provide both signal amplification and filtering, improving the system SNR after each operation cycle. A comparative study of their performance is done as a first step towards a future array implementation (THz camera). For both chips, electrical and terahertz characterization results of the designed structures are presented and discussed
Color masterbatches for polyamide 6 fibers. Optimization of compounding and spinning processes. Physical-chemical characterization of industrial products.
Get PDFThe objective of this work is the investigation of the industrial production process of the Color Masterbatches and of the parameters that influence the pigment dispersion into the polymer matrix. In particular, the project is focused on the production process optimization in order to increase the quality of the final product and to minimize their environmental impact
Optimisation of Performance of 4G Mobile Networks in High Load Conditions
No full textThe signalling subsystem of the LTE (Long Term Evolution) networks inherited some of the limitations of its preceding technologies. It is vulnerable to overload situations that occur as a consequence of unpredicted user behaviour. The most sensitive zones are the paging procedure and random access procedure and the signalling channels associated with them. Reliable paging procedure is particularly important. As of the current design, in case of overload of paging channels it blocks the possibility of modification of configuration of a cell, thus limiting the possibilities of the system to recover. This research proposes and analyses a solution to overload of the paging channels in LTE systems. It shows that there is a possibility to completely avoid overload of the paging channels in surging load conditions. The research develops and verifies a mathematical model of the paging procedure. This model is incorporated in the solution, thus allowing computation of the critical load thresholds that trigger the reconfiguration of the paging channels. The solution is explained by a detailed algorithm and validated in a simulator of the LTE paging channels. It is partially compliant with the 3GPP specifications. The research includes a compatibility analysis and underlines the operational procedures that must be defined in the standard. It is important that the implementation of the solution does not affect already deployed hardware but requires a modification of the eNb software. Thus it is possible to prevent development of the paging overload situations, and the solution can be implemented in the hardware that is already deployed in the LTE networks. The main result of this research is a reliable paging procedure that opens further opportunities for optimisation of other signalling procedures and channels
Seeking Protection in Europe: Refugees, Human Rights, and Bilateral Agreements Linked to Readmission
Get PDFThis thesis lies at the junction of migration control and refugee protection. As asylum is a migration-related matter, it can be difficult for States to dissociate it from the fight against irregular immigration. Asylum, as a measure for protecting refugees and other persons in need of international protection, may thus easily come into conflict with policies and practices derived from strict border control considerations. This thesis concentrates upon this tension and aims, primarily, to investigate - with a specific focus on the European Union (EU) geographical context - whether the implementation of bilateral agreements linked to the readmission of irregular migrants can hamper refugees’ access to protection, understood here as the combination of the right to non-refoulement and an individual’s right to have access to asylum procedures and effective remedies before return. The material content and the normative scope of these protection standards is thus analysed through the lens of international refugee and human rights law and in respect of the traditional rules of treaty interpretation.
The central objective of this thesis is to develop the concept of agreements linked to readmission by broadening – to my knowledge, for the first time - the scope of legal analysis to the multifaceted framework of bilateral cooperation arrangements connected to the readmission of irregular migrants from the EU to third countries of
origin or transit. This encompasses written accords employed to facilitate the forced return of undocumented migrants from the territory of an EU Member State (standard readmission agreements and diplomatic assurances on the fair and humane treatment of the deportee, especially if formalized within MoUs), and those agreements for technical and police cooperation that are de facto utilized by EU Member States to divert migrants back to the ports of departure before they arrive to the destination country.
In order to fully understand the real impact of bilateral agreements linked to readmission on refugee rights, it is necessary to acknowledge that the study of legal texts alone will not suffice in gaining a sufficiently comprehensive approach. Rather, equal attention has also to be accorded to the implementation of the law, and, as a result, a number of case studies have been incorporated as an integral element of the methodological framework. This thesis concludes that the text of agreements linked to readmission does not seem to raise per se issues of incompatibility with core refugee rights. However, in situations of informal border controls, massive arrivals, public emergency, and pre-arrival maritime interceptions, the enforcement of these bilateral agreements can de facto hamper refugees’ access to protection. Therefore, this thesis will make a number of recommendations as a platform for further discussion among legal scholars and policy-makers