524 research outputs found

    Local-based semantic navigation on a networked representation of information

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    The size and complexity of actual networked systems hinders the access to a global knowledge of their structure. This fact pushes the problem of navigation to suboptimal solutions, one of them being the extraction of a coherent map of the topology on which navigation takes place. In this paper, we present a Markov chain based algorithm to tag networked terms according only to their topological features. The resulting tagging is used to compute similarity between terms, providing a map of the networked information. This map supports local-based navigation techniques driven by similarity. We compare the efficiency of the resulting paths according to their length compared to that of the shortest path. Additionally we claim that the path steps towards the destination are semantically coherent. To illustrate the algorithm performance we provide some results from the Simple English Wikipedia, which amounts to several thousand of pages. The simplest greedy strategy yields over an 80% of average success rate. Furthermore, the resulting content-coherent paths most often have a cost between one- and threefold compared to shortest-path lengths.The authors acknowledge financial support through Grant No. FIS2008-01240, FIS2009-13364-C02-01, Holopedia (Grant No. TIN2010-21128-C02-01), MOSAICO (Grant No. FIS2006-01485), PRODIEVO (Grant No. FIS2011-22449), and Complexity-NET RESINEE, all of them from Ministerio de Educacion y Ciencia in Spain, as well as support from Research Networks MODELICO-CM (Grant No. S2009/ESP-1691) and MA2VICMR (Grant NÂş. S2009/TIC-1542) from Comunidad de Madrid, and Network 2009-SGR-838 from Generalitat de Catalunya. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Information measures and cognitive limits in multilayer navigation

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    Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder if it is possible to quantitatively characterize our difficulty to navigate in them and whether such navigation exceeds our cognitive limits. A transition between different searching strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of another limit associated to the cognitive overload and caused by large amounts of information to process. In this light, we analyzed the world's 15 largest metropolitan networks and estimated the information limit for determining a trip in a transportation system to be on the order of 8 bits. Similar to the "Dunbar number," which represents a limit to the size of an individual's friendship circle, our cognitive limit suggests that maps should not consist of more than about 250250 connections points to be easily readable. We also show that including connections with other transportation modes dramatically increases the information needed to navigate in multilayer transportation networks: in large cities such as New York, Paris, and Tokyo, more than 80%80\% of trips are above the 8-bit limit. Multimodal transportation systems in large cities have thus already exceeded human cognitive limits and consequently the traditional view of navigation in cities has to be revised substantially.Comment: 16 pages+9 pages of supplementary materia

    Planar growth generates scale free networks

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    In this paper we introduce a model of spatial network growth in which nodes are placed at randomly selected locations on a unit square in R2\mathbb{R}^2, forming new connections to old nodes subject to the constraint that edges do not cross. The resulting network has a power law degree distribution, high clustering and the small world property. We argue that these characteristics are a consequence of the two defining features of the network formation procedure; growth and planarity conservation. We demonstrate that the model can be understood as a variant of random Apollonian growth and further propose a one parameter family of models with the Random Apollonian Network and the Deterministic Apollonian Network as extreme cases and our model as a midpoint between them. We then relax the planarity constraint by allowing edge crossings with some probability and find a smooth crossover from power law to exponential degree distributions when this probability is increased.Comment: 27 pages, 9 figure

    Meta-analysis of Research and Innovation Strategies for Smart Specialisation: Priorities and Policy Measures

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    This report presents a review and elaboration of meta-analysis of Research and Innovation Strategies for Smart Specialisation (RIS3), focusing on the priorities identified by regions/countries, and policy measures at regional and national level. The first part of the report presents the key findings of a structured dialogue with experienced practitioners from across Europe. It benefits from a methodology of structured interactions with regional and national policymakers, across time, adapting and pursuing a cohort-type approach. It has also relied on results of a Smart Specialisation Platform (S3 Platform) survey of policymakers. On the one hand, analysis has brought new dimensions to the fore. First, coherent policy road-mapping, fostering regional economic transformation, emerged as a pivotal issue that deserves more attention. Regardless of the label used (policy road-mapping, techno-economic road-mapping, regional transformation road-mapping), the key point is the realisation that there is a host of policies that must be in tune with the transformational promise of S3, in order to reap its fruits. One of the most powerful examples is the importance of human capital for the success of S3 - or any sustainable exercise pursuing growth - and the way S3 can be undermined by relentless austerity drives that push human capital away. Other notable messages emerged in this meta-analysis, especially through the active structured involvement of front-line policymakers. Quite encouragingly, it was stressed that the Smart Specialisation approach is perceived as a broad development strategy, and not just a mere setting for the use of regional funds. Policymakers also confirmed the importance of maintaining momentum in the Entrepreneurial Discovery Process (EDP), as well as the need to simplify and harmonise financing instruments. Furthermore, certain underappreciated issues have been identified as critical: they include ensuring consistency in communication about the Smart Specialisation approach and policies to stakeholders, and nurturing a continuous dialogue across sectors and disciplines to boost cross-fertilisation. On the other hand, the review of priorities led to a methodology, which can still be implemented without recourse to computational power at this stage. However, as the number of priorities grows, a programmable algorithm may well be needed. This report hints at how such an algorithm can be built; the goal would be, in a sense, the obverse of what is sought by web navigators' rank algorithms. Instead of seeking many relevant responses to queries, the objective would be to provide concise syntheses reflecting many different contributions, seeking common elements among them. Developing it would require policy backing, and a separate, prioritised, and resource-demanding project. Finally, the meta-analysis of priorities allows regrouping them to extract common vectors of emphases across regions, as bottom-up input towards mission-oriented themes that carry cross-regional economic transformation potential. Through the process above, eighteen groupings of priorities (priority families) were identified. Some of the highest ranked ones, reflecting many regions/countries priorities, involve activities that are always high in such lists (e.g. health-related); others however entail activities that are often overlooked. One very important such grouping/family, with many countries and regions in its ranks, is the agri-food family, where research and innovation can often be high-tech indeed. Another very important - and usually overlooked - grouping involves tourism and culture. This includes targeted tourism, as well as quality-of-life experiential tourism, and indirectly proposes a new 21st century approach to the concept of competitiveness. Beyond such groupings and examples, the ultimate specific identification of vectors should ideally involve a broader discussion/validation process.JRC.B.3-Territorial Developmen

    Navigable networks as Nash equilibria of navigation games

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    Common sense suggests that networks are not random mazes of purposeless connections, but that these connections are organized so that networks can perform their functions well. One function common to many networks is targeted transport or navigation. Here, using game theory, we show that minimalistic networks designed to maximize the navigation efficiency at minimal cost share basic structural properties with real networks. These idealistic networks are Nash equilibria of a network construction game whose purpose is to find an optimal trade-off between the network cost and navigability. We show that these skeletons are present in the Internet, metabolic, English word, US airport, Hungarian road networks, and in a structural network of the human brain. The knowledge of these skeletons allows one to identify the minimal number of edges, by altering which one can efficiently improve or paralyse navigation in the network

    Biosignals reflect pair-dynamics in collaborative work : EDA and ECG study of pair-programming in a classroom environment

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    Collaboration is a complex phenomenon, where intersubjective dynamics can greatly affect the productive outcome. Evaluation of collaboration is thus of great interest, and can potentially help achieve better outcomes and performance. However, quantitative measurement of collaboration is difficult, because much of the interaction occurs in the intersubjective space between collaborators. Manual observation and/or self-reports are subjective, laborious, and have a poor temporal resolution. The problem is compounded in natural settings where task-activity and response-compliance cannot be controlled. Physiological signals provide an objective mean to quantify intersubjective rapport (as synchrony), but require novel methods to support broad deployment outside the lab. We studied 28 student dyads during a self-directed classroom pair-programming exercise. Sympathetic and parasympathetic nervous system activation was measured during task performance using electrodermal activity and electrocardiography. Results suggest that (a) we can isolate cognitive processes (mental workload) from confounding environmental effects, and (b) electrodermal signals show role-specific but correlated affective response profiles. We demonstrate the potential for social physiological compliance to quantify pair-work in natural settings, with no experimental manipulation of participants required. Our objective approach has a high temporal resolution, is scalable, non-intrusive, and robust.Peer reviewe

    DREAMWALKER: Mental Planning for Continuous Vision-Language Navigation

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    VLN-CE is a recently released embodied task, where AI agents need to navigate a freely traversable environment to reach a distant target location, given language instructions. It poses great challenges due to the huge space of possible strategies. Driven by the belief that the ability to anticipate the consequences of future actions is crucial for the emergence of intelligent and interpretable planning behavior, we propose DREAMWALKER -- a world model based VLN-CE agent. The world model is built to summarize the visual, topological, and dynamic properties of the complicated continuous environment into a discrete, structured, and compact representation. DREAMWALKER can simulate and evaluate possible plans entirely in such internal abstract world, before executing costly actions. As opposed to existing model-free VLN-CE agents simply making greedy decisions in the real world, which easily results in shortsighted behaviors, DREAMWALKER is able to make strategic planning through large amounts of ``mental experiments.'' Moreover, the imagined future scenarios reflect our agent's intention, making its decision-making process more transparent. Extensive experiments and ablation studies on VLN-CE dataset confirm the effectiveness of the proposed approach and outline fruitful directions for future work.Comment: Accepted at ICCV 2023; Project page: https://github.com/hanqingwangai/Dreamwalke
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