942 resultados para Hilbert symbol


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Celem niniejszego artykułu jest wskazanie i przedyskutowanie (z perspektywy filozofii komunikacji i teorii komunikacji) kilku konsekwencji wynikających z badań nad fenomenem komunikacji. Oprócz zagadnień związanych z filozoficznym ujęciem procesu komunikacji podejmuje się również problematykę wyłonienia się myślenia metafizycznego w starożytnej Grecji. Artykuł ten jest próbą wskazania warunków, które należy spełnić, aby prowadzić filozoficznie uprawnioną refleksję nad procesem komunikacji. Całość została podzielona na trzy główne działy: w pierwszym są prezentowane dwa poziomy rekonstrukcji sytuacji komunikacyjnej w kulturze archaicznej; w drugim rozważa się zagadnienie początków relacji symbolizowania oraz zjednoczenia myślenia i działania. Trzecia część poświęcona jest źródłom myślenia metafizycznego oraz symboliczności komunikacji. Najistotniejszy wniosek wynikający z rozważań zawarty w artykule dotyczy nie-symbolicznego ujęcia procesów komunikacyjnych.

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Tolkien’s oeuvre and its problematic relationships with classical tradition serve in my paper as an illustration of the diverse approaches, methods, and styles of lecture concerning the nature of literary allusivity. As a point of departure in the paper has been taken the reflection on the common phrase about “antiquity in something” deployed broadly in the reception studies. T he questions raised here are as follows: what does precisely “in” mean in that metaphor? O r, to put it in more general terms, when an allusion to another text can be treated as an inherent part of interpretation? Answer to these questions was possible due to U mberto E co’s statements in the well-known dispute relating to the interpretation and overinterpretation; in conclusion I was trying to show that his criterion of textual economy in interpretation justifies somehow (as I believe) the new look on the essential T olkien’s symbol, i.e. the ring of power, as a symbol of the R oman imperial rule. This means (in the context of the translatio imperii and cultural change from pagan to Christian empire) that The Lord of the Rings can be seen in a way as a novelistic version of Augustine’s The City of God.

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One can say that our times are dominated by visual communication. Usually all day long we have been faced by various pictures, visual forms and symbols. According to the subject of the book 'Archaeology-Culture-Ideologies' I found it interesting to pay attention to the problem of visual representation, or better say visual symbols in nowadays communication and culture, their meaning and importance. From this point of view I would like to show the role of archaeologists who discover, interpret or even create some of them. The subject is not new of course, but the most often it is taken into consideration by the scholars who practice in social anthropology or philosophy and quite rarely it appear in studies of archaeologies, especially in Polish tradition. In my opinion the subject concerning visual symbols communication and archaeology arise several important questions that are also valid for the theme of book 'Archaeology-Culture-Ideologies'. The first is socio-cultural role of our discipline, next the danger of political and propaganda misuse of the results of archaeological research and then also commercialisation of the archaeological activities. The problem of visualisation and visual-communication can be the matter of various studies. In my paper from the beginning I would like to present the general view concerning visual symbols and figural motifs and the main ideas and approaches to study them from different humanistic perspectives. Then in my presentation I am going to discuss the question why in our culture the visual symbols and representations became so popular – compare to other ways of human expression, for example verbal symbol communication. I would like to see the problem in historical perspective as well. There are a lot of evidences, which support the statement about the power of visual symbols in history. In ancient times for example Horace in 'Ars Poetica' suggested that human mind usually is much more impressed by eyes than by ears. In my opinion that is quite often in human culture that visual impression is before mental one. Visual representations and symbols are very powerful, they can show and communicate various phenomena, they act immediately and quite often in easily way they can associate. So for archaeological research it could be very important to make some studies concerning the ancient symbols and general iconography and also it would be grateful to make some attempts for the study what kind of potential meaning could have visual symbols. In my paper I can only make some general statement about it. But the most important for the topic is reflection on prehistoric and ancient visual symbols and representation and their presence in contemporary culture. So after some general statements concerning the visual symbols examined from various perspectives finally I would like to point out with support of some examples how ancient and prehistoric visual symbols and images are still used and captured by contemporary culture and what is or should be the role of archaeologists activity concerning this matter.

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The present work examines the beginnings of ancient hermeneutics. More specifically, it discusses the connection between the rise of the practice of allegoresis, on the one hand, and the emergence of the first theory of figurative language, on the other. Thus, this book investigates the specific historical and cultural circumstances that enabled the ancient Greeks not only to discover the possibility of allegorical interpretation, but also to treat figurative language as a philosophical problem. By posing difficulties in understanding the enigmatic sense of various esoteric doctrines, poems, oracles and riddles, figurative language created the context for theoretical reflection on the meaning of these “messages”. Hence, ancient interpreters began to ponder over the nature and functions of figurative (“enigmatic”) language as well as over the techniques of its proper use and interpretation. Although the practice of allegorical interpretation was closely linked to the development of the whole of ancient philosophy, the present work covers only the period from the 6th to the 4th century B.C. It concentrates, then, on the philosophical and cultural consequences of allegoresis in the classical age. The main thesis advocated here has it that the ancient Greeks were in-clined to regard allegory as a cognitive problem rather than merely as a stylistic or a literary one. When searching for the hidden meanings of various esoteric doc-trines, poems, oracles and riddles, ancient interpreters of these “messages” assumed allegory to be the only tool suitable for articulating certain matters. In other words, it was their belief that the use of figurative language resulted from the necessity of expressing things that were otherwise inexpressible. The present work has been organized in the following manner. The first part contains historical and philological discussions that provide the point of departure for more philosophical considerations. This part consists of two introductory chapters. Chapter one situates the practice of allegorical interpretation at the borderline of two different traditions: the rhetorical-grammatical and the hermeneutical. In order to clearly differentiate between the two, chapter one distinguishes between allegory and allegoresis, on the one hand, and allegoresis and exegesis, on the other. While pointing to the conventionality (and even arbitrariness) of such distinctions, the chapter argues, nevertheless, for their heuristic usefulness. The remaining part of chapter one focuses on a historical and philological reconstruction of the most important conceptual tools of ancient hermeneutics. Discussing the semantics of such terms as allēgoría, hypónoia, ainigma and symbolon proves important for at least two crucial reasons. Firstly, it reveals the mutual affinity between allegoresis and divination, i.e., practices that are inherently connected with the need to discover the latent meaning of the “message” in question (whether poem or oracle). Secondly, these philological analyses bring to light the specificity of the ancient understanding of such concepts as allegory or symbol. It goes without saying that antiquity employed these terms in a manner quite disparate from modernity. Chapter one concludes with a discussion of ancient views on the cognitive value of figurative (“enigmatic”) language. Chapter two focuses on the role that allegoresis played in the process of transforming mythos into logos. It is suggested here that it was the practice of allegorical interpretation that made it possible to preserve the traditional myths as an important point of reference for the whole of ancient philosophy. Thus, chapter two argues that the existence of a clear opposition between mythos into logos in Preplatonic philosophy is highly questionable in light of the indisputable fact that the Presocratics, Sophists and Cynics were profoundly convinced about the cognitive value of mythos (this conviction was also shared by Plato and Aristotle, but their attitude towards myth was more complex). Consequently, chapter two argues that in Preplatonic philosophy, myth played a function analogous to the concepts discussed in chapter one (i.e., hidden meanings, enigmas and symbols), for in all these cases, ancient interpreters found tools for conveying issues that were otherwise difficult to convey. Chapter two concludes with a classification of various types of allegoresis. Whilst chapters one and two serve as a historical and philological introduction, the second part of this book concentrates on the close relationship between the development of allegoresis, on the one hand, and the flowering of philosophy, on the other. Thus, chapter three discusses the crucial role that allegorical interpretation came to play in Preplatonic philosophy, chapter four deals with Plato’s highly complex and ambivalent attitude to allegoresis, and chapter five has been devoted to Aristotle’s original approach to the practice of allegorical interpretation. It is evident that allegoresis was of paramount importance for the ancient thinkers, irrespective of whether they would value it positively (Preplatonic philosophers and Aristotle) or negatively (Plato). Beginning with the 6th century B.C., the ancient practice of allegorical interpretation is motivated by two distinct interests. On the one hand, the practice of allegorical interpretation reflects the more or less “conservative” attachment to the authority of the poet (whether Homer, Hesiod or Orpheus). The purpose of this apologetic allegoresis is to exonerate poetry from the charges leveled at it by the first philosophers and, though to a lesser degree, historians. Generally, these allegorists seek to save the traditional paideia that builds on the works of the poets. On the other hand, the practice of allegorical interpretation reflects also the more or less “progressive” desire to make original use of the authority of the poet (whether Homer, Hesiod or Orpheus) so as to promote a given philosophical doctrine. The objective of this instrumental allegoresis is to exculpate philosophy from the accusations brought against it by the more conservative circles. Needless to say, these allegorists significantly contribute to the process of the gradual replacing of the mythical view of the world with its more philosophical explanation. The present book suggests that it is the philosophy of Aristotle that should be regarded as a sort of acme in the development of ancient hermeneutics. The reasons for this are twofold. On the one hand, the Stagirite positively values the practice of allegoresis, rehabilitating, thus, the tradition of Preplatonic philosophy against Plato. And, on the other hand, Aristotle initiates the theoretical reflection on figurative (“enigmatic”) language. Hence, in Aristotle we encounter not only the practice of allegoresis, but also the theory of allegory (although the philosopher does not use the term allēgoría). With the situation being as it is, the significance of Aristotle’s work cannot be overestimated. First of all, the Stagirite introduces the concept of metaphor into the then philosophical considerations. From that moment onwards, the phenomenon of figurative language becomes an important philosophical issue. After Aristo-tle, the preponderance of thinkers would feel obliged to specify the rules for the appropriate use of figurative language and the techniques of its correct interpretation. Furthermore, Aristotle ascribes to metaphor (and to various other “excellent” sayings) the function of increasing and enhancing our knowledge. Thus, according to the Stagirite, figurative language is not only an ornamental device, but it can also have a significant explanatory power. Finally, Aristotle observes that figurative expressions cause words to become ambiguous. In this context, the philosopher notices that ambiguity can enrich the language of a poet, but it can also hinder a dialectical discussion. Accordingly, Aristotle is inclined to value polysemy either positively or negatively. Importantly, however, the Stagirite is perfectly aware of the fact that in natural languages ambiguity is unavoidable. This is why Aristotle initiates a syste-matic reflection on the phenomenon of ambiguity and distinguishes its various kinds. In Aristotle, ambiguity is, then, both a problem that needs to be identified and a tool that can help in elucidating intricate philosophical issues. This unique approach to ambiguity and figurative (“enigmatic”) language enabled Aristotle to formulate invaluable intuitions that still await appropriate recognition.

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Dissertação apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Arquitetura e Urbanismo

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A quantum Monte Carlo algorithm is constructed starting from the standard perturbation expansion in the interaction representation. The resulting configuration space is strongly related to that of the Stochastic Series Expansion (SSE) method, which is based on a direct power series expansion of exp(-beta*H). Sampling procedures previously developed for the SSE method can therefore be used also in the interaction representation formulation. The new method is first tested on the S=1/2 Heisenberg chain. Then, as an application to a model of great current interest, a Heisenberg chain including phonon degrees of freedom is studied. Einstein phonons are coupled to the spins via a linear modulation of the nearest-neighbor exchange. The simulation algorithm is implemented in the phonon occupation number basis, without Hilbert space truncations, and is exact. Results are presented for the magnetic properties of the system in a wide temperature regime, including the T-->0 limit where the chain undergoes a spin-Peierls transition. Some aspects of the phonon dynamics are also discussed. The results suggest that the effects of dynamic phonons in spin-Peierls compounds such as GeCuO3 and NaV2O5 must be included in order to obtain a correct quantitative description of their magnetic properties, both above and below the dimerization temperature.

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A method called "SymbolDesign" is proposed that can be used to design user-centered interfaces for pen-based input devices. It can also extend the functionality of pointer input devices such as the traditional computer mouse or the Camera Mouse, a camera-based computer interface. Users can create their own interfaces by choosing single-stroke movement patterns that are convenient to draw with the selected input device and by mapping them to a desired set of commands. A pattern could be the trace of a moving finger detected with the Camera Mouse or a symbol drawn with an optical pen. The core of the SymbolDesign system is a dynamically created classifier, in the current implementation an artificial neural network. The architecture of the neural network automatically adjusts according to the complexity of the classification task. In experiments, subjects used the SymbolDesign method to design and test the interfaces they created, for example, to browse the web. The experiments demonstrated good recognition accuracy and responsiveness of the user interfaces. The method provided an easily-designed and easily-used computer input mechanism for people without physical limitations, and, with some modifications, has the potential to become a computer access tool for people with severe paralysis.

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For pt. I see ibid., vol. 44, p. 927-36 (1997). In a digital communications system, data are transmitted from one location to another by mapping bit sequences to symbols, and symbols to sample functions of analog waveforms. The analog waveform passes through a bandlimited (possibly time-varying) analog channel, where the signal is distorted and noise is added. In a conventional system the analog sample functions sent through the channel are weighted sums of one or more sinusoids; in a chaotic communications system the sample functions are segments of chaotic waveforms. At the receiver, the symbol may be recovered by means of coherent detection, where all possible sample functions are known, or by noncoherent detection, where one or more characteristics of the sample functions are estimated. In a coherent receiver, synchronization is the most commonly used technique for recovering the sample functions from the received waveform. These sample functions are then used as reference signals for a correlator. Synchronization-based coherent receivers have advantages over noncoherent receivers in terms of noise performance, bandwidth efficiency (in narrow-band systems) and/or data rate (in chaotic systems). These advantages are lost if synchronization cannot be maintained, for example, under poor propagation conditions. In these circumstances, communication without synchronization may be preferable. The theory of conventional telecommunications is extended to chaotic communications, chaotic modulation techniques and receiver configurations are surveyed, and chaotic synchronization schemes are described

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This thesis explores the evolution of kingship in early medieval Ireland (AD 400–1150) through a kingdom based and multi-scalar approach to royal landscapes. Through exploring the role of place and landscape in the construction of early medieval Irish kingship, this study will assess the relationship between the social, economic and ideological roles of the king in Irish society. Kingship in Ireland was vested in places, such that royal landscapes were the pre-eminent symbol of regality and authority. As such, an interdisciplinary study of kingship grounded in archaeological methodologies has a unique potential to contribute to our knowledge of the practice of kingship. Consequently, this research considers the material apparatus of different scales of kingships and explores the role of landscape in the construction of kingship and the evolution of kingdoms. It takes two major case studies; (i) Cashel, Munster and the Éoganachta federation; and (ii) the Uí Néill, Tara and the Síl nÁedo Sláine kingdom of Brega. Through interdisciplinary methodologies it charts the genesis and development of political federations, focusing specifically on the role that royal landscapes’ played in their evolution. Similarly, this thesis engages critically with the nature of assembly places and practices in Ireland, and focuses specifically on issues pertaining to the nature of assembly and the archaeological manifestation of such practices. It includes a list of 115 landscapes identified as assembly places, and through the analysis of this material, this thesis examines the ways in which different types of royal sites articulated together to create royal landscapes implicated in the exercise of kingship, and the construction and maintenance of authority. Moreover, through the analysis of assembly places within the context of the development of kingdoms, and structures of jurisdiction and administration, it also investigates the evolution of supra-regional scales of identity and community associated with the emergence of major political federations in early medieval Ireland.

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The demand for optical bandwidth continues to increase year on year and is being driven primarily by entertainment services and video streaming to the home. Current photonic systems are coping with this demand by increasing data rates through faster modulation techniques, spectrally efficient transmission systems and by increasing the number of modulated optical channels per fibre strand. Such photonic systems are large and power hungry due to the high number of discrete components required in their operation. Photonic integration offers excellent potential for combining otherwise discrete system components together on a single device to provide robust, power efficient and cost effective solutions. In particular, the design of optical modulators has been an area of immense interest in recent times. Not only has research been aimed at developing modulators with faster data rates, but there has also a push towards making modulators as compact as possible. Mach-Zehnder modulators (MZM) have proven to be highly successful in many optical communication applications. However, due to the relatively weak electro-optic effect on which they are based, they remain large with typical device lengths of 4 to 7 mm while requiring a travelling wave structure for high-speed operation. Nested MZMs have been extensively used in the generation of advanced modulation formats, where multi-symbol transmission can be used to increase data rates at a given modulation frequency. Such nested structures have high losses and require both complex fabrication and packaging. In recent times, it has been shown that Electro-absorption modulators (EAMs) can be used in a specific arrangement to generate Quadrature Phase Shift Keying (QPSK) modulation. EAM based QPSK modulators have increased potential for integration and can be made significantly more compact than MZM based modulators. Such modulator designs suffer from losses in excess of 40 dB, which limits their use in practical applications. The work in this thesis has focused on how these losses can be reduced by using photonic integration. In particular, the integration of multiple lasers with the modulator structure was considered as an excellent means of reducing fibre coupling losses while maximising the optical power on chip. A significant difficultly when using multiple integrated lasers in such an arrangement was to ensure coherence between the integrated lasers. The work investigated in this thesis demonstrates for the first time how optical injection locking between discrete lasers on a single photonic integrated circuit (PIC) can be used in the generation of coherent optical signals. This was done by first considering the monolithic integration of lasers and optical couplers to form an on chip optical power splitter, before then examining the behaviour of a mutually coupled system of integrated lasers. By operating the system in a highly asymmetric coupling regime, a stable phase locking region was found between the integrated lasers. It was then shown that in this stable phase locked region the optical outputs of each laser were coherent with each other and phase locked to a common master laser.

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This dissertation examines the role of communications technology in social change. It examines secondary data on contemporary China arguing that many interpretations of events in China are unsuitable at best and at worst conceptually damages our understanding of social change in China. This is especially the case in media studies under the ‘democratic framework’. It proposes that there is an alternative framework in studying the media and social change. This alternative conceptual framework is termed a zone of interpretative development offering a means by which to discuss events that take place in a mediated environment. Taking a theoretical foundation using the philosophy of Mikhail Bakhtin this dissertation develops a platform with which to understand communication technology from an anthropological perspective. Three media events from contemporary China are examined. The first examines the Democracy Wall event and the implications of using a public sphere framework. The second case examines the phenomenon of the Grass Mud Horse, a symbol that has gained popular purchase as a humorous expression of political dissatisfaction and develops the problems seen in the first case but with some solutions. Using a modification of Lev Vygotskiĭ’s zone of proximal development this symbol is understood as an expression of the collective recognition of a shared experience. In the second example from the popular TV talent show contests in China further expressions of collective experience are introduced. With the evidence from these media events in contemporary China this dissertation proposes that we can understand certain modes of communication as occurring in a zone of interpretative development. This proposed anthropological feature of social change via communication and technology can fruitfully describe meaning-formation in society via the expression and recognition of shared experiences.

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Recently, a number of investigators have examined the neural loci of psychological processes enabling the control of visual spatial attention using cued-attention paradigms in combination with event-related functional magnetic resonance imaging. Findings from these studies have provided strong evidence for the involvement of a fronto-parietal network in attentional control. In the present study, we build upon this previous work to further investigate these attentional control systems. In particular, we employed additional controls for nonattentional sensory and interpretative aspects of cue processing to determine whether distinct regions in the fronto-parietal network are involved in different aspects of cue processing, such as cue-symbol interpretation and attentional orienting. In addition, we used shorter cue-target intervals that were closer to those used in the behavioral and event-related potential cueing literatures. Twenty participants performed a cued spatial attention task while brain activity was recorded with functional magnetic resonance imaging. We found functional specialization for different aspects of cue processing in the lateral and medial subregions of the frontal and parietal cortex. In particular, the medial subregions were more specific to the orienting of visual spatial attention, while the lateral subregions were associated with more general aspects of cue processing, such as cue-symbol interpretation. Additional cue-related effects included differential activations in midline frontal regions and pretarget enhancements in the thalamus and early visual cortical areas.

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We present a theory of hypoellipticity and unique ergodicity for semilinear parabolic stochastic PDEs with "polynomial" nonlinearities and additive noise, considered as abstract evolution equations in some Hilbert space. It is shown that if Hörmander's bracket condition holds at every point of this Hilbert space, then a lower bound on the Malliavin covariance operatorμt can be obtained. Informally, this bound can be read as "Fix any finite-dimensional projection on a subspace of sufficiently regular functions. Then the eigenfunctions of μt with small eigenvalues have only a very small component in the image of Π." We also show how to use a priori bounds on the solutions to the equation to obtain good control on the dependency of the bounds on the Malliavin matrix on the initial condition. These bounds are sufficient in many cases to obtain the asymptotic strong Feller property introduced in [HM06]. One of the main novel technical tools is an almost sure bound from below on the size of "Wiener polynomials," where the coefficients are possibly non-adapted stochastic processes satisfying a Lips chitz condition. By exploiting the polynomial structure of the equations, this result can be used to replace Norris' lemma, which is unavailable in the present context. We conclude by showing that the two-dimensional stochastic Navier-Stokes equations and a large class of reaction-diffusion equations fit the framework of our theory.

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El presente trabajo tiene como objetivo dar a conocer a los educadores matemáticos y a los etnomatemáticos la existencia y la labor que ha desempeñado, en sus primeros cinco años, la Red Latinoamericana de Etnomatemática (RELAET) en América Latina, en la conformación y consolidación de una comunidad académica interesada en los aspectos sociales y culturales de la Educación Matemática.

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En este artículo, presento las ideas del profesor Ubiratan D’Ambrosio sobre la Etnomatemática, sus objetivos, su metodología, la relación entre Etnomatemática y Educación Matemática, la enseñanza de las matemáticas en aulas multiculturales, y sus comentarios sobre una caracterización de los trabajos de investigación en Etnomatemática realizados en Colombia. Caracterización publicada en: Blanco, H. La Etnomatemática en Colombia. Un programa en construcción. BOLEMA, año 19, No. 26. 2006. Esta entrevista fue realizada el sábado, 20 de marzo de 2004 en el VI Congreso de Historia de las Ciencias y la Tecnología. Buenos Aires, Argentina.