| 1. |
- Andrejev, Andrej, 1980-
(författare)
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Semantic Web Queries over Scientific Data
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Semantic Web and Linked Open Data provide a potential platform for interoperability of scientific data, offering a flexible model for providing machine-readable and queryable metadata. However, RDF and SPARQL gained limited adoption within the scientific community, mainly due to the lack of support for managing massive numeric data, along with certain other important features – such as extensibility with user-defined functions, query modularity, and integration with existing environments and workflows.We present the design, implementation and evaluation of Scientific SPARQL – a language for querying data and metadata combined, represented using the RDF graph model extended with numeric multidimensional arrays as node values – RDF with Arrays. The techniques used to store RDF with Arrays in a scalable way and process Scientific SPARQL queries and updates are implemented in our prototype software – Scientific SPARQL Database Manager, SSDM, and its integrations with data storage systems and computational frameworks. This includes scalable storage solutions for numeric multidimensional arrays and an efficient implementation of array operations. The arrays can be physically stored in a variety of external storage systems, including files, relational databases, and specialized array data stores, using our Array Storage Extensibility Interface. Whenever possible SSDM accumulates array operations and accesses array contents in a lazy fashion.In scientific applications numeric computations are often used for filtering or post-processing the retrieved data, which can be expressed in a functional way. Scientific SPARQL allows expressing common query sub-tasks with functions defined as parameterized queries. This becomes especially useful along with functional language abstractions such as lexical closures and second-order functions, e.g. array mappers.Existing computational libraries can be interfaced and invoked from Scientific SPARQL queries as foreign functions. Cost estimates and alternative evaluation directions may be specified, aiding the construction of better execution plans. Costly array processing, e.g. filtering and aggregation, is thus preformed on the server, saving the amount of communication. Furthermore, common supported operations are delegated to the array storage back-ends, according to their capabilities. Both expressivity and performance of Scientific SPARQL are evaluated on a real-world example, and further performance tests are run using our mini-benchmark for array queries.
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| 2. |
- Andrejev, Andrej, et al.
(författare)
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Strategies for array data retrieval from a relational back-end based on access patterns
- 2020
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Ingår i: Computing. - : Springer Science and Business Media LLC. - 0010-485X .- 1436-5057. ; 102:5, s. 1139-1158
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Tidskriftsartikel (refereegranskat)abstract
- Multidimensional numeric arrays are often serialized to binary formats for efficient storage and processing. These representations can be stored as binary objects in existing relational database management systems. To minimize data transfer overhead when arrays are large and only parts of arrays are accessed, it is favorable to split these arrays into separately stored chunks. We process queries expressed in an extended graph query language SPARQL, treating arrays as node values and having syntax for specifying array projection, element and range selection operations as part of a query. When a query selects parts of one or more arrays, only the relevant chunks of each array should be retrieved from the relational database. The retrieval is made by automatically generated SQL queries. We evaluate different strategies for partitioning the array content, and for generating the SQL queries that retrieve it on demand. For this purpose, we present a mini-benchmark, featuring a number of typical array access patterns. We draw some actionable conclusions from the performance numbers.
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| 3. |
- Badiozamany, Sobhan, 1983-, et al.
(författare)
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Framework for real-time clustering over sliding windows
- 2016
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Ingår i: Proc. 28th International Conference on Scientific and Statistical Database Management. - New York : ACM Press. - 9781450342155 ; , s. 1-13
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Konferensbidrag (refereegranskat)
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| 4. |
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| 5. |
- Haoxue, Ma, et al.
(författare)
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Distribution and synchronisation of engineering information using active database technology
- 2005
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Ingår i: Advances in Engineering Software. - : Elsevier BV. - 0965-9978 .- 1873-5339. ; 36:11-12, s. 720-728
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Tidskriftsartikel (refereegranskat)abstract
- Today, work collaboration is normal practice in developing modern products. Engineering collaborative work involves a number of team members that need to share and exchange design ideas while working with engineering analysis tools such as mechanical computer aided engineering systems. This work presents the M-Sync prototype system that uses an active database approach to enable exchange of engineering information among distributed team members in a timely manner. The distributed data is fully accessible by the local member and is automatically synchronised between different places using a database management system that support event-condition-action (ECA) database rules. Only updates introduced at one location are distributed to other locations, thereby minimizing information transfer and enhancing performance. Members working at different locations can therefore work in a peer-to-peer (P2P) manner and interactively manipulate the same set of information at the same time.
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| 6. |
- Haoxue, Ma, et al.
(författare)
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Distribution and synchronisation of engineering information using active database technology
- 2003
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Ingår i: Proceedings of the Seventh International Conference on the Application of Artificial Intelligence to Civil and Structural Engineering. - Stirling : Civil-Comp Press.
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Konferensbidrag (refereegranskat)abstract
- Work collaboration is today normal practice in developing modern products. Engineering collaborative work involve a number of team members that need to share and exchange design ideas working with engineering analysis tools, such as mechanical computer aided engineering systems. This work presents a data mediation approach, using active database technology, which enables exchange of engineering information among distributed team members in a timely manner. The distributed data is automatically synchronised between different places using a database management system that support event-condition-action (ECA) database rules. Only the updates introduced at one location are distributed to the other locations, minimizing the information transfer and enhancing the performance. Members working at different locations can therefore interactively manipulate the same set of information at the same time
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| 7. |
- Haoxue, Ma, et al.
(författare)
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Integration of multibody system analysis information based on database technology
- 2002
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Ingår i: Proceedings of the Third International Conference on Engineering Computational Technology. - Stirling : Civil-Comp Press. - 0948749849 ; , s. 123-124
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Konferensbidrag (refereegranskat)abstract
- Computer-based tools and methods have become important means of design, simulation and manufacturing in the product development process. Today, many companies function as global enterprises where practically all work is distributed and coordinated worldwide. Consequently large amounts of heterogeneous and distributed engineering data are produced. Furthermore, Computer-based analysis activities within different analysis domains normally need to combine, exchange, and share relevant product data to each other. Product development thus requires product information to be communicated between computer-based tools in such a globally distributed and heterogeneous computing environment. This paper presents how modem database technology can be used to facilitate the integration of product data, specifically information concerning multibody system (MBS) analysis. Through the examples provided, this paper shows how to use multi-database facilities to integrate MBS data between different engineering analysis tools through network; How to access MBS data by using a CORBA-based client-server model. Furthermore, it shows how to use database query language to pose queries to retrieve MBS information that is stored in the embedded database.
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| 8. |
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| 9. |
- Johansson, Henrik, et al.
(författare)
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A system for information management in simulation of manufacturing processes
- 2002
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Ingår i: Proceedings of the Third International Conference on Engineering Computational Technology. - Stirling : Civil-Comp Press. - 0948749849 ; , s. 131-132
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Konferensbidrag (refereegranskat)abstract
- The usage of virtual prototyping has had great impact on the product development process during the last decade. It has evolved from mainly being applied to high-priced and low series products to include advanced analyses on everyday products This includes analysis of many of the processes that are performed in manufacturing of a product, such as cutting, welding and heat treatment. The focus of this project is to support the use of simulation tools for the manufacturing process with efficient information management. A system is being developed using database technology were it is possible to handle information prepared for and generated by simulation of analysis models for various types of manufacturing processes
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| 10. |
- Johansson, Henrik, et al.
(författare)
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A system for information management in simulation of manufacturing processes
- 2004
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Ingår i: Advances in Engineering Software. - : Elsevier BV. - 0965-9978 .- 1873-5339. ; 35:10-11, s. 725-733
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Tidskriftsartikel (refereegranskat)abstract
- A system has been developed to manage simulation information of manufacturing processes, such as mesh information, boundary conditions and process parameters. The goal is to enable information sharing and exchange to make it possible to simulate a whole chain of manufacturing processes, and thereby predict how a modification in one manufacturing process affects the characteristics of the final product. The system has been used to predict successful simulation of a cutting process using mesh information and process parameters. An object-relational database management system is embedded in the system that uses a conceptual EXPRESS schema as database schema. The database management system is lightweight main-memory resident and incorporates an extensible and object-oriented query language. Uniform storage using database technology enables information manipulation independently of any specific simulation tool.
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