949 resultados para message broker


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Large-scale evacuations are a recurring theme on news channels, whether in response to major natural or manmade disasters. The role of warning dissemination is a key part in the success of such large-scale evacuations and its inadequacy in certain cases has been a 'primary contribution to deaths and injuries' (Hayden et al.; 2007). Along with technology-driven 'official warning channels' (e.g. sirens, mass media), the role of unofficial channel (e.g. neighbours, personal contacts, volunteer wardens) has proven to be significant in warning the public of the need to evacuate. Although post-evacuation studies identify the behaviours of evacuees as disseminators of the warning message, there has not been a detailed study that quantifies the effects of such behaviour on the warning message dissemination. This paper develops an Agent-Based Simulation (ABS) model of multiple agents (evacuee households) in a hypothetical community to investigate the impact of behaviour as an unofficial channel on the overall warning dissemination. Parameters studied include the percentage of people who warn their neighbours, the efficiency of different official warning channels, and delay time to warn neighbours. Even with a low proportion of people willing to warn their neighbour, the results showed considerable impact on the overall warning dissemination. © 2012 Elsevier B.V. All rights reserved.

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The inference and optimization in sparse graphs with real variables is studied using methods of statistical mechanics. Efficient distributed algorithms for the resource allocation problem are devised. Numerical simulations show excellent performance and full agreement with the theoretical results. © Springer-Verlag Berlin Heidelberg 2006.

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This paper introduces a new technique for optimizing the trading strategy of brokers that autonomously trade in re- tail and wholesale markets. Simultaneous optimization of re- tail and wholesale strategies has been considered by existing studies as intractable. Therefore, each of these strategies is optimized separately and their interdependence is generally ignored, with resulting broker agents not aiming for a glob- ally optimal retail and wholesale strategy. In this paper, we propose a novel formalization, based on a semi-Markov deci- sion process (SMDP), which globally and simultaneously op- timizes retail and wholesale strategies. The SMDP is solved using hierarchical reinforcement learning (HRL) in multi- agent environments. To address the curse of dimensionality, which arises when applying SMDP and HRL to complex de- cision problems, we propose an ecient knowledge transfer approach. This enables the reuse of learned trading skills in order to speed up the learning in new markets, at the same time as making the broker transportable across market envi- ronments. The proposed SMDP-broker has been thoroughly evaluated in two well-established multi-agent simulation en- vironments within the Trading Agent Competition (TAC) community. Analysis of controlled experiments shows that this broker can outperform the top TAC-brokers. More- over, our broker is able to perform well in a wide range of environments by re-using knowledge acquired in previously experienced settings.

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Published in the Front Matter

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Among the actual cultural-heritage-related problems is the one of effectively managing and globally distributing digitized cultural (and scientific) information. The only feasible way to realize this goal is via the Internet. Hence, a significant issue to be considered is the adequate design of software applications which to realize brokerage tasks within the global space. However, due to the great complexity of this cultural-heritage- related task (compared to other brokerage tasks successfully realized by software systems), the usage of the existing popular modeling instrumentarium seems inadequate. Hence, in this paper, an approach is presented and it is briefly discussed how the approach could be useful for building cultural heritage sector brokers.

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This paper details the development and evaluation of AstonTAC, an energy broker that successfully participated in the 2012 Power Trading Agent Competition (Power TAC). AstonTAC buys electrical energy from the wholesale market and sells it in the retail market. The main focus of the paper is on the broker’s bidding strategy in the wholesale market. In particular, it employs Markov Decision Processes (MDP) to purchase energy at low prices in a day-ahead power wholesale market, and keeps energy supply and demand balanced. Moreover, we explain how the agent uses Non-Homogeneous Hidden Markov Model (NHHMM) to forecast energy demand and price. An evaluation and analysis of the 2012 Power TAC finals show that AstonTAC is the only agent that can buy energy at low price in the wholesale market and keep energy imbalance low.

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Welcome to the Second International Workshop on Multimedia Communications and Networking held in conjunction with IUCC-2012 during 25 June – 27 June 2012 in Liverpool, UK. MultiCom-2012 is dedicated to address the challenges in the areas of elivering multimedia content using modern communication and networking techniques. The multimedia & networking computing domain emerges from the integration of multimedia content such as audio and video with content distribution technologies. This workshop aims to cover contributions in both design and analysis aspects in the context of multimedia, wired/wireless/heterogeneous networks, and quality evaluation. It also intends to bring together researchers and practitioners from academia and industry to share their latest achievements in this field with others and establish new collaborations for future developments. All papers received are peer reviewed by three members of the Technical Programme Committee. The papers are assessed by their originality, technical quality, presentation and relevance to the theme of the workshop. Based on the criteria set, four papers have been accepted for presentation at the workshop and will appear in the IUCC conference proceedings. We would like to take this opportunity to thank the IUCC-2012 Organizing Committee, the TPC members of MultiCom-2012 and the authors for their s upport, dedicated work and contributions. Finally, we look forward to meeting you at the workshop in Liverpool.

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The increase in renewable energy generators introduced into the electricity grid is putting pressure on its stability and management as predictions of renewable energy sources cannot be accurate or fully controlled. This, with the additional pressure of fluctuations in demand, presents a problem more complex than the current methods of controlling electricity distribution were designed for. A global approximate and distributed optimisation method for power allocation that accommodates uncertainties and volatility is suggested and analysed. It is based on a probabilistic method known as message passing [1], which has deep links to statistical physics methodology. This principled method of optimisation is based on local calculations and inherently accommodates uncertainties; it is of modest computational complexity and provides good approximate solutions.We consider uncertainty and fluctuations drawn from a Gaussian distribution and incorporate them into the message-passing algorithm. We see the effect that increasing uncertainty has on the transmission cost and how the placement of volatile nodes within a grid, such as renewable generators or consumers, effects it.

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Credible endorsers are often used in advertisements. However, there is conflicting evidence on the role source credibility plays in persuasion. Early research found that source credibility affects persuasion when subjects pay attention to the communication. Other research indicates that a credible source enhances persuasion when people do not scrutinize the message claims carefully and thoroughly. This effect is opposite to what was indicated by early research. More recent research indicates that source credibility may affect persuasion when people scrutinize the message claims, but limits this effect to advertisements with certain type of claims (i.e., ambiguous or extreme claims). This dissertation proposes that source credibility might play a broader role during persuasion than suggested by the empirical literature. Source credibility may affect persuasion, at low levels of involvement, by serving as a peripheral cue. It may also affect persuasion, at high involvement, by serving as an argument or biasing elaboration. ^ Each of these possibilities was explored in an experiment using a 3 (source credibility) x 2 (type of claim) x 2 (levels of involvement) full factorial design. The sample consisted of 180 undergraduate students from a major southeastern University. ^ Results indicated that, at high levels of involvement, the credibility of the source affected persuasion. This effect was due to source credibility acting as an argument within the advertisement. This study did not find that source credibility affected persuasion by biasing elaboration, at high involvement, or by serving as a peripheral cue, at low involvement. ^

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The increasing nationwide interest in intelligent transportation systems (ITS) and the need for more efficient transportation have led to the expanding use of variable message sign (VMS) technology. VMS panels are substantially heavier than flat panel aluminum signs and have a larger depth (dimension parallel to the direction of traffic). The additional weight and depth can have a significant effect on the aerodynamic forces and inertial loads transmitted to the support structure. The wind induced drag forces and the response of VMS structures is not well understood. Minimum design requirements for VMS structures are contained in the American Association of State Highway Transportation Officials Standard Specification for Structural Support for Highway Signs, Luminaires, and Traffic Signals (AASHTO Specification). However the Specification does not take into account the prismatic geometry of VMS and the complex interaction of the applied aerodynamic forces to the support structure. In view of the lack of code guidance and the limited number research performed so far, targeted experimentation and large scale testing was conducted at the Florida International University (FIU) Wall of Wind (WOW) to provide reliable drag coefficients and investigate the aerodynamic instability of VMS. A comprehensive range of VMS geometries was tested in turbulence representative of the high frequency end of the spectrum in a simulated suburban atmospheric boundary layer. The mean normal, lateral and vertical lift force coefficients, in addition to the twisting moment coefficient and eccentricity ratio, were determined using the measured data for each model. Wind tunnel testing confirmed that drag on a prismatic VMS is smaller than the 1.7 suggested value in the current AASHTO Specification (2013). An alternative to the AASHTO Specification code value is presented in the form of a design matrix. Testing and analysis also indicated that vortex shedding oscillations and galloping instability could be significant for VMS signs with a large depth ratio attached to a structure with a low natural frequency. The effect of corner modification was investigated by testing models with chamfered and rounded corners. Results demonstrated an additional decrease in the drag coefficient but a possible Reynolds number dependency for the rounded corner configuration.

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Le présent travail est une étude sur Le Petit Prince, d’Antoine de Saint-Exupéry. Le but principal du mémoire est d’analyser la réception du message chez le lecteur adulte et chez le lecteur enfant. Nous avons analysé comment l’enfant et l’adulte interprètent le message donné par l’oeuvre, parsemée d’images et d’allégories, des citations qui son devenues symboliques avec le temps. Ensuite, nous avons analysé les personnages dans le but d’interpréter leur sens symbolique. Pour réaliser cette recherche, nous avons regardé plusieurs interprétations allégoriques. Les résultats de notre étude nous ont permis d’affirmer que la réception du message n’est pas la même chez le lecteur adulte et le lecteur enfant. Les résultats de cette étude montrent enfin qu’il est trop difficile pour le lecteur enfant de comprendre le sens moral d’une image allégorique, tandis que le lecteur adulte est plus apte à interpréter l’image allégorique en s’appuyant sur son expérience de la lecture et de son expérience de la vie quotidienne. L’auteur utilise l’image symbolique dans la littérature pour montrer avec plus de clarté la condition humaine. En conclusion nous apprenons que Le Petit Prince nous fait réfléchir sur la vie de la façon plus profonde et philosophique.

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Nonadherence to treatment is a worldwide problem among people with severe mental disorders. Patient treatment adherence may be supported with simple reminding methods e.g. text message reminders. However, there is limited evidence of its benefits. Intervention evaluation is essential in mHealth research. Therefore, this evaluative study was conducted. This study aimed to evaluate text message reminder use in encouraging patients’treatment adherence among people with antipsychotic medication. The data were collected between September 2011 and December 2013. First, a systematic literature review revealed that text message reminders were widely used in healthcare. However, its impacts were conflicting. Second, a sub-sample (n = 562) analysis showed that patients preferred humorous text message reminders and preferred to receive them in the morning, at the beginning of the week. Age, gender and marital status seemed to have different effects on the preferred amount and timing of the selected reminders. Third, a cross-sectional survey revealed that people with antipsychotic medication (n = 408) expressed overall satisfaction towards the reminder system. Finally, the evaluative design showed that patient recruitment for a randomized controlled trial concerning people with antipsychotic medication was challenging due to low rates of eligible participants. Follow-up drop-out rates varied depending on the data collection method. Participants’ demographic characteristics were associated with the risk of dropping out from the trial. This study suggests that text messages are a potential reminder system in healthcare services among people with antipsychotic medication. More research is needed to gain a comprehensive picture of the impacts and effectiveness of text message reminders.

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Transparency has been proposed to both change the way journalism is being produced and increase its credibility. However, little research has been conducted to assess the connection between transparency and credibility. This study utilizes an experimental setting (N=1320) to measure what impact transparency have on source and message credibility from the user perspective. The results reveals an almost absence of any transparency effect on both source and message credibility although some small significant effects could be observed primarily regarding internal hyperlinks, comments and contextual information. Although further research is desperately needed in this area the study suggest that transparency does not affect the credibility of journalism in the eyes of the contemporary audience and thus have limited appeal as a new norm in journalism.