917 resultados para linguistic interference


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In this dissertation I study language complexity from a typological perspective. Since the structuralist era, it has been assumed that local complexity differences in languages are balanced out in cross-linguistic comparisons and that complexity is not affected by the geopolitical or sociocultural aspects of the speech community. However, these assumptions have seldom been studied systematically from a typological point of view. My objective is to define complexity so that it is possible to compare it across languages and to approach its variation with the methods of quantitative typology. My main empirical research questions are: i) does language complexity vary in any systematic way in local domains, and ii) can language complexity be affected by the geographical or social environment? These questions are studied in three articles, whose findings are summarized in the introduction to the dissertation. In order to enable cross-language comparison, I measure complexity as the description length of the regularities in an entity; I separate it from difficulty, focus on local instead of global complexity, and break it up into different types. This approach helps avoid the problems that plagued earlier metrics of language complexity. My approach to grammar is functional-typological in nature, and the theoretical framework is basic linguistic theory. I delimit the empirical research functionally to the marking of core arguments (the basic participants in the sentence). I assess the distributions of complexity in this domain with multifactorial statistical methods and use different sampling strategies, implementing, for instance, the Greenbergian view of universals as diachronic laws of type preference. My data come from large and balanced samples (up to approximately 850 languages), drawn mainly from reference grammars. The results suggest that various significant trends occur in the marking of core arguments in regard to complexity and that complexity in this domain correlates with population size. These results provide evidence that linguistic patterns interact among themselves in terms of complexity, that language structure adapts to the social environment, and that there may be cognitive mechanisms that limit complexity locally. My approach to complexity and language universals can therefore be successfully applied to empirical data and may serve as a model for further research in these areas.

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Leevi Haapala explores moving image works, sculptures and installations from a psychoanalytic perspective in his study The Unconscious in Contemporary Art. The Gaze, Voice and Time in Finnish Contemporary Art at the Turn of the Millennium . The artists included in the study are Eija-Liisa Ahtila, Hans-Christian Berg, Markus Copper, Liisa Lounila and Salla Tykkä. The theoretical framework includes different psychoanalytic readings of the concepts of the gaze, voice and temporality. The installations are based on spatiality and temporality, and their detailed reading emphasizes the medium-specific features of the works as well as their fragmentary nature, heterogeneity and affectivity. The study is cross-disciplinary in that it connects perspectives from the visual culture, new art history and theory to the interpretation of contemporary art. The most important concepts from psychoanalysis, affect theory and trauma discourse used in the study include affect, object a (objet petit a) as articulated by Jacques Lacan, Sigmund Freud s uncanny (das Unheimliche) and trauma. Das Unheimliche has been translated as uncanny in art history under the influence of Rosalind Krauss. The object of the study, the unconscious in contemporary art, is approached through these concepts. The study focuses on Lacan s additions to the list of partial drives: the gaze and voice as scopic and invocative drives and their interpretations in the studies of the moving image. The texts by the American film theorist and art historian Kaja Silverman are in crucial role. The study locates contemporary art as part of trauma culture, which has a tendency to define individual and historical experiences through trauma. Some of the art works point towards trauma, which may appear as a theoretic or fictitious construction. The study presents a comprehensive collection of different kinds of trauma discourse in the field of art research through the texts of Hal Foster, Cathy Caruth, Ruth Leys and Shoshana Felman. The study connects trauma theory with the theoretical analysis of the interference and discontinuity of the moving image in the readings by Susan Buck-Morss, Mary Ann Doane and Peter Osborn among others. The analysis emphasizes different ways of seeing and multisensoriality in the reception of contemporary art. With their reflections and inverse projections, the surprising mechanisms of Hans-Christian Berg s sculptures are connected with Lacan s views on the early mirroring and imitation attempts of the individual s body image. Salla Tykkä s film trilogy Cave invites one to contemplate the Lacanian theory of the gaze in relation to the experiences of being seen. The three oceanic sculpture installations by Markus Copper are studied through the vocality they create, often through an aggressive way of acting, as well as from the point of view of the functioning of an invocative drive. The study compares the work of fiction and Freud s texts on paranoia and psychosis to Eija-Liisa Ahtila s manuscripts and moving image installations about the same topic. The cinematic time in Liisa Lounila s time-slice video installations is approached through the theoretical study of the unconscious temporal structure. The viewer of the moving image is inside the work in an in-between state: in a space produced by the contents of the work and its technology. The installations of the moving image enable us to inhabit different kinds of virtual bodies or spaces, which do not correspond with our everyday experiences. Nevertheless, the works of art often try to deconstruct the identification to what has been shown on screen. This way, the viewer s attention can be fixed on his own unconscious experiences in parallel with the work s deconstructed nature as representation. The study shows that contemporary art is a central cultural practice, which allows us to discuss the unconscious in a meaningful way. The study suggests that the agency that is discursively diffuse and consists of several different praxes should be called the unconscious. The emergence of the unconscious can happen in two areas: in contemporary art through different senses and discursive elements, and in the study of contemporary art, which, being a linguistic activity is sensitive to the movements of the unconscious. One of the missions of art research is to build different kinds of articulated constructs and to open an interpretative space for the nature of art as an event.

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Asperger Syndrome (AS) belongs to autism spectrum disorders where both verbal and non-verbal communication difficulties are at the core of the impairment. Social communication requires a complex use of affective, linguistic-cognitive and perceptual processes. In the four studies included in the current thesis, some of the linguistic and perceptual factors that are important for face-to-face communication were studied using behavioural methods. In all four studies the results obtained from individuals with AS were compared with typically developed age, gender and IQ matched controls. First, the language skills of school-aged children were characterized in detail with standardized tests that measured different aspects of receptive and expressive language (Study I). The children with AS were found to be worse than the controls in following complex verbal instructions. Next, the visual perception of facial expressions of emotion with varying degrees of visual detail was examined (Study II). Adults with AS were found to have impaired recognition of facial expressions on the basis of very low spatial frequencies which are important for processing global information. Following that, multisensory perception was investigated by looking at audiovisual speech perception (Studies III and IV). Adults with AS were found to perceive audiovisual speech qualitatively differently from typically developed adults, although both groups were equally accurate in recognizing auditory and visual speech presented alone. Finally, the effect of attention on audiovisual speech perception was studied by registering eye gaze behaviour (Study III) and by studying the voluntary control of visual attention (Study IV). The groups did not differ in eye gaze behaviour or in the voluntary control of visual attention. The results of the study series demonstrate that many factors underpinning face-to-face social communication are atypical in AS. In contrast with previous assumptions about intact language abilities, the current results show that children with AS have difficulties in understanding complex verbal instructions. Furthermore, the study makes clear that deviations in the perception of global features in faces expressing emotions as well as in the multisensory perception of speech are likely to harm face-to-face social communication.

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Many of the most intriguing quantum effects are observed or could be measured in transport experiments through nanoscopic systems such as quantum dots, wires and rings formed by large molecules or arrays of quantum dots. In particular, the separation of charge and spin degrees of freedom and interference effects have important consequences in the conductivity through these systems. Charge-spin separation was predicted theoretically in one-dimensional strongly inter-acting systems (Luttinger liquids) and, although observed indirectly in several materials formed by chains of correlated electrons, it still lacks direct observation. We present results on transport properties through Aharonov-Bohmrings (pierced by a magnetic flux) with one or more channels represented by paradigmatic strongly-correlated models. For a wide range of parameters we observe characteristic dips in the conductance as a function of magnetic flux which are a signature of spin and charge separation. Interference effects could also be controlled in certain molecules and interesting properties could be observed. We analyze transport properties of conjugated molecules, benzene in particular, and find that the conductance depends on the lead configuration. In molecules with translational symmetry, the conductance can be controlled by breaking or restoring this symmetry, e.g. by the application of a local external potential. These results open the possibility of observing these peculiar physical properties in anisotropic ladder systems and in real nanoscopic and molecular devices.

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In uplink orthogonal frequency division multiple access (OFDMA) systems, multiuser interference (MUI) occurs due to different carrier frequency offsets (CFO) of different users at the receiver. In this paper, we present a multistage linear parallel interference cancellation (LPIC) approach to mitigate the effect of this MUI in uplink OFDMA. The proposed scheme first performs CFO compensation (in time domain), followed by K DFT operations (where K is the number of users) and multistage LPIC on these DFT outputs. We scale the MUI estimates by weights before cancellation and optimize these weights by maximizing the signal-to-interference ratio (SIR) at the output of the different stages of the LPIC. We derive closed-form expressions for these optimum weights. The proposed LPIC scheme is shown to effectively cancel the MUI caused by the other user CFOs in uplink OFDMA.

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In this paper, we present the design and bit error performance analysis of weighted linear parallel interference cancellers (LPIC) for multicarrier (MC) DS-CDMA systems. We propose an LPIC scheme where we estimate (and cancel) the multiple access interference (MAI) based on the soft outputs on individual subcarriers, and the interference cancelled outputs on different subcarriers are combined to form the final decision statistic. We scale the MAI estimate on individual subcarriers by a weight before cancellation; these weights are so chosen to maximize the signal-to-interference ratios at the individual subcarrier outputs. For this weighted LPIC scheme, using an approach involving the characteristic function of the decision variable, we derive exact bit error rate (BER) expressions for different cancellation stages. Using the same approach, we also derive exact BER expressions for the matched filter (MF) and decorrelating detectors for the considered MC DS-CDMA system. We show that the proposed weighted LPIC scheme performs better than the MF detector and the conventional LPIC (where the weights are taken to be unity), and close to the decorrelating detector.

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Several of the most interesting quantum effects can or could be observed in nanoscopic systems. For example, the effect of strong correlations between electrons and of quantum interference can be measured in transport experiments through quantum dots, wires, individual molecules and rings formed by large molecules or arrays of quantum dots. In addition, quantum coherence and entanglement can be clearly observed in quantum corrals. In this paper we present calculations of transport properties through Aharonov-Bohm strongly correlated rings where the characteristic phenomenon of charge-spin separation is clearly observed. Additionally quantum interference effects show up in transport through pi-conjugated annulene molecules producing important effects on the conductance for different source-drain configurations, leading to the possibility of an interesting switching effect. Finally, elliptic quantum corrals offer an ideal system to study quantum entanglement due to their focalizing properties. Because of an enhanced interaction between impurities localized at the foci, these systems also show interesting quantum dynamical behaviour and offer a challenging scenario for quantum information experiments.

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In the present study, a lug joint fitted with an interference fit (oversized) pin is considered with radial through cracks situated at diametrically opposite points perpendicular to the loading direction. A finite element contact stress algorithm is developed with linear elastic assumptions to deal with varying partial contact/separation at the pin-plate interface using a marching solution. Stress Intensity Factor (SIF) at the crack tips is evaluated using the Modified Crack Closure Integral (MCCI) method. The effect of change in crack length and edge distance on the load-contact relation, SIFs and stress distributions are studied. A rigorous plane stress elasticity solution of the pin-plate interface at the crack mouth confirmed the existence of the stress concentration leading to a local peak in the radial stress at the crack mouth and provided a method of estimating it quantitatively. Copyright (C) 1996 Elsevier Science Ltd.

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Raman experiments have been carried out on single crystals of BaTiO3 as a function of pressure up to 3.5 GPa across the ferroelectric (tetragonal) to paraelectric (cubic) phase transition. The unusual features in the Raman spectra associated with the interference effects due to coupling of the three A1(TO) phonons are studied quantitatively to obtain the pressure dependence of the line shape parameters and the coupling constants. The frequencies of the middle and highest-frequency modes as well as the linewidth of the middle mode show interesting pressure dependence.

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Recently, Guo and Xia gave sufficient conditions for an STBC to achieve full diversity when a PIC (Partial Interference Cancellation) or a PIC-SIC (PIC with Successive Interference Cancellation) decoder is used at the receiver. In this paper, we give alternative conditions for an STBC to achieve full diversity with PIC and PIC-SIC decoders, which are equivalent to Guo and Xia's conditions, but are much easier to check. Using these conditions, we construct a new class of full diversity PIC-SIC decodable codes, which contain the Toeplitz codes and a family of codes recently proposed by Zhang, Xu et. al. as proper subclasses. With the help of the new criteria, we also show that a class of PIC-SIC decodable codes recently proposed by Zhang, Shi et. al. can be decoded with much lower complexity than what is reported, without compromising on full diversity.

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Cavitation-noise measurements from an axisymmetric body with ‘controlled’ generation of cavitation are reported. The control was achieved by seeding artificial nuclei in the boundary layer by electrolysis. It was possible to alter the number density of nuclei by varying the electrolysis voltage, polarity and the geometry of the electrode. From the observed trend of cavitation-noise data it is postulated that there exists an ‘interference effect’ which influences cavitation noise. When the nucleus-number density is high and cavitation numbers are low this effect is strong. Under these conditions the properties of cavitation noise are found to differ considerably from those expected based on theories concerning noise from single-spherical-bubble cavitation.

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Multiple beam interference of light in a wedge is considered when the wedge is filled with an absorbing medium. The aim is to examine a method that may give values of both the real and the imaginary parts of the refractive index of the absorbing medium. We propose here a method to determine these quantities from simple techniques like fringe counting and interferometry, by using as the incident wave either a single Gaussian beam or two parallel Gaussian beams.