Is the P300 Speller Independent?

The P300 speller is being considered as an independent brain-computer interface. That means it measures the user's intent, and does not require the user to move any muscles. In particular it should not require eye fixation of the desired character. However, it has been shown that posterior electrodes provide significant discriminative information, which is likely related to visual processing. These findings imply the need for studies controlling the effect of eye movements. In experiments with a 3x3 character matrix, attention and eye fixation was directed to different characters. In the event-related potentials, a P300 occurred for the attended character, and N200 was seen for the trials showing the focussed character. It occurred at posterior sites, reaching its peak at 200ms after stimulus onset. The results suggest that gaze direction plays an important role in P300 speller paradigm. By controlling gaze direction it is possible to separate voluntary and involuntary EEG responses to the highlighting of characters.Comment: 7 pages, 5 figure

Functional Demand Satiation and Industrial Dynamcis - The Emergence of the Global Value Chain for the U.S. Footwear Industry

Around 1940 Schumpeter draws on an analysis of the U.S. footwear industry as an exemplar case to formulate his famous hypothesis about the positive relation between market concentration and innovative activity. Starting in the 1970s the value chain of U.S. footwear producers disintegrates, eventually separating the process of product innovation from manufacturing in this industry. Studies testing Schumpeter’s hypothesis commonly do not account for the modularity and globalization of an industry’s value chain. Schumpeter having neglected the demand side in his theorizing, we argue that the separation of product innovation and manufacturing in the U.S. footwear industry is influenced by functional satiation effects on demand. If the functional requirements of consumers are met, their willingness to pay for ever more product varieties decreases. Since the early 1970s the ‘oversupply’ of new product varieties and the simultaneously decreasing price level drive market growth beyond functional satiation (Frenzel Baudisch, 2006b). In this paper we argue that this simultaneous price and innovation competition separates the product innovation process from manufacturing to gain economies in both of these processes simultaneously. Discussing the consumers’ motivations to buy products beyond their functional requirements offers a deeper qualitative understanding of the business practices revealed in the historical case of the U.S. footwear industry.Industrial organization, Schumpeter hypothesis, Modular Value Chain, Consumer Behavior, Footwear Industry

Matrix Product State Representation without explicit local Hilbert Space Truncation with Applications to the Sub-Ohmic Spin-Boson Model

We present an alternative to the conventional matrix product state representation, which allows us to avoid the explicit local Hilbert space truncation many numerical methods employ. Utilising chain mappings corresponding to linear and logarithmic discretizations of the spin-boson model onto a semi-infinite chain, we apply the new method to the sub-ohmic SBM. We are able to reproduce many well-established features of the quantum phase transition, such as the critical exponent 1/2 predicted by mean-field theory. Via extrapolation of finite-chain results, we are able to determine the infinite-chain critical couplings at which the transition occurs and, in general, study the behaviour of the system well into the localised phase.Comment: 8 pages, 8 figure

A gradient system with a wiggly energy and relaxed EDP-convergence

If gradient systems depend on a microstructure, we want to derive a macroscopic gradient structure describing the effective behavior of the microscopic effects. We introduce a notion of evolutionary Gamma-convergence that relates the microscopic energy and the microscopic dissipation potential with their macroscopic limits via Gamma-convergence. This new notion generalizes the concept of EDP-convergence, which was introduced in arXiv:1507.06322, and is called "relaxed EDP-convergence". Both notions are based on De Giorgi's energy-dissipation principle, however the special structure of the dissipation functional in terms of the primal and dual dissipation potential is, in general, not preserved under Gamma-convergence. By investigating the kinetic relation directly and using general forcings we still derive a unique macroscopic dissipation potential. The wiggly-energy model of James et al serves as a prototypical example where this nontrivial limit passage can be fully analyzed.Comment: 43 pages, 8 figure

LifeWatch – A European e-Science and observatory infrastructure supporting access and use of biodiversity and ecosystem data

There are many promising earth and biodiversity-monitoring projects underway across the globe, but they often operate in information islands, unable easily to share data with others. This is not convenient: It is a barrier to scientists collaborating on complex, cross-disciplinary projects which is an essential nature of biodiversity research. 

LifeWatch (www.lifewatch.eu) is an ESFRI (European Strategy Forum on Research Infrastructures) initiative which has just entered its construction phase. It is aiming at new ways of collaboration, in an open-access research environment to solve complex societal and scientific questions on biodiversity and ecosystems. It installs a range of new services and tools to help the researchers communicate, share data, create models, analyze results, manage projects and organize the community. The power of LifeWatch comes from linking all kinds of biodiversity related databases (e.g. collections, long-term monitoring data) to tools for analysis and modeling, opening entirely new avenues for research with the potential for new targeted data generation. At this level the interface with national data repositories becomes most important, as this opens the opportunity for users to gain advantage from data availability on the European level. LifeWatch will provide common methods to discover, access, and develop available and new data, analytical capabilities, and to catalog everything, to track citation and re-use of data, to annotate, and to keep the system secure. This includes computing tool-kits for researchers: for instance, an interoperable computing environment for statistical analysis, cutting-edge software to manage the workflow in scientific projects, and access to new or existing computing resources. The result: ‘e-laboratories’ or virtual labs, through which researchers distributed across countries, time zones and disciplines can collaborate. With emphasis on the open sharing of data and workflows (and associated provenance information) the infrastructure allows scientists to create e-laboratories across multiple organizations, controlling access where necessary

Can slum tourism reverse the plight of Johannesburg’s marginalised communities?

As slum tourism takes off in inner city Johannesburg, Fabian Frenzel asks whether it is enough to break the cycle of advanced urban marginality.This post is part of our joint series with the Africa at LSE blog on Social Development Challenges for Africa

Inert gas accumulation in sonoluminescing bubbles

In this paper we elaborate on the idea [Lohse et al., Phys. Rev. Lett. 78, 1359-1362 (1997)] that (single) sonoluminescing air bubbles rectify argon. The reason for the rectification is that nitrogen and oxygen dissociate and their reaction products dissolve in water. We give further experimental and theoretical evidence and extend the theory to other gas mixtures. We show that in the absence of chemical reactions (e.g., for inert gas mixtures) gas accumulation in strongly acoustically driven bubbles can also occur.Comment: J. Chem. Phys., in press (to appear in November 1997), 30 pages, 15 eps-figure

UN INDICADOR PARA LA EVALUACION ORGANIZACIONAL

La universidad genera conocimiento, investigación, extensión y asistencia a la sociedad. En el marco de la acreditación de carreras se plantea la necesidad de adoptar estándares e indicadores de medición del rendimiento de instituciones educativas. Estos parámetros cuantificables son claros y consensuados por los organismos intervinientes. Cuando se requiere medir la calidad de la institución como organización gestora de conocimiento, tales indicadores son insuficientes. Se propone el concepto de emergía para medir la calidad de gestión del conocimiento institucional, considerando que es la energía invertida, insumida y generada, para producir bienes y servicios de la sociedad a partir de la combinación de diferentes formas de energía, su proceso de incorporación y su uso. Se usa el concepto de tasa de transformación de energía y se propone la creación de una unidad de medida. Con estos conceptos se analizará una institución a partir de los elementos concurrentes y de las relaciones que entre ellos se establecen: estudiantes, profesores, no docentes, además edificio, muebles y equipamiento, la experiencia de sus cuerpos docente y de investigación, el conocimiento remanente en las actividades que se desarrollan, las metodologías usadas en cada grupo y espacio curricular, los procedimientos administrativos, entre otros