216 research outputs found
Summarizing sensors data in vehicular ad hoc networks
International audienceThis article focuses on data aggregation in vehicular ad hoc networks. In such networks, sensor data are usually produced and exchanged between vehicles in order to warn or inform the drivers when an event is detected (e.g., accident, emergency braking, parking space released, vehicle with non-functioning brake lights, etc.). In the following, we present a solution to aggregate and store these data in order to have a history of past events. We therefore use Flajolet-Martin sketches. Our goal is to generate additional knowledge to assist drivers by providing them useful information even if no event is transmitted by vehicles in the vicinity
A scalable dynamic parking allocation framework
International audienceCities suffer from high traffic c ongestion of which one of the main causes is the unorganized pursuit for available parking. Apart from traffic congestion, the blind search for a parking slot causes financial and environmental losses. We consider a general parking allocation scenario in which the GPS data of a set of vehicles, such as the current locations and destinations of the vehicles, are available to a central agency which will guide the vehicles toward a designated parking lot, instead of the entered destination. In its natural form, the parking allocation problem is dynamic, i.e., its input is continuously updated. Therefore, standard static allocation and assignment rules do not apply in this case. In this paper, we propose a framework capable of tackling these real-time updates. From a methodological point of view, solving the dynamic version of the parking allocation problem represents a quantum leap compared with solving the static version. We achieve this goal by solving a sequence of 0-1 programming models over the planning horizon, and we develop several parking policies. The proposed policies are empirically compared on real data gathered from three European cities: Belgrade, Luxembourg, and Lyon. The results show that our framework is scalable and can improve the quality of the allocation, in particular when parking capacities are low
The parking allocation problem for connected vehicles
International audienceIn this paper, we propose a parking allocation model that takes into account the basic constraints and objectives of a problem where parking lots are assigned to vehicles. We assume vehicles are connected and can exchange information with a central intelligence. Vehicle arrival times can be provided by a GPS device, and the estimated number of available parking slots, at each future time moment and for each parking lot is used as an input. Our initial model is static and may be viewed as a variant of the generalized assignment problem. However, the model can be rerun, and the algorithm can handle dynamic changes by frequently solving the static model, each time producing an updated solution. In practice this approach is feasible only if reliable quality solutions of the static model are obtained within a few seconds since the GPS can continuously provide new input regarding the vehicle’s positioning and its destinations. We propose a 0–1 programming model to compute exact solutions, together with a variable neighborhood search-based heuristic to obtain approximate solutions for larger instances. Computational results on randomly generated instances are provided to evaluate the performance of the proposed approaches
The parking allocation problem for connected vehicles
In this paper, we propose a parking allocation model that takes into account the basic constraints and objectives of a problem where parking lots are assigned to vehicles. We assume vehicles are connected and can exchange information with a central intelligence. Vehicle arrival times can be provided by a GPS device, and the estimated number of available parking slots, at each future time moment and for each parking lot is used as an input. Our initial model is static and may be viewed as a variant of the generalized assignment problem. However, the model can be rerun, and the algorithm can handle dynamic changes by frequently solving the static model, each time producing an updated solution. In practice this approach is feasible only if reliable quality solutions of the static model are obtained within a few seconds since the GPS can continuously provide new input regarding the vehicle’s positioning and its destinations. We propose a 0–1 programming model to compute exact solutions, together with a variable neighborhood search-based heuristic to obtain approximate solutions for larger instances. Computational results on randomly generated instances are provided to evaluate the performance of the proposed approaches.</p
Sharing with Caution: Managing Parking Spaces in Vehicular Networks
By exchanging events in a vehicular ad hoc network (VANET), drivers can receive interesting information while driving. For example, they can be informed of available parking spaces in their vicinity. A suitable protocol is needed to disseminate the events efficiently within the area where they are relevant. Moreover, in such a competitive context where each vehicle may be interested in a resource, it is crucial not to communicate that resource to each driver in the vicinity. Otherwise, those drivers would waste time trying to reach a parking space and only one of them would be fulfilled, which would lead to a poor satisfaction in the system. To solve this problem, we detail in this paper a reservation protocol that efficiently allocates parking spaces in vehicular ad hoc networks and avoids the competition among the vehicles. We have integrated our protocol within VESPA, a system that we have designed for vehicles to share information in VANETs. An experimental evaluation is provided, which proves the usefulness and benefits of our reservation protocol in both parking lots and urban scenarios. Besides, we present an in-depth study of the state of the art on this topic, that shows the interest and the originality of our approach
Les Peuples de l’art, tomes 1 et 2 ; Howard S. Becker. Les Mondes de l’art
Sous le titre générique Les Peuples de l’art, s’est tenu à l’Université de Nantes un colloque de sociologie dont les contributions ont exploré les relations complexes qui lient l’art et le peuple. L’approche retenue a été de bien veiller à introduire un regard pluriel sur les territoires de la High et de la Low culture. Selon Joëlle Deniot, il faut donner « un caractère fictionnel » à ce syntagme polysémique. Dans son article « Anatomie du goût », Pierre Bourdieu avait dressé en 1976 un table..
Aux origines de la condition humaine : de la naissance selon Hannah Arendt à l'enfance chez Gaston Bachelard
La tradition philosophique a défini l'être humain par sa faculté de penser qui, face à cette fatalité qu'est la mort, le caractérise comme le seul être conscient de sa finitude. Hannah Arendt, au lendemain de l'expérience totalitaire, cherchait à reconstruire philosophiquement ce qui avait été ébranlé, à savoir le sens et la valeur de la vie humaine. Or, pour contrer l'hypothèse totalitaire de la super fuite de l'homme, il lui fallait un fondement indiscutable, un fondement ontologique, qu'elle trouva dans un élément occulté par l'ensemble de la tradition philosophique : la naissance. La question que pose Arendt est la suivante : en quoi la naissance détermine-t-elle la condition humaine ? Selon son hypothèse, la naissance engendrerait la faculté d'agir et, par extension, le monde ainsi que la liberté. Cette analyse possède le mérite de traiter, par le biais de la naissance, de l'enfant en soi, alors que ce dernier est généralement envisagé en philosophie à travers la question de l'éducation. Sur ce point, Arendt rejoint Gaston Bachelard, dont les travaux relatifs aux spécificités de l'enfance viendraient compléter et confirmer sa théorie de la natalité
Proyecto Cruz Ámbar
El proyecto Cruz Ámbar nació de la necesidad de aumentar la cantidad de horas disponibles del personal médico, a la demanda de servicios médicos de los peruanos que no cuentan con seguro médico privado. La solución se presenta como un ecosistema que permite enlazar dicha demanda con la oferta de horas médico disponibles compuestos por aplicativos para smartphones, y aplicaciones web que crean un ecosistema de servicio que garantizaría cubrir, al menos, parte de la demanda, garantizando la atención de las necesidades en un tiempo racional a un precio justo. Los principales motivadores de la idea fueron que la mayor parte de la población trabaja de manera informal y que, los que trabajan de manera formal, en su mayoría, no cuentan con un seguro privado. Por otro lado, el sistema de salud público está constantemente colapsado, entregando un servicio bastante lejano a lo deseable. Se ha identificado que existe un gran número de médicos que requieren mejorar sus ingresos, porque no tienen capital para estudiar una especialización y/o para manejar un consultorio privado. Hacer visitas a domicilio, cerca de su ubicación y en sus tiempos libres les generaría ingresos adicionales considerables. Este modelo de negocios tiene que sustentarse en grandes volúmenes de transacciones para ser rentable, por ello la idea es implementarlo inicialmente por ciudad. Se realizó un estudio de mercado, y se halló que sí existe interés y mercado potencial. Por otro lado, es completamente factible hacer el desarrollo tecnológico a un costo adecuado. Sobre la base de ello, se diseñó una solución que satisface los intereses de las partes interesadas, Se ha investigado tecnología acorde a la idea central para smartphones, los servicios en la nube sobre los que se montaría dicha solución, se realizaron comparativos de costos en desarrollo, base de datos, conectividad. Evaluando los flujos económicos proyectados para confirmar la viabilidad del proyecto.The Cruz Ámbar project was born out of the need to increase the number of hours available from medical professionals, to the demand for medical services from Peruvians who do not have private health insurance. The solution is presented as an ecosystem that allows linking said demand with the supply of available medical hours formed by smartphone and web applications that create an ecosystem of service that would guarantee to cover at least part of the demand, guaranteeing the coverage of these needs in a rational time at a fair price. The main motives of this idea were that the majority of the population works informally, and those who work formally, for the most part, do not have access to insurance. On the other hand, the public health system is constantly collapsing, providing a service quite far from ideal. Additionally, it has been identified that there are many doctors who would like to increase their income, but they do not have the resources to study a specialization and/or to run a private practice. Therefore, making house calls, close to their location and in their free time, would generate considerable additional income. This business model has to be based on large volumes of transactions to be profitable, thus, the idea is to initially implement it by city.A market study was conducted, and it has been found that there is interest and a potential market. On the other hand, it is completely feasible to implement this technological development at a reasonable cost. Based on this, a solution was designed to satisfy the interests of all parties, technology according to the central idea for smartphones has been researched, as well as cloud services on which this solution would be used, comparative costs in development, database and connectivity; and evaluation of the projected economic flows to confirm the viability of the project
Benchmarking long-read genome sequence alignment tools for human genomics applications
Background The utility of long-read genome sequencing platforms has been shown in many fields including whole genome assembly, metagenomics, and amplicon sequencing. Less clear is the applicability of long reads to reference-guided human genomics, which is the foundation of genomic medicine. Here, we benchmark available platform-agnostic alignment tools on datasets from nanopore and single-molecule real-time platforms to understand their suitability in producing a genome representation. Results For this study, we leveraged publicly-available data from sample NA12878 generated on Oxford Nanopore and sample NA24385 on Pacific Biosciences platforms. We employed state of the art sequence alignment tools including GraphMap2, long-read aligner (LRA), Minimap2, CoNvex Gap-cost alignMents for Long Reads (NGMLR), and Winnowmap2. Minimap2 and Winnowmap2 were computationally lightweight enough for use at scale, while GraphMap2 was not. NGMLR took a long time and required many resources, but produced alignments each time. LRA was fast, but only worked on Pacific Biosciences data. Each tool widely disagreed on which reads to leave unaligned, affecting the end genome coverage and the number of discoverable breakpoints. No alignment tool independently resolved all large structural variants (1,001–100,000 base pairs) present in the Database of Genome Variants (DGV) for sample NA12878 or the truthset for NA24385. Conclusions These results suggest a combined approach is needed for LRS alignments for human genomics. Specifically, leveraging alignments from three tools will be more effective in generating a complete picture of genomic variability. It should be best practice to use an analysis pipeline that generates alignments with both Minimap2 and Winnowmap2 as they are lightweight and yield different views of the genome. Depending on the question at hand, the data available, and the time constraints, NGMLR and LRA are good options for a third tool. If computational resources and time are not a factor for a given case or experiment, NGMLR will provide another view, and another chance to resolve a case. LRA, while fast, did not work on the nanopore data for our cluster, but PacBio results were promising in that those computations completed faster than Minimap2. Due to its significant burden on computational resources and slow run time, Graphmap2 is not an ideal tool for exploration of a whole human genome generated on a long-read sequencing platform
Opportunistic Data Services in Least Developed Countries: Benefits, Challenges and Feasibility Issues
International audiencefacilitator in establishing primary education, reducing mortality or supporting commercial initiatives in Least Developed Countries. The main barrier to the development of IT services in these regions is not only the lack of communication facilities, but also the lack of consistent information systems, security procedures, economic and legal support, as well as political commitment. In this paper, we propose the vision of an infrastructure-less data platform well suited for the development of innovative IT services in Least Developed Countries. We propose a participatory approach, called Folk-IS, where each individual implements a small subset of a complete information system thanks to highly secure, portable and low-cost personal devices as well as opportunistic networking, without the need for any form of infrastructure. In this paper, we focus on the exploitation and feasibility analysis of the Folk-IS vision. We also review the technical challenges that are specific to this approac
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