2,132 research outputs found

    Adaptive Partitioning for Large-Scale Dynamic Graphs

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    Abstract—In the last years, large-scale graph processing has gained increasing attention, with most recent systems placing particular emphasis on latency. One possible technique to improve runtime performance in a distributed graph processing system is to reduce network communication. The most notable way to achieve this goal is to partition the graph by minimizing the num-ber of edges that connect vertices assigned to different machines, while keeping the load balanced. However, real-world graphs are highly dynamic, with vertices and edges being constantly added and removed. Carefully updating the partitioning of the graph to reflect these changes is necessary to avoid the introduction of an extensive number of cut edges, which would gradually worsen computation performance. In this paper we show that performance degradation in dynamic graph processing systems can be avoided by adapting continuously the graph partitions as the graph changes. We present a novel highly scalable adaptive partitioning strategy, and show a number of refinements that make it work under the constraints of a large-scale distributed system. The partitioning strategy is based on iterative vertex migrations, relying only on local information. We have implemented the technique in a graph processing system, and we show through three real-world scenarios how adapting graph partitioning reduces execution time by over 50 % when compared to commonly used hash-partitioning. I

    Reusable model transformation components with bentō

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    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-21155-8_5Building high-quality transformations that can be used in real projects is complex and time-consuming. For this reason, the ability to reuse existing transformations in different, unforeseen scenarios is very valuable. However, there is scarce tool support for this task. This paper presents bentō, a tool which supports the development and execution of reusable transformation components. In bentō, a reusable transformation is written as a regular ATL transformation, but it uses concepts as meta-models. Reuse is achieved by binding such concepts to meta-models, which induces the transformation adaptation. Moreover, composite components enable chaining transformations, and it is possible to convert an existing transformation into a reusable component. Bentō is implemented as an Eclipse plug-in, available as free software.This work was supported by the Spanish Ministry of Economy and Competitivity with project Go-Lite (TIN2011-24139), the R&D programme of the Madrid Region with project (SICOMORO S2013/ICE-3006), and the EU commission with project MONDO (FP7-ICT 2013-10, #611125)

    Medical Aspects of mTOR Inhibition in Kidney Transplantation

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    The advances in transplant immunosuppression have reduced substantially the incidence of kidney graft rejection. In recent years, the focus has moved from preventing rejection to preventing the long-term consequences of long-standing immunosuppression, including nephrotoxicity induced by calcineurin inhibitors (CNI), as well as infectious and neoplastic complications. Since the appearance in the late 1990s of mTOR inhibitors (mTORi), these unmet needs in immunosuppression management could be addressed thanks to their benefits (reduced rate of viral infections and cancer). However, management of side effects can be troublesome and hands-on experience is needed. Here, we review all the available information about them. Thanks to all the basic, translational and clinical research achieved in the last twenty years, we now use mTORi as de novo immunosuppression in association with CNI. Another possibility is represented by the conversion of either CNI or mycophenolate (MPA) to an mTORi later on after transplantation in low-risk kidney transplant recipients. © 2022 by the authors

    Analiziranje pozicioniranja glazbenih usluga putem kvalitativnog istraživanja

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    Information technologies have produced new ways of distributing and consuming music, mainly by youth, in relation to both goods and services. In the case of goods, there has been a dramatic shift from traditional ways of buying and listening to music to new digital platforms. There has also been an evolution in relation to music services. In this sense, live music concerts have been losing their audiences over the past few years, as have music radio stations, in favor of streaming platforms. Curious about this phenomenon, we conducted an exploratory research in order to analyze how all these services, both traditional and new ones were perceived. Specifically, we aimed to study youth´s assessment of the three most relevant music service categories: music radio stations, digital streaming platforms, and pop-rock music festivals. To do so, we used the projective technique of image association to gather information. The population of the study consisted of individuals between 18 and 25 years of age. Our results, after using content analysis, were poor due to spontaneous recall. Therefore, we duplicated the study, but in a more focus-oriented way. Information gathered this time allowed us not only to better know how all these organizations are positioned but also to obtain a list of descriptors to be used in a subsequent descriptive research study.Informacijske tehnologije stvaraju nove načine distribucije i konzumiranja glazbe, pretežno od strane mladih, po pitanju i proizvoda i usluga. Kod proizvoda događa se dramatična promjena od tradicionalnih načina kupovine i slušanja glazbe prema novim digitalnim platformama. Isto se tako razvijaju i glazbene usluge. Tako tijekom proteklih nekoliko godina koncerti žive glazbe gube publiku, isto kao i radio postaje,a u korist digitalnih platformi za slušanje glazbe. Zbog te smo pojave proveli eksplorativno istraživanje kako bi analizirali percepcije svih tih usluga, i tradicionalnih i novih. Konkretno, želimo istražiti procjene mladih o tri najrelevantnije kategorije glazbenih usluga: radio postaja, digitalnih platformi za slušanje glazbe i pop rock-festivala. U tu svrhu koristili smo projektivne tehnike slikovnih asocijacija za prikupljanje informacija. Populacija u istraživanju bili su pojedinci u dobi od 18 do 25 godina. Nakon korištenja analize sadržaja,rezultati su bili slabi uslijed spontanog prisjećanja. Stoga smo ponovili istraživanje na više fokusiran način. Tako prikupljene informacije omogućile su nam da saznamo ne samo kako su te organizacije pozicionirane, već smo tako dobili i popis opisnih karakteristika za korištenje u sljedećem deskriptivnom istraživanju

    xDGP: A Dynamic Graph Processing System with Adaptive Partitioning

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    13 pagesMany real-world systems, such as social networks, rely on mining efficiently large graphs, with hundreds of millions of vertices and edges. This volume of information requires partitioning the graph across multiple nodes in a distributed system. This has a deep effect on performance, as traversing edges cut between partitions incurs a significant performance penalty due to the cost of communication. Thus, several systems in the literature have attempted to improve computational performance by enhancing graph partitioning, but they do not support another characteristic of real-world graphs: graphs are inherently dynamic, their topology evolves continuously, and subsequently the optimum partitioning also changes over time. In this work, we present the first system that dynamically repartitions massive graphs to adapt to structural changes. The system optimises graph partitioning to prevent performance degradation without using data replication. The system adopts an iterative vertex migration algorithm that relies on local information only, making complex coordination unnecessary. We show how the improvement in graph partitioning reduces execution time by over 50%, while adapting the partitioning to a large number of changes to the graph in three real-world scenarios

    Academic Contest and Social Networking to Promote Technology and Information Literacy among University Students

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    AbstractSpanish universities have recently adapted their studies to the requirements of the European Higher Education Area (EHEA). This process has involved the consideration of the development of computer and informational skills as an academic objective. In order to develop these skills, among other activities, an informative video has been disseminated. The design of the communication campaign, developed through viral marketing and social networks has been the result of and empirical research carried out by students of the University of Valencia. This paper describes the research objectives, questions, techniques and main findings

    Piracy Revisited: Exploring Music Users in the Age of Technology Dependency

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    This paper empirically investigates and characterizes users of recorded music, both downloaders and purchasers. To this end we analyse the role of the variables defining the different segments of music users. In doing so, we have considered two main traits influencing the use of music. First, objective variables such as demographics, music consumption habits, music genres and technology. Second, subjective variables such as motives and attitudes towards piracy. Using data from a personal survey, subsequent latent class and fuzzy analyses show that while the former characteristics are relevant in those getting music for free from the Internet, the latter don´t pay any special part, contrary to what literature had suggested. Specifically, we find evidence of age, gender, technology, and genre of music confirming previous studies carried out on this topic before the existing gap in the literature. However, there is no evidence of these variables defining patterns of purchase behaviour.JEL Codes - M300; M31
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