559 research outputs found

    A review of experiences with reliable multicast

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    PlinyCompute: A Platform for High-Performance, Distributed, Data-Intensive Tool Development

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    This paper describes PlinyCompute, a system for development of high-performance, data-intensive, distributed computing tools and libraries. In the large, PlinyCompute presents the programmer with a very high-level, declarative interface, relying on automatic, relational-database style optimization to figure out how to stage distributed computations. However, in the small, PlinyCompute presents the capable systems programmer with a persistent object data model and API (the "PC object model") and associated memory management system that has been designed from the ground-up for high performance, distributed, data-intensive computing. This contrasts with most other Big Data systems, which are constructed on top of the Java Virtual Machine (JVM), and hence must at least partially cede performance-critical concerns such as memory management (including layout and de/allocation) and virtual method/function dispatch to the JVM. This hybrid approach---declarative in the large, trusting the programmer's ability to utilize PC object model efficiently in the small---results in a system that is ideal for the development of reusable, data-intensive tools and libraries. Through extensive benchmarking, we show that implementing complex objects manipulation and non-trivial, library-style computations on top of PlinyCompute can result in a speedup of 2x to more than 50x or more compared to equivalent implementations on Spark.Comment: 48 pages, including references and Appendi

    An intelligent Geographic Information System for design

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    Recent advances in geographic information systems (GIS) and artificial intelligence (AI) techniques have been summarised, concentrating on the theoretical aspects of their construction and use. Existing projects combining AI and GIS have also been discussed, with attention paid to the interfacing methods used and problems uncovered by the approaches. AI and GIS have been combined in this research to create an intelligent GIS for design. This has been applied to off-shore pipeline route design. The system was tested using data from a real pipeline design project. [Continues.

    Integrated persistent object manager (IPOM) : a model to support persistence and data sharing in object-oriented database systems

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    Computer Scienc

    Protein Structure Data Management System

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    With advancement in the development of the new laboratory instruments and experimental techniques, the protein data has an explosive increasing rate. Therefore how to efficiently store, retrieve and modify protein data is becoming a challenging issue that most biological scientists have to face and solve. Traditional data models such as relational database lack of support for complex data types, which is a big issue for protein data application. Hence many scientists switch to the object-oriented databases since object-oriented nature of life science data perfectly matches the architecture of object-oriented databases, but there are still a lot of problems that need to be solved in order to apply OODB methodologies to manage protein data. One major problem is that the general-purpose OODBs do not have any built-in data types for biological research and built-in biological domain-specific functional operations. In this dissertation, we present an application system with built-in data types and built-in biological domain-specific functional operations that extends the Object-Oriented Database (OODB) system by adding domain-specific additional layers Protein-QL, Protein Algebra Architecture and Protein-OODB above OODB to manage protein structure data. This system is composed of three parts: 1) Client API to provide easy usage for different users. 2) Middleware including Protein-QL, Protein Algebra Architecture and Protein-OODB is designed to implement protein domain specific query language and optimize the complex queries, also it capsulates the details of the implementation such that users can easily understand and master Protein-QL. 3) Data Storage is used to store our protein data. This system is for protein domain, but it can be easily extended into other biological domains to build a bio-OODBMS. In this system, protein, primary, secondary, and tertiary structures are defined as internal data types to simplify the queries in Protein-QL such that the domain scientists can easily master the query language and formulate data requests, and EyeDB is used as the underlying OODB to communicate with Protein-OODB. In addition, protein data is usually stored as PDB format and PDB format is old, ambiguous, and inadequate, therefore, PDB data curation will be discussed in detail in the dissertation

    label-based security enforcement for web applications

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    This paper presents SELinks, a programming language focused on building secure multi-tier web applications. SE-Links provides a uniform programming model, in the style of LINQ and Ruby on Rails, with language syntax for accessing objects residing either in the database or at the server. Object-level security policies are expressed as fullycustomizable, first-class labels which may themselves be subject to security policies. Access to labeled data is mediated via trusted, user-provided policy enforcement functions. SELinks has two novel features that ensure security policies are enforced correctly and efficiently. First, SELinks implements a type system called Fable that allows a protected object’s type to refer to its protecting label. The type system can check that labeled data is never accessed directly by the program without first consulting the appropriate policy enforcement function. Second, SELinks compiles policy enforcement code to database-resident user-defined functions that can be called directly during query processing. Database-side checking avoids transferring data to the server needlessly, while still allowing policies to be expressed in a customizable and portable manner. Our experience with two sizable web applications, a model health-care database and a secure wiki with fine-grained security policies, indicates that cross-tier policy enforcement in SELinks is flexible, relatively easy to use, and, when compared to a single-tier approach, improves throughput by nearly an order of magnitude. SELinks is freely available

    Methodology and tools for realising product service systems for consumer products.

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    EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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