119 research outputs found

    Cultures of (Un)Sustainability:Ecovillages as Seedbeds for a Cultural Transition

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    This essay shows how sustainability can and should be understood in terms of a cultural perspective and why it is vital to do so. More than simply adding a cultural dimension to the three pillars of economy, society and the environment, this entails a deeper transition from a culture of unsustainability to a culture of sustainability. It is argued that such a cultural transformation requires in particular a transcendent shift from modern to holistic worldviews and ways of life. A distinction is made between culture as ways of life and worldviews in order to explicate how culture relates to sustainability. Particular focus lies on the holistic worldview, which is explained by means of contrasting it to the dominant worldview of modern culture. This perspective proposes a way for resolving the fundamental failures of modernity and for building the structures of a sustainable future. Finally, ecovillages are presented as models for a sustainable culture: for one, as demonstration sites for such ways of life that can offer a concrete alternative to the unsustainable culture of modernity, and secondly, as dissemination sites for a new culture that is based on a holistic worldview

    An Overview of Fairness Notions in Multi-Party Computation

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    Die sichere Mehrparteienberechnung (``Multi-party Computation\u27\u27, MPC) ist eine kryptografische Technik, die es mehreren Parteien, die sich gegenseitig misstrauen, ermöglicht, gemeinsam eine Funktion ĂŒber ihre privaten Eingaben zu berechnen. Fairness in MPC ist definiert als die Eigenschaft, dass, wenn eine Partei die Ausgabe erhĂ€lt, alle ehrlichen Parteien diese erhalten. Diese Arbeit befasst sich mit dem Defizit an umfassenden Übersichten ĂŒber verschiedene Fairnessbegriffe in MPC. VollstĂ€ndige Fairness (``complete fairness\u27\u27), die oft als Ideal angesehen wird, garantiert, dass entweder alle ehrlichen Parteien ein Ergebnis erhalten oder keine. Dieses Ideal ist jedoch aufgrund theoretischer und kontextbezogener BeschrĂ€nkungen im Allgemeinen nicht zu erreichen. Infolgedessen haben sich alternative Begriffe herausgebildet, um diese EinschrĂ€nkungen zu ĂŒberwinden. In dieser Arbeit werden verschiedene Fairnessbegriffe in MPC untersucht, darunter vollstĂ€ndige Fairness, partielle Fairness (``Partial Fairness\u27\u27), Delta-Fairness, graduelle Freigabe, Fairness mit Strafen und probabilistische Fairness. Jedes Konzept stellt unterschiedliche Anforderungen und EinschrĂ€nkungen fĂŒr reale Szenarien dar. Wir stellen fest, dass vollstĂ€ndige Fairness eine ehrliche Mehrheit erfordert, um fĂŒr allgemeine Funktionen ohne stĂ€rkere Annahmen, wie z. B. den Zugang zu öffentlichen Ledgern, erreicht zu werden, wĂ€hrend bestimmte Funktionen auch ohne diese Annahmen mit vollstĂ€ndiger Fairness berechnet werden können. Andere Begriffe, wie Delta-Fairness, erfordern sichere Hardwarekomponenten. Wir geben einen Überblick ĂŒber die Begriffe, ihre ZusammenhĂ€nge, Kompromisse und praktischen Implikationen dieser Begriffe. DarĂŒber hinaus fassen wir die Ergebnisse in einer vergleichenden Tabelle zusammen, die einen kompakten Überblick ĂŒber die Protokolle bietet, die diese Fairnessbegriffe erfĂŒllen, und die Kompromisse zwischen Sicherheit, Effizienz und Anwendbarkeit aufzeigt. In der Arbeit werden Annahmen und EinschrĂ€nkungen im Zusammenhang mit verschiedenen Fairnessbegriffe aufgezeigt und Protokolle aus grundlegenden Arbeiten auf diesem Gebiet zitiert. Es werden auch mehrere Unmöglichkeitsergebnisse vorgestellt, die die inhĂ€renten Herausforderungen beim Erreichen von Fairness im MPC aufzeigen. Die praktischen Implikationen dieser Fairnesskonzepte werden untersucht und geben Einblicke in ihre Anwendbarkeit und Grenzen in realen Szenarien

    A fast and tight heuristic for A∗ in road networks

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    We study exact, efficient and practical algorithms for route planning in large road networks. Routing applications often require integrating the current traffic situation, planning ahead with traffic predictions for the future, respecting forbidden turns, and many other features depending on the exact application. While Dijkstra’s algorithm can be used to solve these problems, it is too slow for many applications. A* is a classical approach to accelerate Dijkstra’s algorithm. A* can support many extended scenarios without much additional implementation complexity. However, A*’s performance depends on the availability of a good heuristic that estimates distances. Computing tight distance estimates is a challenge on its own. On road networks, shortest paths can also be quickly computed using hierarchical speedup techniques. They achieve speed and exactness but sacrifice A*’s flexibility. Extending them to certain practical applications can be hard. In this paper, we present an algorithm to efficiently extract distance estimates for A* from Contraction Hierarchies (CH), a hierarchical technique. We call our heuristic CH-Potentials. Our approach allows decoupling the supported extensions from the hierarchical speed-up technique. Additionally, we describe A* optimizations to accelerate the processing of low degree nodes, which often occur in road networks

    Using Incremental Many-to-One Queries to Build a Fast and Tight Heuristic for A* in Road Networks

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    We study exact, efficient, and practical algorithms for route planning applications in large road networks. On the one hand, such algorithms should be able to answer shortest path queries within milliseconds. On the other hand, routing applications often require integrating the current traffic situation, planning ahead with predictions for future traffic, respecting forbidden turns, and many other features depending on the specific application. Therefore, such algorithms must be flexible and able to support a variety of problem variants. In this work, we revisit the A* algorithm to build a simple, extensible, and unified algorithmic framework applicable to many route planning problems. A* has been previously used for routing in road networks. However, its performance was not competitive because no sufficiently fast and tight distance estimation function was available. We present a novel, efficient, and accurate A* heuristic using Contraction Hierarchies, another popular speedup technique. The core of our heuristic is a new Contraction Hierarchies query algorithm called Lazy RPHAST, which can efficiently compute shortest distances from many incrementally provided sources toward a common target. Additionally, we describe A* optimizations to accelerate the processing of low-degree vertices, which are typical in road networks, and present a new pruning criterion for symmetrical bidirectional A*. An extensive experimental study confirms the practicality of our approach for many applications

    Space-Efficient, Fast and Exact Routing in Time-Dependent Road Networks

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    We study the problem of computing shortest paths in massive road networks with traffic predictions. Incorporating traffic predictions into routing allows, for example, to avoid commuter traffic congestions. Existing techniques follow a two-phase approach: In a preprocessing step, an index is built. The index depends on the road network and the traffic patterns but not on the path start and end. The latter are the input of the query phase, in which shortest paths are computed. All existing techniques have either large index size, slow query running times, or may compute suboptimal paths. In this work, we introduce CATCHUp (Customizable Approximated Time-dependent Contraction Hierarchies through Unpacking), the first algorithm that simultaneously achieves all three objectives. The core idea of CATCHUp is to store paths instead of travel times at shortcuts. Shortcut travel times are derived lazily from the stored paths. We perform an experimental study on a set of real world instances and compare our approach with state-of-the-art techniques. Our approach achieves the fastest preprocessing, competitive query running times and up to 30 times smaller indexes than competing approaches

    Sediment dynamics and geohazards offshore Uruguay and northern Argentina: first results from the multi-disciplinary Meteor-cruise M78-3

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    About 90% of the sediments generated by weathering and erosion on land get finally deposited at the ocean margins. The sediment distribution processes and landscape evolution on land are relatively well understood, but comparably little is known about the role and relative importance of marine sediment dynamics in controlling the architectural evolution of ocean margins. Important players include hemi-pelagic settling, down-slope and current-controlled along-slope sediment transport, depositional and post-depositional sedimentary processes (e.g. consolidation and diagenesis), as well as the destabilization of sediment bodies and their erosion. Submarine landslides in this context thus may represent an important sediment transport process, but also a major geo-hazard due to the increasing number of offshore constructions as well as their potential to instantaneously displace large water masses triggering waves in densely populated coastal areas. Here we present first results from a seagoing expedition that aimed at investigating the interaction processes of sediment redistribution, partitioning, deposition and diagenesis from the coast to the deep-sea along the western South-Atlantic passive continental margin. During RV Meteor Cruise M78/3 in May-July 2009 the shelf, slope and rise offshore Argentina and Uruguay have been investigated by means of hydroacoustic and seismic mapping as well as geological sampling with conventional coring tools as well as the new MARUM seafloor drill rig (MeBo) that revealed recovery of geological strata sampled from up to 50m below seafloor. The working area is characterized by a high amount of fluvial input by the Rio de la Plata river. The continental slope is relatively wide and shows average slope gradients between 1 and 2.5 but locally higher slope gradients may occur (>5). The transition for the continental rise with low slope gradients is found in ~3000 m water depth. The working area is located in a highly dynamic oceanographic regime. Cold Antarctic water masses of the northward flowing Malvina current meet warm water masses of the southward flowing Brazil current in the working area. Various types of sediment instabilities have been imaged in geophysical and core data, documenting particularly the continental slope offshore Uruguay to be locus of frequent submarine landslides. Apart from individual landslides, however, gravitational downslope sediment transport along the continental slope is restricted to the prominent Mar del Plata Canyon and possibly to smaller canyons indentified in the bathymetric data. The location of the canyons might be controlled by tectonics. In contrast, many morphological features (e.g. progradational terraces and slope parallel scarps with scour-geometries) reveal that sediment transport is predominantly influenced/controlled by strong contour bottom currents. This suggests a significant impact of the western boundary currents on the overall architectural evolution of the margin. Future studies using the acquired geophysical, sedimentological, physical property and geochemical data will (i) quantify the relative contribution of gravitational down-slope vs. along-slope processes through time in shaping this ocean margin and how it relates to the global ocean circulation pattern and sea-level change through time, (ii) investigate depositional and post-depositional processes and how they control submarine slope stability and submarine landslide initiation and (iii) explore the interaction and relative contribution of the various processes in controlling margin evolution, sediment dynamics and geohazard off Uruguay and Northern Argentina

    TRANSIT Deliverable 2.3. Cross-cutting theme: Social Learning

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    Theme [ssh.2013.3.2-1][Social Innovation- Empowering People, changing societies]Project Full Title: “Transformative Social Innovation Theory project”[Abstract] The object of the present deliverable is the integration of the main outcomes of empirical research and integration activities developed within the TRANSIT project on the cross-cutting theme of “social learning” as well as the distilling of main insights for the development of “practical briefs and tools”. Deliverable 2.3 reports on the outcomes of these activities, and consists of the following sections: 1. Working paper: " The role of social learning in transformative social innovations" 2. Synthesis of the third integration workshop: Motivations, relations and transformations. The role of social learning in individual and collective agency for social innovation 3. Social Learning with PEERs: Practitioner Engagement for Empowering Reflections 4. Insights on Social Learning for Transformative Social Innovation Practice (input for practice brief and practice tool.This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 61316

    Community engagement: A central feature of NOSM’s socially accountable distributed medical education

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    Background: Northern Ontario School of Medicine (NOSM) serves as the Faculty of Medicine of Lakehead and Laurentian Universities, and views the entire geography of Northern Ontario as its campus. This paper explores how community engagement contributes to achieving social accountability in over 90 sites through NOSM’s distinctive model, Distributed Community Engaged Learning (DCEL).Methods: Studies involving qualitative and quantitative methods contribute to this paper, which draws on administrative data from NOSM and external sources, as well as surveys and interviews of students, graduates and other informants including the joint NOSM-CRaNHR (Centre for Rural and Northern Health Research) tracking and impact studies.Results: Community engagement contributes throughout the lifecycle stages of preadmission, admission, and undergraduate medical education. High school students from 70 Northern Ontario communities participate in NOSM’s week-long Health Sciences Summer Camps. The MD admissions process involves approximately 128 volunteers assessing written applications and over 100 volunteer interviewers. Thirty-six Indigenous communities host first year students and third-year students learn their core clinical medicine in 15 communities, throughout Northern Ontario. In general, learners and communities report net benefits from participation in NOSM programs.Conclusion: Community engagement makes a key contribution to the success of NOSM’s socially accountable distributed medical education

    TRANSIT Working Paper # 7

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    A previous version of this paper has been part of TRANSIT Deliverable 3.3 (July 2016), the second prototype of TSI theory.[Abstract] This working paper presents a set of propositions about the agency and dynamics of transformative social innovation (TSI) that have been developed as part of an EU-funded research project entitled “TRANsformative Social Innovation Theory” (TRANSIT; 2014-2017). These TSI propositions represent first steps towards the development of a new theory of TSI, taking the form of proto-explanations of the agency and dynamics of TSI, based on the bringing together of our empirical observations on TSI and the project's theoretical reviews and theoretical framings. Ideally this working paper should be read in conjunction with the working paper entitled “A framework for transformative social innovation” (Haxeltine et al 2016) which presents in skeletal terms the theoretical and conceptual framing of TSI developed in the TRANSIT project. This TSI framework builds on sustainability transition studies, social innovation research, social psychology studies of empowerment and other several other areas of social theory to deliver a bespoke theoretical and conceptual framework that is grounded in a relational ontology and which is being employed as a platform for the development of a middle-range theory of TSI. Next we provide a very brief overview of some key elements of the framework, in particular how we conceptualise social innovation, transformative change, and transformative social innovation. Propositions were developed for each of four relational dimensions implied by the TSI framework with also a brief statement of the topic addressed by each of the twelve propositions.This article is based on research carried out as part of the Transformative Social Innovation Theory (“TRANSIT”) project, which is funded by the European Union's Seventh Framework Programme (FP7) under grant agreement 61316
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