uu.seUppsala University Publications
Change search
Refine search result
45678910 301 - 350 of 831
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 301.
    Fomkin, Ruslan
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Risch, Tore
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Cost-based Optimization of Complex Scientific Queries2007In: 19th International Conference on Scientific and Statistical Database Management (SSDBM 2007), 2007Conference paper (Refereed)
  • 302.
    Fomkin, Ruslan
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Risch, Tore
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Framework for Querying Distributed Objects Managed by a Grid Infrastructure2005In: Data Management in Grids: First VLDB Workshop, DMG 2005, Trondheim, Norway, September 2-3, 2005, Revised Selected Papers, 2005Conference paper (Refereed)
    Abstract [en]

    Queries over scientific data often imply expensive analyses of data requiring a lot of computational resources available in Grids. We are developing a customizable query processor built on top of an established Grid infrastructure, the NorduGrid middleware, and have implemented a framework for managing long running queries in Grid environment. With the framework the user does not specify the detailed job and parallelization descriptions required by NorduGrid. Instead s/he specifies queries in terms of an application-oriented schema describing contents of files managed by the Grid and accessed through wrappers. When a query is received by the system it generates NorduGrid job descriptions submitted to NorduGrid for execution. The framework considers limitations of NorduGrid. It includes a submission mechanism, a job babysitter, and a generic data exchange mechanism. The submission mechanism generates a number of jobs for parallel execution of a user query over wrapped data files. The task of the babysitter is to submit generated jobs to NorduGrid for the execution, to monitor their execution status, and to download results from the execution. The generic exchange mechanism provides a way to exchange objects through files between Grid execution nodes and user applications.

  • 303.
    Fomkin, Ruslan
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Risch, Tore
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science.
    Managing Long Running Queries in Grid Environment,2004In: 1st Intl. Workshop on GRID Computing and its Applications to Data Analysis (GADA'04), 2004Conference paper (Refereed)
  • 304.
    Fomkin, Ruslan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Risch, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Optimization and Execution of Complex Scientific Queries over Uncorrelated Experimental Data2009In: Scientific and Statistical Database Management / [ed] Winslett, Marianne, Berlin: Springer-Verlag , 2009, p. 320-338Conference paper (Refereed)
    Abstract [en]

    Scientific experiments produce large volumes of data represented as complex objects that describe independent events such as particle collisions. Scientific analyses can be expressed as queries selecting objects that satisfy complex local conditions over properties of each object. The conditions include joins, aggregate functions, and numerical computations. Traditional query processing where data is loaded into a database does not perform well, since it takes time and space to load and index data. Therefore, we developed SQISLE to efficiently process in one pass large queries selecting complex objects from sources. Our contributions include runtime query optimization strategies, which during query execution collect runtime query statistics, reoptimize the query using collected statistics, and dynamically switch optimization strategies. Furthermore, performance is improved by query rewrites, temporary view materializations, and compile time evaluation of query fragments. We demonstrate that queries in SQISLE perform close to hard-coded C++ implementations of the same analyses.

  • 305.
    Forslid, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Wikén, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Automatic irony- and sarcasm detection in Social media2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis looks at different methods that have been used for irony and sarcasm detection and also includes the design and programming of a machine learning model that classifies text as sarcastic or non-sarcastic. This is done with supervised learning. Two different data set where used, one with Amazon reviews and one from Twitter. An accuracy of 87% was obtained on the Amazon data with the Support Vector Machine. For the Twitter data was an accuracy of 71% obtained with the Adaboost classifier was used. The thesis is done in collaboration with Gavagai AB, which is company working with Big-data text with expertise in semantic analysis and opinion mining.

  • 306.
    Francisco Rodríguez, María Andreína
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computing Science. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Analysis, synthesis and application of automaton-based constraint descriptions2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Constraint programming (CP) is a technology in which a combinatorial problem is modelled as a conjunction of constraints on variables ranging over given initial domains, and optionally an objective function on the variables. Such a model is given to a general-purpose solver performing systematic search to find constraint-satisfying domain values for the variables, giving an optimal value to the objective function. A constraint predicate (also known as a global constraint) does two things: from the modelling perspective, it allows a modeller to express a commonly occurring combinatorial substructure, for example that a set of variables must take distinct values; from the solving perspective, it comes with a propagation algorithm, called a propagator, which removes some but not necessarily all impossible values from the current domains of its variables when invoked during search.

    Although modern CP solvers have many constraint predicates, often a predicate one would like to use is not available. In the past, the choices were either to reformulate the model or to write one's own propagator. In this dissertation, we contribute to the automatic design of propagators for new predicates.

    Integer time series are often subject to constraints on the aggregation of the features of all maximal occurrences of some pattern. For example, the minimum width of the peaks may be constrained. Automata allow many constraint predicates for variable sequences, and in particular many time-series predicates, to be described in a high-level way. Our first contribution is an algorithm for generating an automaton-based predicate description from a pattern, a feature, and an aggregator.

    It has previously been shown how to decompose an automaton-described constraint on a variable sequence into a conjunction of constraints whose predicates have existing propagators. This conjunction provides the propagation, but it is unknown how to propagate it efficiently. Our second contribution is a tool for deriving, in an off-line process, implied constraints for automaton-induced constraint decompositions to improve propagation. Further, when a constraint predicate functionally determines a result variable that is unchanged under reversal of a variable sequence, we provide as our third contribution an algorithm for deriving an implied constraint between the result variables for a variable sequence, a prefix thereof, and the corresponding suffix.

    List of papers
    1. Automatic generation of descriptions of time-series constraints
    Open this publication in new window or tab >>Automatic generation of descriptions of time-series constraints
    2017 (English)In: IEEE 29th International Conference on Tools with Artificial Intelligence (ICTAI), IEEE Computer Society, 2017, p. 102-109Conference paper, Published paper (Refereed)
    Abstract [en]

    Integer time series are often subject to constraints on the aggregation of the features of all occurrences of some pattern within the series. For example, the number of inflexions may be constrained, or the sum of the peak maxima, or the minimum of the valley widths. Many time-series constraints can be described by transducers. The output alphabet of such a transducer consists of symbols that denote the phases of identifying the maximal occurrences of a pattern. It was recently shown how to synthesise automatically a constraint propagator and a constraint checker from such a transducer, which however has to be designed manually from a pattern. Here we define a large class of patterns, present an algorithm for automatically generating a low-level transducer from such a high-level pattern, and prove it correct. This class covers all 20 patterns of the Time-Series Constraint Catalogue, which can now be automatically extended at will.

    Place, publisher, year, edition, pages
    IEEE Computer Society, 2017
    Series
    Proceedings-International Conference on Tools With Artificial Intelligence, ISSN 1082-3409
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-332145 (URN)10.1109/ICTAI.2017.00027 (DOI)000435294700016 ()978-1-5386-3876-7 (ISBN)
    Conference
    IEEE 29th International Conference on Tools with Artificial Intelligence (ICTAI), Boston, MA, November 6–8, 2017
    Funder
    Swedish Research Council, 2012-4908Swedish Research Council, 2015-0491
    Available from: 2018-06-07 Created: 2017-10-24 Last updated: 2019-08-28Bibliographically approved
    2. Generation of implied constraints for automaton-induced decompositions
    Open this publication in new window or tab >>Generation of implied constraints for automaton-induced decompositions
    2013 (English)In: Proc. 25th International Conference on Tools with Artificial Intelligence, IEEE Computer Society, 2013, p. 1076-1083Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    IEEE Computer Society, 2013
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-218040 (URN)10.1109/ICTAI.2013.160 (DOI)978-1-4799-2971-9 (ISBN)
    Conference
    ICTAI 2013, November 4-6, Herndon, VA
    Available from: 2014-02-06 Created: 2014-02-06 Last updated: 2018-01-11Bibliographically approved
    3. Implied constraints for AUTOMATON constraints
    Open this publication in new window or tab >>Implied constraints for AUTOMATON constraints
    2015 (English)In: Global Conference on Artificial Intelligence: GCAI 2015, Manchester, UK: Cool Press , 2015, p. 113-126Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    Manchester, UK: Cool Press, 2015
    Series
    EasyChair Proceedings in Computing, ISSN 2040-557X ; 36
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-268653 (URN)
    Conference
    GCAI 2015, October 16–18, Tbilisi, Georgia
    Funder
    Swedish Research Council
    Available from: 2015-12-18 Created: 2015-12-09 Last updated: 2018-01-10Bibliographically approved
    4. Time-series constraints: Improvements and application in CP and MIP contexts
    Open this publication in new window or tab >>Time-series constraints: Improvements and application in CP and MIP contexts
    Show others...
    2016 (English)In: Integration of AI and OR Techniques in Constraint Programming, Springer, 2016, p. 18-34Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    Springer, 2016
    Series
    Lecture Notes in Computer Science, ISSN 0302-9743 ; 9676
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-298447 (URN)10.1007/978-3-319-33954-2_2 (DOI)000378993700002 ()978-3-319-33953-5 (ISBN)
    Conference
    CPAIOR 2016, May 29 – June 1, Banff, Canada
    Available from: 2016-05-12 Created: 2016-07-04 Last updated: 2018-01-10Bibliographically approved
    5. Linking prefixes and suffixes for constraints encoded using automata with accumulators
    Open this publication in new window or tab >>Linking prefixes and suffixes for constraints encoded using automata with accumulators
    Show others...
    2014 (English)In: Principles and Practice of Constraint Programming: CP 2014, Springer, 2014, p. 142-157Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    Springer, 2014
    Series
    Lecture Notes in Computer Science ; 8656
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-238534 (URN)10.1007/978-3-319-10428-7_13 (DOI)978-3-319-10427-0 (ISBN)
    Conference
    CP 2014, September 8–12, Lyon, France
    Funder
    Swedish Research Council
    Available from: 2014-09-12 Created: 2014-12-13 Last updated: 2018-01-11Bibliographically approved
    6. Systematic derivation of bounds and glue constraints for time-series constraints
    Open this publication in new window or tab >>Systematic derivation of bounds and glue constraints for time-series constraints
    Show others...
    2016 (English)In: Principles and Practice of Constraint Programming: CP 2016, Springer, 2016, p. 13-29Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    Springer, 2016
    Series
    Lecture Notes in Computer Science ; 9892
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-302048 (URN)10.1007/978-3-319-44953-1_2 (DOI)000389019700003 ()978-3-319-44952-4 (ISBN)
    Conference
    CP 2016, September 5–9, Toulouse, France
    Funder
    Swedish Research Council, 2011-6133Swedish Research Council, 2012-4908
    Available from: 2016-08-23 Created: 2016-08-29 Last updated: 2018-01-10Bibliographically approved
  • 307.
    Francisco Rodríguez, María Andreína
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Automatic generation of descriptions of time-series constraints2017In: IEEE 29th International Conference on Tools with Artificial Intelligence (ICTAI), IEEE Computer Society, 2017, p. 102-109Conference paper (Refereed)
    Abstract [en]

    Integer time series are often subject to constraints on the aggregation of the features of all occurrences of some pattern within the series. For example, the number of inflexions may be constrained, or the sum of the peak maxima, or the minimum of the valley widths. Many time-series constraints can be described by transducers. The output alphabet of such a transducer consists of symbols that denote the phases of identifying the maximal occurrences of a pattern. It was recently shown how to synthesise automatically a constraint propagator and a constraint checker from such a transducer, which however has to be designed manually from a pattern. Here we define a large class of patterns, present an algorithm for automatically generating a low-level transducer from such a high-level pattern, and prove it correct. This class covers all 20 patterns of the Time-Series Constraint Catalogue, which can now be automatically extended at will.

  • 308. Francisco Rodríguez, María Andreína
    et al.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Consistency of constraint networks induced by automaton-based constraint specifications2011In: Proc. 10th International Workshop on Constraint Modelling and Reformulation, Italy: Department of Mathematics and Informatics, University of Perugia , 2011, p. 117-131Conference paper (Refereed)
  • 309.
    Francisco Rodríguez, María Andreína
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Generation of implied constraints for automaton-induced decompositions2013In: Proc. 25th International Conference on Tools with Artificial Intelligence, IEEE Computer Society, 2013, p. 1076-1083Conference paper (Refereed)
  • 310.
    Francisco Rodríguez, María Andreína
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Implied constraints for AUTOMATON constraints2015In: Global Conference on Artificial Intelligence: GCAI 2015, Manchester, UK: Cool Press , 2015, p. 113-126Conference paper (Refereed)
  • 311. Franco, Juliana
    et al.
    Clebsch, Sylvan
    Drossopoulou, Sophia
    Vitek, Jan
    Wrigstad, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Correctness of a concurrent object collector for actor languages2018In: Programming Languages and Systems, Springer, 2018, p. 885-911Conference paper (Refereed)
  • 312. Franco, Juliana
    et al.
    Hagelin, Martin
    Wrigstad, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Drossopoulou, Sophia
    Eisenbach, Susan
    You can have it all: abstraction and good cache performance2017Conference paper (Refereed)
  • 313.
    Franco, Juliana
    et al.
    Microsoft Research Cambridge.
    Tasos, Alexandros
    Imperial College London.
    Drossopoulou, Sophia
    Imperial College London.
    Wrigstad, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Eisenbach, Susan
    Imperial College London.
    Safely Abstracting Memory Layouts2018In: 20th Workshop on Formal Techniques for Java-like Programs, 2018Conference paper (Refereed)
    Abstract [en]

    Modern architectures require applications to make effective use of caches to achieve high performance and hide memory latency. This in turn requires careful consideration of placement of data in memory to exploit spatial locality, leverage hardware prefetching and conserve memory bandwidth. In unmanaged languages like C++, memory optimisations are common, but at the cost of losing object abstraction and memory safety. In managed languages like Java and C#, the abstract view of memory and proliferation of moving compacting garbage collection does not provide enough control over placement and layout. We have proposed SHAPES, a type-driven abstract placement specification that can be integrated with object-oriented languages to enable memory optimisations. SHAPES preserves both memory and object abstraction. In this paper, we formally specify the SHAPES semantics and describe its memory safety model.

  • 314.
    Franco, Juliana
    et al.
    Imperial College London.
    Wrigstad, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Drossopoulou, Sophia
    Imperial College London.
    Towards Enabling Low-Level Memory Optimisations at the High-Level with Ownership Annotations2016Conference paper (Refereed)
    Abstract [en]

    In modern architectures, due to the huge gap between CPU performance and memory bandwidth, an application’s performance highly depends on the speed at which the system is able to deliver data to operate on. The placement of data in memory affects the number of cache misses, and thus the overall speed of the application. To address this, pooling and splitting are two techniques that allow to group or split data in memory, according to whether they are usually accessed together or separately. However, theseare either low-level optimisations, or outside the control of the programmer. We propose OHMM, an object-oriented programming language that uses ownership-like annotations to express high-level constraintson how objects should be placed in memory. These annotations will allow the runtime to allocate objects using pooling andsplitting, and thus lead to efficient data accesses. In this short paper, we explain OHMM through an example, show how the objects will be laid out, and informally argue the benefits in terms of cache performance.

  • 315. Fredriksson, Jesper
    et al.
    Svensson, Per
    Risch, Tore
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Mediator-Based Evolutionary design and Meta-Analysis Environments2001In: Journal of Intelligent Information Systems, Vol. 17, no 2-3, p. 301-322Article in journal (Refereed)
  • 316.
    Gengelbach, Arve
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Weber, Tjark
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Model-theoretic Conservative Extension of Definitional Theories2018In: Electronical Notes in Theoretical Computer Science, ISSN 1571-0661, E-ISSN 1571-0661, Vol. 338, p. 133-145Article in journal (Refereed)
    Abstract [en]

    Many logical frameworks allow extensions, i.e. the introduction of new symbols, by definitions. Different from asserting arbitrary non-logical axioms, extensions by definitions are expected to be conservative: they should entail no new theorems in the original language. The popular theorem prover Isabelle implements a variant of higher-order logic that allows ad hoc overloading of constants. In 2015, Kunčar and Popescu introduced definitional theories, which impose a non-circularity condition on constant and type definitions in this logic, and showed that this condition is sufficient for definitional extensions to preserve consistency. We strengthen and generalize this result by showing that extensions of definitional theories are model-theoretic conservative, i.e. every model of the original theory can be expanded to a model of the extended theory.

  • 317. Gerakios, Prodromos
    et al.
    Papaspyrou, Nikolaos
    Sagonas, Konstantinos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    A concurrent language with a uniform treatment of regions and locks2010In: Proc. 2nd Workshop on Programming Language Approaches to Concurrency and communication-cEntric Software: PLACES 2009, 2010, p. 79-93Conference paper (Refereed)
  • 318. Gerakios, Prodromos
    et al.
    Papaspyrou, Nikolaos
    Sagonas, Konstantinos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    A type and effect system for deadlock avoidance in low-level languages2011In: Proc. 6th International Workshop on Types in Language Design and Implementation, New York: ACM Press , 2011, p. 15-28Conference paper (Refereed)
  • 319. Gerakios, Prodromos
    et al.
    Papaspyrou, Nikolaos
    Sagonas, Konstantinos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Race-free and memory-safe multithreading: Design and implementation in Cyclone2010In: Proc. 5th International Workshop on Types in Language Design and Implementation, New York: ACM Press , 2010, p. 15-26Conference paper (Refereed)
  • 320. Gerakios, Prodromos
    et al.
    Papaspyrou, Nikolaos
    Sagonas, Konstantinos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Static safety guarantees for a low-level multithreaded language with regions2014In: Science of Computer Programming, ISSN 0167-6423, E-ISSN 1872-7964, Vol. 80, no Part B, p. 223-263Article in journal (Refereed)
    Abstract [en]

    We present the design of a formal low-level multithreaded language with advanced region-based memory management and thread synchronization primitives, where well-typed programs are memory safe and race free. In our language, regions and locks are combined in a single hierarchy and are subject to uniform ownership constraints imposed by this hierarchical structure: deallocating a region causes its sub-regions to be deallocated. Similarly, when a region is read/write-protected, then its sub-regions inherit the same access rights. We discuss aspects of the integration and implementation of the formal language within Cyclone and evaluate the performance of code produced by the modified Cyclone compiler against highly optimized C programs using pthreads. Our results show that the performance overhead for guaranteed race freedom and memory safety is in most cases acceptable.

  • 321. Ghani, Neil
    et al.
    Yemane, Kidane
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Victor, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Relationally Staged Computations in Calculi of Mobile Processes2004In: Proc. 7th Workshop on Coalgebraic Methods in Computer Science / [ed] J. Adámek, S. Milius, Elsevier , 2004, p. 105-120Conference paper (Refereed)
    Abstract [en]

    We apply the recently developed techniques of higher order abstract syntax and functorial operational semantics to give a compositional and fully abstract semantics for the π-calculus equipped with open bisimulation. The key novelty in our work is the realisation that the sophistication of open bisimulation requires us to move from the usual semantic domain of presheaves over subcategories of Set to presheaves over subcategories of Rel. This extra structure is crucial in controlling the renaming of extruded names and in providing a variety of different dynamic allocation operators to model the different binders of the π-calculus.

  • 322.
    Ghariblou, Saeed
    et al.
    Univ Tehran, Fac New Sci & Technol, Tehran, Iran; Inst Res Fundamental Sci IPM, Sch Comp Sci, Tehran, Iran.
    Salehi, Mostafa
    Univ Tehran, Fac New Sci & Technol, Tehran, Iran; Inst Res Fundamental Sci IPM, Sch Comp Sci, Tehran, Iran.
    Magnani, Matteo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Jalili, Mahdi
    RMIT Univ, Sch Engn, Melbourne, Vic, Australia.
    Shortest Paths in Multiplex Networks2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 2142Article in journal (Refereed)
    Abstract [en]

    The shortest path problem is one of the most fundamental networks optimization problems. Nowadays, individuals interact in extraordinarily numerous ways through their offline and online life (e.g., co-authorship, co-workership, or retweet relation in Twitter). These interactions have two key features. First, they have a heterogeneous nature, and second, they have different strengths that are weighted based on their degree of intimacy, trustworthiness, service exchange or influence among individuals. These networks are known as multiplex networks. To our knowledge, none of the previous shortest path definitions on social interactions have properly reflected these features. In this work, we introduce a new distance measure in multiplex networks based on the concept of Pareto efficiency taking both heterogeneity and weighted nature of relations into account. We then model the problem of finding the whole set of paths as a form of multiple objective decision making and propose an exact algorithm for that. The method is evaluated on five real-world datasets to test the impact of considering weights and multiplexity in the resulting shortest paths. As an application to find the most influential nodes, we redefine the concept of betweenness centrality based on the proposed shortest paths and evaluate it on a real-world dataset from two-layer trade relation among countries between years 2000 and 2015.

  • 323.
    Giantsios, Aggelos
    et al.
    Natl Tech Univ Athens, Sch Elect & Comp Engn, Athens, Greece.
    Papaspyrou, Nikolaos
    Natl Tech Univ Athens, Sch Elect & Comp Engn, Athens, Greece.
    Sagonas, Konstantinos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science. Natl Tech Univ Athens, Sch Elect & Comp Engn, Athens, Greece.
    Concolic testing for functional languages2017In: Science of Computer Programming, ISSN 0167-6423, E-ISSN 1872-7964, Vol. 147, p. 109-134Article in journal (Refereed)
    Abstract [en]

    Concolic testing is a software testing technique that simultaneously combines concrete execution of a program (given specific input, along specific paths) with symbolic execution (generating new test inputs that explore other paths, which gives better path coverage than random test case generation). So far, concolic testing has been applied, mainly at the level of bytecode or assembly code, to programs written in imperative languages that manipulate primitive data types such as integers and arrays. In this article, we demonstrate its application to a functional programming language core, the functional subset of Core Erlang, that supports pattern matching, structured recursive data types such as lists, recursion and higher-order functions. We present CutEr, a tool implementing this testing technique, and describe its architecture, the challenges that it needs to address, its current limitations, and report some experiences from its use.

  • 324.
    Gidófalvi, Gyözö
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Bach Pedersen, Torben
    Instant Social Ride-Sharing2008In: Proc. 15th World Congress on Intelligent Transport Systems, Intelligent Transportation Society of America , 2008, p. 8-Conference paper (Refereed)
  • 325.
    Gidófalvi, Gyözö
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Bach Pedersen, Torben
    Mining long, sharable patterns in trajectories of moving objects2009In: Geoinformatica, ISSN 1384-6175, E-ISSN 1573-7624, Vol. 13, no 1, p. 27-55Article in journal (Refereed)
  • 326.
    Gidófalvi, Gyözö
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Bach Pedersen, Torben
    Risch, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Zeitler, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Highly Scalable Trip Grouping for Large Scale Collective Transportation Systems2008In: Proc. 11th International Conference on Extending Database Technology, EDBT 2008, 2008Conference paper (Refereed)
    Abstract [en]

    Transportation–related problems, like road congestion, park-ing, and pollution are increasing in most cities. In order toreduce traffic, recent work has proposed methods for vehiclesharing, for example for sharing cabs by grouping “closeby”cab requests and thus minimizing transportation cost andutilizing cab space. However, the methods proposed so fardo not scale to large data volumes, which is necessary tofacilitate large scale collective transportation systems, e.g.,ride–sharing systems for large cities.This paper presents highly scalable “trip grouping” algo-rithms, that generalize previous techniques and support in-put rates that can be orders of magnitude larger. The follow-ing three contributions make the grouping algorithms scal-able. First, the basic grouping algorithm is expressed as acontinuous stream query in a data stream management sys-tem to allow for very large flows of requests. Second, follow-ing the divide–and–conquer paradigm, four space–partition-ing policies for dividing the input data stream into sub–streams are developed and implemented using continuousstream queries. Third, using the partitioning policies, par-allel implementations of the grouping algorithm in a paral-lel computing environment are described. Extensive experi-mental results show that the parallel implementation usingsimple adaptive partitioning methods can achieve speed–upsof several orders of magnitudes without significantly effect-ing the quality of the grouping.

  • 327.
    Gidófalvi, Gyözö
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Huang, Xuegang
    Bach Pedersen, Torben
    Privacy-Preserving Trajectory Collection2008In: Proc. 16th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, New York: ACM Press , 2008, p. 46:1-4Conference paper (Refereed)
  • 328. Gomes, Victor B. F.
    et al.
    Guttmann, Walter
    Höfner, Peter
    Struth, Georg
    Weber, Tjark
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Kleene Algebras with Domain2016In: Archive of Formal Proofs, ISSN 2150-914xArticle in journal (Refereed)
  • 329.
    Gordon, Andrew D.
    et al.
    Microsoft Research, Cambridge.
    Aizatulin, Mihhail
    Open University.
    Borgström, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Claret, Guillaume
    Microsoft Research.
    Graepel, Thore
    Microsoft Research.
    Nori, Aditya
    Microsoft Research.
    Rajamani, Sriram
    Microsoft Research.
    Russo, Claudio
    Microsoft Research.
    A Model-Learner Pattern for Bayesian Reasoning2013In: Proceedings of the 40th annual ACM SIGPLAN-SIGACT symposium on Principles of programming languages / [ed] Roberto Giacobazzi, Radhia Cousot, New York, NY: Association for Computing Machinery (ACM), 2013, p. 403-416Conference paper (Refereed)
    Abstract [en]

    A Bayesian model is based on a pair of probability distributions, known as the prior and sampling distributions. A wide range of fundamental machine learning tasks, including regression, classification, clustering, and many others, can all be seen as Bayesian models. We propose a new probabilistic programming abstraction, a typed Bayesian model, which is based on a pair of probabilistic expressions for the prior and sampling distributions. A sampler for a model is an algorithm to compute synthetic data from its sampling distribution, while a learner for a model is an algorithm for probabilistic inference on the model. Models, samplers, and learners form a generic programming pattern for model-based inference. They support the uniform expression of common tasks including model testing, and generic compositions such as mixture models, evidence-based model averaging, and mixtures of experts. A formal semantics supports reasoning about model equivalence and implementation correctness. By developing a series of examples and three learner implementations based on exact inference, factor graphs, and Markov chain Monte Carlo, we demonstrate the broad applicability of this new programming pattern.

  • 330. Gordon, Andrew D.
    et al.
    Graepel, Thore
    Rolland, Nicolas
    Russo, Claudio
    Borgström, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Guiver, John
    Tabular: a schema-driven probabilistic programming language2014In: Proc. 41st ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, New York: ACM Press, 2014, p. 321-334Conference paper (Refereed)
    Abstract [en]

    We propose a new kind of probabilistic programming language for machine learning. We write programs simply by annotating existing relational schemas with probabilistic model expressions. We describe a detailed design of our language, Tabular, complete with formal semantics and type system. A rich series of examples illustrates the expressiveness of Tabular. We report an implementation, and show evidence of the succinctness of our notation relative to current best practice. Finally, we describe and verify a transformation of Tabular schemas so as to predict missing values in a concrete database. The ability to query for missing values provides a uniform interface to a wide variety of tasks, including classification, clustering, recommendation, and ranking.

  • 331. Gordon, Andrew D.
    et al.
    Russo, Claudio
    Szymczak, Marcin
    Borgström, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Rolland, Nicolas
    Graepel, Thore
    Tarlow, Daniel
    Probabilistic programs as spreadsheet queries2015In: Programming Languages and Systems, Springer Berlin/Heidelberg, 2015, p. 1-25Conference paper (Refereed)
  • 332.
    Grande, Virginia
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Parrow, Joachim
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Motivation and Grade Gap Related to Gender in a Programming Course2015Conference paper (Refereed)
  • 333. Grinchtein, Olga
    et al.
    Carlsson, Mats
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    A constraint optimisation model for analysis of telecommunication protocol logs2015In: Tests and Proofs: TAP 2015, Springer, 2015, p. 137-154Conference paper (Refereed)
    Abstract [en]

    Testing a telecommunication protocol often requires protocol log analysis. A protocol log is a sequence of messages with timestamps. Protocol log analysis involves checking that the content of messages and timestamps are correct with respect to the protocol specification. We model a protocol specification using constraint programming (MiniZinc), and we present an approach where a constraint solver is used to perform protocol log analysis. Our case study is the Public Warning System service, which is a part of the Long Term Evolution (LTE) 4G standard. We were able to analyse logs containing more than 3000 messages with more than 4000 errors.

  • 334.
    Grinchtein, Olga
    et al.
    Ericsson AB, Stockholm, Sweden..
    Carlsson, Mats
    SICS, Stockholm, Sweden..
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Testing of a telecommunication protocol using constraint programming2015In: 2015 IEEE Eighth International Conference On Software Testing, Verification And Validation Workshops (ICSTW), 2015Conference paper (Refereed)
    Abstract [en]

    We present an approach of implementing part of a telecommunication test harness using constraint programming. Our case study is the Public Warning System service, which is a part of the Long Term Evolution (LTE) 4G standard.

  • 335. Grufman, S
    et al.
    Samson, F
    Embury, S.M.
    Gray, P.M.D
    Risch, Tore
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Distributing Semantic Constraints Between Heterogeneous Databases1997In: The 13th International Conference on Data Engineering (ICDE'97), 1997Conference paper (Refereed)
  • 336.
    Gustafsson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science.
    Sagonas, Konstantinos
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science.
    Adaptive Pattern Matching on Binary Data2004In: In Programming Languages and Systems. Proceedings of the 13th European Symposium On Programming: Volume 2986 in LNCS, 2004, p. 124-139Conference paper (Refereed)
  • 337.
    Gustafsson, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Sagonas, Konstantinos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Applications, Implementation and Performance Evaluation of Bit Stream Programming in Erlang2007In: Practical Aspects of Declarative Languages: PADL 2007 / [ed] Hanus, M, 2007, p. 94-108Conference paper (Refereed)
    Abstract [en]

    Writing code that manipulates bit streams is a painful and error-prone programming task, often performed via bit twiddling techniques such as explicit bit shifts and bit masks in programmer-allocated buffers. Still, this kind of programming is necessary in many application areas ranging from decoding streaming media files to implementing network protocols. In this paper we employ high-level constructs from declarative programming, such as pattern matching at the bit level and bit stream comprehensions, and show how a variety of bit stream programming applications can be written in a succinct, less error-prone, and totally memory-safe manner. We also describe how these constructs can be implemented efficiently. The resulting performance is superior to that of other (purely) functional languages and competitive to that of low-level languages such as C.

  • 338.
    Gustafsson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Sagonas, Konstantinos
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. Datalogi.
    Bit-level Binaries and Generalized Comprehensions in Erlang2005In: Proceedings of the Fourth ACM SIGPLAN Erlang Workshop, 2005, p. 1-8Conference paper (Refereed)
  • 339.
    Gustafsson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science. CSD.
    Sagonas, Konstantinos
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Computing Science.
    Native Code Compilation of Erlang's Bit Syntax2002In: Proceedings of the ACM SIGPLAN Erlang Workshop, Pittsburgh, Pennsylvania, 2002, p. 6-15Conference paper (Refereed)
  • 340.
    Gutkovas, Ramunas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computing Science. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Advancing concurrent system verification: Type based approach and tools2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Concurrent systems, i.e., systems of parallel processes, are nearly ubiquitous and verifying the correctness of such systems is becoming an important subject. Many formalisms were invented for such purpose, however, new types of systems are introduced and there is a need for handling larger systems. One examples is wireless sensor networks that are being deployed in increasing numbers in various areas; and in particular safety-critical areas, e.g., bush fire detection. Thus, ensuring their correctness is important.

    A process calculus is a formal language for modeling concurrent systems. The pi-calculus is a prominent example of such a language featuring message-passing concurrency. Psi-calculi is a parametric framework that extends the pi-calculus with arbitrary data and logics. Psi-calculi feature a universal theory with its results checked in an automated theorem prover ensuring their correctness.

    In this thesis, we extend psi-calculi expressiveness and modeling precision by introducing a sort system and generalised pattern matching. We show that the extended psi-calculi enjoy the same meta-theoretical results.

    We have developed the Pwb, a tool for the psi-calculi framework. The tool provides a high-level interactive symbolic execution and automated behavioral equivalence checking. We exemplify the use of the tool by developing a high-level executable model of a data collection protocol for wireless sensor networks.

    We are the first to introduce a session types based system for systems with unreliable communication. Remarkably, we do not need to add specific extensions to the types to accommodate such systems. We prove the standard desirable properties for type systems hold also for our type system.

    List of papers
    1. The Psi-Calculi Workbench: A Generic Tool for Applied Process Calculi
    Open this publication in new window or tab >>The Psi-Calculi Workbench: A Generic Tool for Applied Process Calculi
    2015 (English)In: ACM Transactions on Embedded Computing Systems, ISSN 1539-9087, E-ISSN 1558-3465, Vol. 14, no 1, article id 9Article in journal (Refereed) Published
    Abstract [en]

    Psi-calculi is a parametric framework for extensions of the pi-calculus with arbitrary data and logic. All instances of the framework inherit machine-checked proofs of the metatheory such as compositionality and bisimulation congruence. We present a generic analysis tool for psi-calculus instances, enabling symbolic execution and (bi)simulation checking for both unicast and broadcast communication. The tool also provides a library for implementing new psi-calculus instances. We provide examples from traditional communication protocols and wireless sensor networks. We also describe the theoretical foundations of the tool, including an improved symbolic operational semantics, with additional support for scoped broadcast communication.

    National Category
    Computer Sciences
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:uu:diva-233750 (URN)10.1145/2682570 (DOI)000349302200009 ()
    Projects
    ProFuNUPMARC
    Funder
    Swedish Foundation for Strategic Research , RIT08­0065
    Available from: 2015-01-21 Created: 2014-10-09 Last updated: 2018-01-11Bibliographically approved
    2. Session types for broadcasting
    Open this publication in new window or tab >>Session types for broadcasting
    2014 (English)In: Proc. 7th Workshop on Programming Language Approaches to Concurrency and Communication-cEntric Software, 2014, p. 25-31Conference paper, Published paper (Refereed)
    Series
    Electronic Proceedings in Theoretical Computer Science ; 155
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-230882 (URN)10.4204/EPTCS.155.4 (DOI)
    Conference
    PLACES 2014, April 12, Grenoble, France
    Projects
    ProFuN
    Available from: 2014-06-13 Created: 2014-09-01 Last updated: 2018-01-11Bibliographically approved
    3. A Sorted Semantic Framework for Applied Process Calculi (extended abstract)
    Open this publication in new window or tab >>A Sorted Semantic Framework for Applied Process Calculi (extended abstract)
    Show others...
    2014 (English)In: Trustworthy Global Computing: TGC 2013, Springer Berlin/Heidelberg, 2014, p. 103-118Conference paper, Published paper (Refereed)
    Abstract [en]

    Applied process calculi include advanced programming constructs such as type systems, communication with pattern matching, encryption primitives, concurrent constraints, nondeterminism, process creation, and dynamic connection topologies. Several such formalisms, e.g. the applied pi calculus,  are extensions of the the pi-calculus; a growing number is geared towards particular applications or computational paradigms.

    Our goal is a unified framework to represent different process calculi and notions of computation. To this end, we extend our previous work on psi-calculi with novel abstract patterns and pattern matching, and add sorts to the data term language, giving sufficient criteria for subject reduction to hold. Our framework can accommodate several existing process calculi; the resulting transition systems are isomorphic to the originals up to strong bisimulation. We also demonstrate  different notions of computation on data terms, including cryptographic primitives and a lambda-calculus with erratic choice. Substantial parts of the meta-theory of sorted psi-calculi have been machine-checked using Nominal Isabelle.

    Place, publisher, year, edition, pages
    Springer Berlin/Heidelberg, 2014
    Series
    Lecture Notes in Computer Science, ISSN 0302-9743 ; 8358
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-203382 (URN)10.1007/978-3-319-05119-2_7 (DOI)978-3-319-05118-5 (ISBN)
    Conference
    8th International Symposium on Trustworthy Global Computing, August 30-31, 2013, Buenos Aires, Argentina
    Projects
    UPMARCProFuN
    Funder
    Swedish Foundation for Strategic Research , RIT08­0065
    Available from: 2014-03-08 Created: 2013-07-09 Last updated: 2018-01-11
  • 341.
    Gutkovas, Ramūnas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computing Science. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Languages, Logics, Types and Tools for Concurrent System Modelling2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A concurrent system is a computer system with components that run in parallel and interact with each other. Such systems are ubiquitous and are notably responsible for supporting the infrastructure for transport, commerce and entertainment. They are very difficult to design and implement correctly: many different modeling languages and verification techniques have been devised to reason about them and verifying their correctness. However, existing languages and techniques can only express a limited range of systems and properties.

    In this dissertation, we address some of the shortcomings of established models and theories in four ways: by introducing a general modal logic, extending a modelling language with types and a more general operation, providing an automated tool support, and adapting an established behavioural type theory to specify and verify systems with unreliable communication.

    A modal logic for transition systems is a way of specifying properties of concurrent system abstractly. We have developed a modal logic for nominal transition systems. Such systems are common and include the pi-calculus and psi-calculi. The logic is adequate for many process calculi with regard to their behavioural equivalence even for those that no logic has been considered, for example, CCS, the pi-calculus, psi-calculi, the spi-calculus, and the fusion calculus.

    The psi-calculi framework is a parametric process calculi framework that subsumes many existing process calculi. We extend psi-calculi with a type system, called sorts, and a more general notion of pattern matching in an input process. This gives additional expressive power allowing us to capture directly even more process calculi than was previously possible. We have reestablished the main results of psi-calculi to show that the extensions are consistent.

    We have developed a tool that is based on the psi-calculi, called the psi-calculi workbench. It provides automation for executing the psi-calculi processes and generating a witness for a behavioural equivalence between processes. The tool can be used both as a library and as an interactive application.

    Lastly, we developed a process calculus for unreliable broadcast systems and equipped it with a binary session type system. The process calculus captures the operations of scatter and gather in wireless sensor and ad-hoc networks. The type system enjoys the usual property of subject reduction, meaning that well-typed processes reduce to well-typed processes. To cope with unreliability, we also introduce a notion of process recovery that does not involve communication. This is the first session type system for a model with unreliable communication.

    List of papers
    1. Modal Logics for Nominal Transition Systems
    Open this publication in new window or tab >>Modal Logics for Nominal Transition Systems
    Show others...
    2016 (English)In: Archive of Formal Proofs, ISSN 2150-914xArticle in journal (Refereed) Published
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-300027 (URN)
    Projects
    UPMARC
    Funder
    Swedish Research Council, 2013-4853
    Available from: 2016-10-25 Created: 2016-08-01 Last updated: 2019-02-25
    2. A Sorted Semantic Framework for Applied Process Calculi
    Open this publication in new window or tab >>A Sorted Semantic Framework for Applied Process Calculi
    Show others...
    2016 (English)In: Logical Methods in Computer Science, ISSN 1860-5974, E-ISSN 1860-5974, Vol. 12, no 1, p. 1-49, article id 8Article in journal (Refereed) Published
    Abstract [en]

    Applied process calculi include advanced programming constructs such as type systems, communication with pattern matching, encryption primitives, concurrent constraints, nondeterminism, process creation, and dynamic connection topologies. Several such formalisms, e.g. the applied pi calculus, are extensions of the the pi-calculus; a growing number is geared towards particular applications or computational paradigms.

    Our goal is a unified framework to represent different process calculi and notions of computation. To this end, we extend our previous work on psi-calculi with novel abstract patterns and pattern matching, and add sorts to the data term language, giving sufficient criteria for subject reduction to hold. Our framework can directly represent several existing process calculi; the resulting transition systems are isomorphic to the originals up to strong bisimulation. We also demonstrate different notions of computation on data terms, including cryptographic primitives and a lambda-calculus with erratic choice. Finally, we prove standard congruence and structural properties of bisimulation; the proof has been machine-checked using Nominal Isabelle in the case of a single name sort.

    Keywords
    Expressiveness, Pattern matching, Type systems, Theorem proving, pi-calculus, Nominal sets
    National Category
    Computer Sciences
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:uu:diva-262199 (URN)10.2168/LMCS-12(1:8)2016 (DOI)000374769600004 ()
    Projects
    UPMARC
    Funder
    Swedish Research Council, 2013-4853
    Available from: 2016-03-31 Created: 2015-09-09 Last updated: 2019-02-25Bibliographically approved
    3. A Session Type System for Unreliable Broadcast Communication
    Open this publication in new window or tab >>A Session Type System for Unreliable Broadcast Communication
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

     Session types are formal specifications of communication protocols, allowing protocol implementations to be verified by typechecking. Up to now, session type disciplines have assumed that the communication medium is reliable, with no loss of messages. However, unreliable broadcast communication is common in a wide class of distributed systems such as ad-hoc and wireless sensor networks. Often such systems have structured communication patterns that should be amenable to analysis by means of session types. We introduce a process calculus with unreliable broadcast communication, and equip it with a session type system that we show is sound. We capture two common operations, scatter and gather, inhabiting dual session types. To cope with unreliability in a session we introduce an autonomous recovery mechanism that does not require acknowledgements from session participants. Our session type formalisation is the first to consider unreliable communication.

    Keywords
    session type, process calculus, broadcast, unreliable
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-300028 (URN)
    Available from: 2016-08-01 Created: 2016-08-01 Last updated: 2018-01-10Bibliographically approved
    4. The Psi-Calculi Workbench: A Generic Tool for Applied Process Calculi
    Open this publication in new window or tab >>The Psi-Calculi Workbench: A Generic Tool for Applied Process Calculi
    2015 (English)In: ACM Transactions on Embedded Computing Systems, ISSN 1539-9087, E-ISSN 1558-3465, Vol. 14, no 1, article id 9Article in journal (Refereed) Published
    Abstract [en]

    Psi-calculi is a parametric framework for extensions of the pi-calculus with arbitrary data and logic. All instances of the framework inherit machine-checked proofs of the metatheory such as compositionality and bisimulation congruence. We present a generic analysis tool for psi-calculus instances, enabling symbolic execution and (bi)simulation checking for both unicast and broadcast communication. The tool also provides a library for implementing new psi-calculus instances. We provide examples from traditional communication protocols and wireless sensor networks. We also describe the theoretical foundations of the tool, including an improved symbolic operational semantics, with additional support for scoped broadcast communication.

    National Category
    Computer Sciences
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:uu:diva-233750 (URN)10.1145/2682570 (DOI)000349302200009 ()
    Projects
    ProFuNUPMARC
    Funder
    Swedish Foundation for Strategic Research , RIT08­0065
    Available from: 2015-01-21 Created: 2014-10-09 Last updated: 2018-01-11Bibliographically approved
  • 342.
    Hanteer, Obaida
    et al.
    IT University Of Copenhagen, DssLab, Denmark.
    Rossi, Luca
    IT University Of Copenhagen, DssLab, Denmark.
    Vega, Davide
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Magnani, Matteo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    From Interaction to Participation: The Role of the Imagined Audience in Social Media Community Detection and an Application to Political Communication on Twitter2018In: 2018 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM), IEEE Computer Society , 2018, p. 531-534Conference paper (Refereed)
    Abstract [en]

    In the context of community detection in online social media, a lot of effort has been put into the definition of sophisticated network clustering algorithms and much less on the equally crucial process of obtaining high-quality input data. User-interaction data explicitly provided by social media platforms has largely been used as the main source of data because of its easy accessibility. However, this data does not capture a fundamental and much more frequent type of participatory behavior where users do not explicitly mention others but direct their messages to an invisible audience following a common hashtag. In the context of multiplex community detection, we show how to construct an additional data layer about user participation not relying on explicit interactions between users, and how this layer can be used to find different types of communities in the context of Twitter political communication.

  • 343.
    Hassani Bijarbooneh, Farshid
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Cloud-Assisted Data Fusion and Sensor Selection for Internet-of-ThingsManuscript (preprint) (Other academic)
    Abstract [en]

    The Internet of Things (IoT) is connecting people and smart devices on a scale that once was unimaginable. One major challenge for the IoT is to handle vast amount of sensing data generated from the smart devices that are resource-limited and subject to missing data due to link or node failures. By exploring cloud computing with the IoT, we present a cloud-based solution that takes into account the link quality and spatio-temporal correlation of data to minimise energy consumption by selecting sensors for sampling and relaying data. We propose a multi-phase adaptive sensing algorithm with belief propagation protocol (ASBP), which can provide high data quality and reduce energy consumption by turning on only a small number of nodes in the network. We formulate the sensor selection problem and solve it using constraint programming (CP) and greedy search. We then use our message passing algorithm (belief propagation) for performing inference to reconstruct the missing sensing data. ASBP is evaluated based on the data collected from real sensors. The results show that while maintaining a satisfactory level of data quality and prediction accuracy, ASBP can provide load balancing among sensors successfully and preserves 80\% more energy compared with the case where all sensor nodes are actively involved.

  • 344.
    Hassani Bijarbooneh, Farshid
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computing Science. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Constraint Programming for Wireless Sensor Networks2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years, wireless sensor networks (WSNs) have grown rapidly and have had a substantial impact in many applications. A WSN is a network that consists of interconnected autonomous nodes that monitor physical and environmental conditions, such as temperature, humidity, pollution, etc. If required, nodes in a WSN can perform actions to affect the environment.

    WSNs present an interesting and challenging field of research due to the distributed nature of the network and the limited resources of the nodes. It is necessary for a node in a WSN to be small to enable easy deployment in an environment and consume as little energy as possible to prolong its battery lifetime. There are many challenges in WSNs, such as programming a large number of nodes, designing communication protocols, achieving energy efficiency, respecting limited bandwidth, and operating with limited memory. WSNs are further constrained due to the deployment of the nodes in indoor and outdoor environments and obstacles in the environment.

    In this dissertation, we study some of the fundamental optimisation problems related to the programming, coverage, mobility, data collection, and data loss of WSNs, modelled as standalone optimisation problems or as optimisation problems integrated with protocol design. Our proposed solution methods come from various fields of research including constraint programming, integer linear programming, heuristic-based algorithms, and data inference techniques.

    List of papers
    1. Energy-efficient task mapping for data-driven sensor network macroprogramming using constraint programming
    Open this publication in new window or tab >>Energy-efficient task mapping for data-driven sensor network macroprogramming using constraint programming
    2011 (English)In: Operations Research, Computing, and Homeland Defense, Hanover, MD: Institute for Operations Research and the Management Sciences , 2011, p. 199-209Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    Hanover, MD: Institute for Operations Research and the Management Sciences, 2011
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-136365 (URN)10.1287/ics.2011.0016 (DOI)978-0-9843378-1-1 (ISBN)
    Conference
    12th INFORMS Computing Society Conference
    Projects
    ProFuN
    Funder
    Swedish Foundation for Strategic Research , RIT08-0065
    Available from: 2011-01-11 Created: 2010-12-12 Last updated: 2018-01-12Bibliographically approved
    2. An optimisation-based approach for wireless sensor deployment in mobile sensing environments
    Open this publication in new window or tab >>An optimisation-based approach for wireless sensor deployment in mobile sensing environments
    2012 (English)In: Proc. Wireless Communications and Networking Conference 2012, IEEE Communications Society, 2012, p. 2108-2112Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    IEEE Communications Society, 2012
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-171536 (URN)10.1109/WCNC.2012.6214140 (DOI)000324580702038 ()978-1-4673-0436-8 (ISBN)
    Conference
    WCNC 2012
    Projects
    ProFuN
    Funder
    Swedish Foundation for Strategic Research , RIT08-0065
    Available from: 2012-06-11 Created: 2012-03-20 Last updated: 2018-01-12Bibliographically approved
    3. Optimising quality of information in data collection for mobile sensor networks
    Open this publication in new window or tab >>Optimising quality of information in data collection for mobile sensor networks
    2013 (English)In: Proc. 21st International Symposium on Quality of Service, IEEE Communications Society, 2013, p. 163-172Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    IEEE Communications Society, 2013
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-208996 (URN)10.1109/IWQoS.2013.6550277 (DOI)000325614100019 ()978-1-4799-0589-8 (ISBN)
    Conference
    IEEE/ACM 21st International Symposium on Quality of Service (IWQoS), 3-4 June, 2013, Montreal, QC
    Projects
    ProFuN
    Funder
    Swedish Foundation for Strategic Research , RIT08-0065
    Available from: 2013-10-13 Created: 2013-10-13 Last updated: 2018-01-11Bibliographically approved
    4. A constraint programming approach for managing end-to-end requirements in sensor network macroprogramming
    Open this publication in new window or tab >>A constraint programming approach for managing end-to-end requirements in sensor network macroprogramming
    Show others...
    2014 (English)In: Proc. 3rd International Conference on Sensor Networks / [ed] Postolache, Octavian; van Sinderen, Marten; Ali, Falah; Benavente-Peces, César, Setúbal, Portugal: SciTePress, 2014, p. 28-40Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    Setúbal, Portugal: SciTePress, 2014
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-210431 (URN)10.5220/0004715200280040 (DOI)978-989-758-001-7 (ISBN)
    Conference
    SENSORNETS 2014
    Projects
    ProFuN
    Funder
    Swedish Foundation for Strategic Research , RIT08-0065
    Available from: 2014-01-09 Created: 2013-11-08 Last updated: 2018-01-11Bibliographically approved
    5. Energy-efficient sensor selection for data quality and load balancing in wireless sensor networks
    Open this publication in new window or tab >>Energy-efficient sensor selection for data quality and load balancing in wireless sensor networks
    2014 (English)In: Proc. 22nd International Symposium on Quality of Service, IEEE Communications Society, 2014, p. 338-343Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    IEEE Communications Society, 2014
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-229594 (URN)10.1109/IWQoS.2014.6914338 (DOI)000355927000044 ()978-1-4799-4852-9 (ISBN)
    Conference
    IWQoS 2014, May 26–27, Hong Kong, China
    Projects
    ProFuN
    Funder
    Swedish Foundation for Strategic Research , RIT08-0065
    Available from: 2014-05-27 Created: 2014-08-11 Last updated: 2018-01-11Bibliographically approved
    6. Cloud-Assisted Data Fusion and Sensor Selection for Internet-of-Things
    Open this publication in new window or tab >>Cloud-Assisted Data Fusion and Sensor Selection for Internet-of-Things
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The Internet of Things (IoT) is connecting people and smart devices on a scale that once was unimaginable. One major challenge for the IoT is to handle vast amount of sensing data generated from the smart devices that are resource-limited and subject to missing data due to link or node failures. By exploring cloud computing with the IoT, we present a cloud-based solution that takes into account the link quality and spatio-temporal correlation of data to minimise energy consumption by selecting sensors for sampling and relaying data. We propose a multi-phase adaptive sensing algorithm with belief propagation protocol (ASBP), which can provide high data quality and reduce energy consumption by turning on only a small number of nodes in the network. We formulate the sensor selection problem and solve it using constraint programming (CP) and greedy search. We then use our message passing algorithm (belief propagation) for performing inference to reconstruct the missing sensing data. ASBP is evaluated based on the data collected from real sensors. The results show that while maintaining a satisfactory level of data quality and prediction accuracy, ASBP can provide load balancing among sensors successfully and preserves 80\% more energy compared with the case where all sensor nodes are actively involved.

    National Category
    Computer Sciences
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:uu:diva-241377 (URN)
    Projects
    ProFuN
    Available from: 2015-01-12 Created: 2015-01-12 Last updated: 2018-01-11
  • 345.
    Hassani Bijarbooneh, Farshid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Du, Wei
    Ngai, Edith C.-H.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Fu, Xiaoming
    Liu, Jiangchuan
    Cloud-assisted data fusion and sensor selection for Internet of Things2016In: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 3, no 3, p. 257-268Article in journal (Refereed)
  • 346.
    Hassani Bijarbooneh, Farshid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Du, Wei
    Ngai, Edith
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Fu, Xiaoming
    Energy-efficient sensor selection for data quality and load balancing in wireless sensor networks2014In: Proc. 22nd International Symposium on Quality of Service, IEEE Communications Society, 2014, p. 338-343Conference paper (Refereed)
  • 347.
    Hassani Bijarbooneh, Farshid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Ngai, Edith C.-H.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    An optimisation-based approach for wireless sensor deployment in mobile sensing environments2012In: Proc. Wireless Communications and Networking Conference 2012, IEEE Communications Society, 2012, p. 2108-2112Conference paper (Refereed)
  • 348.
    Hassani Bijarbooneh, Farshid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Ngai, Edith
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Energy-efficient task mapping for data-driven sensor network macroprogramming using constraint programming2011In: Operations Research, Computing, and Homeland Defense, Hanover, MD: Institute for Operations Research and the Management Sciences , 2011, p. 199-209Conference paper (Refereed)
  • 349.
    Hassani Bijarbooneh, Farshid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Ngai, Edith
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Energy-efficient task-mapping for data-driven sensor network macroprogramming using constraint programming2010In: Proc. 9th International Workshop on Constraint Modelling and Reformulation, Uppsala, Sweden: Department of Information Technology, Uppsala University , 2010, p. 13-Conference paper (Other academic)
  • 350.
    Hassani Bijarbooneh, Farshid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Flener, Pierre
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Ngai, Edith
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Pearson, Justin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Optimising quality of information in data collection for mobile sensor networks2013In: Proc. 21st International Symposium on Quality of Service, IEEE Communications Society, 2013, p. 163-172Conference paper (Refereed)
45678910 301 - 350 of 831
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf