902 resultados para Gecko-inspired
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Hydroperoxidation studies on a series of alkene substrates demonstrate the introduction of the hydroperoxide functional group into the required position for a biosynthetically inspired synthesis of mycaperoxide B.
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Recent experiments have demonstrated that nanoparticles which sparsely distributed over a solid substrate can substantially change the flow conditions at the solid surface in the presence of slip. Inspired by these observations, the flow past tiny particles seeded on a solid substrate is investigated theoretically in the framework of an interface formation model. It has been shown, that even a single seeded nanoparticle can reduce significantly the measurable tangential component of hydrodynamic velocity at the substrate and affect the amount of the observed apparent slippage of the liquid. The effect from the particle manifests in a form of a long relaxation tail defined by the characteristic time of the interface formation process. A comparison with experiments has demonstrated a good agreement between theoretically predicted and experimentally observed values of the relaxation tail length scale.
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A key reason for pessimism with respect to greenhouse gas emissions reduction relates to the ‘motivation problem’, whereby those who could make the biggest difference prima facie have the least incentive to act because they are most able to adapt: how can we motivate such people (and thereby everyone else) to accept, indeed to initiate, the changes to their lifestyles that are required for effective emissions reductions? This paper offers an account inspired by Rawls of the good of membership of ‘intergenerational cooperative union’ to achieve justice that provides a solution to the motivation problem.
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In recent years researchers in the Department of Cybernetics have been developing simple mobile robots capable of exploring their environment on the basis of the information obtained from a few simple sensors. These robots are used as the test bed for exploring various behaviours of single and multiple organisms: the work is inspired by considerations of natural systems. In this paper we concentrate on that part of the work which involves neural networks and related techniques. These neural networks are used both to process the sensor information and to develop the strategy used to control the robot. Here the robots, their sensors, and the neural networks used and all described. 1.
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A novel Neuropredictive Teleoperation (NPT) Scheme is presented. The design results from two key ideas: the exploitation of the measured or estimated neural input to the human arm or its electromyograph (EMG) as the system input and the employment of a predictor of the arm movement, based on this neural signal and an arm model, to compensate for time delays in the system. Although a multitude of such models, as well as measuring devices for the neural signals and the EMG, have been proposed, current telemanipulator research has only been considering highly simplified arm models. In the present design, the bilateral constraint that the master and slave are simultaneously compliant to each other's state (equal positions and forces) is abandoned, thus obtaining a simple to analyzesuccession of only locally controlled modules, and a robustness to time delays of up to 500 ms. The proposed designs were inspired by well established physiological evidence that the brain, rather than controlling the movement on-line, programs the arm with an action plan of a complete movement, which is then executed largely in open loop, regulated only by local reflex loops. As a model of the human arm the well-established Stark model is employed, whose mathematical representation is modified to make it suitable for an engineering application. The proposed scheme is however valid for any arm model. BIBO-stability and passivity results for a variety of local control laws are reported. Simulation results and comparisons with traditional designs also highlight the advantages of the proposed design.
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Inspired by the dystopian fiction of Yevgeny Zamyatin and the minimal synthesiser music of the early 80s, London-based artist duo Pil and Galia Kollectiv are joined by Victor M. Jakeman and Ruth Angel Edwards to present popular chart hits in new versions, turning songs about 'me' and 'you' into songs about 'us', and replacing the individual 'I' with the collective 'WE'. The performance WE reveals the latent politics of the love song by annihilating its liberal subject; through the simple substitution of the plural for the singular, intimacy becomes a form of collective action and the unique the universal. Sonically, WE follows in the footsteps of bands like The Better Beatles, who sought to improve on the canon of popular music by stripping it bare, even. WE, performed at Kunsthall Oslo, Royal Standard Liverpool and ICA London, is also released on a 10" vinyl record and accompanied by a music video commissioned by Tate Britain for Tate Shots.
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Svetlana is a series of photographs documenting rehearsals for an opera that was never performed. Written by Waw Pierogi, founder of the 1980s group Xex, little is known of the opera, only that it was inspired by Svetlana, a character from one of their songs and the daughter of Stalin, who defected from the Soviet Union twice. A fictional Svetlana and a bogus Leon Theremin - inventor of the eponymous hands-free electronic musical instrument who was later kidnapped by the KGB - inhabit an archive of photographs from a session of stage rehearsals and location shots. Combining Svetlana’s narrative with a conspiracy to create sound weapons, this documentation of theatre workshops, styled after Bauhaus drama class exercises, produces an entirely spurious story of espionage, sonic weaponry and the clash between love and ideology. The performers sport geometric military costumes, brandishing sculptural forms fashioned after the acoustic locators that preceded radar technology. These redundant locators were still kept in use as props, concealing the introduction of radar from the Germans. They perfectly capture the theatricality of military might and suggest the rhetorical force of sound or even the political power of art. Svetlana was originally produced as part of a residency at S1 Artspace, Sheffield, and was later shown at Tatty Devine, alongside a special capsule collection of jewellery made by Tatty Devine.
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Asparagus: A Horticultural Ballet was a live performance and film narrating the rise of capital in the medium of asparagus. The project stemmed from an obscure reference to an art piece of the same name by Waw Pierogi of the band xex. However, the its re-enactment had little to do with the original exploration of the growth and branching patterns of the asparagus plant. Instead, a rigid choreography inspired by Oskar Schlemmer's Triadic Ballet and based on Karl Marx's Capital dictated the movements of six performers in asparagus costumes. Bringing together the organic and the geometric, the ballet investigated the transition from the Fordist assembly line to immaterial labour through a reanimation of modernist abstraction. Being itself the story of abstraction, Capital shows how human relationships are replaced by those between commodities in the joyless grind of endless accumulation. This process results in the transcendent mythical figure of capital, which frames, transfigures and even produces the natural world. Asparagus: A Horticultural Ballet was produced in collaboration with Montreal based band Les Georges Leningrad and commissioned by The Showroom Gallery, London. It was presented live at Conway Hall in London on 6.3.07 and at the Montreal Biennale at SAT on 12.5.07. The performance was accompanied by a film at the Showroom gallery and preceded by a production residency at the Pump House Gallery. The film has subsequently been shown at The Golden Thread Gallery, Bluecoat Liverpool and as part of A-Lot-Ment in Portsmouth. Props from Asparagus: A Horticultural Ballet, were included in The Eagle Document at the Stephen Lawrence Gallery, London.
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The intention of this paper is to explore traditions and current trends in art with particular reference to the depiction of female experiences such as pregnancy, abortion, birth and motherhood. The inclusion and exclusion of such images in art history over time and across societies reflects prevailing attitudes, whilst affirming various stereotypical and gendered constructions developed and sustained within those societies. These constructions in turn relate to criteria defined by class, access to education and notions of femininity. Work by artists which feature aspects of these experiences (particularly childbirth), is considered taboo by many in a Western society which continues to render the essentially female experience as private, invisible and stigmitised and confuses the natural with the sexual. The work of undergraduate art students, inspired by the artwork of women artists who make explicit or are influenced by essentially female experiences, is discussed and attempts made to connect their work to the issues outlined.
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Human resource management (HRM) plays a pivotal role in attracting and retaining talents. However, there is growing recognition in international HRM literature that the adoption of the widely accepted US/Harvard-inspired HRM model ignores the influences of cultural contexts on HRM practices in different countries. This notion has not been empirically investigated in the construction industry. Based on survey responses from 604 construction professionals from Australia and Hong Kong, this study examines whether: (i) national cultural differences influence individuals’ preference for types of remuneration and job autonomy, (ii) actual organizational HRM practices reflect such preferences and (iii) gaps between individuals’ preferences and actual organizational HRM practices affect job satisfaction. Results showed significant difference in HRM preferences between Australian and Hong Kong respondents and these are reflected in the distinct types of HRM practices adopted by construction firms in the two countries. Findings further indicated that the gap between individuals’ preferences and actual organizational HRM practices is associated with job satisfaction. The results support existing mainstream research and highlight the deficiency of the acultural treatment of HRM that is still apparent in construction management literature. An uncritical literature in the area not only hinders theory development but also potentially undermines the ability of construction firms to attract, recruit, and retain scarce talents.
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In order to fabricate a biomimetic skin for an octopus inspired robot, a new process was developed based on mechanical properties measured from real octopus skin. Various knitted nylon textiles were tested and the one of 10-denier nylon was chosen as reinforcement. A combination of Ecoflex 0030 and 0010 silicone rubbers was used as matrix of the composite to obtain the right stiffness for the skin-analogue system. The open mould fabrication process developed allows air bubble to escape easily and the artificial skin produced was thin and waterproof. Material properties of the biomimetic skin were characterised using static tensile and instrumented scissors cutting tests. The Young’s moduli of the artificial skin are 0.08 MPa and 0.13 MPa in the longitudinal and transverse directions, which are much lower than those of the octopus skin. The strength and fracture toughness of the artificial skin, on the other hand are higher than those of real octopus skins. Conically-shaped skin prototypes to be used to cover the robotic arm unit were manufactured and tested. The biomimetic skin prototype was stiff enough to maintain it conical shape when filled with water. The driving force for elongation was reduced significantly compared with previous prototypes.
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In the recent years, the area of data mining has been experiencing considerable demand for technologies that extract knowledge from large and complex data sources. There has been substantial commercial interest as well as active research in the area that aim to develop new and improved approaches for extracting information, relationships, and patterns from large datasets. Artificial neural networks (NNs) are popular biologically-inspired intelligent methodologies, whose classification, prediction, and pattern recognition capabilities have been utilized successfully in many areas, including science, engineering, medicine, business, banking, telecommunication, and many other fields. This paper highlights from a data mining perspective the implementation of NN, using supervised and unsupervised learning, for pattern recognition, classification, prediction, and cluster analysis, and focuses the discussion on their usage in bioinformatics and financial data analysis tasks. © 2012 Wiley Periodicals, Inc.
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The concept of ‘homonationalism’ refers to deployments of gay rights for racist and Islamophobic ends, resulting in the consolidation of more sexually inclusive, but racially exclusionary, ideas of citizenship. This article critiques some of the analyses that the concept has inspired in both activist and academic contexts. The critique concentrates on two texts, showing that they make inappropriate rhetorical moves and inaccurate or unsubstantiated claims, and that rather than unearthing structural undercurrents of racism from certain texts or events, they project such structures onto them. While the validity of ‘homonationalism’ as an analytical category is not disputed, some of its propounders assume its explanatory power to be greater than it appears to be. The implications of this critique for gay rights activism and reform are explored.
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Alverata: a typeface design for Europe This typeface is a response to the extraordinarily diverse forms of letters of the Latin alphabet in manuscripts and inscriptions in the Romanesque period (c. 1000–1200). While the Romanesque did provide inspiration for architectural lettering in the nineteenth century, these letterforms have not until now been systematically considered and redrawn as a working typeface. The defining characteristic of the Romanesque letterform is variety: within an individual inscription or written text, letters such as A, C, E and G might appear with different forms at each appearance. Some of these forms relate to earlier Roman inscriptional forms and are therefore familiar to us, but others are highly geometric and resemble insular and uncial forms. The research underlying the typeface involved the collection of a large number of references for lettering of this period, from library research and direct on-site ivestigation. This investigation traced the wide dispersal of the Romanesque lettering tradition across the whole of Europe. The variety of letter widths and weights encountered, as well as variant shapes for individual letters, offered both direct models and stylistic inspiration for the characters and for the widths and weight variants of the typeface. The ability of the OpenType format to handle multiple stylistic variants of any one character has been exploited to reflect the multiplicity of forms available to stonecutters and scribes of the period. To make a typeface that functions in a contemporary environment, a lower case has been added, and formal and informal variants supported. The pan-European nature of the Romanesque design tradition has inspired an pan-European approach to the character set of the typeface, allowing for text composition in all European languages, and the typeface has been extended into Greek and Cyrillic, so that the broadest representation of European languages can be achieved.
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Spontaneous activity of the brain at rest frequently has been considered a mere backdrop to the salient activity evoked by external stimuli or tasks. However, the resting state of the brain consumes most of its energy budget, which suggests a far more important role. An intriguing hint comes from experimental observations of spontaneous activity patterns, which closely resemble those evoked by visual stimulation with oriented gratings, except that cortex appeared to cycle between different orientation maps. Moreover, patterns similar to those evoked by the behaviorally most relevant horizontal and vertical orientations occurred more often than those corresponding to oblique angles. We hypothesize that this kind of spontaneous activity develops at least to some degree autonomously, providing a dynamical reservoir of cortical states, which are then associated with visual stimuli through learning. To test this hypothesis, we use a biologically inspired neural mass model to simulate a patch of cat visual cortex. Spontaneous transitions between orientation states were induced by modest modifications of the neural connectivity, establishing a stable heteroclinic channel. Significantly, the experimentally observed greater frequency of states representing the behaviorally important horizontal and vertical orientations emerged spontaneously from these simulations. We then applied bar-shaped inputs to the model cortex and used Hebbian learning rules to modify the corresponding synaptic strengths. After unsupervised learning, different bar inputs reliably and exclusively evoked their associated orientation state; whereas in the absence of input, the model cortex resumed its spontaneous cycling. We conclude that the experimentally observed similarities between spontaneous and evoked activity in visual cortex can be explained as the outcome of a learning process that associates external stimuli with a preexisting reservoir of autonomous neural activity states. Our findings hence demonstrate how cortical connectivity can link the maintenance of spontaneous activity in the brain mechanistically to its core cognitive functions.