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Search Results: 1 - 10 of 404 matches for " Niklas Wilming "
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Measures and Limits of Models of Fixation Selection
Niklas Wilming, Torsten Betz, Tim C. Kietzmann, Peter K?nig
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024038
Abstract: Models of fixation selection are a central tool in the quest to understand how the human mind selects relevant information. Using this tool in the evaluation of competing claims often requires comparing different models' relative performance in predicting eye movements. However, studies use a wide variety of performance measures with markedly different properties, which makes a comparison difficult. We make three main contributions to this line of research: First we argue for a set of desirable properties, review commonly used measures, and conclude that no single measure unites all desirable properties. However the area under the ROC curve (a classification measure) and the KL-divergence (a distance measure of probability distributions) combine many desirable properties and allow a meaningful comparison of critical model performance. We give an analytical proof of the linearity of the ROC measure with respect to averaging over subjects and demonstrate an appropriate correction of entropy-based measures like KL-divergence for small sample sizes in the context of eye-tracking data. Second, we provide a lower bound and an upper bound of these measures, based on image-independent properties of fixation data and between subject consistency respectively. Based on these bounds it is possible to give a reference frame to judge the predictive power of a model of fixation selection . We provide open-source python code to compute the reference frame. Third, we show that the upper, between subject consistency bound holds only for models that predict averages of subject populations. Departing from this we show that incorporating subject-specific viewing behavior can generate predictions which surpass that upper bound. Taken together, these findings lay out the required information that allow a well-founded judgment of the quality of any model of fixation selection and should therefore be reported when a new model is introduced.
Saccadic Momentum and Facilitation of Return Saccades Contribute to an Optimal Foraging Strategy
Niklas Wilming ,Simon Harst,Nico Schmidt,Peter K?nig
PLOS Computational Biology , 2013, DOI: 10.1371/journal.pcbi.1002871
Abstract: The interest in saccadic IOR is funneled by the hypothesis that it serves a clear functional purpose in the selection of fixation points: the facilitation of foraging. In this study, we arrive at a different interpretation of saccadic IOR. First, we find that return saccades are performed much more often than expected from the statistical properties of saccades and saccade pairs. Second, we find that fixation durations before a saccade are modulated by the relative angle of the saccade, but return saccades show no sign of an additional temporal inhibition. Thus, we do not find temporal saccadic inhibition of return. Interestingly, we find that return locations are more salient, according to empirically measured saliency (locations that are fixated by many observers) as well as stimulus dependent saliency (defined by image features), than regular fixation locations. These results and the finding that return saccades increase the match of individual trajectories with a grand total priority map evidences the return saccades being part of a fixation selection strategy that trades off exploration and exploitation.
Signal Enhancements in Plasmon Assisted Fluorescence Ratiometric Imaging Optodes  [PDF]
Niklas Str?mberg
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.31022
Abstract:

The objective of this study was to benchmark the different signal enhancements found in a recently exploited fluorescence ratiometric optode design used for nano-molar imaging of ammonium and ammonia. The sensing scheme of these optodes are based on a mediated transfer of the analyte together with a fluorescent dye in a two-phase system consisting of a gold nanoparticle (GNP) doped ether (organic phase), emulsified in a hydrogel (hydrous phase). The coextraction of the ion dye pair causes changes in fluorescence in relation to the analyte concentration. Performances of optodes with and without GNPs using the gradually improved instrumentation and signal processing were evaluated and normalized to be comparable. Signal to noise was enhanced due to signal processing based on ensemble averaging (1.7× - 3.2×), CCD sensitivity (2×), and plasmon assisted fluorescence (10× - 100×), which altogether with the ratiometric treatment of the fluorescence contributed to the great sensitivity for ammonium and ammonia. The study shows that GNP doped sensors are relatively more sensitive to matrix effects but if they are isolated by a protective layer they will dramatically increase in sensitivity. Proper isolation of the active chemical components from the matrix will make the sensor design one of the most powerful and versatile concepts for chemical imaging and single point detection in complex environments as the optodes likely can be constructed for most ions that have selective ionophores.

Thermodynamic work from operational principles
R. Gallego,J. Eisert,H. Wilming
Physics , 2015,
Abstract: In recent years we have witnessed a concentrated effort to make sense of thermodynamics for small-scale systems. One of the main difficulties is to capture a suitable notion of work that models realistically the purpose of quantum machines, in an analogous way to the role played, for macroscopic machines, by the energy stored in the idealisation of a lifted weight. Despite of several attempts to resolve this issue by putting forward specific models, these are far from capturing realistically the transitions that a quantum machine is expected to perform. In this work, we adopt a novel strategy by considering arbitrary kinds of systems that one can attach to a quantum thermal machine and seeking for work quantifiers. These are functions that measure the value of a transition and generalise the concept of work beyond the model of a lifted weight. We do so by imposing simple operational axioms that any reasonable work quantifier must fulfil and by deriving from them stringent mathematical condition with a clear physical interpretation. Our approach allows us to derive much of the structure of the theory of thermodynamics without taking as a primitive the definition of work. We can derive, for any work quantifier, a quantitative second law in the sense of bounding the work that can be performed using some non-equilibrium resource by the work that is needed to create it. We also discuss in detail the role of reversibility and correlations in connection with the second law. Furthermore, we recover the usual identification of work with energy in degrees of freedom with vanishing entropy as a particular case of our formalism. Our mathematical results can be formulated abstractly and are general enough to carry over to other resource theories than quantum thermodynamics.
Second laws under control restrictions
H. Wilming,R. Gallego,J. Eisert
Physics , 2014,
Abstract: The second law of thermodynamics, formulated as an ultimate bound on the maximum extractable work, has been rigorously derived in multiple scenarios. However, the unavoidable limitations that emerge due to the lack of control on small systems are often disregarded when deriving such bounds, which is specifically important in the context of quantum thermodynamics. Here, we study the maximum extractable work with limited control over the working system and its interaction with the heat bath. We derive a general second law when the set of accessible Hamiltonians of the working-system is arbitrarily restricted. We then apply our bound to particular scenarios that are important in realistic implementations: limitations on the maximum energy gap and local control over many-body systems. We hence demonstrate in what precise way the lack of control affects the second law. In particular, contrary to the unrestricted case, we show that the optimal work extraction is not achieved by simple thermal contacts. Our results do not only generalize the second law to scenarios of practical relevance, but also take first steps in the direction of local thermodynamics.
ACERCA DE LA FUNCIóN EMANCIPATORIA Y EL ESTATUTO CRíTICO DE LA INTERPRETACIóN EN PSICOANáLISIS
Bornhauser,Niklas;
Alpha (Osorno) , 2009, DOI: 10.4067/S0718-22012009002900017
Abstract: psychoanalysis is a plural, multiple and open practice. its dialogue with other disciplines not only constitutes a relevant contribution to the present public debate, but is an indispensable exigency towards its own future as a discourse interested in getting rid of the trusteeship or servitude of established knowledge. in that sense, the exercise of psychoanalysis is bound to the critical practice in its strict sense. this critical function is associated to the corresponding conception of interpretation and the respective interpretative practice. interpretation, insofar as it pretends to be truly revealing, entails the necessity to promote a judicious analysis of the relations of power that condition and contextualize it. a psychoanalytical ethics must consider these elements if it wants to make a contribution to the contemporary debate and particularly to the emancipatory project of which it is part.
Entre la identidad y la diferencia Acerca de la lógica constitutiva del sujeto en el pensar de Jürgen Habermas y Michel Foucault _ una controversia pendiente
Bornhauser,Niklas;
Revista de filosofía , 2006, DOI: 10.4067/S0718-43602006000100007
Abstract: the notion of subject is a multiple, polyvalent, overdetermined concept, in short, a problematic concept. aiming at its clarification the place statute of the subject is discussed starting with the consideration of its respective processes of constitution in so much in jürgen habermas as in michel foucault. it is examined, fundamentally, the relation of the subject toward language and history. by the way of the subjective constitution highly different productive modalities are distinguished, that, at the same time, imply divergent theoretical concepts, causing contrasted subjective modalities, with extremely discordant possibilities and ways of action. recovering certain concepts of the critical theory there is proposed a type of dialogical subjectivity, that collects these differences without annulling them or to ignore them
EU AND RUSSIA IN THE BLACK SEA REGION: INCREASINGLY COMPETING INTERESTS?
Niklas Nilsson
Romanian Journal of European Affairs (RJEA) , 2008,
Abstract: This article examines two fields of geopolitical competition in the Black Sea region, in which an increasing EU involvement is increasingly challenging Russian interests. First, the EU’s effort to diversify its energy sources through new transportation routes is meeting competition in the form of Russian-sponsored projects. The EU has realized the partial incompatibility of Russian and EU interests in this regard; however, the lack of cohesion within the EU prevents the formation of common external energy policies. Second, the EU is increasingly recognizing its interest in engaging with conflict resolution in the region. This also runs contrary to Russian strategy, which strives to maintain the status quo in the conflicts rather than working for solutions, in order to maintain Russian leverage over the South Caucasus and Moldova. In this field, the EU has yet to officially recognize its interest conflict with Russia. However, due to the intertwinement of the conflict resolution processes with the EU’s deeper policy goals in the Black Sea region, namely the promotion of a stable, secure and democratic European neighborhood, the EU will likely find it increasingly difficult to pursue its key interests in the region, while simultaneously maintaining a passive stance towards Russian policies in the region.
"Mediman" – Smartphone als Plattform zum Lernen? ["Mediman" – The smartphone as a learning platform?]
Boeder, Niklas
GMS Zeitschrift für Medizinische Ausbildung , 2013, DOI: 10.3205/zma000848
Abstract: [english] Mobile devices with a connection to the internet – smartphones – are seen all over the place since the popular introduction of the Apple iPhone. Similar products existed but no company managed to combine simplicity and functionality so seamlesly. Their market share increases constantly and web sites get optimised for the small display sizes (often referred to as responsive webdesign“) otherwise the usability lacks. Students seem to like smartphones aswell and a good question is if and to what extend those devices can play a role in e-learning. Mediman“, an adaptation of the common game Hangman has been developed for smartphones. Test users asked to complete an online questionnaire. So far, only few e-learning applications for smartphones seem to exist. This is reflected in the low usage frequency. Especially the fact that most of the test users wear a smartphone with them all the time makes it an ideal learning plattform. Short learning sessions were rated more important than continuous text. The majority of the 11 test users rated Mediman as well developed. The foremost question whether a smartphone e-learning application is feasible must be answered positive – acceptance in the test user group was shown. E-learning applications on smartphones will be an important topic in the future as market shares increase constantly. Further studies are required due to the small number of partitipants in our survey. [german] Mobile Endger te mit Internetzugang (Smartphones) sind seit Apples revolution rer iPhone-Markteinführung nicht mehr aus dem Alltag wegzudenken und erfreuen sich ausgesprochener Beliebtheit. Ihr Marktanteil w chst stetig und Webseitenbetreiber kommen nicht umher, ihre Webseiten an die neuen kleinen Displaygr en und Bedienungstechniken anzupassen – h ufig als Responsive Webdesign“ beschrieben. Anwendungen, die nicht für die Anzeige auf kleinen Bildschirmen optimiert sind, schr nken den Bedienkomfort ein. Auch bei Studierenden sind Smartphones sehr verbreitet und so stellt sich die Frage, ob sie nicht auch als Plattform für Lernanwendungen dienen k nnen. Mediman“, eine Portierung des klassischen Spielprinzips von Galgenm nnchen, wurde für Smartphones entwickelt. Testbenutzer wurden dann gebeten, einen Onlinefragebogen auszufüllen. Zur Zeit scheinen nur wenige Lernanwendungen für Smartphones zu existieren, was sich in der eingeschr nkten Benutzungsh ufigkeit widerspiegelt. Vor allem die Tatsache, dass Smartphone-Besitzer ihre Ger te meist bei sich tragen, wird als ideale Voraussetzung gesehen, die Ger te für Lernanwendungen einzusetzen
Il nostro futuro dipende da decisioni
Niklas Luhmann
Topologik : Rivista Internazionale di Scienze Filosofiche, Pedagogiche e Sociali , 2010,
Abstract:
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