45,366 research outputs found

    Systematization of a 256-bit lightweight block cipher Marvin

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    In a world heavily loaded by information, there is a great need for keeping specific information secure from adversaries. The rapid growth in the research field of lightweight cryptography can be seen from the list of the number of lightweight stream as well as block ciphers that has been proposed in the recent years. This paper focuses only on the subject of lightweight block ciphers. In this paper, we have proposed a new 256 bit lightweight block cipher named as Marvin, that belongs to the family of Extended LS designs.Comment: 12 pages,6 figure

    From art to engineering

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    This paper describes work which emerged through a need to understand more about the potential of laser surface engineering for use in the creative industries. The method of creation of contemporary jewellery pieces and the resultant ‘Ocular’ jewellery series are described from the points of view of an artist and an engineer. The work demonstrates how laser controlled oxide growth on commercially pure titanium under ambient conditions can be used as an artistic tool by producing even, defined colours or by reproducing a simulation of freehand drawings on a titanium surface. It also asks the question: how different are artists from scientists and engineers

    Laser surface colouring of titanium for contemporary jewellery

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    This paper describes work which emerged through a need to understand more about the potential of laser surface engineering for use in the creative industries. The method of creation of contemporary jewellery pieces and the resultant 'Ocular' jewellery series are described from the creative point of view. The work demonstrates how laser controlled oxide growth on Ti–6Al–4V alloy under ambient conditions can be used as an artistic tool by producing precisely defined colours. Use of the method to produce regular areas of even colour and to reproduce freehand drawings on a titanium alloy surface is described. Analysis highlights interference as the main colouring mechanism and suggests a graded surface layer, progressing from an outer layer of TiO2 to lower layers rich in TiO and Ti2O. The model of research by practice presented in this paper offers a contribution to the current debate on partnerships between art and science and engineering

    Compositional structures in mural design : towards a site-specific deconstructive mural methodology

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    A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements of the degree of Doctor of Philosophy (PhD)Murals have been the formal visual interpretation of the cultural, social and political life of all ages. Throughout they have been consistently combined with their architectural setting, for example, in ancient Egyptian tombs, in Renaissance churches and on the external walls of buildings in Mexico in the twentieth century. This is a central feature of mural painting. However many contemporary murals do not integrate with their architectural settings, in other words, do not fulfil the site-specificity of the architectural spaces for which they were made. This means that the most important aspect that distinguishes murals from other types of painting is absent. I studied and analysed a number of murals produced in the Italian Renaissance, Baroque and Rococo as this particular period is considered to be not only one of the most significant in the history of art but also a period in which painting and architecture were very closely allied as practices. In particular the radical developments in painting of pictorial space took place along side the developments in architecture. I argue that Renaissance murals could be described, using the terminology of contemporary art, as site-specific art. By identifying the relationship between pictorial space, architectural space and compositional structure I was able to test, through my own practice, the importance of these relationships in understanding the site-specificity of the compositional structure of murals. To address the issue of sitespecificity in murals, I investigated and developed a set of compositional structures through my mural practice that could be applied in the design, execution, and teaching of contemporary mural design. I have developed the notion of a deconstructive method of mural design in which the illusory space of the mural derives its compositional structure from the architectural space in which it sited. I have applied it, tested it and refined it through the execution of a number of hypothetical and live mural commissions. I believe that the approach to the study and practice of mural design I have developed from the perspective of a practice lead researcher contributes to the furtherance of mural design as both a profession and field of study. In particular the identification of compositional structures in mural design and the proposal of a deconstructive method contributes to our understanding of what a mural is as well as current notions of site-specificity in contemporary art

    Plants lacking the main light-harvesting complex retain photosystem II macro-organization

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    Photosystem II (PSII) is a key component of photosynthesis, the process of converting sunlight into the chemical energy of life. In plant cells, it forms a unique oligomeric macrostructure in membranes of the chloroplasts. Several light-harvesting antenna complexes are organized precisely in the PSII macrostructure—the major trimeric complexes (LHCII) that bind 70% of PSII chlorophyll and three minor monomeric complexes—which together form PSII supercomplexes. The antenna complexes are essential for collecting sunlight and regulating photosynthesis, but the relationship between these functions and their molecular architecture is unresolved. Here we report that antisense Arabidopsis plants lacking the proteins that form LHCII trimers have PSII supercomplexes with almost identical abundance and structure to those found in wild-type plants. The place of LHCII is taken by a normally minor and monomeric complex, CP26, which is synthesized in large amounts and organized into trimers. Trimerization is clearly not a specific attribute of LHCII. Our results highlight the importance of the PSII macrostructure: in the absence of one of its main components, another protein is recruited to allow it to assemble and function

    Towards constructing one-bit binary adder in excitable chemical medium

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    Light-sensitive modification (ruthenium catalysed) of the Belousov-Zhabotinsky medium exhibits various regimes of excitability depending on the levels of illumination. For certain values of illumination the medium switches to a sub-excitable mode. An asymmetric perturbation of the medium leads to formation of a travelling localized excitation, a wave-fragment which moves along a predetermined trajectory, ideally preserving its shape and velocity. To implement collision-based computing with such wave-fragments we represent values of Boolean variables in presence/absence of a wave-fragment at specific sites of medium. When two wave-fragments collide they either annihilate, or form new wave-fragments. The trajectories of the wave-fragments after the collision represent a result of the computation, e.g. a simple logical gate. Wave-fragments in the sub-excitable medium are famously difficult to control. Therefore, we adopted a hybrid procedure in order to construct collision-based logical gates: we used channels, defined by lower levels illumination to subtly tune the shape of a propagating wave-fragment and allow the wave-fragments to collide at the junctions between channels. Using this methodology we were able to implement both in theoretical models (using the Oregonator) and in experiment two interaction-based logical gates and assemble the gates into a basic one-bit binary adder. We present the first ever experimental approach towards constructing arithmetical circuits in spatially-extended excitable chemical systems
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