150 research outputs found

    Natural 2HDMs without FCNCs

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    Motivated by the fermion mass hierarchy we study the phenomenology of two flavorful two-Higgs-doublet model (2HDM) scenarios. By virtue of the flavor or singular alignment ansatz it is possible to link the mass of a subset of fermions to the vacuum-expectation-value (VEV) of a unique Higgs doublet and to simultaneously avoid flavor-changing-neutral-currents at tree-level. We explicitly construct two models called Type-A and B. There, either the top quark alone or all third generation fermions couple to the doublet with the larger VEV. The other fermions acquire their masses through the small VEV of the other doublet. Thus, more natural values for the Yukawa couplings can be obtained. The main differences between these models and conventional ones are studied including a discussion of both their structure and phenomenological consequences. In particular, as distinctive deviations for the Yukawa couplings of the light fermions are predicted we discuss possible tests at the LHC based on searches for h→J/Κ+Îłh\to J/\Psi + \gamma, h→ΌΌh\to\mu\mu, and heavy scalar resonances decaying to muon pairs. We find that for a wide region of parameter space this specific set of signatures can be used to distinguish among the new proposed types and the conventional ones

    Automated Planning Techniques for Robot Manipulation Tasks Involving Articulated Objects

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    The goal-oriented manipulation of articulated objects plays an important role in real-world robot tasks. Current approaches typically pose a number of simplifying assumptions to reason upon how to obtain an articulated object’s goal configuration, and exploit ad hoc algorithms. The consequence is two-fold: firstly, it is difficult to generalise obtained solutions (in terms of actions a robot can execute) to different target object’s configurations and, in a broad sense, to different object’s physical characteristics; secondly, the representation and the reasoning layers are tightly coupled and inter-dependent. In this paper we investigate the use of automated planning techniques for dealing with articulated objects manipulation tasks. Such techniques allow for a clear separation between knowledge and reasoning, as advocated in Knowledge Engineering. We introduce two PDDL formulations of the task, which rely on conceptually different representations of the orientation of the objects. Experiments involving several planners and increasing size objects demonstrate the effectiveness of the proposed models, and confirm its exploitability when embedded in a real-world robot software architecture

    Recognising Complex Activities with Histograms of Relative Tracklets

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    One approach to the recognition of complex human activities is to use feature descriptors that encode visual inter-actions by describing properties of local visual features with respect to trajectories of tracked objects. We explore an example of such an approach in which dense tracklets are described relative to multiple reference trajectories, providing a rich representation of complex interactions between objects of which only a subset can be tracked. SpeciïŹcally, we report experiments in which reference trajectories are provided by tracking inertial sensors in a food preparation sce-nario. Additionally, we provide baseline results for HOG, HOF and MBH, and combine these features with others for multi-modal recognition. The proposed histograms of relative tracklets (RETLETS) showed better activity recognition performance than dense tracklets, HOG, HOF, MBH, or their combination. Our comparative evaluation of features from accelerometers and video highlighted a performance gap between visual and accelerometer-based motion features and showed a substantial performance gain when combining features from these sensor modalities. A considerable further performance gain was observed in combination with RETLETS and reference tracklet features

    The Paradox of Being a Teacher: Institutionalized Relevance and Organized Mistrust

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    In the article "The Paradox of Being a Teacher: Institutionalized Relevance and Organized MistrustW Daniel Tröhler describes the paradoxical nature of the teaching profession which arises out of the mismatch between the excessive expectations imposed on teachers and, at the same time, the constant mistrust shown to them for fulfilling these expectations. The paradox is related to the cultural shift of the educationalization of the Western world – that not only are a wide variety of social, economic and moral problems defined as educational problems but, in addition, education itself is placed at the core of the historical process and expected to fulfil future ideals. According to Tröhler, educationalization was reinforced by the tradition of modern educational thinking and especially by certain inherent fundamental religious motives. The author defends this thesis with the help of two, at first sight very divergent, figures in the history of education: Johan Heinrich Pestalozzi and Burrhus F. Skinner. Common to these thinkers is, according to Tröhler, their argument which is constitutive of the cultural shift of educationalization but, also, their shared view that in order to save the younger generation from the corrupting forces of external society, certain ideal conditions for making the natural development of the children possible are needed. Tröhler underlines the religious motives behind this idea. The task of education is to take care of the salvation of the younger generation, to protect the “God’s creation” against the world of artificial moral corruption. The educator’s task is, then, to be God’s deputy, substitute and imitator, to secure the existence of this moral order. This religious background helps us, according to Tröhler, to understand those enormous expectations that schools and teachers meet even in secular contemporary societies. This raises the question: should one reject expectations, which no one can fulfill

    Role and task allocation framework for Multi-Robot Collaboration with latent knowledge estimation

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    In this work a novel framework for modeling role and task allocation in Cooperative Heterogeneous Multi-Robot Systems (CHMRSs) is presented. This framework encodes a CHMRS as a set of multidimensional relational structures (MDRSs). This set of structure defines collaborative tasks through both temporal and spatial relations between processes of heterogeneous robots. These relations are enriched with tensors which allow for geometrical reasoning about collaborative tasks. A learning schema is also proposed in order to derive the components of each MDRS. According to this schema, the components are learnt from data reporting the situated history of the processes executed by the team of robots. Data are organized as a multirobot collaboration treebank (MRCT) in order to support learning. Moreover, a generative approach, based on a probabilistic model, is combined together with nonnegative tensor decomposition (NTD) for both building the tensors and estimating latent knowledge. Preliminary evaluation of the performance of this framework is performed in simulation with three heterogeneous robots, namely, two Unmanned Ground Vehicles (UGVs) and one Unmanned Aerial Vehicle (UAV)

    Non-affirmative Theory of Education as a Foundation for Curriculum Studies, Didaktik and Educational Leadership

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    This chapter presents non-affirmative theory of education as the foundation for a new research program in education, allowing us to bridge educational leadership, curriculum studies and Didaktik. We demonstrate the strengths of this framework by analyzing literature from educational leadership and curriculum theory/didaktik. In contrast to both socialization-oriented explanations locating curriculum and leadership within existing society, and transformation-oriented models viewing education as revolutionary or super-ordinate to society, non-affirmative theory explains the relation between education and politics, economy and culture, respectively, as non-hierarchical. Here critical deliberation and discursive practices mediate between politics, culture, economy and education, driven by individual agency in historically developed cultural and societal institutions. While transformative and socialization models typically result in instrumental notions of leadership and teaching, non-affirmative education theory, previously developed within German and Nordic education, instead views leadership and teaching as relational and hermeneutic, drawing on ontological core concepts of modern education: recognition; summoning to self-activity and Bildsamkeit. Understanding educational leadership, school development and teaching then requires a comparative multi-level approach informed by discursive institutionalism and organization theory, in addition to theorizing leadership and teaching as cultural-historical and critical-hermeneutic activity. Globalisation and contemporary challenges to deliberative democracy also call for rethinking modern nation-state based theorizing of education in a cosmopolitan light. Non-affirmative education theory allows us to understand and promote recognition based democratic citizenship (political, economical and cultural) that respects cultural, ethical and epistemological variations in a globopolitan era. We hope an American-European-Asian comparative dialogue is enhanced by theorizing education with a non-affirmative approach

    Open-EASE: A Cloud-Based Knowledge Service for Autonomous Learning

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    What constitutes the perfect research environment?

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    Centralization versus Decentralization in University Management

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