153 research outputs found

    Collective schedules: axioms and algorithms

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    The collective schedules problem consists in computing a schedule of tasks shared between individuals. Tasks may have different duration, and individuals have preferences over the order of the shared tasks. This problem has numerous applications since tasks may model public infrastructure projects, events taking place in a shared room, or work done by co-workers. Our aim is, given the preferred schedules of individuals (voters), to return a consensus schedule. We propose an axiomatic study of the collective schedule problem, by using classic axioms in computational social choice and new axioms that take into account the duration of the tasks. We show that some axioms are incompatible, and we study the axioms fulfilled by three rules: one which has been studied in the seminal paper on collective schedules (Pascual et al. 2018), one which generalizes the Kemeny rule, and one which generalizes Spearman's footrule. From an algorithmic point of view, we show that these rules solve NP-hard problems, but that it is possible to solve optimally these problems for small but realistic size instances, and we give an efficient heuristic for large instances. We conclude this paper with experiments

    Optimizing egalitarian performance when colocating tasks with types for cloud data center resource management

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    International audienceIn data centers, up to dozens of tasks are colocated on a single physical machine. Machines are used more efficiently, but the performance of the tasks deteriorates, as the colocated tasks compete for shared resources. Since the tasks are heterogeneous, the resulting performance dependencies are complex. In our previous work [26], [27] we proposed a new combinatorial optimization model that uses two parameters of a task-its size and its type-to characterize how a task influences the performance of other tasks allocated to the same machine. In this paper, we study the egalitarian optimization goal: the aim is to optimize the performance of the worst-off task. This problem generalizes the classic makespan minimization on multiple processors (P||C max). We prove that polynomially-solvable variants of P||C max are NP-hard for this generalization, and that the problem is hard to approximate when the number of types is not constant. For a constant number of types, we propose a PTAS, a fast approximation algorithm, and a series of heuristics. We simulate the algorithms on instances derived from a trace of one of Google clusters. Compared with baseline algorithms solving P||C max , our proposed algorithms aware of the types of the jobs lead to significantly better tasks' performance. The notion of type enables us to extend standard combinatorial optimization methods to handle degradation of performance caused by colocation. Types add a layer of additional complexity. However, our results-approximation algorithms and good average-case performance-show that types can be handled efficiently

    Collective Schedules: Scheduling Meets Computational Social Choice

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    International audienceWhen scheduling public works or events in a shared facility one needs to accommodate preferences of a population. We formalize this problem by introducing the notion of a collective schedule. We show how to extend fundamental tools from social choice theory—positional scoring rules, the Kemeny rule and the Con-dorcet principle—to collective scheduling. We study the computational complexity of finding collective schedules. We also experimentally demonstrate that optimal collective schedules can be found for instances with realistic sizes

    La neuroplasticité en physiothérapie : un concept central à démystifier chez les clientÚles amputées, neurologiques et de douleurs chroniques : une revue de littérature

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    Dans le cadre du cours PHT-6123 _ A-A17 – Travail d'intĂ©grationIntroduction : La neuroplasticitĂ© est un concept central et important pour la rĂ©cupĂ©ration fonctionnelle de toutes les clientĂšles traitĂ©es en physiothĂ©rapie. Toutefois, ce concept est encore peu maitrisĂ© par les cliniciens physiothĂ©rapeutes. Objectif(s): DĂ©finir et dĂ©crire la neuroplasticitĂ© chez une variĂ©tĂ© de clientĂšles : amputĂ©, accident vasculaire cĂ©rĂ©bral (AVC), douleur chronique et lĂ©sion mĂ©dullaire (LM), afin de pouvoir exploiter davantage le potentiel de rĂ©cupĂ©ration de ces patients vus en physiothĂ©rapie, tout en faisant Ă©tat de l’avancĂ©e des recherches en neuroplasticitĂ©. StratĂ©gie mĂ©thodologique : Revue de littĂ©rature narrative Ă  partir des bases de donnĂ©es Embase, CINAHL et MEDLINE. RĂ©sultats : La neuroplasticitĂ© consiste en la capacitĂ© du systĂšme nerveux Ă  changer et Ă  s’adapter, tout au long de la vie. Elle peut ĂȘtre soit adaptive telle qu’observĂ©e lors d’une Ă©volution positive chez les patients LM ou AVC, ou maladaptive comme dans les cas de douleurs chroniques ou fantĂŽmes chez les patients amputĂ©s. En contexte de rĂ©adaptation, les modalitĂ©s de traitement utilisĂ©es actuellement amĂšnent des gains fonctionnels grĂące Ă  la neuroplasticitĂ©. Ainsi, toute rĂ©cupĂ©ration sensorimotrice est directement en lien avec des changements plastiques au niveau neural. En combinant ces approches usuelles avec des technologies ciblant spĂ©cifiquement le tissu neural, cela potentialiserait la neuroplasticitĂ© et optimiserait ainsi l’efficacitĂ© des traitements en physiothĂ©rapie. Conclusion : MalgrĂ© l’absence de consensus scientifique, l’optimisation de la neuroplasticitĂ© Ă  l’aide d’interventions physiothĂ©rapeutiques dĂ©montrerait une tendance Ă  amĂ©liorer la rĂ©cupĂ©ration des patients. Nous supportons donc l’importance de rendre ces notions accessibles aux physiothĂ©rapeutes praticiens pour le futur de la physiothĂ©rapie

    An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles

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    Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences

    Examining Associations Between Smartphone Use and Clinical Severity in Frontotemporal Dementia: Proof-of-Concept Study

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    BackgroundFrontotemporal lobar degeneration (FTLD) is a leading cause of dementia in individuals aged <65 years. Several challenges to conducting in-person evaluations in FTLD illustrate an urgent need to develop remote, accessible, and low-burden assessment techniques. Studies of unobtrusive monitoring of at-home computer use in older adults with mild cognitive impairment show that declining function is reflected in reduced computer use; however, associations with smartphone use are unknown.ObjectiveThis study aims to characterize daily trajectories in smartphone battery use, a proxy for smartphone use, and examine relationships with clinical indicators of severity in FTLD.MethodsParticipants were 231 adults (mean age 52.5, SD 14.9 years; n=94, 40.7% men; n=223, 96.5% non-Hispanic White) enrolled in the Advancing Research and Treatment of Frontotemporal Lobar Degeneration (ARTFL study) and Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects (LEFFTDS study) Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) Mobile App study, including 49 (21.2%) with mild neurobehavioral changes and no functional impairment (ie, prodromal FTLD), 43 (18.6%) with neurobehavioral changes and functional impairment (ie, symptomatic FTLD), and 139 (60.2%) clinically normal adults, of whom 55 (39.6%) harbored heterozygous pathogenic or likely pathogenic variants in an autosomal dominant FTLD gene. Participants completed the Clinical Dementia Rating plus National Alzheimer's Coordinating Center Frontotemporal Lobar Degeneration Behavior and Language Domains (CDR+NACC FTLD) scale, a neuropsychological battery; the Neuropsychiatric Inventory; and brain magnetic resonance imaging. The ALLFTD Mobile App was installed on participants' smartphones for remote, passive, and continuous monitoring of smartphone use. Battery percentage was collected every 15 minutes over an average of 28 (SD 4.2; range 14-30) days. To determine whether temporal patterns of battery percentage varied as a function of disease severity, linear mixed effects models examined linear, quadratic, and cubic effects of the time of day and their interactions with each measure of disease severity on battery percentage. Models covaried for age, sex, smartphone type, and estimated smartphone age.ResultsThe CDR+NACC FTLD global score interacted with time on battery percentage such that participants with prodromal or symptomatic FTLD demonstrated less change in battery percentage throughout the day (a proxy for less smartphone use) than clinically normal participants (P<.001 in both cases). Additional models showed that worse performance in all cognitive domains assessed (ie, executive functioning, memory, language, and visuospatial skills), more neuropsychiatric symptoms, and smaller brain volumes also associated with less battery use throughout the day (P<.001 in all cases).ConclusionsThese findings support a proof of concept that passively collected data about smartphone use behaviors associate with clinical impairment in FTLD. This work underscores the need for future studies to develop and validate passive digital markers sensitive to longitudinal clinical decline across neurodegenerative diseases, with potential to enhance real-world monitoring of neurobehavioral change

    Social data in fisheries (STECF 23-17)

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    Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. This report builds on earlier EWG results (19-03, 20-14, 22-14) and further develops the methodologies for the collection and analysis of social data in fisheries. In particular it addresses the development of National Fisheries Profiles (NFP) and advocates the development of a web based version of the NFP. In addition, it reflects on policy questions generated by DG MARE and indicates how social data could assist in answering these policy questions. Finally, the report evaluates responses of the Member States towards the European Commission’s (EC) questionnaire about the implementation of Article 17 of Regulation (EU) No 1380/2013.Peer reviewe
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