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  • 1. Ahlkrona, Josefin
    et al.
    Lötstedt, Per
    Kirchner, Nina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi.
    Zwinger, Thomas
    Dynamically coupling the non-linear Stokes equations with the shallow ice approximation in glaciology: Description and first applications of the ISCAL method2016Ingår i: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 308, 1-19 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We propose and implement a new method, called the Ice Sheet Coupled Approximation Levels (ISCAL) method, for simulation of ice sheet flow in large domains during long time-intervals. The method couples the full Stokes (FS) equations with the Shallow Ice Approximation (SIA). The part of the domain where SIA is applied is determined automatically and dynamically based on estimates of the modeling error. For a three dimensional model problem, ISCAL computes the solution substantially faster with a low reduction in accuracy compared to a monolithic FS. Furthermore, ISCAL is shown to be able to detect rapid dynamic changes in the flow. Three different error estimations are applied and compared. Finally, ISCAL is applied to the Greenland Ice Sheet on a quasi-uniform grid, proving ISCAL to be a potential valuable tool for the ice sheet modeling community.

  • 2. Alpcan, Tansu
    et al.
    Everitt, Tom
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen.
    Hutter, Marcus
    Can we measure the difficulty of an optimization problem?2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Can we measure the difficulty of an optimization problem? Although optimization plays a crucial role in modernscience and technology, a formal framework that puts problemsand solution algorithms into a broader context has not beenestablished. This paper presents a conceptual approach which gives a positive answer to the question for a broad class of optimization problems. Adopting an information and computational perspective, the proposed framework builds upon Shannon and algorithmic information theories. As a starting point, a concrete model and definition of optimization problems is provided. Then, a formal definition of optimization difficulty is introduced which builds upon algorithmic information theory. Following an initial analysis, lower and upper bounds on optimization difficulty are established. One of the upper-bounds is closely related to Shannon information theory and black-box optimization. Finally, various computational issues and future research directions are discussed.

  • 3. Angleby, Helen
    et al.
    Oskarsson, Mattias
    Pang, Junfeng
    Zhang, Ya-ping
    Leitner, Thomas
    Braham, Caitlyn
    Arvestad, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). Stockholms universitet, Science for Life Laboratory (SciLifeLab).
    Lundeberg, Joakim
    Webb, Kristen M.
    Savolainen, Peter
    Forensic Informativity of similar to 3000bp of Coding Sequence of Domestic Dog mtDNA2014Ingår i: Journal of Forensic Sciences, ISSN 0022-1198, E-ISSN 1556-4029, Vol. 59, nr 4, 898-908 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The discriminatory power of the noncoding control region (CR) of domestic dog mitochondrial DNA alone is relatively low. The extent to which the discriminatory power could be increased by analyzing additional highly variable coding regions of the mitochondrial genome (mtGenome) was therefore investigated. Genetic variability across the mtGenome was evaluated by phylogenetic analysis, and the three most variable similar to 1kb coding regions identified. We then sampled 100 Swedish dogs to represent breeds in accordance with their frequency in the Swedish population. A previously published dataset of 59 dog mtGenomes collected in the United States was also analyzed. Inclusion of the three coding regions increased the exclusion capacity considerably for the Swedish sample, from 0.920 for the CR alone to 0.964 for all four regions. The number of mtDNA types among all 159 dogs increased from 41 to 72, the four most frequent CR haplotypes being resolved into 22 different haplotypes.

  • 4. Austrin, Per
    et al.
    Manokaran, Rajsekar
    Wenner, Cenny
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). KTH - Royal Institute of Technology, Sweden.
    On the NP-Hardness of Approximating Ordering-Constraint Satisfaction Problems2015Ingår i: Theory of Computing, ISSN 1557-2862, Vol. 11, 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We show improved NP-hardness of approximating Ordering Constraint Satis-faction Problems (OCSPs). For the two most well-studied OCSPs, Maximum Acyclic Subgraph and Maximum Betweenness, we prove NP-hard approximation factors of 14/15+ε and 1/2+ε. When it is hard to approximate an OCSP by a constant better than takinga uniformly-at-random ordering, then the OCSP is said to be approximation resistant. We show that the Maximum Non-Betweenness Problem is approximation resistant and that there are width-m approximation-resistant OCSPs accepting only a fraction 1/(m/2)! of assignments. These results provide the first examples of approximation-resistant OCSPs only to P != NP.

  • 5.
    Ayele, Workneh Yilma
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Juell-Skielse, Gustaf
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Social Media Analytics and Internet of Things: Survey2017Ingår i: International Conference on Internet of Things and Machine Learning, Association for Computing Machinery (ACM) , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to the emergence of social media, there is a paradigm shift in the area of information production, processing and consumption. Hence, investigation in the utilization of open social media data is a relevant research topic. The openness of data, social media data, enables innovation and societal value creation. Social media analytics is an evolving research domain with interdisciplinary methods that are common in data mining such as text mining, social network analysis, trend analysis, and sentiment analysis. Also, social media analytics deals with development and evaluation of frameworks and informatics tools to process noisy and unstructured social media data. On the other hand, Internet of Things (IoT) enables the utilization of digital artifacts with well-established solutions and allows things to be connected regardless of location and time. However, a literature review about social media analytics and IoT integration is missing. In this paper, we conducted a systematic literature review of social media analytics and IoT integration. The literature review indicates that there are fewer research works done in the area of social media analytics and IoT compared to Data Mining and IoT. This paper facilitates discussion and elicits research potentials in social media analytics and IoT integration.

  • 6.
    Berthet, Pierre
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). Royal Institute of Technology, Sweden.
    Hellgren-Kotaleski, Jeanette
    Lansner, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). Royal Institute of Technology, Sweden.
    Action selection performance of a reconfigurable basal ganglia inspired model with Hebbian-Bayesian Go- NoGo connectivity2012Ingår i: Frontiers in Behavioral Neuroscience, ISSN 1662-5153, E-ISSN 1662-5153, Vol. 6, 65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several studies have shown a strong involvement of the basal ganglia (BG) in action selection and dopamine dependent learning. The dopaminergic signal to striatum, the input stage of the BG, has been commonly described as coding a reward prediction error (RPE), i.e., the difference between the predicted and actual reward. The RPE has been hypothesized to be critical in the modulation of the synaptic plasticity in cortico-striatal synapses in the direct and indirect pathway. We developed an abstract computational model of the BG, with a dual pathway structure functionally corresponding to the direct and indirect pathways, and compared its behavior to biological data as well as other reinforcement learning models. The computations in our model are inspired by Bayesian inference, and the synaptic plasticity changes depend on a three factor Hebbian-Bayesian learning rule based on co-activation of pre- and post-synaptic units and on the value of the RPE. The model builds on a modified Actor-Critic architecture and implements the direct (Go) and the indirect(NoGo) pathway, as well as the reward prediction (RP) system, acting in a complementary fashion. We investigated the performance of the model system when different configurations of the Go, NoGo, and RP system were utilized, e.g., using only the Go, NoGo, or RP system, or combinations of those. Learning performance was investigated in several types of learning paradigms, such as learning-relearning, successive learning, stochastic learning, reversal learning and a two-choice task. The RPE and the activity of the model during learning were similar to monkey electrophysiological and behavioral data. Our results, however, show that there is not a unique best way to configure this BG model to handle well all the learning paradigms tested. We thus suggest that an agent might dynamically configure its action selection mode, possibly depending on task characteristics and also on how much time is available.

  • 7.
    Berthet, Pierre
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). Royal Institute of Technology, Sweden.
    Lansner, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). Royal Institute of Technology, Sweden.
    Optogenetic Stimulation in a Computational Model of the Basal Ganglia Biases Action Selection and Reward Prediction Error2014Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 3, e90578Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Optogenetic stimulation of specific types of medium spiny neurons (MSNs) in the striatum has been shown to bias the selection of mice in a two choices task. This shift is dependent on the localisation and on the intensity of the stimulation but also on the recent reward history. We have implemented a way to simulate this increased activity produced by the optical flash in our computational model of the basal ganglia (BG). This abstract model features the direct and indirect pathways commonly described in biology, and a reward prediction pathway (RP). The framework is similar to Actor-Critic methods and to the ventral/ dorsal distinction in the striatum. We thus investigated the impact on the selection caused by an added stimulation in each of the three pathways. We were able to reproduce in our model the bias in action selection observed in mice. Our results also showed that biasing the reward prediction is sufficient to create a modification in the action selection. However, we had to increase the percentage of trials with stimulation relative to that in experiments in order to impact the selection. We found that increasing only the reward prediction had a different effect if the stimulation in RP was action dependent (only for a specific action) or not. We further looked at the evolution of the change in the weights depending on the stage of learning within a block. A bias in RP impacts the plasticity differently depending on that stage but also on the outcome. It remains to experimentally test how the dopaminergic neurons are affected by specific stimulations of neurons in the striatum and to relate data to predictions of our model.

  • 8.
    Beskow, Jonas
    et al.
    KTH Speech, Music and Hearing.
    Carlson, Rolf
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Granström, Björn
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Hjalmarsson, Anna
    KTH Speech, Music and Hearing.
    Skantze, Gabriel
    KTH Speech, Music and Hearing.
    Multimodal Interaction Control2009Ingår i: Computers in the Human Interaction Loop / [ed] Waibel, Alex and Stiefelhagen, Rainer, Berlin/Heidelberg: Springer Berlin/Heidelberg, 2009, 143-158 s.Kapitel i bok, del av antologi (Refereegranskat)
  • 9.
    Beskow, Jonas
    et al.
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Gustafson, Joakim
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Hjalmarsson, Anna
    KTH Speech, Music and Hearing.
    House, David
    KTH Speech, Music and Hearing.
    Research focus: Interactional aspects of spoken face-to-face communication2010Ingår i: Proceedings from Fonetik 2010, Lund: Lund University , 2010, 7-10 s.Konferensbidrag (Övrigt vetenskapligt)
  • 10.
    Boye, Johan
    et al.
    TeliaSonera.
    Wirén, Mats
    TeliaSonera.
    Multi-slot semantics for natural-language call routing systems2007Ingår i: Proceedings of Bridging the Gap: Academic and Industrial Research in Dialog Technology, 2007, 68-75 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Statistical classification techniques for natural-language call routing systems have matured to the point where it is possible to distinguish between several hundreds of semantic categories with an accuracy that is sufficient for commercial deployments. For category sets of this size, the problem of maintaining consistency among manually tagged utterances becomes limiting, as lack of consistency in the training data will degrade performance of the classifier. It is thus essential that the set of categories be structured in a way that alleviates this problem, and enables consistency to be preserved as the domain keeps changing. In this paper, we describe our experiences of using a two-level multi-slot semantics as a way of meeting this problem. Furthermore, we explore the ramifications of the approach with respect to classification, evaluation and dialogue design for call routing systems.

  • 11.
    Brouwers, Lisa
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Microsimulation Models for Disaster Policy Making2005Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Two executable simulation models for answering policy questions were designed and implemented. The first for a flood management case, and the second for a disease transmission case that is currently underway. The flood simulation model differs from earlier natural disaster simulation models in several respects. It represents explicitly the geographical location and the economic strength of each household. It is also equipped with a graphical user interface, making it possible to design policies interactively, and to test their outcomes. If policy options are compared, the simulation results can automatically be transformed into decision trees. The flood simulation model shows that a micro-level representation makes it possible to investigate the distributional effects of policy changes. Novel features of the disease transmission model include the use of (anonymized) data representing nine million individuals, the inclusion of important parts of the contact patterns, and the explicit representation of places. The disease transmission model shows that the incorporation of social structure allows for a more realistic representation of disease spread than do models that assume homogenous mixing. Using this model, it is possible to conduct experiments of significant policy relevance, such as investigating the initial growth of an epidemic on a real-world network. Together, the two cases demonstrate the usefulness of a spatially explicit micro-level representation for policy simulation models in the area of disaster management.

  • 12.
    Brouwers, Lisa
    et al.
    KTH.
    Cakici, Baki
    KTH.
    Camitz, Martin
    Swedish Institute for Infectious Control (SMI).
    Tegnell, Anders
    National Board of Health and Welfare.
    Boman, Magnus
    KTH.
    Economic consequences to society of pandemic H1N1 influenza 2009 – preliminary results for Sweden2009Ingår i: Eurosurveillance, ISSN 1025-496X, Vol. 14, nr 37Artikel i tidskrift (Refereegranskat)
  • 13.
    Cakici, Baki
    et al.
    KTH.
    Boman, Magnus
    KTH.
    A Workflow for Software Development within Computational Epidemiology2011Ingår i: Journal of Computational Science, ISSN 1877-7503, Vol. 2, nr 3, 216-222 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A critical investigation into computational models developed for studying the spread of communicable disease is presented. The case in point is a spatially explicit micro-meso-macro model for the entire Swedish population built on registry data, thus far used for smallpox and for influenza-like illnesses. The lessons learned from a software development project of more than 100 person months are collected into a check list. The list is intended for use by computational epidemiologists and policy makers, and the workflow incorporating these two roles is described in detail.

  • 14. Cerrito, Serenella
    et al.
    David, Amélie
    Goranko, Valentin
    Stockholms universitet, Humanistiska fakulteten, Filosofiska institutionen.
    Optimal Tableaux Method for Constructive Satisfiability Testing and Model Synthesis in the Alternating-time Temoral Logic ATL+2015Ingår i: ACM Transactions on Computational Logic, ISSN 1529-3785, E-ISSN 1557-945X, Vol. 17, nr 1, 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We develop a sound, complete, and practically implementable tableau-based decision method for constructive satisfiability testing and model synthesis for the fragment ATL+ of the full alternating-time temporal logic ALT*. The method extends in an essential way a previously developed tableau-based decision method for ATL and works in 2EXPTIME, which is the optimal worst-case complexity of the satisfiability problem for ATL+. We also discuss how suitable parameterizations and syntactic restrictions on the class of input ATL+formulas can reduce the complexity of the satisfiability problem.

  • 15.
    Cöster, Rickard
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Algorithms and Representations for Personalised Information Access2005Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Personalised information access systems use historical feedback data, such as implicit and explicit ratings for textual documents and other items, to better locate the right or relevant information for individual users.

    Three topics in personalised information access are addressed: learning from relevance feedback and document categorisation by the use of concept-based text representations, the need for scalable and accurate algorithms for collaborative filtering, and the integration of textual and collaborative information access.

    Two concept-based representations are investigated that both map a sparse high-dimensional term space to a dense concept space. For learning from relevance feedback, it is found that the representation combined with the proposed learning algorithm can improve the results of novel queries, when queries are more elaborate than a few terms. For document categorisation, the representation is found useful as a complement to a traditional word-based one.

    For collaborative filtering, two algorithms are proposed: the first for the case where there are a large number of users and items, and the second for use in a mobile device. It is demonstrated that memory-based collaborative filtering can be more efficiently implemented using inverted files, with equal or better accuracy, and that there is little reason to use the traditional in-memory vector approach when the data is sparse. An empirical evaluation of the algorithm for collaborative filtering on mobile devices show that it can generate accurate predictions at a high speed using a small amount of resources.

    For integration, a system architecture is proposed where various combinations of content-based and collaborative filtering can be implemented. The architecture is general in the sense that it provides an abstract representation of documents and user profiles, and provides a mechanism for incorporating new retrieval and filtering algorithms at any time.

    In conclusion this thesis demonstrates that information access systems can be personalised using scalable and accurate algorithms and representations for the increased benefit of the user.

  • 16.
    Danielson, Mats
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Ekenberg, Love
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Larsson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Riabacke, Mona
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Weighting Under Ambiguous Preferences and Imprecise Differences in a Cardinal Rank Ordering Process2014Ingår i: International Journal of Computational Intelligence Systems, ISSN 1875-6891, Vol. 7, nr S1, 105-112 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The limited amount of good tools for supporting elicitation of preference information in multi-criteria decision analysis (MCDA) causes practical problem. In our experiences, this can be remedied by allowing more relaxed input statements from decision-makers, causing the elicitation process to be less cognitively demanding. Furthermore, it should not be too time consuming and must be able to actually use of the information the decision-maker is able to supply. In this paper, we propose a useful weight elicitation method for MAVT/MAUT decision making, which builds on the ideas of rank-order methods, but increases the precision by adding numerically imprecise cardinal information as well.

  • 17. Demri, Stephane
    et al.
    Goranko, Valentin
    Stockholms universitet, Humanistiska fakulteten, Filosofiska institutionen.
    Lange, Martin
    Temporal logics in computer science: Finite-state systems2016Bok (Övrigt vetenskapligt)
    Abstract [en]

    This comprehensive text provides a modern and technically precise exposition of the fundamental theory and applications of temporal logics in computer science. Part I presents the basics of discrete transition systems, including constructions and behavioural equivalences. Part II examines the most important temporal logics for transition systems and Part III looks at their expressiveness and complexity. Finally, Part IV describes the main computational methods and decision procedures for model checking and model building - based on tableaux, automata and games - and discusses their relationships. The book contains a wealth of examples and exercises, as well as an extensive annotated bibliography. Thus, the book is not only a solid professional reference for researchers in the field but also a comprehensive graduate textbook that can be used for self-study as well as for teaching courses.

  • 18.
    Dudas, Catarina
    et al.
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Ng, Amos
    Högskolan i Skövde, Institutionen för teknik och samhälle.
    Boström, Henrik
    Högskolan i Skövde, Institutionen för kommunikation och information.
    Knowledge Extraction in Manufacturing using Data Mining Techniques2008Ingår i: Proceedings of the Swedish Production Symposium 2008, Stockholm, Sweden, November 18-20, 2008, 2008, 8 sidor- s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nowadays many production companies collect and store production and process data in large databases. Unfortunately the data is rarely used in the most value generating way, i.e.,  finding  patterns  of  inconsistencies  and  relationships  between  process  settings  and quality  outcome.  This  paper  addresses  the  benefits  of  using  data  mining  techniques  in manufacturing  applications.  Two  different  applications  are  being  laid  out  but  the  used technique  and  software  is  the  same  in  both  cases.  The  first  case  deals  with  how  data mining  can  be  used  to  discover  the  affect  of  process  timing  and  settings  on  the  quality outcome in the casting industry. The result of a multi objective optimization of a camshaft process  is  being  used  as  the  second  case.  This  study  focuses  on  finding  the  most appropriate dispatching rule settings in the buffers on the line.  The  use  of  data  mining  techniques  in  these  two  cases  generated  previously  unknown knowledge. For example, in order to maximize throughput in the camshaft production, let the dispatching rule for the most severe bottleneck be of type Shortest Processing Time (SPT) and for the second bottleneck use any but Most Work Remaining (MWKR).

  • 19.
    Edirisuriya, Ananda
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Design Support for e-Commerce Information Systems using Goal, Business and Process Modelling  2009Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Enterprises use various models to find design solutions to their e-Commerce information systems. Goal, business and process models are parts of a chain of models used for this purpose. Business modelling requires structured methods to support design and traceability. Process modelling also needs structured methods to manage design complexity, traceability and flexibility. The thesis proposes several artifacts to address these challenges.

     It proposes a method to design business models from goal models. We start by analyzing strategic goals and express goal model notions using business notions. A set of guidelines is proposed to design a business model. The method provides structured business model design and traceability of the decisions from business to strategic level.

    The thesis also discusses a set of mappings to relate goal modelling language constructs to process modelling notions. We use BMM, i* and KAOS for goal modelling. The mappings are used to identify how these techniques can support process design. In addition, a set of mappings is proposed to relate business modelling language constructs to process modelling notions. We use the e3value model for business modelling. Based on these mappings a number of activities are identified to structure process activities from a business viewpoint.

    We also propose a method to design process models using goal and business models as inputs. As a bridge between two input models and a process model, the notion of an activity dependency model is introduced. The transitions between models are performed by using guidelines. The method provides structured process model design, flexibility for process models and traceability of the decisions from operational to strategic and business levels.

    These artifacts can be used for designing enterprise business and process models. We follow the design science research method used in information systems research. The evaluation builds on scenarios, implementations and a literature review.

  • 20.
    Edlund, Jens
    et al.
    KTH Speech, Music and Hearing.
    Gustafson, Joakim
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Hjalmarsson, Anna
    KTH Speech, Music and Hearing.
    Towards human-like spoken dialogue systems2008Ingår i: Speech Communication, ISSN 0167-6393, Vol. 50, nr 8-9, 630-645 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an overview of methods that can be used to collect and analyse data on user responses to spoken dialogue system components intended to increase human-likeness, and to evaluate how well the components succeed in reaching that goal. Wizard-of-Oz variations, human-human data manipulation, and micro-domains are discussed ill this context, as is the use of third-party reviewers to get a measure of the degree of human-likeness. We also present the two-way mimicry target, a model for measuring how well a human-computer dialogue mimics or replicates some aspect of human-human dialogue, including human flaws and inconsistencies. Although we have added a measure of innovation, none of the techniques is new in its entirely. Taken together and described from a human-likeness perspective, however, they form a set of tools that may widen the path towards human-like spoken dialogue systems.

  • 21.
    Edlund, Jens
    et al.
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Exploring prosody in interaction control2005Ingår i: Phonetica, ISSN 0031-8388, E-ISSN 1423-0321, Vol. 62, nr 2-4, 215-226 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates prosodic aspects of turn-taking in conversation with a view to improving the efficiency of identifying relevant places at which a machine can legitimately begin to talk to a human interlocutor. It examines the relationship between interaction control, the communicative function of which is to regulate the flow of information between interlocutors, and its phonetic manifestation. Specifically, the listener's perception of such interaction control phenomena is modelled. Algorithms for automatic online extraction of prosodic phenomena liable to be relevant for interaction control, such as silent pauses and intonation patterns, are presented and evaluated in experiments using Swedish map task data. We show that the automatically extracted prosodic features can be used to avoid many of the places where current dialogue systems run the risk of interrupting their users, as well as to identify suitable places to take the turn.

  • 22.
    Edlund, Jens
    et al.
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Underpinning /nailon/: automatic estimation of pitch range and speaker relative pitch2007Ingår i: Speaker Classification II / [ed] Müller, Christian, Berlin/Heidelberg, Germany: Springer Berlin/Heidelberg, 2007, 229-242 s.Kapitel i bok, del av antologi (Refereegranskat)
  • 23.
    Edlund, Jens
    et al.
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Al Moubayed, Samer
    KTH Speech, Music and Hearing.
    Gravano, Agustìn
    Hirschberg, Julia
    Columbia University Computer Science.
    Very short utterances in conversation2010Ingår i: Proceedings from Fonetik 2010, Lund: Lund University , 2010, 11-16 s.Konferensbidrag (Övrigt vetenskapligt)
  • 24.
    Edlund, Jens
    et al.
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Hirschberg, Julia
    Columbia University Computer Science.
    Pause and gap length in face-to-face interaction2009Ingår i: Proceedings of Interspeech 2009, Brighton, UK: ISCA , 2009, 2779-2782 s.Konferensbidrag (Refereegranskat)
  • 25.
    Edlund, Jens
    et al.
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Pelcé, Antoine
    KTH Speech, Music and Hearing.
    Prosodic features of very short utterances in dialogue2009Ingår i: Nordic Prosody: Proceedings of the Xth Conference, Helsinki 2008, Frankfurt am Main: Peter Lang Publishing Group, 2009, 57-68 s.Konferensbidrag (Refereegranskat)
  • 26.
    Eiderbäck, Björn
    Stockholms universitet.
    Object oriented frameworks with design patterns for building distributed information sharing2001Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    The construction and programming of interactive graphical user interfaces is hard work with conventional programming tools. Investigations have shown that as much as 80% of the programming code could be related to the interactive parts in modern applications with a graphical interface.

    Another difficult task is the development of distributed applications. There are several frameworks and packages around for development of distributed interactive applications, but none is fully satisfactory, and more research and development is needed.

    Interest in applications that provide Computer Supported Co-operative Work (CSCW) is rapidly growing, particularly during the recent years with increasing interest in Internet solutions. CSCW applications are usually interactive and, in one way or another, distributed. It is a challenge to provide mechanisms and tools that allow rapid and easy development of interactive and distributed applications. Another challenge is the development of various means for sharing information. Different applications require different types of sharing and a particular application may require several sharing mechanisms. Two major challenges for an application are the ability to allow users to view data in different ways and the possibility of tailoring the interface to meet the different needs of different users. Therefore, further development of frameworks, tools, and modern interface-builders is required. In particular, we need better means for experimenting with and prototyping new ideas for CSCW applications.

    In this thesis, I define a framework of high-level mechanisms for the interactive distribution and sharing of information, founded on the object-oriented paradigm. The mechanisms are demonstrated as extensions to the existing class library of a Smalltalk environment. I describe how I have integrated the framework into the Interface Building tools of the environment, and in this way obtained a system that allows rapid development and easy experimentation with many techniques.

    Another aim of this thesis is to develop and demonstrate ways to describe essential structures, solutions, and intentions using powerful explanatory techniques. This means that the way the descriptions are made has a value in itself. One particular reason for exploring such techniques is that traditional techniques are either too weak, too imprecise, or too formal to be of real practical value. However, traditional techniques are very useful for defining overall structures, collaborations between components, algorithms, and more intricate functionality. But they are not usually suitable for communicating the essence and intentions of the software. I believe that it will become more important to communicate the structures of software solutions, as applications become more complex. Further, the software market is becoming ever more competitive, and a short time to market is necessary to provide competitive advantage. Design patterns a new field of research and development, has recently emerged. With design patterns one can make clear descriptions of soft-ware application and therefore contribute to shorten the time taken for applications to reach the market. In this thesis I use design patterns as the main ingredient when describing a particular software structure or solution.

  • 27.
    Ekanayake, Hiran B.
    et al.
    University of Colombo School of Computing, Sri Lanka.
    Karunarathna, Damitha D.
    University of Colombo School of Computing, Sri Lanka.
    Hewagamage, Kamalanath P.
    University of Colombo School of Computing, Sri Lanka.
    Determining the Psychological Involvement in Multimedia Interactions2009Ingår i: The International Journal on Advances in ICT for Emerging Regions, ISSN 1800-4156, Vol. 2, nr 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Human computer interaction (HCI) is currently aimed at the design of interactive computer applications for human use while preventing user frustration. When considering the nature of modern computer applications, such as e-learning systems and computer games, it appears that human involvement cannot be improved only by using traditional approaches, such as nice user interfaces. For a pleasant human involvement, these computer applications require that the computers should have the ability to naturally adapt to their users and this requires the computers to have the ability to recognize user emotions. For recognizing emotions currently most preferred research approach is aimed at facial expression based emotion recognition, which seems to have many limitations. Therefore, in this paper, we propose a method to determine the psychological involvement of a human during a multimedia interaction session using the eye movement activity and arousal evaluation. In our approach we use a low cost hardware/software combination, which determines eye movement activity based on electrooculogram (EOG) signals and the level of arousal using galvanic skin response (GSR) signals. The results obtained using six individuals show that the nature of involvement can be recognized using these affect signals as optimal levels and distracted conditions.

  • 28.
    Eriksson-Granskog, Agneta
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    General Metarules for Interactive Modular Construction of Natural Deduction Proofs2003Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    This thesis proposes a set of general metarules for interactive modular construction of natural deduction proofs.

    Interactive proof support systems are used for the construction of formal proofs in formal program development. They support the user interaction in the derivation of programs from specifications and in the development of proofs of properties of programs. Moreover, interactive proof support systems are often general theorem provers and provide general support for proof development. Natural deduction with its similarity to intuitive informal reasoning and its lucid proof explanations is ideal for interactive proof development. However, the formal proofs in formal program development tend to be long and detailed, and metarules for the development of proofs in natural deduction would give shorter proofs and facilitate the user interaction.

    The focus of the thesis is the characterization of general metarules for the interactive construction of proofs in natural deduction. The solution presented supports modularity and flexibility in interactive proof development and it provides interactive construction of proofs at metalevel and facilitates the presentation of the proofs at different levels of abstraction.

    The main contributions are:

    · General metarules for modular proof development.

    The general metarules for the interactive construction of derivations in natural deduction support the construction of proofs from proof parts. They compute parts of proofs on the demand of the user. By computing derived rules for each application, a user has important leeway in the number of rules to use.

    · Flexibility in the development of proofs.

    The flexibility in the interactive development of proofs is supported by general metarules for changes. The method for performing changes to proofs is based upon the replacement of parts of proofs.

    · A proof structure supporting the development of fragmentary proofs.

    · Explanations of proofs at different levels in accordance with the inference rules of natural deduction and the general metarules.

  • 29.
    Esteban, Pablo G.
    et al.
    Universidad Rey Juan Carlos, Madrid, Spain.
    Rázuri, Javier G.
    Universidad Rey Juan Carlos, Madrid, Spain.
    Rios Insua, David
    Royal Academy of Sciences, Madrid, Spain.
    An Adversarial Risk Analysis Model for a Decision Agent facing Multiple Users2012Ingår i: 2012 3rd International Workshop on Cognitive Information Processing (CIP), IEEE Computer Society, 2012, 1-6 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    We provide a model supporting the decision making process of an autonomous synthetic agent which interacts with several users. The approach is decision analytic and incorporates models forecasting the users' behavior. We sketch the implementation of our model with an edutainment robot.

  • 30.
    Everitt, Tom
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen.
    Universal Induction and Optimisation: No Free Lunch2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 31.
    Everitt, Tom
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen.
    Lattimore, Tor
    Hutter, Marcus
    Free Lunch for Optimisation under the Universal Distribution2014Ingår i: 2014 IEEE Congress on Evolutionary Computation (CEC), New York: IEEE Computer Society, 2014, 167-174 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Function optimisation is a major challenge in computer science. The No Free Lunch theorems state that if all functions with the same histogram are assumed to be equally probable then no algorithm outperforms any other in expectation. We argue against the uniform assumption and suggest a universal prior exists for which there is a free lunch, but where no particular class of functions is favoured over another. We also prove upper and lower boundson the size of the free lunch.

  • 32.
    Fernaeus, Ylva
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Tholander, Jakob
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Patcher: A Tangible Game for Making Ecology Simulations in Museum Setting2007Ingår i: Tangible Play: Research and Design for Tangible and Tabletop Games, 2007, 25-28 s.Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    We present a tangible game for collaborative construction of ecological simulations. The system has been designed for and evaluated in the context of school classes visiting the Nature in Sweden exhibition at the Museum of Natural History in Stockholm. Based on card-based interaction using RFID-technology, the system affords discussion and collaborative play, leading to animated simulations displayed on a large screen. We discuss how technologies like this afford playful learning experience, especially in collaborative activities such as field trips to a museum.

  • 33. Fiebig, Florian
    et al.
    Lansner, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). Royal Institute of Technology, Sweden.
    Memory consolidation from seconds to weeks: a three-stage neural network model with autonomous reinstatement dynamics2014Ingår i: Frontiers in Computational Neuroscience, ISSN 1662-5188, Vol. 8, 64- s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Declarative long-term memories are not created in an instant. Gradual stabilization and temporally shifting dependence of acquired declarative memories in different brain regions called systems consolidation- can be tracked in time by lesion experiments. The observation of temporally graded retrograde amnesia(RA) following hippocampal lesions points to a gradual transfer of memory from hippocampus to neocortical long-term memory. Spontaneous reactivations of hippocampal memories, asobserved in place cell reactivations during slow wave- sleep, are supposed to driven eocortical reinstatements and facilitate this process. We proposea functional neural network implementation of these ideas and further more suggest anextended three-state framework that includes the prefrontal cortex( PFC). It bridges the temporal chasm between working memory percepts on the scale of seconds and consolidated long-term memory on the scale of weeks or months. Wes how that our three-stage model can autonomously produce the necessary stochastic reactivation dynamics for successful episodic memory consolidation. There sulting learning system is shown to exhibit classical memory effects seen in experimental studies, such as retrograde and anterograde amnesia(AA) after simulated hippocampal lesioning; further more the model reproduces peculiar biological findings on memory modulation, such as retrograde facilitation of memory after suppressed acquisition of new longterm memories- similar to the effects of benzodiazepines on memory.

  • 34. Fried, Dror
    et al.
    Shimony, Solomon Eyal
    Benbassat, Amit
    Wenner, Cenny
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA). KTH Royal Inst Technol, SE-10044 Stockholm, Sweden.
    Complexity of Canadian traveler problem variants2013Ingår i: Theoretical Computer Science, ISSN 0304-3975, Vol. 487, 1-16 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Canadian traveler problem (CTP) is the problem of traversing a given graph, where some of the edges may be blocked a state which is revealed only upon reaching an incident vertex. Originally stated by Papadimitriou and Yannakakis (1991) [1], the adversarial version of the CTP was shown to be PSPACE-complete, with the stochastic version shown to be in PSPACE and #P-hard. We show that the stochastic CTP is also PSPACE-complete: initially proving PSPACE-hardness for the dependent version of the stochastic CTP, and proceeding with gadgets that allow us to extend the proof to the independent case. Since for disjoint-path graphs, the CTP can be solved in polynomial time, we examine the complexity of the more general remote-sensing CTP, and show that it is NP-hard even for disjoint-path graphs.

  • 35. Garg, Shilpa
    et al.
    Martin, Marcel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik. Stockholms universitet, Science for Life Laboratory (SciLifeLab).
    Marschall, Tobias
    Read-based phasing of related individuals2016Ingår i: Bioinformatics, ISSN 1367-4803, E-ISSN 1367-4811, Vol. 32, nr 12, 234-242 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Motivation: Read-based phasing deduces the haplotypes of an individual from sequencing reads that cover multiple variants, while genetic phasing takes only genotypes as input and applies the rules of Mendelian inheritance to infer haplotypes within a pedigree of individuals. Combining both into an approach that uses these two independent sources of information-reads and pedigree-has the potential to deliver results better than each individually. Results: We provide a theoretical framework combining read-based phasing with genetic haplotyping, and describe a fixed-parameter algorithm and its implementation for finding an optimal solution. We show that leveraging reads of related individuals jointly in this way yields more phased variants and at a higher accuracy than when phased separately, both in simulated and real data. Coverages as low as 2 x for each member of a trio yield haplotypes that are as accurate as when analyzed separately at 15 x coverage per individual.

  • 36.
    Giannoulis, Constantinos
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Zdravkovic, Jelena
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Model-Centric Strategy2IS Linkage: an Empirical Study2014Konferensbidrag (Refereegranskat)
  • 37.
    Glimming, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Numerisk analys och datalogi (NADA), (tills m KTH).
    Primitive Direcursion and Difunctorial Semantics of Typed Object Calculus2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In the first part of this thesis, we contribute to the semantics of typed object calculus by giving (a) a category-theoretic denotational semantics using partial maps making use of an algebraic compactness assumption, (b) a notion of "wrappers'' by which algebraic datatypes can be represented as object types, and (c) proofs of computational soundness and adequacy of typed object calculus via Plotkin's FPC (with lazy operational semantics), thus making models of FPC suitable also for first-order typed object calculus (with recursive objects supporting method update, but not subtyping). It follows that a valid equation in the model induces operationally congruent terms in the language, so that program algebras can be studied. For (c), we also develop an extended first-order typed object calculus, and prove subject reduction. The second part of the thesis concerns recursion principles on datatypes including the untyped lambda calculus as a special case. Freyd showed that in certain domain theoretic categories, locally continuous functors have minimal invariants, which possess a structure that he termed dialgebra. This gives rise to a category of dialgebras and homomorphisms, where the minimal invariants are initial, inducing a powerful recursion scheme (direcursion) on a complete partial order. We identify a problem that appears when we translate (co)iterative functions to direcursion, and as a solution to this problem we develop a recursion scheme (primitive direcursion). This immediately gives a number of examples of direcursive functions, improving on the situation in the literature where only a few examples have appeared. By means of a case study, this line of work is connected to object calculus models.

  • 38.
    Goranko, Valentin
    et al.
    Stockholms universitet, Humanistiska fakulteten, Filosofiska institutionen. University of Johannesburg, South Africa.
    Jamroga, Wojciech
    State and Path Coalition Effectivity Models for Logics of Multi-Player Games2016Ingår i: Autonomous Agents and Multi-Agent Systems, ISSN 1387-2532, E-ISSN 1573-7454, Vol. 30, nr 3, 446-485 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We consider models of multi-player games where abilities of players and coalitions are defined in terms of sets of outcomes which they can effectively enforce. We extend the well-studied state effectivity models of one-step games in two different ways. On the one hand, we develop multiple state effectivity functions associated with different long-term temporal operators. On the other hand, we define and study coalitional path effectivity models where the outcomes of strategic plays are infinite paths. For both extensions we obtain representation results with respect to concrete models arising from concurrent game structures. We also apply state and path coalitional effectivity models to provide alternative, arguably more natural and elegant semantics to the alternating-time temporal logic ATL*, and discuss their technical and conceptual advantages.

  • 39.
    Goranko, Valentin
    et al.
    Stockholms universitet, Humanistiska fakulteten, Filosofiska institutionen. University of Johannesburg, South Africa.
    Kuijer, Louwe B.
    On the Length and Depth of Temporal Formulae Distinguishing Non-bisimilar Transition Systems2016Ingår i: 23rd International Symposium on Temporal Representation and Reasoning: Proceedings / [ed] Curtis Dyreson, Michael R. Hansen, Luke Hunsberger, IEEE Computer Society, 2016, 177-185 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    We investigate the minimal length and nesting depth of temporal formulae that distinguish two given non-bisimilar finite pointed transition systems. We show that such formula can always be constructed in length at most exponential in the combined number of states of both transition systems, and give an example with exponential lower bound, for several common temporal languages. We then show that by using renamings of subformulae or explicit assignments the length of the distinguishing formula can always be reduced to one that is bounded above by a cubic polynomial on the combined size of both transition systems. This is also a bound for the size obtained by using DAG representation of formulae. We also prove that the minimal nesting depth for such formula is less than the combined size of the two state spaces and obtain some tight upper bounds.

  • 40.
    Goranko, Valentin
    et al.
    Stockholms universitet, Humanistiska fakulteten, Filosofiska institutionen.
    Kuusisto, Antti
    University of Bremen, Germany.
    Rönnholm, Raine
    University of Tampere, Finland.
    Game-Theoretic Semantics for Alternating-Time Temporal Logic2016Ingår i: Proceedings of the 2016 International Conference on Autonomous Agents & Multiagent Systems / [ed] J. Thangarajah, K. Tuyls, C. M. Jonker, S. Marsella, The International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS), 2016, 671-679 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    We introduce versions of game-theoretic semantics (GTS) for Alternating-Time Temporal Logic (ATL). In GTS, truth is defined in terms of existence of a winning strategy in a semantic evaluation game, and thus the game-theoretic perspective appears in the framework of ATL on two semantic levels: on the object level, in the standard semantics of the strategic operators, and on the meta-level, where game-theoretic logical semantics can be applied to ATL. We unify these two perspectives into semantic evaluation games specially designed for ATL. The novel game-theoretic perspective enables us to identify new variants of the semantics of ATL, based on limiting the time resources available to the verifier and falsifier in the semantic evaluation game; we introduce and analyse an unbounded and bounded GTS and prove these to be equivalent to the standard (Tarski-style) compositional semantics. We also introduce a non-equivalent finitely bounded semantics and argue that it is natural from both logical and game-theoretic perspectives.

  • 41.
    Guerrero, Javier
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Decision-making content of an agent affected by emotional feedback provided by capture of human’s emotions through a Bimodal System2015Ingår i: International Journal of Computer Science Issues, ISSN 1694-0784, E-ISSN 1694-0814, Vol. 12, nr 6Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affective computing allows for widening the view of the complex world in human-machine interaction through the comprehension of emotions, which allows an enriched coexistence of natural interactions between them. Corporal features such as facial expression, kinetics, structural components of the voice or vision, to mention just a few, provide us with valid information of how a human behaves. Among all the carriers of emotional information we may point out two, voice and facial gestures as holders of an ample potential for identifying emotions with a high degree of accuracy. This paper focuses on the development of a system that will track a human’s affective state using facial expressions and speech signals with the purpose of modifying the actions of an autonomous agent. The system uses a fusion of two baseline unimodal classifiers based on bayes Net giving rise to a multi-classifier. The union of the three classifiers forms a bimodal scheme of emotion classification. The outputs from the baseline unimodal classifiers are combined together through a probability fusion framework applied in the general multi-classifier. The system classifies six universal basic emotions using audiovisual data extracted from the eNTERFACE05 audiovisual emotion database. The emotional information obtained could provide an agent with the basis for taking an affective decision. It is shown by experimental results that the proposed system can detect emotions with good accuracy achieving the change of the emotional behavior of the agent faced with a human.

  • 42.
    Guerrero Rázuri, Javier Francisco
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Larsson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Sundgren, David
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Bonet, Isis
    Moran, Antonio
    Recognition of emotions by the emotional feedback through behavioral human poses2015Ingår i: International Journal of Computer Science Issues, ISSN 1694-0784, E-ISSN 1694-0814, Vol. 12, nr 1, 7-17 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The sensory perceptions from humans are intertwined channels,which assemble diverse data in order to decrypt emotionalinformation. Just by associations, humans can mix emotionalinformation, i.e. emotion detection through facial expressionscriteria, emotional speech, and the challenging field of emotionalbody language over the body poses and motion. In this work, wepresent an approach that can predict six basic universal emotionscollected by responses linked to human body poses, from acomputational perspective. The emotional outputs could be fedas inputs to a synthetic socially skilled agent capable ofinteraction, in the context of socially intelligent systems. Themethodology uses a classification technique of information fromsix images extracted from a video, entirely developed using themotion sensing input device of Xbox 360 by Microsoft. We aretaking into account that the emotional body language containsadvantageous information about the emotional state of humans,especially when bodily reaction brings about consciousemotional experiences. The body parts are windows that showemotions and they would be particularly suitable to decodingaffective states. The group of extracted images is merged in oneimage with all the relevant information. The recovered image willserve as input to the classifiers. The analysis of images fromhuman body poses makes it possible to obtain relevantinformation through the combination of proper data in the sameimage. It is shown by experimental results that the SVM candetect emotion with good accuracy compared to other classifiers.

  • 43.
    Gustafson, Joakim
    et al.
    KTH Speech, Music and Hearing.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Potential benefits of human-like dialogue behaviour in the call routing domain2008Ingår i: Perception in Multimodal Dialogue Systems, Berlin/Heidelberg, Germany: Springer Berlin/Heidelberg, 2008, 240-251 s.Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This paper presents a Wizard-of-Oz (Woz) experiment in the call routing domain that took place during the development of a call routing system for the TeliaSonera residential customer care in Sweden. A corpus of 42,000 calls was used as a basis for identifying problematic dialogues and the strategies used by operators to overcome the problems. A new Woz recording was made, implementing some of these strategies. The collected data is described and discussed with a view to explore the possible benefits of more human-like dialogue behaviour in call routing applications.

  • 44.
    Heldner, Mattias
    KTH Speech, Music and Hearing.
    Detection thresholds for gaps, overlaps and no-gap-no-overlaps2011Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, Vol. 130, nr 1, 508-513 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Detection thresholds for gaps and overlaps, that is acoustic and perceived silences and stretches of overlapping speech in speaker changes, were determined. Subliminal gaps and overlaps were cate- gorized as no-gap-no-overlaps. The established gap and overlap detection thresholds both corre- sponded to the duration of a long vowel, or about 120 ms. These detection thresholds are valuable for mapping the perceptual speaker change categories gaps, overlaps, and no-gap-no-overlaps into the acoustic domain. Furthermore, the detection thresholds allow generation and understanding of gaps, overlaps, and no-gap-no-overlaps in human-like spoken dialogue systems.

  • 45.
    Heldner, Mattias
    et al.
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Pauses, gaps and overlaps in conversations2010Ingår i: Journal of Phonetics, ISSN 0095-4470, E-ISSN 1095-8576, Vol. 38, nr 4, 555-568 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    is paper explores durational aspects of pauses gaps and overlaps in three different conversational corpora with a view to challenge claims about precision timing in turn-taking Distributions of pause gap and overlap durations in conversations are presented and methodological issues regarding the statistical treatment of such distributions are discussed The results are related to published minimal response times for spoken utterances and thresholds for detection of acoustic silences in speech It is shown that turn-taking is generally less precise than is often claimed by researchers in the field of conversation analysis or interactional linguistics These results are discussed in the light of their implications for models of timing in turn-taking and for interaction control models in speech technology In particular it is argued that the proportion of speaker changes that could potentially be triggered by information immediately preceding the speaker change is large enough for reactive interaction controls models to be viable in speech technology

  • 46.
    Heldner, Mattias
    et al.
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Carlson, Rolf
    KTH Speech, Music and Hearing.
    Interruption impossible2006Ingår i: Nordic Prosody: Proceedings of the IXth Conference, Lund 2004, Frankfurt am Main: Peter Lang Publishing Group, 2006, 97-105 s.Konferensbidrag (Refereegranskat)
  • 47.
    Heldner, Mattias
    et al.
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Hirschberg, Julia
    Columbia University Computer Science.
    Pitch similarity in the vicinity of backchannels2010Ingår i: Proceedings Interspeech 2010, Makuhari, Japan: ISCA , 2010, 3054-3057 s.Konferensbidrag (Refereegranskat)
  • 48.
    Heldner, Mattias
    et al.
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Hjalmarsson, Anna
    KTH Speech, Music and Hearing.
    Laskowski, Kornel
    KTH Speech, Music and Hearing.
    Very short utterances and timing in turn-taking2011Ingår i: Proceedings Interspeech 2011, Florence, Italy: ISCA , 2011, 2837-2840 s.Konferensbidrag (Refereegranskat)
  • 49.
    Heldner, Mattias
    et al.
    KTH Speech, Music and Hearing.
    Edlund, Jens
    KTH Speech, Music and Hearing.
    Laskowski, Kornel
    KTH Speech, Music and Hearing.
    Pelcé, Antoine
    KTH Speech, Music and Hearing.
    Prosodic features in the vicinity of silences and overlaps2009Ingår i: Nordic Prosody: Proceedings of the Xth Conference, Helsinki 2008, Frankfurt am Main: Peter Lang , 2009, 95-105 s.Konferensbidrag (Refereegranskat)
  • 50.
    Henriksson, Aron
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Institutionen för data- och systemvetenskap.
    Ensembles of Semantic Spaces: On Combining Models of Distributional Semantics with Applications in Healthcare2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Distributional semantics allows models of linguistic meaning to be derived from observations of language use in large amounts of text. By modeling the meaning of words in semantic (vector) space on the basis of co-occurrence information, distributional semantics permits a quantitative interpretation of (relative) word meaning in an unsupervised setting, i.e., human annotations are not required. The ability to obtain inexpensive word representations in this manner helps to alleviate the bottleneck of fully supervised approaches to natural language processing, especially since models of distributional semantics are data-driven and hence agnostic to both language and domain.

    All that is required to obtain distributed word representations is a sizeable corpus; however, the composition of the semantic space is not only affected by the underlying data but also by certain model hyperparameters. While these can be optimized for a specific downstream task, there are currently limitations to the extent the many aspects of semantics can be captured in a single model. This dissertation investigates the possibility of capturing multiple aspects of lexical semantics by adopting the ensemble methodology within a distributional semantic framework to create ensembles of semantic spaces. To that end, various strategies for creating the constituent semantic spaces, as well as for combining them, are explored in a number of studies.

    The notion of semantic space ensembles is generalizable across languages and domains; however, the use of unsupervised methods is particularly valuable in low-resource settings, in particular when annotated corpora are scarce, as in the domain of Swedish healthcare. The semantic space ensembles are here empirically evaluated for tasks that have promising applications in healthcare. It is shown that semantic space ensembles – created by exploiting various corpora and data types, as well as by adjusting model hyperparameters such as the size of the context window and the strategy for handling word order within the context window – are able to outperform the use of any single constituent model on a range of tasks. The semantic space ensembles are used both directly for k-nearest neighbors retrieval and for semi-supervised machine learning. Applying semantic space ensembles to important medical problems facilitates the secondary use of healthcare data, which, despite its abundance and transformative potential, is grossly underutilized.

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