Suchergebnisse

In this paper, a cognitive radio (CR) scenario comprised of a secondary interference channel (IC) and a primary point-to-point link (PPL) is studied, when the former interferes the latter. In order to satisfy a given rate requirement at the PPL, typical approaches impose an interference temperature constraint (IT).When the PPL transmits multiple streams, however, the spatial structure of the interference comes into play. In such cases, we show that spatial interference shaping constraints can provide higher sum-rate performance to the IC while ensuring the required rate at the PPL. Then, we extend the interference leakage minimization algorithm (MinIL) to incorporate such constraints. An additional power control step is included in the optimization procedure to improve the sum-rate when the interference alignment (IA) problem becomes infeasible due to the additional constraint. Numerical examples are provided to illustrate the effectiveness of the spatial shaping constraint in comparison to IT when the PPL transmits multiple data streams. ; The research leading to these results has received funding from the Spanish Government (MICINN) under projects TEC2010-19545-C04-03 (COSIMA), CONSOLIDER-INGENIO 2010 CSD2008-00010 (COMONSENS), and FPU Grant AP2010-2189. This research has been funded by the Deutsche Forschungsgemeinschaft (DFG) under the grant Ut36/15-1.

Increasingly, the images we regard as authoritative – those with a seem - ingly direct relation to the "˜truth' of our brains, profiling our identities, or mapping our universe – are not generated optically. They are composed out of other media, notably sonic and electromagnetic materialities, and other processes, primarily algebraic and statistical transforms. In actuality they are transmaterial assemblages. Yet such heterogeneous image enti - ties continue to command the epistemological privilege of indexicality that light-based images previously claimed. If the scientific, authoritative image is already constituted "˜transgenically, ' what implication does this have for interference as a viable aesthetic strategy? To what extent can artists and cultural producers visually interfere with the politics and ethics of such im - aging practices? This article suggests that we should abandon the strategy of interference as intervention in favour of a better understanding of in - terference as pattern, indeed fabric, subtending many contemporary non - visual imaging practices. I argue for a transversal diagrammatic approach to the nonvisual image; to diagramming as both a holding together and a dynamic deformation of images into new assemblages. In turn, such dia - grammatic practices reflexively remind us that what we see as fixed and authoritative images are instead processual, virtual and speculative modes of "˜viewing' and engaging life.

Alternating minimization and steepest descent are commonly used strategies to obtain interference alignment (IA) solutions in the K-user multiple-input multiple-output (MIMO) interference channel (IC). Although these algorithms are shown to converge monotonically, they experience a poor convergence rate, requiring an enormous amount of iterations which substantially increases with the size of the scenario. To alleviate this drawback, in this letter we resort to the Gauss-Newton (GN) method, which is well-known to experience quadratic convergence when the iterates are sufficiently close to the optimum. We discuss the convergence properties of the proposed GN algorithm and provide several numerical examples showing that it always converges to the optimum with quadratic rate, reducing dramatically the required computation time in comparison to other algorithms, hence paving a new way for the design of IA algorithms. ; The authors were supported by the Spanish Government (MICINN) under projects TEC2010-19545-C04-03 (COSIMA), CONSOLIDER-INGENIO 2010 CSD2008-00010 (COMONSENS) and FPU grants AP2009-1105 and AP2010-2189.

We consider the design of an image representation that embeds and aggregates a set of local descriptors into a single vector. Popular representations of this kind include the bag-of-visual-words, the Fisher vector and the VLAD. When two such image representations are compared with the dot-product, the image-to-image similarity can be interpreted as a match kernel. In match kernels, one has to deal with interference, i.e., with the fact that even if two descriptors are unrelated, their matching score may contribute to the overall similarity. We formalise this problem and propose two related solutions, both aimed at equalising the individual contributions of the local descriptors in the final representation. These methods modify the aggregation stage by including a set of per-descriptor weights. They differ by the objective function that is optimised to compute those weights. The first is a "democratisation" strategy that aims at equalising the relative importance of each descriptor in the set comparison metric. The second one involves equalising the match of a single descriptor to the aggregated vector. These concurrent methods give a substantial performance boost over the state of the art in image search with short or mid-size vectors, as demonstrated by our experiments on standard public image retrieval benchmarks.

Powerful entanglements and meanings of difference between machines and humans, designers and users, women and men become enacted in technical devices. Is there a potential for an emancipatory interference with industrial machines, their users and their designers? To answer this question, this paper develops a theoretical account from a feminist new materialist perspective on phenomena as political objects, machines as material agents, and gender as a material-discursive practice. To exemplify the theoretical claim, findings from an interdisciplinary research and development project are presented and discussed. Thereby, I argue for emancipatory interferences with machines on three levels. First, emancipatory interferences take place in the everyday "intra-action" between professional users and their machines with regard to the production of goods and thus gainful (self-) employment. Second, emancipatory interferences occur within collaborative research of these practices, and intervene in the apparatus of that research. Third, emancipatory interferences occur in the machine design process by enacting heterogeneous processes of experiencing and knowing that are diversely situated within both practices and practitioners in the workplace. I demonstrate how the project supported transformative becomings in the situated production of knowledge and items created with industrial machines.

Previous psycholinguistics studies have shown that when forming a long distance dependency in online processing, the parser sometimes accepts a sentence even though the required grammatical constraints are only partially met. A mechanistic account of how such errors arise sheds light on both the underlying linguistic representations involved and the processing mechanisms that put such representations together. In the current study, we contrast the negative polarity items (NPI) interference effect, as shown by the acceptance of an ungrammatical sentence like "The bills that democratic senators have voted for will ever become law," with the well-known phenomenon of agreement attraction ("The key to the cabinets are … "). On the surface, these two types of errors look alike and thereby can be explained as being driven by the same source: similarity based memory interference. However, we argue that the linguistic representations involved in NPI licensing are substantially different from those of subject-verb agreement, and therefore the interference effects in each domain potentially arise from distinct sources. In particular, we show that NPI interference at least partially arises from pragmatic inferences. In a self-paced reading study with an acceptability judgment task, we showed NPI interference was modulated by participants' general pragmatic communicative skills, as quantified by the Autism-Spectrum Quotient (AQ, Baron-Cohen et al., 2001), especially in offline tasks. Participants with more autistic traits were actually less prone to the NPI interference effect than those with fewer autistic traits. This result contrasted with agreement attraction conditions, which were not influenced by individual pragmatic skill differences. We also show that different NPI licensors seem to have distinct interference profiles. We discuss two kinds of interference effects for NPI licensing: memory-retrieval based and pragmatically triggered.