911 resultados para Symbolic and Algebraic Manipulation


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Boosted by a proliferation in metal-detected finds, categories of personal adornment now constitute a vital archaeological source for interpreting Viking-age cultural interaction in the North Sea region. Previous research in England has explored the potential of this metalwork in relation to the formation of ‘Anglo-Scandinavian’ identity, but without due consideration of a wider spectrum of cultural influences. This article redresses the balance by shifting attention to twenty-eight belt fittings derived from richly embellished baldrics, equestrian equipment, and waist belts manufactured on the Frankish continent during the period of Carolingian hegemony in the later eighth and ninth centuries ad. The metalwork is classified and then contextualized in order to track import mechanisms and to assess the impact of Carolingian culture on the northern peripheries of the Frankish empire. The main conclusion is that the adoption, adaptation, and strategic manipulation of Carolingian/northern Frankish identity formed an embedded component of cultural dynamics in Viking-age England, scrutiny of which sheds new light on patterns of interconnectivity linking peoples of the North Sea world.

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Modern database applications are increasingly employing database management systems (DBMS) to store multimedia and other complex data. To adequately support the queries required to retrieve these kinds of data, the DBMS need to answer similarity queries. However, the standard structured query language (SQL) does not provide effective support for such queries. This paper proposes an extension to SQL that seamlessly integrates syntactical constructions to express similarity predicates to the existing SQL syntax and describes the implementation of a similarity retrieval engine that allows posing similarity queries using the language extension in a relational DBM. The engine allows the evaluation of every aspect of the proposed extension, including the data definition language and data manipulation language statements, and employs metric access methods to accelerate the queries. Copyright (c) 2008 John Wiley & Sons, Ltd.

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Using a new proposal for the ""picture lowering"" operators, we compute the tree level scattering amplitude in the minimal pure spinor formalism by performing the integration over the pure spinor space as a multidimensional Cauchy-type integral. The amplitude will be written in terms of the projective pure spinor variables, which turns out to be useful to relate rigorously the minimal and non-minimal versions of the pure spinor formalism. The natural language for relating these formalisms is the. Cech-Dolbeault isomorphism. Moreover, the Dolbeault cocycle corresponding to the tree-level scattering amplitude must be evaluated in SO(10)/SU(5) instead of the whole pure spinor space, which means that the origin is removed from this space. Also, the. Cech-Dolbeault language plays a key role for proving the invariance of the scattering amplitude under BRST, Lorentz and supersymmetry transformations, as well as the decoupling of unphysical states. We also relate the Green`s function for the massless scalar field in ten dimensions to the tree-level scattering amplitude and comment about the scattering amplitude at higher orders. In contrast with the traditional picture lowering operators, with our new proposal the tree level scattering amplitude is independent of the constant spinors introduced to define them and the BRST exact terms decouple without integrating over these constant spinors.

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This paper describes the processes of creating a hybrid experience of live performance and virtual imagery in 1 + x: Mid-range Projections, a dance work that uses real-time processing of live feed video to create a duet between dancers and their virtual images. 1 + x is about creating experiences of interiority and intimacy, ironically, through the juxtaposition of virtual images of performers with their real selves. This paper examines how the ideal of reinserting intimacy, humanity and 'presence' into a technologically generated image space, in the case of 1 + x, depends on the precise and delicate manipulation of live-feed video in collaboration with the audience's experience of interactivity. The result is a performance work that creates a poesis of 'presence', through a diegesis that melds real and virtual images on the same screen and the same conceptual and spatial plane - a 'becoming virtual'.

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Control of tele-operated remote robot’s is nothing new; the public was introduced to this 'new' field in 1986 when the Chernobyl cleanup began. Pictures of weird and wonderful robotic workers pouring concrete or moving rubble flooded the world. Integration of force feedback or 'haptics' to remote robot's is a new development and one that is likely to make a big difference in man-machine interaction. Development of haptic capable tele-operation schema is a challenge. Often platform specific software is developed for one off tasks. This research focussed on the development of an open software platform for haptic control of multiple remote robotic platforms. The software utilises efficient server/client architecture for low data latency, while efficiently performing required kinematic transforms and data manipulation in real time. A description of the algorithm, software interface and hardware is presented in this paper. Preliminary results are encouraging as haptic control has been shown to greatly enhances remote positioning tasks.

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Technology in classrooms has brought opportunities to develop new ways of teaching and learning, as well as new ways of thinking and communicating. The author describes a lesson which aimed to have the grade four children in the class construct on the computer screen images of rectangles. The lesson provided the opportunity to learn about some powerful generalisations about rectangles as well to learn about their geometric and algebraic understandings.

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The use of information is preceded by its availability. For post-industrial economies to exploit information to full potential it is important for knowledge to be free of vested-interest censorship and manipulation. History suggests that a range of vested-interests have manipulated explicit> information availability through various forms of sectarian, state and business manipulation of the systems of information storage and transfer. The OECD 1996 report "The Knowledge-Based Economy" recognized that the diffusion of knowledge was as significant as its creation, and that knowledge distribution networks were crucial to innovation, production processes and product development. The success of enterprises and national economies is considered reliant on the effectiveness of their ability to gather, distribute and utilize knowledge. The increasing need for ready access (of information that might become knowledge) in accordance with the OEDC definition is particularly relevant to this paper as it assumes infrastructures capable of providing that need. Wherever there are infrastructures there are opportunities to benefit from them, either for profit or power. This paper considers the implications of sectarian, state and business-model control over the selective content, storage and dissemination of information and knowledge, both from historical and current perspectives. The advent of new technologies and how they have enabled the flow of information adds new dimensions to knowledge control but the quality of knowledge is less certain and who controls or influences distribution of knowledge less transparent. It could be argued that at each step in the development of knowledge distribution networks, knowledge and its distribution, is not free of the possibility of third-party vested interest.

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Some knowledge of what it means to construct a proof is an extremely important part of mathematics. All mathematics teachers and students should have some exposure to the ideas of proof and proving. This paper deals with the issue of creating proofs in mathematics problems.

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A study under controlled conditions of ovarian development and rematuration in the yabby (Cherax destructot) was undertaken. The purpose of the study was to improve fundamental understanding of the reproductive biology of the species and provide a basis for application to hatchery management in culture. A review was made of the current status of yabby culture in Australia and the present understanding of reproductive biology of decapod Crustacea. The review emphasised factors controlling several aspects of ovarian development, in particular the processes of vitellogenesis. The subsequent study was designed within the context of current hatchery practice and was based on existing knowledge of decapod reproduction, The sexual differentiation of the yabby after hatching was investigated by serial histological sections, and experiments were carried out to investigate the possibility of sex reversal of males. Most of this Investigation was concerned with removing the influence of the androgenic gland in directing male development, with the intent of observing the development of the elementary gonadal tissue into ovary. It was found that in contrast to other crustacean species, the sex of the yabby becomes fixed before the development of external secondary sexual characteristics, and before the androgenic gland can be discerned. Ovarian tissue developed in females at less than 8 weeks after hatching. A preliminary examination was undertaken for feminising parasites in gonadal tissue of a hermaphrodite yabby. Investigation of the ovary after spawning demonstrated that whilst the female was held under constant conditions of temperature and photoperiod, little rematuration occurred. Except for generation of previtellogenic oocytes during the first two days, the gonaciosomatic index remained low for up to 5 months after spawning. If the temperature of the female was reduced to 10°C and maintained constant, the previtellogenic oocytes were partially resorbed over a three week period. Rematuration then commenced, albeit at a low rate because of the reduced temperature, A method for standardising gonadosomatic indices was developed which took into account differences in hepatopancreatic nutrient reserves of individuals and loss of one or more appendages. This part of the study also considered constraints to rematuration and developed a method of accounting for differences in the ability of females to remature after spawning. Experiments were carried out to investigate the effect of crowding and temperature manipulation on initiating ovarian rematuration and to determine the rate of rematuration at 22°C once initiated. The duration of low temperature had no effect on rematuration; an overnight cooling was sufficient to initiate the process, Rematuration to the end of stage 2 vltellogenesis was substantially complete within 10 days. Crowding of females suppressed rematuration, but less than ideal water quality was not found to have any effect. The presence of a male initiated rematuration at a similar rate, but also led to stage 3 vitetlogenesis and spawning. A study was made of the pheromonal influence of the male through water borne factors without success. Rematuration could not be induced in ovigerous females. The literature review indicated that ovarian rematuration was under the control of an ovary stimulating hormone produced by the thoracic nerve ganglia. Attempts were therefore made to stimulate ovarian rematuration by incorporating the thoracic nerve into the diet of females. Attempts were also made to induce the release of ovary stimulating hormone from the thoracic nerve with 5-hydroxytryptamine, and also with octopamine. No effects were found, but a significant difference between the neurophysiology of the yabby and northern hemisphere crayfish was observed, and the implications of this finding are discussed. The study did not produce any conclusive evidence of an ovary stimulating hormone for the yabby. A model of ovarian rematuration which collects the findings of the experimental investigations was developed, and was used to suggest a hatchery broodstock management protocol. This model differs from existing models in that rematuration triggers and nutritional status are considered.

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In exercising vision we employ strategies to perceive space and to distinguish the objects of attention. Some processes however remain invisible to us; how we process binocular vision; and how we resolve vision in motion. This work images invisible motion perspective. Revelation of invisible mechanisms of vision exposes the haptic qualities of sight and their contribution to proprioception and ʻaffordanceʼ. Figuring the ʻvortex of visionʼ also releases symbolic and metaphoric potentials. This innovative outcome of practical research develops imagery which depicts relative movement in space using the principles of motion perspective (Herschel) and optic flow (J. J. Gibson); the locative awareness of volumes in space through the dimensions of time and space presented in 2D imagery. The mural scale (3.5 metres) work presented in 'Circle', a group show of work around the idea of 'the circle' curated by Melinda Capp is derived from a large production of digital photographs made in the London Underground. In this work, the circle is associated with the orbit of the commuter which bends around the twin poles of home and employment, work and rest, circulating in an ellipse around the Ideal Life. Each traveller's path is a braid woven through gyrations of force and resistance. Optic flow, emulated with the rotating lens, tracing the moving subject, makes this visible.

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Compared with research on the role of student engagement with expert representations in learning science, investigation of the use and theoretical justification of student-generated representations to learn science is less common. In this paper, we present a framework that aims to integrate three perspectives to explain how and why representational construction supports learning in science. The first or semiotic perspective focuses on student use of particular features of symbolic and material tools to make meanings in science. The second or epistemic perspective focuses on how this representational construction relates to the broader picture of knowledge-building practices of inquiry in this disciplinary field, and the third or epistemological perspective focuses on how and what students can know through engaging in the challenge of representing causal accounts through these semiotic tools. We argue that each perspective entails productive constraints on students’ meaning-making as they construct and interpret their own representations. Our framework seeks to take into account the interplay of diverse cultural and cognitive resources students use in these meaning-making processes. We outline the basis for this framework before illustrating its explanatory value through a sequence of lessons on the topic of evaporation.

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In this paper, we propose a novel approach to secure ownership transfer in RFID systems based on the quadratic residue property. We present two secure ownership transfer schemes-the closed loop and open loop schemes. An important property of our schemes is that ownership transfer is guaranteed to be atomic. Further, both our schemes are suited to the computational constraints of EPC Class-1 Gen-2 passive RFID tags as they only use operations that such passive RFID tags are capable of. We provide a detailed security analysis to show that our schemes achieve strong privacy and satisfy the required security properties of tag anonymity, tag location privacy, forward secrecy, and forward untraceability. We also show that the schemes are resistant to replay (both passive and algebraic), desynchronization, and server impersonation attacks. Performance comparisons demonstrate that our schemes are practical and can be implemented on low-cost passive RFID tags.

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This paper discusses the intensified role of the media in shaming ‘ordinary' people when they commit minor offences. We argue that shaming is a powerful cultural practice assumed by the news media in western societies after it was all but phased out as a formal punishment imposed by the judiciary during the early nineteenth century. While shaming is no longer a physically brutal practice, we reconceptualize the idea of a ‘lasting mark of shame' at the hands of the media in the digital age. We argue that this form of shaming should be considered through a lens of media power to highlight its symbolic and disciplinary dimensions. We also discuss the role new and traditional media forms play in shaming alongside formal punishments imposed by the judiciary. While ‘ordinary' people armed with digital tools increase the degree of disciplinary surveillance in wider social space, traditional news media continue to play a particularly powerful role in shaming because of their symbolic power to contextualize information generated in social and new media circles and their privileged position to other fields of power.

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Work-integrated learning (WIL) is regarded as an important vehicle to assist students’ development of relevant professional skills, knowledge and attributes that can enhance their employability. WIL arrangement for international students is a challenging issue for institutions, international students themselves as well as other related stakeholders. While there is an emerging body of literature that examines WIL for international students, how the value of WIL is perceived by this cohort is little known. This paper responds to this dearth of the literature by exploring the different meanings that international students in the vocational education and training sector attach to WIL. Using Bourdieu’s thinking tools of capitals and habitus to interpret interview data from 105 international students, this paper shows that WIL is seen to not only add value to student learning, career aspiration and employability but also transform and enhance their symbolic and social capitals. The paper underscores the instrumental, symbolic and developmental meanings that international students associate with WIL. In particular, it highlights the reciprocal relationship between students’ development of vocational ‘being’ and personal ‘being’ through WIL.