643 research outputs found

    MetTeL: A Generic Tableau Prover.

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    Sensible Agnosticism: An Updated Approach to Domain-Name Trademark Infringement

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    The Internet era has brought a new battlefield to U.S.-trademark-law disputes: domain names. Trademark owners have vigorously challenged the registration of domain names that consist of-or merely include-their trademarked terms, suing these domain-name registrants in U.S. courts for trademark infringement. During the early years of the Internet, courts often found consumer confusion-and thus trademark infringement-in these cases. As Internet use has developed, however, many courts have not recognized the growing sophistication of online consumers. This Note proposes that U.S. courts adapt their analyses to recognize evolving consumer behavior and expectations. This updated analysis, based on a 2010 Ninth Circuit opinion, will promote trademark law\u27s historical focus on accuracy by encouraging courts to recognize the right of domain-name registrants to engage in accurate, nonconfusing speech

    Logic-based Technologies for Intelligent Systems: State of the Art and Perspectives

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    Together with the disruptive development of modern sub-symbolic approaches to artificial intelligence (AI), symbolic approaches to classical AI are re-gaining momentum, as more and more researchers exploit their potential to make AI more comprehensible, explainable, and therefore trustworthy. Since logic-based approaches lay at the core of symbolic AI, summarizing their state of the art is of paramount importance now more than ever, in order to identify trends, benefits, key features, gaps, and limitations of the techniques proposed so far, as well as to identify promising research perspectives. Along this line, this paper provides an overview of logic-based approaches and technologies by sketching their evolution and pointing out their main application areas. Future perspectives for exploitation of logic-based technologies are discussed as well, in order to identify those research fields that deserve more attention, considering the areas that already exploit logic-based approaches as well as those that are more likely to adopt logic-based approaches in the future

    Highly efficient low-level feature extraction for video representation and retrieval.

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    PhDWitnessing the omnipresence of digital video media, the research community has raised the question of its meaningful use and management. Stored in immense multimedia databases, digital videos need to be retrieved and structured in an intelligent way, relying on the content and the rich semantics involved. Current Content Based Video Indexing and Retrieval systems face the problem of the semantic gap between the simplicity of the available visual features and the richness of user semantics. This work focuses on the issues of efficiency and scalability in video indexing and retrieval to facilitate a video representation model capable of semantic annotation. A highly efficient algorithm for temporal analysis and key-frame extraction is developed. It is based on the prediction information extracted directly from the compressed domain features and the robust scalable analysis in the temporal domain. Furthermore, a hierarchical quantisation of the colour features in the descriptor space is presented. Derived from the extracted set of low-level features, a video representation model that enables semantic annotation and contextual genre classification is designed. Results demonstrate the efficiency and robustness of the temporal analysis algorithm that runs in real time maintaining the high precision and recall of the detection task. Adaptive key-frame extraction and summarisation achieve a good overview of the visual content, while the colour quantisation algorithm efficiently creates hierarchical set of descriptors. Finally, the video representation model, supported by the genre classification algorithm, achieves excellent results in an automatic annotation system by linking the video clips with a limited lexicon of related keywords

    Reversible carbon dioxide gels, synthesis and characterization of energetic ionic liquids, synthesis and characterization of tetrazole monomers and polymers, encapsulation of sodium azide for controlled release

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    Hydrazine and monomethylhydrazine are widely used as propellants in aerospace and defense industries. However these chemicals are volatile, carcinogenic, and sensitive to impact, which impose serious threats during their usage. In this thesis, we have demonstrated two novel ways to immobilize hydrazine chemicals. In one approach hydrazine, monomethylhydrazine have been gelled using carbon dioxide. Chemical and structural properties of these gels are studied by NMR (1H, 15N, 13C), diffusion-ordered NMR spectroscopy, and Cryo-HRSEM. Thermal reversibility of these gels is also demonstrated. In another approach, hydrazine, monomethylhydrazine and 1,1-dimethylhydrazine are reacted with 5-methyltetrazole to form ionic liquids. Synthesis of novel tetrazole monomers and polymers, .and new method for encapsulating sodium azide have also reported in this thesisPh.D.Committee Chair: Prof. Charles L. Liotta; Committee Member: Prof. Arthur J. Ragauskas; Committee Member: Prof. Charles A. Eckert; Committee Member: Prof. John D. Muzzy; Committee Member: Prof. Rigiberto Hernande

    Strategies for Controlling Bulk Heterojunction Morphology

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    Organic photovoltaic devices have been extensively studied as a means to produce sustainable energy. However, the performance of organic-photovoltaic (OPV) devices is dependent upon a number of factors including the morphology of the active layer, device architecture, and processing conditions. Recent research has indicated that fullerenes in the bulk heterojunction are entropically driven to the silicon and air interfaces upon crystallization of P3HT, which occurs during thermal annealing. The first chapter of this research focuses on investigating the structure and function of end-tethered poly(3-hexylthiophene) chains to a transparent electrode as an anode buffer layer. Neutron reactivity reveals that these P3HT brush layers have severe effects in the vertical distribution of PCBM across the depth of the BHJ films, the extent of which depends on the grafting density of the P3HT brush layer. These results are confirmed by energy-filtered transmission electron microscopy measurements. Another emerging trend in the advancement of OPVs is through the addition of a third component to impose morphological or electronic benefits to BHJ-based devices. In Chapter 3 of this dissertation, three different low MW P3HTs are incorporated into BHJ films as additives to reveal fundamental aspects of their behavior as a function of size and loading level. The best performing loading levels for each additive are found to be inversely proportional to the MW of the P3HT additive and appear to be driven by a coarsening of BHJ film morphology. The incorporation of porphyrin-based additives into BHJ OPV devices has been an emerging trend in recent years due to their strong solar absorption and π - π interactions between PCBM nanoparticles and porphyrin centers. Building on these reports, and the investigations of low MW P3HTs, porphyrin-capped low MW P3HTs (PP-P3HT)s are synthesized and incorporated into BHJ films as additives. Although PP-P3HTs impose many substantial morphological benefits to BHJ films, these favorable properties are overshadowed by lackluster device performances, ostensibly due to the presence of the Si-O linkage between the porphyrin and P3HT chains

    Protein complexes in chlorophyll biosynthetic enzymes

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    Proteins are found on the inside, in the membrane, on the surface and on the outside of cells. They form complicated structures and they interact with other molecules and proteins. Protein complexes and protein-protein interactions are challenging to investigate and in the beginning of protein research most studies were done with single proteins, often in water. Although, in vivo proteins rarely function alone.To study protein complexes, two enzymes in the chlorophyll biosynthetic pathway were selected, Mg-chelatase in Rhodobacter capsulatus (bacteria) and the MPE cyclase complex in Hordeum vulgare (barley) and Arabidopsis thaliana (mouse-ear cress). Chlorophyll is a pigment formed through a complicated reaction path. Chlorophyll biosynthesis takes place in chlorophyll-producing organisms. The firstcommitted step towards chlorophyll biosynthesis is performed by the enzyme complex Mg-chelatase. Mg-chelatase inserts a Mg2+ ion into the porphyrin substrate. The pathway is continued by a methyltransferase and thereafter the MPE cyclase complex which performs a complicated ring-closure in the porphyrin.Mg-chelatase is composed of three proteins, BchI (40 kDa), BchD (60 kDa) and BchH (130 kDa). A cryo-electron microscopy model of the BchID complex (7.5 Ã…) revealed a two-tired hexameric ring structure with an arrangement of the subunits as a trimer of dimers. The transient full complex of Mg-chelatase, BchIDH, was chemically cross-linked and BchH was found to interact with the Dside of the BchID complex.The MPE cyclase complex was more difficult to study and two of the three core components of the complex are still unknown. An interesting enzyme, NADPH-dependent thioredoxin reductase C (NTRC), was found to stimulate the MPE cyclase reaction together with a 2-Cys peroxiredoxin. NTRC was characterised further with regards to function and structure. The enzyme consists of a fusion between a NADPH-dependent thioredoxin reductase polypeptide and a thioredoxin polypeptide in the C-terminal. The three-dimensional structure ofNTRC was determined with cryo-electron microscopy (10.0 Ã…) and revealed a tetramer

    Characterisation of self-assembled engineered proteins on gold nanoparticles and their application to biosensing

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    PhD ThesisThe use of gold nanoparticles (AuNP) has a long and varied history, thought to cover several thousand years. More recently the unique properties of nanoscale materials have stimulated extensive work on nanoparticles and other nanomaterials leading to their use in novel technologies. AuNPs have been of particular interest for bioscience applications due to their biocompatibility and the ease with which biological molecules can be conjugated to their surface. In this study the assembly of engineered proteins, specifically the transmembrane domain of Escherichia coli outer membrane protein A (OmpATM), onto the surface of AuNPs was investigated both in solution and with the particles attached to a SiO2 substrate. AuNPs were adhered to SiO2 surfaces using a novel silane treatment developed by the industrial sponsor and were characterised using spectroscopy, electron and atomic force microscopy. The addition of a single cysteine residue to the OmpATM structure was shown, by UV-Vis and fluorescence spectroscopy, to increase protein binding at equilibrium and form higher stability protein-AuNP complexes in solution. Following this, engineered OmpATM proteins containing tandem antibody-binding domains from Streptococcal protein G were assembled on the AuNP surface and their structure interrogated using neutron and light scattering. This revealed an oriented protein layer where the functional domains extend away from the AuNP surface and are available to bind antibodies. OmpATM-AuNP conjugates were used to develop biosensing assays using both well-established methods, such as lateral flow assays, and novel spectroscopic methods, which use the unique optical properties of AuNPs. Detection of influenza A nucleoprotein, an antigen used to clinically diagnose influenza, was achieved using a bespoke anti-nucleoprotein single-chain antibody domain fused to OmpATM and assembled on 20 nm diameter AuNPs. The results demonstrate that engineered OmpATM proteins conjugated to AuNPs can be used to develop novel diagnostics using a range of read out technologies
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