his.sePublications
Change search
Refine search result
197198199200201202203 9951 - 10000 of 10835
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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.
  • 9951.
    Torra, Vicenç
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Derivation of Priorities and Weights for Set-Valued Matrices Using the Geometric Mean Approach2015In: Applied Artificial Intelligence, ISSN 0883-9514, E-ISSN 1087-6545, Vol. 29, no 5, p. 500-513Article in journal (Refereed)
    Abstract [en]

    Priorities are essential in the analytic hierarchy process (AHP). Several approaches have been proposed to derive priorities in the framework of the AHP. Priorities correspond to the weights in the weighted mean as well as in other aggregation operators as the ordered weighted averaging (OWA) operators, and the quasi-arithmetic means.

    Derivation of priorities for the AHP typically starts by eliciting a preference matrix from an expert and then using this matrix to obtain the vector priorities. For consistent matrices, the vector of priorities is unique. Nevertheless, it is usual that the matrix is not consistent. In this case, different methods exist for extracting this vector from the matrix.

    This article introduces a method for this purpose when the cells of the matrix are not a single value but a set of values. That is, we have a set-valued preference matrix. We discuss the relation of this type of matrices and hesitant fuzzy preference relations.

  • 9952.
    Torra, Vicenç
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Entropy for non-additive measures in continuous domains2017In: Fuzzy sets and systems (Print), ISSN 0165-0114, E-ISSN 1872-6801, Vol. 324, p. 49-59Article in journal (Refereed)
    Abstract [en]

    In a recent paper we introduced a definition of f-divergence for non-additive measures. In this paper we use this result to give a definition of entropy for non-additive measures in a continuous setting. It is based on the KL divergence for this type of measures. We prove some properties and show that we can use it to find a measure satisfying the principle of minimum discrimination.

  • 9953.
    Torra, Vicenç
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Fuzzy microaggregation for the transparency principle2017In: Journal of Applied Logic, ISSN 1570-8683, E-ISSN 1570-8691, Vol. 23, p. 70-80Article in journal (Refereed)
    Abstract [en]

    Microaggregation has been proven to be an effective method for data protection in the areas of Privacy Preserving Data Mining (PPDM) and Statistical Disclosure Control (SDC). This method consists of applying a clustering method to the data set to be protected, and then replacing each of the data by the cluster representative. In this paper we propose a new method for microaggregation based on fuzzy clustering. This new approach has been defined with the main goal of being nondeterministic on the assignment of cluster centers to the original data, and at the same time being simple in its definition. Being nondeterministic permits us to overcome some of the attacks standard microaggregation suffers. 

  • 9954.
    Torra, Vicenç
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    On fuzzy c-means and membership based clustering2015In: Advances in Computational Intelligence: 13th International Work-Conference on Artificial Neural Networks, IWANN 2015, Palma de Mallorca, Spain, June 10-12, 2015: Proceedings, Part I / [ed] Ignacio Rojas, Gonzalo Joya & Andreu Catala, Springer, 2015, p. 597-607Conference paper (Refereed)
    Abstract [en]

    Fuzzyc" role="presentation">c-means is one of the most well known fuzzy clustering algorithms. It is usually solved using an iterative algorithm. This algorithm does not ensure that the solution is the global optimum. In this paper we study the distribution of values of the objective function of fuzzyc" role="presentation">c

    -means.

    We also propose a new fuzzy clustering method related to fuzzy c-means. The method presumes that the shape of the membership function is known and can be calculated from the cluster centers, which are the only results of the clustering algorihm.

  • 9955.
    Torra, Vicenç
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    On the selection of m for Fuzzy c-Means2015In: Proceedings of the 2015 Conference of the International Fuzzy Systems Association and the European Society for Fuzzy Logic and Technology / [ed] José M. Alonso, Humberto Bustince & Marek Reformat, Paris: Atlantis Press , 2015, p. 1571-1577Conference paper (Refereed)
    Abstract [en]

    Fuzzy c-means is a well known fuzzy clustering algorithm. It is an unsupervised clustering algorithmthat permits us to build a fuzzy partition from data. The algorithm depends on a parameter m whichcorresponds to the degree of fuzziness of the solution. Large values of m will blur the classes andall elements tend to belong to all clusters. The solutionsof the optimization problem depend on theparameter m. That is, different selections of m willtypically lead to different partitions. In this paper we study and compare the effect ofthe selection of m obtained from the fuzzy c-means.

  • 9956.
    Torra, Vicenç
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre. Hamilton Institute, Maynooth University, Maynooth, Ireland.
    Random dictatorship for privacy-preserving social choice2019In: International Journal of Information Security, ISSN 1615-5262, E-ISSN 1615-5270, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Social choice provides methods for collective decisions. They include methods for voting and for aggregating rankings. These methods are used in multiagent systems for similar purposes when decisions are to be made by agents. Votes and rankings are sensitive information. Because of that, privacy mechanisms are needed to avoid the disclosure of sensitive information. Cryptographic techniques can be applied in centralized environments to avoid the disclosure of sensitive information. A trusted third party can then compute the outcome. In distributed environments, we can use a secure multiparty computation approach for implementing a collective decision method. Other privacy models exist. Differential privacy and k-anonymity are two of them. They provide privacy guarantees that are complementary to multiparty computation approaches, and solutions that can be combined with the cryptographic ones, thus providing additional privacy guarantees, e.g., a differentially private multiparty computation model. In this paper, we propose the use of probabilistic social choice methods to achieve differential privacy. We use the method called random dictatorship and prove that under some circumstances differential privacy is satisfied and propose a variation that is always compliant with this privacy model. Our approach can be implemented using a centralized approach and also a decentralized approach. We briefly discuss these implementations.

  • 9957.
    Torra, Vicenç
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Scala: from a functional programming perspective: An Introduction to the Programming Language2016Book (Other academic)
    Abstract [en]

    This book gives an introduction to the programming language Scala. It presents it from a functional programming perspective. The book explains with detail functional programming and recursivity, and includes chapters on lazy and eager evaluation, streams, higher-order functions (including map, fold, reduce, and aggregate), and algebraic data types. The book also describes the object-oriented aspects of Scala, as they are a fundamental part of the language. In addition, the book includes a chapter on parallelism in Scala, giving an overview of the actor model.

  • 9958.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Aliahmadipour, Laya
    Departement of Computer Science Shahid Bahonar University of Kerman, Iran.
    Dahlbom, Anders
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Fuzzy, I-fuzzy, and H-fuzzy partitions to describe clusters2016In: Fuzzy Systems (FUZZ-IEEE), 2016 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), IEEE, 2016, p. 524-530Conference paper (Refereed)
    Abstract [en]

    In this paper we discuss how three types of fuzzy partitions can be used to describe the results of three types of cluster structures. Standard fuzzy partitions are suitable for centroid based clusters, and I-fuzzy partitions for clusters represented by segments or lines (e.g., c-varieties). In this paper, we introduce hesitant fuzzy partitions. They are suitable for clusters defined by sets of centroids. Because of that, we show that they are useful for hierarchical clustering. We also establish the relationship between hesitant fuzzy partitions and I-fuzzy partitions.

  • 9959.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Guillen, Montserrat
    Department of Econometrics, Riskcenter-IREA, University of Barcelona, Spain.
    Santolino, Miguel
    Department of Econometrics, Riskcenter-IREA, University of Barcelona, Spain.
    Continuous m-dimensional distorted probabilities2018In: Information Fusion, ISSN 1566-2535, E-ISSN 1872-6305, Vol. 44, p. 97-102Article in journal (Refereed)
  • 9960.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Jonsson, Annie
    University of Skövde, School of Bioscience. University of Skövde, The Systems Biology Research Centre.
    Navarro‐Arribas, Guillermo
    Universitat Autònoma de Barcelona, Spain / Center for Cybersecurity Research of Catalonia (CYBERCAT), Spain.
    Salas, Julián
    Center for Cybersecurity Research of Catalonia (CYBERCAT), Spain / Universitat Oberta de Catalunya (UOC), Barcelona, Spain.
    Synthetic generation of spatial graphs2018In: International Journal of Intelligent Systems, ISSN 0884-8173, E-ISSN 1098-111X, Vol. 32, no 12, p. 2364-2378Article in journal (Refereed)
    Abstract [en]

    Graphs can be used to model many different types of interaction networks, for example, online social networks or animal transport networks. Several algorithms have thus been introduced to build graphs according to some predefined conditions. In this paper, we present an algorithm that generates spatial graphs with a given degree sequence. In spatial graphs, nodes are located in a space equiped with a metric. Our goal is to define a graph in such a way that the nodes and edges are positioned according to an underlying metric. More particularly, we have constructed a greedy algorithm that generates nodes proportional to an underlying probability distribution from the spatial structure, and then generates edges inversely proportional to the Euclidean distance between nodes. The algorithm first generates a graph that can be a multigraph, and then corrects multiedges. Our motivation is in data privacy for social networks, where a key problem is the ability to build synthetic graphs. These graphs need to satisfy a set of required properties (e.g., the degrees of the nodes) but also be realistic, and thus, nodes (individuals) should be located according to a spatial structure and connections should be added taking into account nearness.

  • 9961.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Steinhauer, H. Joe
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Berglund, Stefan
    University of Skövde, School of Bioscience. University of Skövde, The Systems Biology Research Centre.
    Artificial Intelligence2019In: Data Science in Practice / [ed] Alan Said, Vicenç Torra, Springer, 2019, p. 9-26Chapter in book (Refereed)
    Abstract [en]

    This chapter gives a brief introduction to what artificial intelligence is. We begin discussing some of the alternative definitions for artificial intelligence and introduce the four major areas of the field. Then, in subsequent sections we present these areas. They are problem solving and search, knowledge representation and knowledge-based systems, machine learning, and distributed artificial intelligence. The chapter follows with a discussion on some ethical dilemma we find in relation to artificial intelligence. A summary closes this chapter.

  • 9962.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Narukawa, Yasuo
    Distances on non-additive measures using the numerical Choquet integrale2015In: The 12th International Conference on Modeling Decisions for Artificial Intelligence: CD-ROM Proceedings, MDAI - HiS , 2015Conference paper (Refereed)
  • 9963.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Narukawa, YasuoToho Gakuen, Tokyo, Japan.
    Modeling Decisions for Artificial Intelligence: 12th International Conference, MDAI 2015, Skövde, Sweden, September 21-23, 2015, Proceedings2015Conference proceedings (editor) (Refereed)
  • 9964.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Narukawa, Yasuo
    Toho Gakuen, Naka, Kunitachi, Tokyo, Japan.
    Numerical integration for the Choquet integral2016In: Information Fusion, ISSN 1566-2535, E-ISSN 1872-6305, Vol. 31, p. 137-145Article in journal (Refereed)
    Abstract [en]

    Choquet integrals with respect to non-additive (or fuzzy measures) have been used in a large number of applications because they permit us to integrate information from different sources when there are interactions. Successful applications use a discrete reference set. In the case of measures on a continuous reference set, as e.g. the real line, few results have been obtained that permit us to have an analytical expression of the integral. However, in most of the cases there is no such analytical expression. In this paper we describe how to perform the numerical integration of a Choquet integral with respect to a non-additive measure.

  • 9965.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre. Hamilton Institute, Maynooth University, Ireland.
    Narukawa, Yasuo
    Department of Management Science, Tamagawa University, Japan.
    On network analysis using non-additive integrals: extending the game-theoretic network centrality2019In: Soft Computing - A Fusion of Foundations, Methodologies and Applications, ISSN 1432-7643, E-ISSN 1433-7479, Vol. 23, no 7, p. 2321-2329Article in journal (Refereed)
    Abstract [en]

    There are large amounts of information that can be represented in terms of graphs. This includes social networks and internet. We can represent people and their interactions by means of graphs. Similarly, we can represent web pages (and sites) as well as links between pages by means of graphs. In order to study the properties of graphs, several indices have been defined. They include degree centrality, betweenness, and closeness. In this paper, we propose the use of Choquet and Sugeno integrals with respect to non-additive measures for network analysis. This is a natural extension of the use of game theory for network analysis. Recall that monotonic games in game theory are non-additive measures. We discuss the expected force, a centrality measure, in the light of non-additive integral network analysis. We also show that some results by Godo et al. can be used to compute network indices when the information associated with a graph is qualitative.

  • 9966.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Narukawa, Yasuo
    Toho Gakuen, Naka, Kunitachi, Tokyo, Japan / Department of Computational Intelligence and Systems Science, Tokyo Institute of Technology, Nagatuta, Midori-ku, Yokohama, Japan.
    Dahlbom, Anders
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    On this book: Clustering, multisets, rough sets and fuzzy sets2017In: Fuzzy sets, rough sets, multisets and clustering / [ed] Vicenç Torra, Anders Dahlbom & Yasuo Narukawa, Springer, 2017, p. 1-5Chapter in book (Other academic)
    Abstract [en]

    This chapter gives an overview of the content of this book, and links them with the work of Prof. Sadaaki Miyamoto, to whom this book is dedicated.

  • 9967.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Narukawa, YasuoDahlbom, AndersUniversity of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    The 12th International Conference on Modeling Decisions for Artificial Intelligence: CD-ROM Proceedings2015Conference proceedings (editor) (Refereed)
  • 9968.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Narukawa, YasuoToho Gakuen, Kunitachi, Tokyo, Japan.Navarro-Arribas, GuillermoUniversitat Autònoma de Barcelona, Bellaterra, Spain.Yañez, CristinaUniversitat d’ Andorra, Sant Julià de Lòria, Andorra.
    Modeling Decisions for Artificial Intelligence: 13th International Conference, MDAI 2016Sant Juliàde Lòria, Andorra, September 19–21, 2016: Proceedings2016Conference proceedings (editor) (Refereed)
  • 9969.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre. IIIA-CSIC, Campus UAB s/n, Bellaterra, Catalonia, Spain.
    Narukawa, Yasuo
    Toho Gakuen, Kunitachi, Tokyo, Japan.
    Sugeno, Michio
    ECSC, c/ Gonzalo Gutiérrez Quirós s/n, Mieres, Spain.
    On the f-divergence for non-additive measures2016In: Fuzzy sets and systems (Print), ISSN 0165-0114, E-ISSN 1872-6801, Vol. 292, p. 364-379Article in journal (Refereed)
    Abstract [en]

    The f -divergence evaluates the dissimilarity between two probability distributions defined in terms of the Radon–Nikodym derivative of these two probabilities. The f -divergence generalizes the Hellinger distance and the Kullback–Leibler divergence among other divergence functions. In this paper we define an analogous function for non-additive measures. We discuss them for distorted Lebesgue measures and give examples. Examples focus on the Hellinger distance.

  • 9970.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Narukawa, Yasuo
    Toho Gakuen, Kunitachi, Japan.
    Yager, Ronald R.
    Iona College, New Rochelle, NY, USA.
    On a Relationship Between Fuzzy Measures and AIFS2016In: International Journal of Uncertainty Fuzziness and Knowledge-Based Systems, ISSN 0218-4885, Vol. 24, no 6, p. 847-858Article in journal (Refereed)
    Abstract [en]

    The literature discusses several extensions of fuzzy sets. AIFS, IVFS, HFS, type-2 fuzzy sets are some of them. Interval valued fuzzy sets is one of the extensions where the membership is not a single value but an interval. Atanassov Intuitionistic fuzzy sets, for short AIFS, are defined in terms of two values for each element: membership and non-membership. In this paper we discuss AIFS and their relationship with fuzzy measures. The discussion permits us to define counter AIFS (cIFS) and discretionary AIFS (dIFS). They are extensions of fuzzy sets that are based on fuzzy measures.

  • 9971.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Department of Information and Communication Engineering, Universitat Autònoma de Barcelona, Catalonia, Spain.
    Big Data Privacy and Anonymization2016In: Privacy and Identity Management. Facing up to Next Steps: 11th IFIP WG 9.2, 9.5, 9.6/11.7, 11.4, 11.6/SIG 9.2.2 International Summer School, Karlstad, Sweden, August 21-26, 2016, Revised Selected Papers / [ed] Anja Lehmann, Diane Whitehouse, Simone Fischer-Hübner, Lothar Fritsch, Charles Raab, Springer, 2016, p. 15-26Chapter in book (Refereed)
    Abstract [en]

    Data privacy has been studied in the area of statistics (statistical disclosure control) and computer science (privacy preserving data mining and privacy enhancing technologies) for at least 40 years. In this period models, measures, methods, and technologies have been developed to effectively protect the disclosure of sensitive information.

    The coming of big data, with large volumes of data, dynamic and streaming data, poses new challenges to the field. In this paper we will review some of these challenges and propose some lines of research in the field.

  • 9972.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Department of Information and Communication Engineering, Universitat Autònoma de Barcelona, Catalonia Spain.
    Integral privacy2016In: Cryptology and Network Security: 15th International Conference, CANS 2016 Milan, Italy, November 14–16, 2016 Proceedings / [ed] Sara Foresti and Giuseppe Persiano, Springer, 2016, Vol. 10052, p. 661-669Conference paper (Refereed)
    Abstract [en]

    When considering data provenance some problems arise from the need to safely handle provenance related functionality. If some modifications have to be performed in a data set due to provenance related requirements, e.g. remove data from a given user or source, this will affect not only the data itself but also all related models and aggregated information obtained from the data. This is specially aggravated when the data are protected using a privacy method (e.g. masking method), since modification in the data and the model can leak information originally protected by the privacy method. To be able to evaluate privacy related problems in data provenance we introduce the notion of integral privacy as compared to the well known definition of differential privacy

  • 9973.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Department of Information and Communications Engineering, CYBERCAT-Center for Cybersecurity Research of Catalonia, Universitat Aut`onoma de Barcelona, Spain.
    Probabilistic Metric Spaces for Privacy by Design Machine Learning Algorithms: Modeling Database Changes2018In: Data Privacy Management, Cryptocurrencies and Blockchain Technology: ESORICS 2018 International Workshops, DPM 2018 and CBT 2018, Barcelona, Spain, September 6-7, 2018, Proceedings / [ed] Joaquin Garcia-Alfaro, Jordi Herrera-Joancomartí, Giovanni Livraga, Ruben Rios, Cham: Springer, 2018, Vol. 11025, p. 422-430Conference paper (Refereed)
    Abstract [en]

    Machine learning, data mining and statistics are used to analyze the data and to build models from them. Data privacy for big data needs to find a compromise between data analysis and disclosure risk. Privacy by design machine learning algorithms need to take into account the space of models and the relationship between the data that generates the models and the models themselves. In this paper we propose the use of probabilistic metric spaces for comparing these models.

  • 9974.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Department of Information and Communication Engineering, Universitat Autònoma de Barcelona, Barcelona, Spain.
    Sanchez-Charles, David
    CA Technologies, Barcelona, Spain.
    Muntes-Mulero, Victor
    CA Technologies, Barcelona, Spain.
    Provenance and Privacy2017In: Modeling Decisions for Artificial Intelligence: 14th International Conference, MDAI 2017 Kitakyushu, Japan, October 18–20, 2017 Proceedings / [ed] Torra V., Narukawa Y., Honda A., Inoue S., Springer, 2017, p. 3-11Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of current needs on data provenance and data privacy, and discusses state-of-the-art results in this area. The paper highlights the difficulties that we need to face and finishes with some lines that require further work.

  • 9975.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Universitat Autònoma de Barcelona, Barcelona, Spain.
    Stokes, Klara
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    An Overview of the Use of Clustering for Data Privacy2016In: Unsupervised Learning Algorithms / [ed] M. Emre Celebi, Kemal Aydin, Springer, 2016, p. 237-251Chapter in book (Refereed)
    Abstract [en]

    In this chapter we review some of our results related to the use of clustering in the area of data privacy. The paper gives a brief overview of data privacy and, more specifically, on data driven methods for data privacy and discusses where clustering can be applied in this setting. We discuss the role of clustering in the definition of masking methods, and on the calculation of information loss and data utility.

  • 9976.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Navarro-Arribas, Guillermo
    Universitat Autònoma de Barcelona, Campus UAB, Bellaterra, Spain.
    Stokes, Klara
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Data privacy2019In: Data science in Practice / [ed] Alan Said, Vicenç Torra, Springer, 2019, p. 121-132Chapter in book (Refereed)
    Abstract [en]

    In this chapter we present an overview of the topic data privacy. We review privacy models and measures of disclosure risk. These models and measures provide computational definitions of what privacy means, and of how to evaluate the privacy level of a data set. Then, we give a summary of data protection mechanisms. We provide a classification of these methods according to three dimensions: whose privacy is being sought, the computations to be done, and the number of data sources. Finally, we describe masking methods. Such methods are the data protection mechanisms used for databases when the data use is undefined and the protected database is required to be useful for several data uses. We also provide a definition of information loss (or data utility) for this type of data protection mechanism. The chapter finishes with a summary.

  • 9977.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre. Hamilton Institute, Maynooth University, Ireland.
    Salas, Julián
    CYBERCAT-Center for Cybersecurity Research of Catalonia, Internet Interdisciplinary Institute (IN3), Universitat Oberta de Catalunya, Barcelona, Spain.
    Graph Perturbation as Noise Graph Addition: A New Perspective for Graph Anonymization2019In: Data Privacy Management, Cryptocurrencies and Blockchain Technology: ESORICS 2019 International Workshops, DPM 2019 and CBT 2019, Luxembourg, September 26–27, 2019, Proceedings / [ed] Cristina Pérez-Solà, Guillermo Navarro-Arribas, Alex Biryukov, Joaquin Garcia-Alfaro, Cham: Springer, 2019, p. 121-137Conference paper (Refereed)
    Abstract [en]

    Different types of data privacy techniques have been applied to graphs and social networks. They have been used under different assumptions on intruders’ knowledge. i.e., different assumptions on what can lead to disclosure. The analysis of different methods is also led by how data protection techniques influence the analysis of the data. i.e., information loss or data utility. One of the techniques proposed for graph is graph perturbation. Several algorithms have been proposed for this purpose. They proceed adding or removing edges, although some also consider adding and removing nodes. In this paper we propose the study of these graph perturbation techniques from a different perspective. Following the model of standard database perturbation as noise addition, we propose to study graph perturbation as noise graph addition. We think that changing the perspective of graph sanitization in this direction will permit to study the properties of perturbed graphs in a more systematic way. 

  • 9978.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Senavirathne, Navoda
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Maximal c consensus meets2019In: Information Fusion, ISSN 1566-2535, E-ISSN 1872-6305, Vol. 51, p. 58-66Article in journal (Refereed)
    Abstract [en]

    Given a set S of subsets of a reference set X, we define the problem of finding c subsets of X that maximize the size of the intersection among the included subsets. Maximizing the size of the intersection means that they are subsets of the sets in S and they are as large as possible. We can understand the result of this problem as c consensus sets of S, or c consensus representatives of S. From the perspective of lattice theory, each representative will be a meet of some sets in S. In this paper we define formally this problem, and present heuristic algorithms to solve it. We also discuss the relationship with other established problems in the literature.

  • 9979.
    Torra, Vicenç
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Shafie, Termeh
    University of Konstanz, Konstanz, Germany.
    Salas, Julián
    Artificial Intelligence Research Institute(IIIA)–Spanish National Research Council (CSIC), Bellaterra 08193, Catalonia, Spain.
    Data Protection for Online Social Networks and P-Stability for Graphs2016In: IEEE Transactions on Emerging Topics in Computing, ISSN 2168-6750, Vol. 4, no 3, p. 374-381Article in journal (Refereed)
    Abstract [en]

    Graphs can be used as a model for online social networks. In this framework, vertices represent individuals and edges relationships between individuals. In recent years, different approaches have been considered to offer data privacy to online social networks and for developing graph protection. Perturbative approaches are formally defined in terms of perturbation and modification of graphs. In this paper, we discuss the concept of P-stability on graphs and its relation to data privacy. The concept of P-stability is rooted in the number of graphs given a fixed degree sequence. In this paper, we show that for any graph there exists a class of P-stable graphs. This result implies that there is a fully polynomial randomized approximation for graph masking for the graphs in the class. In order to further refine the classification of a given graph, we introduce the concept of natural class of a graph. It is based on a class of scale-free networks.

  • 9980.
    Torra, Vicenç
    et al.
    Institut d'Investigacío en Intellig̀encia Artificial, Consejo Superior de Investigaciones Cient́ficas, Universitat Aut̀onoma de Barcelona, Bellaterra, Catalonia, Spain.
    Stokes, Klara
    Departments of Computer Science and Mathematics, Universitat Rovira i Virgili, Tarragona, Spain / UNESCO Chair in Data Privacy, Tarragona, Catalonia, Spain.
    Narukawa, Yasuo
    Toho Gakuen, Tokyo, Japan / Department of Computational Intelligence and Systems Science, Tokyo Institute of Technology, Yokohama, Japan.
    An extension of fuzzy measures to multisets and its relation to distorted probabilities2012In: IEEE transactions on fuzzy systems, ISSN 1063-6706, E-ISSN 1941-0034, Vol. 20, no 6, p. 1032-1045Article in journal (Refereed)
    Abstract [en]

    Fuzzy measures are monotonic set functions on a reference set; they generalize probabilities replacing the additivity condition by monotonicity. The typical application of these measures is with fuzzy integrals. Fuzzy integrals integrate a function with respect to a fuzzy measure, and they can be used to aggregate information from a set of sources (opinions from experts or criteria in a multicriteria decision-making problem). In this context, background knowledge on the sources is represented by means of the fuzzy measures. For example, interactions between criteria are represented by means of nonadditive measures. In this paper, we introduce fuzzy measures on multisets. We propose a general definition, and we then introduce a family of fuzzy measures for multisets which we show to be equivalent to distorted probabilities when the multisets are restricted to proper sets

  • 9981.
    Torsson, Mattias
    et al.
    University of Skövde, School of Health and Education.
    Örvell, Emma
    University of Skövde, School of Health and Education.
    Att balansera på en hängbro: Om upplevelsen av att leva med ALS2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: Amyotrophic lateral sclerosis is a motor neuron disease that leads to total paralysis of the body's involuntary muscles and death within a few years, while consciousness is retained unaffected throughout the course of the disease. The disease contributes to physical, psychological and existential suffering. In order to offer the right support to the patient, the nurse should have a greater knowledge and understanding of how patients with ALS experience life with their disease.

    Purpose: To describe patients' experiences of living with ALS.

    Method: The study is based on a qualitative approach based on autobiographies that illuminate people's experience of living with ALS. To analyze the autobiographies the authors in the foregoing study used a significance analysis.

    Results: Five themes appeared after analyses which illustrate how individuals can experience life with ALS. It emerged in the results that despite the losses, sadness, uncertainty and suffering the informants could still accept, manage and find meaning in their illness.

    Conclusion: To suffer from ALS causes an existential suffering. It is important as a nurse to provide the right support and personalized information to provide guidance throughout the course of the disease, creating opportunities to promote manageability, meaningfulness and well-being for the patient

  • 9982.
    Torstensson, Eleonor
    University of Skövde, Department of Computer Science.
    Intressenters behov av en kravspecifikation från utgångspunkten kommunicerbarhet2001Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    En kravspecifikation kan benämnas som en bro mellan analysfasen och design- och implementationsfasen, vilket innebär att kravspecifikationen är en viktigt kommunikationslänk för en bra slutprodukt. Detta arbete berör kravspecifikationen och de behov analytiker och implementatörer har på en kravspecifikation. Behoven gäller innehåll och presentation av innehåll för att uppnå egenskapen kommunicerbarhet. Kommunicerbarhet är att kravspecifikationen skall fungera som en kommunikationskanal kring produkten mellan intressenter och att den ska vara förståelig för samtliga intressenter.

    Frågeställningen i arbetet har undersökts genom att genomföra en survey med intervjuer. Målgrupp var analytiker och implementatörer på IT-företag som utvecklar administrativa system. Resultatet tyder på att innehållsmässiga krav skiljer sig mellan olika intressenter. Vid skapande av en kravspecifikation bör det bl.a. strävas efter att ha hög sökbarhet och tydlighet. Vidare ska det finnas en beskrivning av systemets funktionalitet, verksamhetsbeskrivning, gränssnittsbeskrivning, icke-funktionella krav. Analytiker har behov verksamhetsnära information och implementatörer har behov av systemets uppbyggnad.

  • 9983.
    Torstensson, Maria
    et al.
    University of Skövde, School of Health and Education.
    Jäderlund, Veronica
    University of Skövde, School of Health and Education.
    Påverkas motivation och egenskattad förmåga?: Utvärdering av mätverktyg för finansiell samordning2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Background Poor health among the unemployed is a major social problem. The recession and rise in unemployment the community requires to take action in form of rehabilitation and employment programs to get people back into employment and hence economic autonomy. The purpose of this study is to evaluate if a change occur in the participators motivation and belief in their own abilities after completing Samordningsförbundet Östergötlands intervention. Method an empirical study was conducted with a quantitative method. Two validated models ORS and Self-efficiacy test with an added self-assessment question of individual motivation. Conclusion There is no significant data to ensure that a change has taken place between test occasion one and two. Based on the results we have, we can not conclude that the participants attitude has changed as a result of the intervention. Whether self-estimated ability or motivation. 

  • 9984.
    Torstensson, Niklas
    University of Skövde, School of Humanities and Informatics.
    Judging the Immigrant: Accents and Attitudes2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Spoken language as a means of communication contains huge amounts of information apart from the linguistic message that is conveyed. It is often the first channel of interaction between people and based on the speaker’s manner of talk, we create a mental image of the speaker as a person, of the speaker’s background, origin and personal qualities. Through five case studies, this dissertation investigates how immigrants to Sweden are judged based on their foreign accents (Cases 1—3) and how the use of an interpreter in court can affect the legal process and the judging of the immigrant (Cases 4—5). Case 1 investigated Swedish students’ attitudes towards immigration and immigrants through a survey-based study and revealed that Swedish students hold predominantly positive attitudes towards immigrations and immigrants. Case 2, using accent imitation, asked if Swedish speakers have a cognitive prototype for British English accented Swedish and found that this was the case. This demonstrated that Swedes have models of accented Swedish accents. Case 3 asked Swedish students to rate their impressions of speakers of nine foreign accented Swedish voices on 18 six-point semantic differential scales. They also rated their impressions of each voice for five social factors. The results suggest that the listeners evaluated the voices based on perceived social desirability, or perceived cultural distance between the listener and the voice’s country of origin. Juxtaposing these findings with those of Case 1 suggests that even among a group who are positive to immigrants and immigration some groups of immigrants are more welcome than others. Case 4 examined discourse disfluencies in a bilingual court hearing and a Swedish-Polish bilingual court hearing in detail. The case showed that most of the dialogue-related difficulties have other sources than the interpreter, even if the interpreter at first glance often appeared to be part of the problem rather than part of the solution. Case 5 examined the interpreter’s role in courtroom dialogue situations through interviews with a court interpreter and a lay judge. The study found that the picture of the interpreter’s role differs between the various actors in the court setting. This, in combination with a lack of knowledge about cultural differences in dialogue strategies, creates complications, can have an impact on the perception of the witness and, ultimately, affect the legal rights of the accused. Furthermore, as the interpreter most frequently speaks foreign accented Swedish, the perception and evaluation of their foreign accented Swedish can further place some immigrant groups at a double legal disadvantage when being judged.

  • 9985.
    Torstensson, Niklas
    University of Skövde, School of Humanities and Informatics.
    Newstalk: reductions in careful, scripted speech2004In: FONETIK 2004: The XVIIth Swedish Phonetics Conference, 2004, p. 16-19Conference paper (Other academic)
    Abstract [en]

    The area of articulatory reductions in spontaneous connected speech has been studied for a number of languages, and has contributed to important knowledge about speech communication, production and perception of speech. The work presented here concerns the domain of connected speech, but instead of spontaneous speech, scripted speech is in the focus of attention. The point of interest is to see to what degree (if any) articulatory reductions appear in a formal context with high demands for intelligibility as in news programs. Read speech from the national Swedish TVnews is analyzed. Reduced forms are viewed more carefully, and related to existing theories on connected speech. ome patterns for reductions are found, and compared to findings in spontaneous speech.

  • 9986.
    Torstensson, Niklas
    et al.
    University of Skövde, School of Humanities and Informatics. Department of Philosophy & Linguistics, Umeå University, Sweden.
    Eriksson, Erik J.
    Department of Philosophy & Linguistics, Umeå University, Sweden.
    Sullivan, Kirk P. H.
    Department of Philosophy & Linguistics, Umeå University, Sweden.
    Mimicked accents: Do speakers have similar cognitive prototypes?2004In: Proceedings of the 10th Australian International Conference on Speech Science & Technology, Australian Speech Science & Technology Association Inc. , 2004, p. 271-276Conference paper (Other academic)
    Abstract [en]

    There are several possible situations in which perpetrators might want to disguise their voices in order to avoid identification and to deflect the search for them to another person or group of individuals. One possible manner that can be used for voice disguise is the adoption of another accent. This paper examines the mimicking of the British-English Swedish accent, that is mimicking of the Swedish spoken by native British English speakers, by native Swedish speakers. It was found that the speakers selected similar and prominent features of the British-English Swedish accent in their first spontaneous recordings, and that the mimicked accent was impacted upon at word and suprasegmental level after having listened to a native speaker.

  • 9987.
    Torstensson, Niklas
    et al.
    University of Skövde, The Informatics Research Centre. University of Skövde, School of Humanities and Informatics.
    Sullivan, Kirk P. H.
    Umeå University.
    The Court Interpreter: Creating an interpretation of the facts2011In: International Journal of Law, Language and Discourse, ISSN 1839-8308, Vol. 1, no 3, p. 64-86Article in journal (Refereed)
    Abstract [en]

    A fair trail is impossible without an interpreter when anyone taking part in the court proceedings does not know the national language, yet the use of an interpreter affects the judging of an immigrant and perhaps their right to a trial as fair as the one offred to a native speaker of the national language. At times courtroom conversation using an interpreter gets confusing, interrupted, and breaks down. These disfluencies can be the result of a lack of linguistic and cultural insight by any of the parties. This paper focuses on how interpreters and legal staff perceive the court interpreter's role, and the creation of the interpretation. Using qualitative semi-structured interviews, it became clear that the interpreter and the lay judge hold different views. The interviews also revealed a degree of mutual mistrust. Yet, in spite of this, a feeling that the bilingual communication in the courts works reasonable well most of the time also came through in the interviews and that with better education for all parties the courtroom could become a fairer legal context.

  • 9988.
    Torstensson, Niklas
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Susi, Tarja
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Online sexual grooming and offender tactics -: What can we learn from social media dialogues?2015In: Proceedings of the 2015 Swecog Conference / [ed] Billing, E., Lindblom, J. & Ziemke, T., Skövde, 2015, Vol. 3, p. 23-23Conference paper (Refereed)
    Abstract [en]

    While online social networking sites and other digital media provide a means for positive online experiences, they are also being misused for offences like online sexual grooming. Attempts have been made to analyse and model online grooming in order to understand this kind of predator behaviour (e.g., O’Connell, 2004; Williams et al., 2013). This research, and the resulting models of the grooming process, is however, invariably based on material where adult decoys (e.g., researchers, law enforcement officers, adults trained to entrap offenders) pose as children in the interaction with potential offenders. We argue that such material, i.e., decoy-offender chat logs, does not reflect real grooming processes; Decoys have an underlying agenda to make prosecutable cases against offenders, which entails decoys resorting to manipulation tactics otherwise typical for offender behaviour. In all essence, this often leads to a dialogue with two adults using grooming tactics on each other, and the resulting models do not capture the patterns of child-offender dialogues.

    Contrary to previous research, we have analysed real-world child-offender chat logs from closed forums. Our data set, selected dialogues (ca. 500 pages) from a corpus of ca. 12 000 A4-pages was thematically analysed and categorised using NVivo 10 software. The coding was done by both authors for inter-rater reliability. Where coding differed, the authors explored the categorisation until agreement was reached (cf., Whittle et al., 2013). The material was also compared to decoy-offender chat logs (ca. 100 pages, publically available on perverted-justice.com).

    The analysis of the different data sets reveal quite different pictures of the grooming process. While previous models describe the grooming process as sequential (O’Connell, 2004) or thematic (Williams et al., 2013), our findings suggest a far more complex behavioural pattern – significantly diverse dialogue patterns with different tactics emerge, depending on whether the respondent is a decoy or a child, and their respective responses. The (preliminary) results show differences in both dialogue and process structure. Dialogues with decoys commonly show what can best be described as “artificial compliance”, presumably due to their underlying agenda of generating prosecutable cases. Furthermore, decoys tease out personal information from the offenders, and also share “personal” information about themselves, even when not asked for it.

    Child-offender dialogues instead show patterns of reluctance or objections to offender requests for personal information, suggestions of sexual nature, etc. Another offender tactic is threats to obtain compliance, which was not found in any of the analysed decoy-offender dialogues. Other deviations include differences in dialogue length, number of dialogue turns, and complexity, with regard to changes in topics and offender tactics. Further research is necessary for a more thorough understanding of online grooming, and new models are needed that reflect real-world grooming processes. This includes offender behaviours, reasoning, decisions, and tactics used in grooming. Further, such knowledge is of outmost importance for risk awareness measures for young people so they can better cope with online challenges and risks, and make sensible judgements and decisions in online interactions.

  • 9989.
    Torstensson, Robbin
    University of Skövde, School of Informatics.
    Jämförelse av evolution och samevolution för att evaluera speltillstånd: I artificiella neurala nätverk kombinerat med minimax2015Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete undersöker två olika tekniker för att evaluera speltillstånd i schack. Teknikerna är samevolution och historiebaserad evolution. De används i kombination med artificiella neurala nätverk och algoritmen minimax. Teknikerna används för att låta två agenter spela schack, genom att välja ut det bästa draget. Kan en agent som bygger på samevolution slå en agent som bygger på historiebaserad evolution?

    Teknikerna har testats genom att låta agenterna evolveras i 200 generationer var för att sedan låta dem spela mot varandra. Den samevolverade agenten vann tre av 24 matcher, den historiebaserade vann en, och resten slutade i remi. Det tyder på att en samevolverad agent kan slå en historiebaserad, men att de är väldigt lika. Undersökningen tyder på att samevolverade schackagenter har stor risk att hamna i ett lokalt maximum medan historiebaserade gör många bra drag, men saknar strategi för att vinna.

  • 9990.
    Torstensson, Sandra
    et al.
    University of Skövde, School of Life Sciences.
    Bådagård, Frida
    University of Skövde, School of Life Sciences.
    Bra med ungdomsmottagningen- men jag vet inte om jag skulle gå dit.: hur killar resonerar kring deras behov av ungdomsmottagningen.2009Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Sammanfattning

    Utav alla ungdomar som besöker ungdomsmottagningar idag, utgörs cirka 15 % av besöken av killar. De killar som besökt ungdomsmottagningen har en mer negativ bild av den än de som inte varit där, vilket visar på att deras behov inte har tillgodosetts. Syftet med studien var därför att undersöka hur killar resonerar kring deras behov av ungdomsmottagningen. Studien inriktades på 18-åriga killar, och de behövde inte ha någon personlig erfarenhet av ungdomsmottagningen. Kvalitativ metod med fokusgrupper användes med 16 killar, indelade i fyra grupper. Intervjuerna analyserades med innehållsanalys. Resultatet visar att den största orsaken till att besöka ungdomsmottagningen är vid frågor kring könssjukdomar. Killarna har ett behov av mer och lättillgängligare information om ungdomsmottagningen och dess verksamhet, samt bättre öppettider. För att underlätta att söka till ungdomsmottagningen önskar killarna att alla får en kallelse. De uttrycker att de inte har så stort behov av ungdomsmottagningen, men att det är tryggt att den finns.

  • 9991.
    Torvmo, Frank
    University of Skövde, School of Humanities and Informatics.
    Övergången till IPv6: Vad hindrar svenska företag att ta steget?2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Det nuvarande kommunikationsprotokollet på Internet, IPv4, utvecklades tidigt under 70-talet och används idag av datorer och andra enheter för att kommunicera med varandra. Det nästan 40 år gamla protokollet räcker endast till drygt fyra miljarder adresser och med tanke på Internets explosionsartade tillväxt har en global adressbrist uppkommit i dagens värld. Fler enheter ansluter sig till Internet och krav ställs på fler IP-adresser samt en förbättrad säkerhet. Vi står idag inför en stegvis övergång till det nya protokollet på Internet, IPv6. Denna nya version löser problemet med adressbristen och har inbyggda säkerhetsfunktioner samt andra fördelar. Trots att nyhetsvärlden och flera entusiastiska organisationer har uppmärksammat de tekniska fördelarna med IPv6 under en längre tid finns det i dagens läge en ointresserad marknad och flera företag har inte påbörjat arbetet ännu. Rapporten undersöker vad som hindrar företagen i Västra Götalandsregionen att påbörja migreringsarbetet mot IPv6. Resultatet pekar på ett nutida samhällsproblem inom IT-världen. Behovet av IPv6 är lågt och få har börjat planera för en övergång. Flera är positivt inställda till NAT-tekniken, som har motverkat adressbristen sedan slutet av 90-talet. Internetleverantörerna ställer inga krav och migreringsarbetet kan komma att bli mycket kostsamt och tidskrävande till en början, men samtidigt öppna upp för nya affärsmöjligheter inom IT-branschen. Vidare kan tydligare statliga direktiv behövas för IPv6, vilket var en avgörande faktor för utvecklingen i Asien.

  • 9992.
    Toräng, Per
    et al.
    University of Skövde, The Systems Biology Research Centre. University of Skövde, School of Bioscience. Department of Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
    Vikström, Linus
    Department of Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
    Wunder, Jörg
    Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
    Wötzel, Stefan
    Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
    Coupland, George
    Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
    Ågren, Jon
    Department of Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
    Evolution of the selfing syndrome: Anther orientation and herkogamy together determine reproductive assurance in a self-compatible plant2017In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 71, no 9, p. 2206-2218Article in journal (Refereed)
    Abstract [en]

    Capacity for autonomous self-fertilization provides reproductive assurance, has evolved repeatedly in the plant kingdom, and typically involves several changes in flower morphology and development (the selfing syndrome). Yet, the relative importance of different traits and trait combinations for efficient selfing and reproductive success in pollinator-poor environments is poorly known. In a series of experiments, we tested the importance of anther-stigma distance and the less studied trait anther orientation for efficiency of selfing in the perennial herb Arabis alpina. Variation in flower morphology among eight self-compatible European populations was correlated with efficiency of self-pollination and with pollen limitation in a common-garden experiment. To examine whether anther-stigma distance and anther orientation are subject to directional and/or correlational selection, and whether this is because these traits affect pollination success, we planted a segregating F2 population at two native field sites. Selection strongly favored a combination of introrse anthers and reduced anther-stigma distance at a site where pollinator activity was low, and supplemental hand-pollination demonstrated that this was largely because of their effect on securing self-pollination. The results suggest that concurrent shifts in more than one trait can be crucial for the evolution of efficient self-pollination and reproductive assurance in pollinator-poor habitats.

  • 9993.
    Tosthage, Lily
    University of Skövde, School of Informatics.
    Dissonans och spelares upplevelser: Spelares uppfattning av en medveten dissonans i en avatars och miljös formspråk2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Den här studien undersöker om en spelare skulle känna av en dissonans mellan en avatar med fredligt formspråk och en spelmiljö med aggressivt formspråk. En spelbar artefakt i form av ett 2D äventyrspel skapades med en runt utformad avatar ochspetsigt utformade fiender och miljöer där övriga faktorer försökte hållas neutrala. Fem testpersoner spelade igenom spelet och intervjuades för att ta reda på hur dekände och upplevde spelets olika delar. Resultatet antyder att spelarna inte kände av någon dissonans. Detta spekuleras bero på ett fokus på spelande och förutfattade meningar kring grafikens motiv. Framtida arbeten kan fokusera på fler element än bara formspråk för att överdriva uttrycken och undersöka om en starkare dissonans kan upptäckas av spelare.

  • 9994.
    Toto, Robert D.
    et al.
    University of Texas Southwestern Medical Center, Dallas, TX, USA.
    Goldenberg, Ronald
    LMC Diabetes & Endocrinology, Thornhill, ON, Canada.
    Chertow, Glenn M.
    Stanford University School of Medicine, CA, USA.
    Cain, Valerie
    Bogier Clinical and IT Solutions, Raleigh, NC, USA.
    Stefánsson, Bergur V.
    Late-stage Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
    Sjöström, Carl David
    Late-stage Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
    Sartipy, Peter
    University of Skövde, School of Bioscience. University of Skövde, The Systems Biology Research Centre. Late-stage Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
    Correction of hypomagnesemia by dapagliflozin in patients with type 2 diabetes: A post hoc analysis of 10 randomized, placebo-controlled trials2019In: Journal of diabetes and its complications, ISSN 1056-8727, E-ISSN 1873-460X, Vol. 33, no 10, article id 107402Article in journal (Refereed)
    Abstract [en]

    Aims: Hypomagnesemia (serum magnesium [Mg] <0.74 mmol/L [<1.8 mg/dL]) is commonly observed in patients with type 2 diabetes (T2D). This study investigated the effect of treatment with dapagliflozin 10 mg on Mg concentrations in patients with T2D. Methods: In this post hoc analysis, we used pooled data from 10 placebo-controlled studies of dapagliflozin over 24 weeks of treatment in patients with T2D. We evaluated the change in Mg in patients receiving dapagliflozin vs. placebo overall, and in subgroups with baseline hypomagnesemia and normal/hypermagnesemia (≥0.74 mmol/L [≥1.8 mg/dL]). We determined the proportion of patients with baseline hypomagnesemia who achieved Mg ≥0.74 mmol/L (≥1.8 mg/dL). Results: A total of 4398 patients with T2D were included. The mean change from baseline to week 24 in Mg was significantly larger with dapagliflozin vs. placebo; difference, 0.06 mmol/L (95% confidence interval [CI]: 0.05, 0.06). The proportion of patients with Mg within the population reference range after 24 weeks of treatment was significantly higher with dapagliflozin vs. placebo; difference, 47.8% (95% CI: 41.4, 53.9). The proportion of patients displaying hypermagnesemia did not increase with dapagliflozin treatment. Conclusions: Treatment with dapagliflozin 10 mg resulted in correction of Mg concentrations in patients with T2D and hypomagnesemia. 

  • 9995.
    Traspaderne Vitoria, Vidal Roa, Txaber, Erlaiz
    University of Skövde, School of Technology and Society.
    WISE SHOP FLOOR DECISION SUPPORT SYSTEM2012Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
  • 9996.
    Trattner, Christoph
    et al.
    University of Bergen, Norway.
    Said, Alan
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Boratto, Ludovico
    EURECAT, Spain.
    Felfernig, Alexander
    Graz University of Technology, Austria.
    Evaluating Group Recommender Systems2018In: Group Recommender Systems: An Introduction / [ed] Alexander Felfernig, Ludovico Boratto, Martin Stettinger, Marko Tkalčič, Springer, 2018, p. 59-71Chapter in book (Refereed)
    Abstract [en]

    In the previous chapters, we have learned how to design group recommender systems but did not explicitly discuss how to evaluate them. The evaluation techniques for group recommender systems are often the same or similar to those that are used for single user recommenders. We show how to apply these techniques on the basis of examples and introduce evaluation approaches that are specifically useful in group recommendation scenarios.

  • 9997.
    Treijner, Christofer
    et al.
    University of Skövde, School of Technology and Society.
    Svensson, Mattias
    University of Skövde, School of Technology and Society.
    Experimentell studie av reversibel axialfläkt: Med avseende på utformning av nav/skovelbas samt minsta/största skovelvinkel2012Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In this thesis a new construction of a reversible axial flow fan is being studied. By performing experiments on different variants of a fan wheel an evaluation is done. Factors to be varied are the design of the hub and the blade base as well as blade angle. All tests is performed in a test rig established by AB Akron-maskiner. The test rig is constructed according to ISO 5801.

    Experiments show that the hub design itself does not have a significant impact on the performance. Changes in performance are detected when various combinations of hubs and blade base are tested. The greatest difference in efficiency between the best and worst hub/blade base combination is about 20%. It is of great interest to have access to this information because a simpler design of the hub allows greater flexibility in the manufacturing. An upper limit for the maximum blade angle is partly due to the appearance of stall but mainly the limitations of the fan motor. The minimum blade angle has also the result founding in engine size. The performance is improved if the radial airflow through the blades cavity is blocked. A blockage causes an increase in efficiency by 5-12% and a reduction in sound power level of 2-3 dB. For optimal performance, the design of the hub should be spherical and the blade base curved and shaped to the hub. This is the same type of hub that is produced today. Maximum and minimum useful blade angle is 50° and 25° to the rotation direction.

  • 9998.
    Treijs, Linus
    University of Skövde, School of Humanities and Informatics.
    Implementation av hierarkiska tillståndsmaskiner2011Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Det här arbetets syfte är att utvärdera olika implementationer av grundläggande mekanismer inom området hierarkiska tillståndsmaskiner. De grundläggande mekanismerna, det vill säga representationerna för tillstånd och händelser, implementeras på fyra olika sätt, och de hierarkiska tillståndsmaskinerna utformas utifrån de möjligheter som de grundläggande mekanismernas implementation ger.

    I arbetet implementeras de hierarkiska tillståndsmaskinerna i programmeringsspråket C++. Dessa hierarkiska tillståndsmaskiners tidseffektivitet i transitioner per sekund mäts genom ett experiment. Utvärderingen av experimentet visar att den hierarkiska tillståndsmaskinen som använder arv i C++ för att koppla samman tillstånden och som utnyttjar objekttillstånd och medlemsfunktionshändelser kan utföra runt 780 000 transitioner per sekund. Den är därför den tidseffektivaste av de fyra hierarkiska tillståndsmaskinerna. Utvärderingen indikerar också att den hierarkiska tillståndsmaskinen som använder en artificiell trädstruktur för att koppla samman tillstånden och som används genom komposition är lättast att använda.

  • 9999.
    Trengereid, Erik
    et al.
    University of Skövde, School of Technology and Society.
    Grönborg, Lucas
    University of Skövde, School of Technology and Society.
    Hållbart Inköp: Hur inköpsfunktionen kan bidra till en hållbarare organisation2012Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study is to analyze how the purchasing function can contribute to a com-pany’s sustainable performance in both the short and long term. Furthermore, the purpose is also to scrutinize how Swedish firms use sustainable procurement today. The study examines that by comparing an empirical investigation of Swedish firms made by the authors to the theoretical frameworks preferred way of working with sustainable procurement, which is es-sentially based on 41 journal articles. This study is of interest since the purchasing function possesses one of the greatest opportunities to influence both the company and its suppliers; this indicates that procurement can play a major role in increasing sustainable development. The use of sustainable procurement can create many advantages for both the company practic-ing, and for the environment. Nonetheless, it is according to earlier studies clear that compa-nies are not taking advantage of the promises found in sustainable procurement. One potential reason companies are not utilizing sustainable procurement is that they lack the knowledge needed to execute a more sustainable purchasing method and also that firms consider sustain-able purchasing as complex and resource intensive.This study explains the fundamental concepts needed to utilize sustainable purchasing; these are green purchasing, social responsible buying and economical responsibility. The conjunc-tion of these three parts constitutes sustainable purchasing.The result of the study is a theoretical framework that highlights the possibilities of sustaina-ble purchasing and provides some overall guidelines for how the work towards it can be con-ducted. The theoretical framework also provides a compiling of the existing litterature to fa-cilitate further studies. The study shows that there exist pure strategies for working towards both environmental and social sustainability. Pure strategies for purchasing towards economic sustainablility where still harder to come by. One clear recognition during the work with the theoretial framework were however that the different parts that makes up sustainable purchas-ing doesn't stand alone, they are rather interrelated. That indicates that it is better to work to-wards sustainability as an overall concept rather than towards its parts. The study also shows how six companies who purports to be working with sustainable procurement does so, and how this conforms to the literature, and how it does not. The found literature on the subject frequently mentions that the biggest problem with sustainable procurement today is compa-nies generally low involvement in sustainability. These problems where however harder to prove in the study. Based on the study, several factors that affect companies involvement in sustainable procurement was identified. Factors such as; company size, line of business, level of globalization proved to affect how the companies work with sustainable procurement.

  • 10000.
    Tressing, Erik
    et al.
    University of Skövde, School of Engineering Science.
    Banck, Gustav
    University of Skövde, School of Engineering Science.
    Utveckling av laddstolpe med befintlig elektronik2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During this project you will see the process behind the development of a charging station for electric vehicles with electronics developed by Sea Ice AB. Sea Ice AB wanted two concepts, one accessory that would allow installations of a charging box without access to a wall. Also a concept of a charging pole. These concepts had to be discreet, and blend in with the surrounding environment, which will be the niche for the produkt. The needs and desires from the user became a central topic for the project. In the prestudy these were found using forms, observations and other methods. The ideageneration were performed on the problems “form, cablemanagement, and function” which later will be welded together and solve the problem as a whole. Mockups, user tests and creative thinking were heavily used during the ideation phase. The project is summarized, evaluated, and communicated with CAD-models and an appearance prototype. All parties are satisfied with the result but its still uncertain if it's going to produktion.

197198199200201202203 9951 - 10000 of 10835
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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