Two-choice regulation in heterogeneous closed networks

A heterogeneous closed network with one-server queues with finite capacity and one infinite-server queue is studied. A target application is bike-sharing systems. Heterogeneity is taken into account through clusters whose queues have the same parameters. Incentives to the customer to go to the least loaded one-server queue among two chosen within a cluster are investigated. By mean-field arguments, the limiting queue length stationary distribution as the number of queues gets large is analytically tractable. Moreover, when all customers follow incentives, the probability that a queue is empty or full is approximated. Sizing the system to improve performance is reachable under this policy.Comment: 19 pages, 4 figure

Developing a Web 2.0 technology for hazard response simulation

Published version used with permission from Higher Education Academy. Miller, S., & France, D. Proceedings of the HEA STEM Learning and Teaching Conference, 2012.Students studying disaster/hazard management in UK Higher Education institutions (HEi's) traditionally focus on hazard mapping and process analysis, but have limited opportunities to develop their risk communication skills which are required during emergency response situations. These skills are vital for the real world and employment. Opportunities to develop risk communication skills are not readily available to students during their studies as employers are reluctant to offer placements due to legal barriers. Therefore, universities have to develop tools to provide students with this vital ‘real-world’ experience. Over the last two years, the department of Geography & Development Studies at the University of Chester has begun to explore and evaluate the role of the Web 2.0 tool, Yammer (microblogging/communication tool) for natural hazard (volcano) simulation exercises. This paper highlights the continuing development of the natural hazard simulation exercise through input from external emergency/contingency practitioners locally and internationally to enhance its usability. Input from practitioners has resulted in the adaptation of the tool to flooding hazard emergency response and to other geographically based scenarios (e.g. crime analysis). The input from professionals in the field has enhanced the quality of the exercise/tool as well as providing students with vital employability skills currently used in the workplace of hazard management. Feedback from students highlighted their feeling of a ‘real-life’ pressure situation in which ‘real-time’ decisions have to be made in response to a rapidly changing environment. At the same time they indicated that their experience was stimulating, fun, innovative and enabled networking and interactive opportunities between tutors and students. The development of the Web 2.0 simulation tool through contributions from practitioners and an assessment as to whether the use of such technologies enhances student-learning experience is the focus of this paper.Higher Education Academ

Qui sont les innovateurs ? Une lecture socio-économique des acteurs de l'innovation

De toutes parts se font entendre aujourd'hui de vibrants plaidoyers pour l'innovation et la créativité. Ces pratiques sont présentées, pour l'entreprise, comme des armes de poids dans un monde de plus en plus concurrentiel et, pour l'individu, comme un mode privilégié de réalisation de soi. Ce qui a longtemps été considéré comme potentiellement dangereux parce que contradictoire avec un ordre stable (en latin médiéval le mot innovation est synonyme d'hérésie – Girard, 2002) est aujourd'hui non seulement fortement souhaité mais, plus encore, encouragé. À ces appels à l'innovation correspond un regain d'intérêt pour la figure du novateur (chercheur, entrepreneur, découvreur, usager-novateur, créateur, artiste, et dans une certaine mesure travailleur du savoir...), en bref, pour celui qui est l'acteur d'un changement remarquable. Le novateur devient la vedette de nombre d'émissions de télévisions, de radios, un sujet idéal pour la presse économique à destination du grand public... La période contemporaine est ainsi peuplée d'inventeurs géniaux, de créateurs inspirés, de chercheurs féconds, d'entrepreneurs imaginatifs. C'est au fond un portrait romantique et enchanté du novateur qui nous est proposé. Au-delà de cette image d'Epinal, on peut se demander jusqu'où les novateurs partagent un certain nombre de traits culturels. Peut-on parler d'un idéal-type de l'acteur de l'innovation ?

Qui sont les innovateurs ? Une lecture socio‐économique des acteurs de l’innovation.

De toutes parts se font entendre aujourd’hui de vibrants plaidoyers pour l’innovation et la créativité. Ces pratiques sont présentées, pour l’entreprise, comme des armes de poids dans un monde de plus en plus concurrentiel et, pour l’individu, comme un mode privilégié de réalisation de soi. Ce qui a longtemps été considéré comme potentiellement dangereux parce que contradictoire avec un ordre stable (en latin médiéval le mot innovation est synonyme d’hérésie – Girard, 2002) est aujourd’hui non seulement fortement souhaité mais, plus encore, encouragé. À ces appels à l’innovation correspond un regain d’intérêt pour la figure du novateur (chercheur, entrepreneur, découvreur, usager-novateur, créateur, artiste, et dans une certaine mesure travailleur du savoir…), en bref, pour celui qui est l’acteur d’un changement remarquable. Le novateur devient la vedette de nombre d’émissions de télévisions, de radios, un sujet idéal pour la presse économique à destination du grand public… La période contemporaine est ainsi peuplée d’inventeurs géniaux, de créateurs inspirés, de chercheurs féconds, d’entrepreneurs imaginatifs. C’est au fond un portrait romantique et enchanté du novateur qui nous est proposé. Au-delà de cette image d’Epinal, on peut se demander jusqu’où les novateurs partagent un certain nombre de traits culturels. Peut-on parler d’un idéal-type de l’acteur de l’innovation!? Les travaux classiques concernant l’innovation, tant en économie qu’en sociologie, nous livrent des pistes pour répondre à ces questions. Cependant, ils s’intéressent de manière privilégiée à l’innovation comme processus et donc davantage à ce que font les innovateurs plutôt qu’à ce qu’ils sont. Sur la base de ce constat, nous proposons d’utiliser la notion d’identité, et la manière dont elle a été conceptualisée en sociologie des organisations, pour dégager quelques dimensions structurantes propres à l’acteur de l’innovation. Le cas de l’usager-novateur, envisagé à partir de travaux d’économistes, permet de tester la pertinence de cette approche en termes d’identité.Novateur; Innovation;

Transitioning to Organic Rice Farming in Thailand: Drivers and Factors

The Thai government has made it part of the long-term strategy to produce more organic rice, particularly for the Chinese market, to sustain Thai economic growth. However, whilst there has been an increase in organic rice farming, the rate has been relatively slow compared to conventional methods. This research focuses on determining the drivers and factors that influences conversion to organic rice farming in order to better inform local and national policies. It provides an insight into the processes in the decision-making process of famers and the practices they use. Questionnaire and interview data from farmers from the leading rice production region, Surin was analyzed using logistic regression to understand the driver for of organic rice farming and well as the barrier and challenges of adopting to this practice. The findings highlight the critical role of extension farm officers in promoting, educating and motivating farmers to take on organic farming. The ability to access (affordable) loans through local cooperative and land-ownership were also key motivational factors. Young people (under 25) are not engaging with farming generally and this is a major barrier to long-term growth in the organic rice industry in Thailand

Towards an Automatic Parking System using Bio-Inspired 1-D Optical Flow Sensors

International audienceAlthough several (semi-) automatic parking systems have been presented throughout the years [1]–[12], car manufacturers are still looking for low-cost sensors providing redundant information about the obstacles around the vehicle, as well as efficient methods of processing this information, in the hope of achieving a very high level of robustness. We therefore investigated how Local Motion Sensors (LMSs) [13], [14], comprising only of a few pixels giving 1-D optical flow (OF) measurements could be used to improve automatic parking maneuvers. For this purpose, we developed a low computational-cost method of detecting and tracking a parking spot in real time using 1-D OF measurements around the vehicle as well as the vehicle's longitudinal velocity and steering angle. The algorithm used was composed of 5 processing steps, which will be described here in detail. In this initial report, we will first present some results obtained in a highly simplified 2-D parking simulation performed using Matlab/Simulink software, before giving some preliminary experimental results obtained with the first step in the algorithm in the case of a vehicle equipped with two 6-pixel LMSs. The results of the closed-loop simulation show that up to a certain noise level, the simulated vehicle detected and tracked the parking-spot assessment in real time. The preliminary experimental results show that the average refresh frequency obtained with the LMSs was about 2-3 times higher than that obtained with standard ultrasonic sensors and cameras, and that these LMSs therefore constitute a promising alternative basis for designing new automatic parking systems

Optic-Flow Based Car-Like Robot Operating in a 5-Decade Light Level Range

International audienceIn this paper, we present (i) a novel bio-inspired 1-D OF sensor which is robust to high-dynamic-range lighting conditions and independent of the visual patterns encountered, and (ii) a low-cost car-like robot called BioCarBot, which estimates its velocity and steering angle by means of an Extended Kalman Filer (EKF) using only the OF measurements delivered by two downward-facing sensors of this kind. Indoor experiments were carried out, in which the robot was driven in the closed-loop mode, using a proportional integral (PI) controller based on the velocity and steering angle estimates. The results presented here show that our novel OF sensor can deliver a wide range of high-frequency (333 Hz) OF measurements (from 1 to 10 rad s) with a relatively high resolution (up to 0.05 rad s) in a 5-decade high-dynamic range of light levels. Neither the refresh rate nor the resolution of the OF sensors presented here depended on either the visual patterns or the lighting conditions, and could be theoretically set at whatever value required

Development of Crisis and Emergency Risk Communication (CERC) activities and an Evaluation of their Impact on Learning: Geoscience students’ perceptions,

Recently, the recognition of Crisis and Emergency Risk Communication (CERC) tools in natural hazard management and disaster reduction has gained prominence. A successful CERC will ensure the relevant stakeholders are effective communicating with each other. This requires a clear plan and set of principles that enables the stakeholders to function effectively in a crisis. Students hoping to work in the emergency and natural hazard management field need to develop these skills. This paper outlines the development of a range of risk communicating activities including simulation exercises for undergraduate Geoscience students. Progress in the development of the students risk communication skill through the series of activities is tracked and evaluated. Results indicate that 87% of the students perceived their risk communication skills were good or excellent after undertaking the exercises compared to 26% before. This paper also evaluates the impact of the activities and if they motivated them to learn more about the subject as a whole. Students generally indicated that the exercises motivated them to learn more about natural hazard management and they felt that they have become better risk communicators. They also indicate that they gained a more in-depth understanding of the requirements of effective and timely communications should they need to develop a CERC strategy during a crisis

François Albera, Fernand Léger et le cinéma

Avec son livre Léger et le cinéma, François Albera relève le défi de proposer à la fois une synthèse minutieuse des contributions de l’artiste au cinéma et de faire penser de façon exaltante à de nouvelles perspectives plus générales de recherche. Ce n’est pas le moindre des mérites de cet ouvrage publié dans la collection « Le Cinéma des poètes » qui s’adresse tant au grand public qu’aux experts, en proposant une synthèse scientifique non illustrée d’une centaine de pages sur les rapports en..