41 research outputs found
POSUM: A Generic Portfolio Scheduler for MapReduce Workloads
No full textMapReduce ecosystems are (still) widely popular for big data processing in data centers. To address the diverse non-functional requirements arising from many and increasingly more sophisticated users, the community has developed many scheduling policies for MapReduce workloads. Although some individual policies can dynamically optimize for single and stable performance objectives, such as minimizing runtime or cost, or meeting deadlines for realtime-jobs, it seems unlikely that individual policies will remain competitive for increasingly more dynamic workloads and objectives. In contrast, in this work we investigate the ability to dynamically balance performance and cost of a portfolio scheduler for MapReduce workloads. To this end, we design and implement a portfolio scheduling technique, that is, a system capable of adapting to the current workload characteristics and target objectives by periodically evaluating its set of potential policies, and of switching to "the best" policy that targets the current system state. We implement and evaluate our system with real-world experiments on a workload containing a mixture of real-time and batch jobs, with the purpose of minimizing deadline violations, while keeping batch job slowdown in check. Our results show that POSUM is a promising alternative: it can predict map task runtimes accurately when calculating average input processing rates, while reduces need a more complex model that accounts for an application-dependent component and variability. However, even without precise predictions, the proposed system can out-perform the individual policies of its portfolio for the combined optimization goal
Digital slot machines: social media platforms as attentional scaffolds
No full textIn this paper we introduce the concept of attentional scaffolds and show the resemblance between social media platforms and slot machines, both functioning as hostile attentional scaffolds. The first section establishes the groundwork for the concept of attentional scaffolds and draws parallels to the mechanics of slot machines, to argue that social media platforms aim to capture users’ attention to maximize engagement through a system of intermittent rewards. The second section shifts focus to the interplay between emotions and attention, revealing how online attentional capture through emotionally triggering stimuli leads to distraction. The final section elucidates the collective implications of scaffolding attention through social media platforms. The examination of phenomena such as emotional contagion and the emergence of group emotions underscores the transition from individual experiences to shared collective outcomes. Employing online moral outrage as a case study, we illustrate how negative emotions serve as scaffolds for individuals’ attention, propagate within social groups, and give rise to collective attitudes
The moral source of collective irrationality during COVID-19 vaccination campaigns
No full textMany hypotheses have been advanced to explain the collective irrationality of COVID-19 vaccine hesitancy, such as partisanship and ideology, exposure to misinformation and conspiracy theories or the effectiveness of public messaging. This paper presents a complementary explanation to epistemic accounts of collective irrationality, focusing on the moral reasons underlying people’s decisions regarding vaccination. We argue that the moralization of COVID-19 risk mitigation measures contributed to the polarization of groups along moral values, which ultimately led to the emergence of collective irrational behaviors. Collective irrationality arises from groups explicitly or implicitly endorsing values that ultimately harm both themselves and those around. The role of social media platforms in amplifying this polarization and contributing to the emergence of collective irrationality is also examined. Finally, potential strategies for addressing the moral sources of collective irrationality are discussed
Book Review of 'Political Attitudes: In Search for Measure' by Camelia Florela Voinea
No full textCamelia Florela Voinea’s new book „Political Attitudes. In Search for Measure”, belongs, as the
author herself says, to a three volume-work which aims at reconfiguring the history of the idea of
„experiment” in psychology, to highlight its relevance for the political thought and, least but not last, to
identify the particular part it played, especially by the end of the 19th century, in the emergence of the new
science of Social Psychology
Two arts come together as one: Painting in Girl Reading
No full textTreball Final de Grau en Estudis Anglesos. Codi: EA0938. Curs acadèmic: 2016/2017Painting and literature are usually two different art branches, however, in this paper
they will be studied altogether in order to identify the different approaches to the art
of painting within the art of literature. To develop this study, Katie Ward’s novel,
Girl Reading (2011), has been analyzed paying special attention to the evolution of
painting and its techniques throughout the centuries, evolution that the author
highlights through a fictional story that lies behind an inspirational real life piece of
art. Furthermore, another important element, the portrayal of women throughout the
years and their societies’ expectations have also been analyzed. Thanks to the fact
that the novel is divided into seven stories, set in different years and centuries, a
variety of paintings and women protagonists was provided. Starting with religious
painting and low-class women and ending with futuristic technology improvements
and accomplished and independent women, the novel emphasizes different types of
painting and also different types of women
The value-added of investable hedge fund indices
No full textThis paper empirically investigates the risk and performance of three types of alternative beta products over the January 2002 to September 2009 time period: funds of hedge funds (FHFs), investable hedge fund indices (IHFIs), and hedge fund replication strategies (HFRS). We show that IHFIs are true alternative beta products with high correlations and beta to noninvestable hedge fund indices. Our results further suggest that, in a best case scenario, IHFIs outperform FHFs and HFRS on a risk-adjusted basis. However, in the worst case scenario, IHFIs underperform both investments. If we take the average of all IHFIs, we find they perform equally well as FHFs. Hence, IHFIs constitute a solid alternative to FHF investments, while costing substantially less, and offering generally more transparency and liquidity. We propose that fee-sensitive investors especially should consider taking a core-satellite approach to their hedge fund portfolio, with the core represented by cheap passive hedge fund beta through IHFIs, and the satellite represented by more expensive and actively managed alphagenerating FHFs. --Hedge funds,investable hedge fund indices,alternative beta,funds of hedge funds,hedge fund replication,Omega ratio
Boston Consulting Group II – A Business Portfolio Analysis Matrix
No full textThe continuous development and market introduction of new businesses can play an important role in the future performance of companies. The business portfolio analysis represents an analytical approach by means of which managers have the possibility to view the corporation as a set of strategic business units that must be managed in a profitable way. Also, by taking into account features specific to the area in which the company operates, by taking into account the competitive advantage and the modalities of earmarking financial resources thereof, the business portfolio analysis provides managers the opportunity to approach companies from a different point of view and to pay increased attention to all activities that need to be undertaken. The present paper aims at presenting from a conceptual standpoint the Boston Consulting Group II Matrix, its strategic consequences and the characteristic advantages and disadvantages. Moreover, the paper will emphasize the importance that the business portfolio analysis holds within a company.BCG II, business, matrix, strategic analysis, portfolio
Studies of Ischemic Preconditioning Mechanisms in Langendorff Rat Heart Model the Impact of Phosphocreatin Kinase and ATP Sensitive Potasium Channels Pharmachological Openers and Blockers on Cardioprotection
No full textAbstractIschemic preconditioning (IPC) induced by administration of brief episodes of ischemia-reperfusion represents a protective mechanism of the heart against prolonged episodes of ischemia. Although the mechanism of ischemic preconditioning has been extensively studied, however, until now it is insufficient elucidated. Using a Langendorff rat heart model with 45minutes ischemia followed by 120minute reperfusion we aimed to evaluate the role of Phosphocreatin Kinase-C (PCK) in ischemic rat myocardium and demonstration of its involvment in the path of pharmachological preconditioning (PP) by using PKC activators 1,2-dioctanoyl-sn-glycerol (DOG) and inhibitors chelerythrine (CHE) and evaluation of the role of KATP channels in pharmachological preconditioning (PP) mechanism by administration of a KATP channel opener (Cromakalim) (CRK) or by blocking the opening of KATP channels with glibenclamide(GLB). The activators of PCK(DOG) and of K ATP channel (CRK) limited the infarct size when perfused before lethal ischemia, mimicking the ischemic preconditioning in rat heart When activator of PCK DOG + GLB, a KATP channel inhibitor were coperfused before the lethal ischemia, there was an increase in myocardial infarct size, expressed as a percentage of the area at risk, versus control, the cardioprotective effect of DOG being abolished by GLB. The same results were obtained when CHE the inhibitor of PCK was coperfused with CRK the activator of K ATP channel. The effect of CHE and GLB perfused at the beginning of IPC resulted in loss of protection accompanied by a significant increase in infarct size area. The finding that treatment with a DOG PKC activator and CRK activator of K ATP channel gives a similar degree of protection against infarction as that seen after ischemic preconditioning and that this protection can be blocked by CHE a PCK pharmachological inhibitor provides support for the hypothesis that PKC plays a pivotal role in ischemic preconditioning. Our data may have a significance in pharmachological preconditioning (PP) with decrease in infarct size as an end point
Correlation Between Transthoracic Contrast-Enhanced Ultrasound and Pulse Oximetry in Hepatopulmonary Syndrome Diagnosis
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