943 research outputs found

    Quality of Service Aware Data Stream Processing for Highly Dynamic and Scalable Applications

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    Huge amounts of georeferenced data streams are arriving daily to data stream management systems that are deployed for serving highly scalable and dynamic applications. There are innumerable ways at which those loads can be exploited to gain deep insights in various domains. Decision makers require an interactive visualization of such data in the form of maps and dashboards for decision making and strategic planning. Data streams normally exhibit fluctuation and oscillation in arrival rates and skewness. Those are the two predominant factors that greatly impact the overall quality of service. This requires data stream management systems to be attuned to those factors in addition to the spatial shape of the data that may exaggerate the negative impact of those factors. Current systems do not natively support services with quality guarantees for dynamic scenarios, leaving the handling of those logistics to the user which is challenging and cumbersome. Three workloads are predominant for any data stream, batch processing, scalable storage and stream processing. In this thesis, we have designed a quality of service aware system, SpatialDSMS, that constitutes several subsystems that are covering those loads and any mixed load that results from intermixing them. Most importantly, we natively have incorporated quality of service optimizations for processing avalanches of geo-referenced data streams in highly dynamic application scenarios. This has been achieved transparently on top of the codebases of emerging de facto standard best-in-class representatives, thus relieving the overburdened shoulders of the users in the presentation layer from having to reason about those services. Instead, users express their queries with quality goals and our system optimizers compiles that down into query plans with an embedded quality guarantee and leaves logistic handling to the underlying layers. We have developed standard compliant prototypes for all the subsystems that constitutes SpatialDSMS

    Solving the Optimal Trading Trajectory Problem Using a Quantum Annealer

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    We solve a multi-period portfolio optimization problem using D-Wave Systems' quantum annealer. We derive a formulation of the problem, discuss several possible integer encoding schemes, and present numerical examples that show high success rates. The formulation incorporates transaction costs (including permanent and temporary market impact), and, significantly, the solution does not require the inversion of a covariance matrix. The discrete multi-period portfolio optimization problem we solve is significantly harder than the continuous variable problem. We present insight into how results may be improved using suitable software enhancements, and why current quantum annealing technology limits the size of problem that can be successfully solved today. The formulation presented is specifically designed to be scalable, with the expectation that as quantum annealing technology improves, larger problems will be solvable using the same techniques.Comment: 7 pages; expanded and update

    10381 Summary and Abstracts Collection -- Robust Query Processing

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    Dagstuhl seminar 10381 on robust query processing (held 19.09.10 - 24.09.10) brought together a diverse set of researchers and practitioners with a broad range of expertise for the purpose of fostering discussion and collaboration regarding causes, opportunities, and solutions for achieving robust query processing. The seminar strove to build a unified view across the loosely-coupled system components responsible for the various stages of database query processing. Participants were chosen for their experience with database query processing and, where possible, their prior work in academic research or in product development towards robustness in database query processing. In order to pave the way to motivate, measure, and protect future advances in robust query processing, seminar 10381 focused on developing tests for measuring the robustness of query processing. In these proceedings, we first review the seminar topics, goals, and results, then present abstracts or notes of some of the seminar break-out sessions. We also include, as an appendix, the robust query processing reading list that was collected and distributed to participants before the seminar began, as well as summaries of a few of those papers that were contributed by some participants

    Studying the effect of multi-query functionality on a correlation-aware SQL-to-mapreduce translator in Hadoop version 2

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    The advent of big data has prompted both the industry and research for numerous solutions in catering to the need for data with high volume, veracity, velocity and variety properties. The notion of ever increasing data was initially publicized in 1944 by Fremont Rider, who argued that the libraries in American Universities are doubling in size every sixteen years (Press, 2013). Then, when the digital storage era came to be, it became easier than ever to store and manage large volumes of data. The need for efficient big data systems is now further fueled by the Internet of Things as it opens floodgates for, never before seen, new information flow. ^ These phenomena have called for a simpler and more scalable environment with high fault tolerance and control over availability. With that motivation in mind, and as an alternative to relational databases, numerous Not-Only Structured Query Language (NoSQL) databases were conceived. Nonetheless, relational databases and their de facto language, Structured Query Language (SQL) are still prominent among wider user groups. ^ This thesis project ventures into bridging the gap between Hadoop and relational databases through allowing multi-query functionality to a SQL-to-MapReduce translator. In addition to that, this research also includes the upgrade of the translator to a newer Hadoop version to utilize newer tools and features added since its original deployment. ^ This study also includes the analysis of the modified translator\u27s behavior under different sets of conditions. A regression model was devised for each of the experiments made and presented as significant means of understanding the data collected and any future estimates

    The feasibility of using feature-flow and label transfer system to segment medical images with deformed anatomy in orthopedic surgery

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    In computer-aided surgical systems, to obtain high fidelity three-dimensional models, we require accurate segmentation of medical images. State-of-art medical image segmentation methods have been used successfully in particular applications, but they have not been demonstrated to work well over a wide range of deformities. For this purpose, I studied and evaluated medical image segmentation using the feature-flow based Label Transfer System described by Liu and colleagues. This system has produced promising results in parsing images of natural scenes. Its ability to deal with variations in shapes of objects is desirable. In this paper, we altered this system and assessed its feasibility of automatic segmentation. Experiments showed that this system achieved better recognition rates than those in natural-scene parsing applications, but the high recognition rates were not consistent across different images. Although this system is not considered clinically practical, we may improve it and incorporate it with other medical segmentation tools
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