84 research outputs found

    Manipulating Managed Execution Runtimes to Support Self-Healing Systems

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    Self-healing systems require that repair mechanisms are available to resolve problems that arise while the system executes. Managed execution environments such as the Common Language Runtime (CLR) and Java Virtual Machine (JVM) provide a number of application services (application isolation, security sandboxing, garbage collection and structured exception handling) which are geared primarily at making managed applications more robust. However, none of these services directly enables applications to perform repairs or consistency checks of their components. From a design and implementation standpoint, the preferred way to enable repair in a self-healing system is to use an externalized repair/adaptation architecture rather than hardwiring adaptation logic inside the system where it is harder to analyze, reuse and extend. We present a framework that allows a repair engine to dynamically attach and detach to/from a managed application while it executes essentially adding repair mechanisms as another application service provided in the execution environment

    4-[(E)-2-(2,4-Dichloro­benzyl­idene)hydrazin-1-yl]quinolin-1-ium chloride monohydrate

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    In the title hydrated salt, C16H12Cl2N3 +·Cl−·H2O, there is a small twist in the cation as seen in the torsion angle linking the benzene ring to the rest of the mol­ecule [171.96 (17)°]. In the crystal, the quinolinium H atom forms a hydrogen bond to the lattice water mol­ecule, which also forms hydrogen bonds to two Cl− anions. Each Cl− ion also accepts a hydrogen bond from the hydrazine H atom. The three-dimensional architecture is also stabilized by π–π inter­actions between centrosymmetrically related quinoline residues [centroid–centroid distance = 3.5574 (11) Å]

    7-Chloro-4-[(E)-2-(2,5-dimeth­oxy­benzyl­idene)hydrazin-1-yl]quinoline

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    In the nearly planar title compound (r.m.s. deviation for the 24 non-H atoms = 0.064 Å), C18H16ClN3O2, the conformation about the N=C bond is E. Supra­molecular chains propagated by glide symmetry along [001] are found in the crystal packing. These are sustained by N—H⋯N hydrogen bonds with the quinoline N atom being the acceptor. The chains are connected into a three-dimensional architecture by π–π inter­actions involving all three aromatic rings [centroid–centroid distances = 3.5650 (9)–3.6264 (9) Å]

    (R*,S*)-(±)-1-(2-{[2,8-Bis(trifluoromethyl)quinolin-4-yl](hydroxy)methyl}piperidin-1-yl)ethanone methanol monosolvate

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    The title mefloquine derivative has been crystallized as its 1:1 methanol solvate, C19H18F6N2O2·CH3OH. Each of the meth­ine­hydroxyl residue [the C—C—C—O torsion angle is −16.35 (17) °] and the piperidinyl group [distorted chair conformation] lies to one side of the quinolinyl ring system. The hydroxyl and carbonyl groups lie to either side of the mol­ecule, enabling their participation in inter­molecular inter­actions. Thus, the hydroxyl and carbonyl groups of two centrosymmetrically related mol­ecules are bridged by two methanol mol­ecules via O—H⋯O hydrogen bonds, leading to a four-mol­ecule aggregate. These are linked into a supra­molecular chain along the a axis via C—H⋯O inter­actions involving the hydroxyl-O atom. The chains assemble into layers that inter­digitate along the c axis being connected by C—H⋯F inter­actions

    What's in a copy?

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    ABSTRACTI will answer the question “What’s in a copy?” by considering three sets of related issues: the importance of copies in academia; in cultural life; and in the economic world. In academia the current capability of making copies is challenging pedagogical practices and the trust of its members, plagiarism being the most immediate problem. The notion of authorship is also undergoing changes provoked by a proliferation of authors and new possibilities opened up by cyberspace. In cultural life, imitation and mimesis have long been fundamental engines of socialization. Our enhanced capacity of copying problematizes, with new intensity, the relationships between homogeneity and heterogeneity, between the genuine and the spurious. In the economic world, the digital era is threatening some of the fundamental tenets of capitalism, especially of its variant called the “knowledge society”, regarding the control of intellectual property rights. The gap between normativity and social practices is widening. The many dilemmas and tensions identified in the text are understood as symptoms of two major characteristics of the current times: hyperfetishism and hyperanimism. ________________________________________________________________________________ RESUMOResponderei à pergunta “O que existe em uma cópia?” considerando três conjuntos de questões relacionadas: a importância das cópias na academia, na vida cultural, no mundo econômico. Na academia a presente capacidade de fazer cópias está desafiando práticas pedagógicas e a confiança dos seus membros, o plágio sendo o problema mais imediato. A noção de autoria também está sofrendo mudanças provocadas por uma proliferação de autores e novas possibilidades abertas pelo ciberespaço. Na vida cultural, a imitação e a mimese de há muito são importantes motores de socialização. A nossa capacidade ampliada de fazer cópias problematiza, com nova intensidade, as relações entre homogeneidade e heterogeneidade, entre o genuíno e o espúrio. No mundo econômico, a era digital ameaça algumas das premissas fundamentais do capitalismo, especialmente da sua variante “sociedade do conhecimento”, no tocante aos direitos de propriedade intelectual. Cresce a distância entre normatividade e práticas sociais. Os muitos dilemas e tensões identificados no texto são compreendidos como sintomas de duas grandes características do presente: o hiperfetichismo e o hiperanimismo

    Prestige, Performance and Social Pressure in Viral Challenge Memes: Neknomination, the Ice-Bucket Challenge and SmearForSmear as Imitative Encounters

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    This article examines social media challenges that emerged in 2013, focusing on Neknomination, the Ice-Bucket Challenge and SmearForSmear. We understand them as ‘viral challenge memes’ that manifest a set of consistent features, making them a distinctive phenomenon within digital culture. Drawing upon Tarde’s concept of the imitative-encounter, we highlight three central features: their basis in social belonging and participation; the role of prestigious people and groups in determining the spread of challenges; and the distinctive techniques of self-presentation undertaken by participants. Based upon focus group interviews, surveys and visual analysis we suggest that viral challenge memes are social practices that diffuse in a wave-like fashion. Negotiating tensions between the social and individual, imitation and innovation, continuity and change, viral challenge memes are best thought of as creative practices, rather than sheep-like acts of conformity, and affirm the usefulness of analytical principles drawn from Tarde

    Conformal and continuous deposition of bifunctional cobalt phosphide layers on p-silicon nanowire arrays for improved solar hydrogen evolution

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    Vertically aligned p-silicon nanowire (SiNW) arrays have been extensively investigated in recent years as promising photocathodes for solar-driven hydrogen evolution. However, the fabrication of SiNW photocathodes with both high photoelectrocatalytic activity and long-term operational stability using a simple and affordable approach is a challenging task. Herein, we report conformal and continuous deposition of a di-cobalt phosphide (Co2P) layer on lithography-patterned highly ordered SiNW arrays via a cost-effective drop-casting method followed by a low-temperature phosphorization treatment. The as-deposited Co2P layer consists of crystalline nanoparticles and has an intimate contact with SiNWs, forming a well-defined SiNW@Co2P core/shell nanostructure. The conformal and continuous Co2P layer functions as a highly efficient catalyst capable of substantially improving the photoelectrocatalytic activity for the hydrogen evolution reaction (HER) and effectively passivates the SiNWs to protect them from photo-oxidation, thus prolonging the lifetime of the electrode. As a consequence, the SiNW@Co2P photocathode with an optimized Co2P layer thickness exhibits a high photocurrent density of -21.9 mA.cm(-2) at 0 V versus reversible hydrogen electrode and excellent operational stability up to 20 h for solar-driven hydrogen evolution, outperforming many nanostructured silicon photocathodes reported in the literature. The combination of passivation and catalytic functions in a single continuous layer represents a promising strategy for designing high-performance semiconductor photoelectrodes for use in solar-driven water splitting, which may simplify fabrication procedures and potentially reduce production costsThis work was funded by ERDF funds through the Portuguese Operational Programme for Competitiveness and Internationalization COMPETE 2020, and national funds through FCT – The Portuguese Foundation for Science and Technology, under the project “PTDC/CTM-ENE/2349/2014” (Grant Agreement No. 016660). The work is also partially funded by the Portugal-China Bilateral Collaborative Programme (FCT/21102/28/12/2016/S). L. F. Liu acknowledges the financial support of the FCT Investigator Grant (IF/01595/2014) and Exploratory Grant (IF/01595/2014/CP1247/CT0001). L. Qiao acknowledges the financial support of the Ministry of Science and Technology of China (Grant Agreement No. 2016YFE0132400).info:eu-repo/semantics/publishedVersio
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