umu.sePublications
Change search
Refine search result
1234567 51 - 100 of 1944
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.
  • 51.
    Armstrong, Django
    et al.
    University of Leeds.
    Espling, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Tordsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Djemame, Karim
    University of Leeds.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Contextualization: dynamic configuration of virtual machines2015In: Journal of Cloud Computing - Advances, Systems and Applications, ISSN 2192-113X, Vol. 4, no 17Article in journal (Refereed)
    Abstract [en]

    New VM instances are created from static templates that contain the basic configuration of the VM to achieve elasticity with regards to capacity. Instance specific settings can be injected into the VM during the deployment phase through means of contextualization. So far this is limited to a single data source and data remains static throughout the lifecycle of the VM.

    We present a layered approach to contextualization that supports different classes of contextualization data available from several sources. The settings are made available to the VM through virtual devices. Inside each VM data from different classes are layered on top of each other to create a unified file hierarchy.

    Context data can be modified during runtime by updating the contents of the virtual devices, making our approach the first contextualization approach to natively support recontextualization. Recontextualization enables runtime reconfiguration of an executing service and can act as a trigger and key enabler of self-* techniques. This trigger provides a service with a mechanism to adapt or optimize itself in response to a changing environment. The runtime reconfiguration using recontextualization and its potential gains are illustrated in an example with a distributed file system, demonstrating the feasibility of our approach.

  • 52.
    Armstrong, Django
    et al.
    University of Leeds.
    Espling, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Tordsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Djemame, Karim
    University of Leeds.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Runtime virtual machine recontextualization for clouds2013In: Euro-Par 2012: Parallel Processing Workshops / [ed] Ioannis Caragiannis et al., Springer Berlin/Heidelberg, 2013, Vol. 7640, p. 567-576Conference paper (Refereed)
    Abstract [en]

    We introduce and define the concept of recontextualization for cloud applications by extending contextualization, i.e. the dynamic configuration of virtual machines (VM) upon initialization, with autonomous updates during runtime. Recontextualization allows VM images and instances to be dynamically re-configured without restarts or downtime, and the concept is applicable to all aspects of configuring a VM from virtual hardware to multi-tier software stacks. Moreover, we propose a runtime cloud recontextualization mechanism based on virtual device management that enables recontextualization without the need to customize the guest VM. We illustrate our concept and validate our mechanism via a use case demonstration: the reconfiguration of a cross-cloud migratable monitoring service in a dynamic cloud environment. We discuss the details of the interoperable recontextualization mechanism, its architecture and demonstrate a proof of concept implementation. A performance evaluation illustrates the feasibility of the approach and shows that the recontextualization mechanism performs adequately with an overhead of 18% of the total migration time.

  • 53.
    Arvidsson, Viktor
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    A model for strategic e-service implementation in the public sector: challenges for local governments in identifying potential candidates for e-service delivery2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As more and more local governments begin to understand that the great promises of e-service delivery are harder than expected to realize, efficient use of ICT-resources have become increasingly important. Since simply providing more e-services is not the solution, the need to understand what constitutes a suitable e-service has arisen. Public services reach beyond the market domain; therefore, the complexities of public value must be dealt with when services are appraised. Furthermore, due to the heterogeneous nature of local government services it is impossible to evaluate all the options in depth; thus, there is a clear need for early-stage appraisal. However, existing methods of appraisal are burdened by intricacy, and associated with high costs. In response, this paper presents a model capable of reducing this intricacy. The model was developed through a participatory design process involving members on both operational and strategic level in the municipality of Skellefteå. The model implements state of the art into the workspace context while taking measures to reduce intricacy such as: incremental filtering, moving high intricacy elements to the end of the process, and exploitation of available data. As a result the organization is enabled to capture not only the low hanging fruit, but also the long tail of services. Furthermore, the improved understanding of e-service delivery has the potential to open up opportunities for new ways of business development and private-public partnerships. Finally, whereas the model presented is highly context-dependent, the implications outlined in this paper are not limited to this narrow scope.

  • 54.
    Arvidsson, Viktor
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Coordination from an Awareness perspective: Mechanisms and techniques for Awareness based Coordination support.2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When a task becomes shared the need for coordination arises. One fundamental factor for coordination is awareness. This study aimed to answer the question of how awareness-based coordination support systems could increase the efficiency in the processing of tasks generated by the Customer Support Unit in Skellefteå municipality, ultimately creating a better work situation for the officers responsible for the handling of tasks and increasing the service level for the customers of their services. This question was answered by conducting interviews, observing system usage and through analysis of pre-existing interviews from earlier studies of the municipality’s CSU project. This study shows that there are aspects in the task management that are in need of coordination support and presents a task classification system based on the logistic nature of the task. Furthermore this paper identifies the main problems related to the current task management and from an awareness perspective discusses and outlines various mechanisms and techniques to address these problems. Alongside these problems the general lack of coordination support in the current Document and Workflow System (FlexiteBPMS) is approached. Furthermore all outlined proposals share the common aspiration of lessening the burden for the officers without simply shifting the workload onto other units in the workflow chain.

  • 55.
    Arvidsson, Viktor
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Evaluating E-Service Candidates: Participatory design of an e-service valuation model2011Conference paper (Refereed)
  • 56.
    Arvidsson, Viktor
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    The revolution that wasn’t: Investigating barriers to platform-based e-service delivery partnerships2012In: Proceedings of the 45th Annual Hawaii International Conference on System Sciences, Wailea, January 4-7, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    In response to the increasing political and popular demand on e-government to deliver, governments have begun to seek out new, alternative forms of operation. One such development in the domain of e-government is the emergence of private-public partnerships (PPP). However, research on PPPs in the service layer of e- government is virtually silent. In this paper we argue that one possible approach to help close this gap is by investigating key partnership issues from a platform perspective. Building on a case study, and using this novel perspective, we identify three key barriers for developing platform-based partnerships for e-service delivery in local government: the bureaucratic barrier, the interface barrier and the business barrier. Based on experiences from this study, we also conclude that the platform approach have proven useful as a means to close the highlighted gap in research. 

  • 57.
    Arvidsson, Viktor
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Towards efficient and effective e-service delivery: Addressing the challenges of e-service evaluation in local government2012In: Transformational Government through eGov: Socio-economic, Cultural, and Technological issues / [ed] Y. Dwivedi & M. Akhter & Norm Archer, UK: Emerald Group Publishing Limited, 2012, p. 155-188Chapter in book (Refereed)
    Abstract [en]

    Purpose: This study present and provide insight into the design of eVAL, an ex ante e-service evaluation model designed for use in local governments with the ambition of helping local governments overcome the challenges of e-service delivery.

    Methodology: The evaluation model has been developed through participatory design research, which takes place within an overarching case study of a Swedish municipality.

    Findings: This paper identifies three key challenges for e-service delivery and evaluation in the local government: managing intricacy, handling public value and forecasting take-up.

    Research limitations/implications: This study stresses the need for researchers to give attention to the dilemma local governments are faced with, and provides a possible middle-way out of the debate on the appropriateness of traditional investment techniques in the public sector.

    Practical implications: The importance of data and organizational capabilities for evaluation and successful implementation of e-services is stressed.

    Originality/value: This study provides an insight into the challenges that local governments have to face as the attempt to implement e-services in an efficient and effective fashion, while at the same time presenting a novel evaluation model capable of addressing some of these challenges. Whereas evaluation models do exist, none of the models reviewed during design were found applicable in the context of local government.

  • 58.
    Arvidsson, Viktor
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Towards efficient and effective E-Service Delivery: Addressing the matter of intricacy in service evaluation2011Manuscript (preprint) (Other academic)
    Abstract [en]

    The great promises of e-government have proven to be harder than expected to realise. Effective and efficient e-service delivery is dependent on making sound choices as to which e- services to implement; consequently, accountability in the use of ICT-resources have become of increasing importance. This generates a need to identify what constitutes a suitable e-service, and to devise models capable of evaluating available options. As public services reach beyond the business rationale of the private sector, such considerations must deal with the complexity of public value. Additionally, due to the heterogeneous nature of local government it is not feasible to evaluate every candidate in depth. For e-service delivery to reach beyond major services governments must lower their demands for accuracy and implement more cost- efficient ways of estimating public value. This paper investigates how this can be achieved while maintaining satisfactory results, and builds an understanding of the challenges that local governments face in doing so. 

  • 59.
    Arvidsson, Viktor
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Holmström, Jonny
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Social Media Strategy: Understanding Social Media, IT Strategy, and Organizational Responsiveness in Times of Crisis2013In: Cutter IT Journal, ISSN 1522-7383, Vol. 26, no 12, p. 18-23Article in journal (Refereed)
    Abstract [en]

    The ability to effectively and efficiently interact with the business environment is key to organizational success. To this end, organizations increasingly use IT to enable new, improved flows of information both within and across organizational boundaries. Social media (SM) technologies hold great potential for enabling new forms of communication with distant actors. For this potential to be fully realized, however, investments in technology should be made alongside changes in organizational practice and design. While all IT strategies should complement high-level organizational goals and identify the organizational changes necessary to realize them,1 this is particularly the case with SM strategy, as it necessarily challenges traditional forms of organizing and blurs organizational boundaries.

  • 60.
    Arvidsson, Viktor
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics. Umeå University, Faculty of Social Sciences, Umeå Centre for Gender Studies (UCGS). Swedish Center for Digital Innovation.
    Holmström, Jonny
    Umeå University, Faculty of Social Sciences, Department of Informatics. Swedish Center for Digital Innovation.
    Lyytinen, Kalle
    Case Western Reserve University.
    Information systems use as strategy practice: a multi-dimensional view of strategic information system implementation and use2014In: Journal of strategic information systems, ISSN 0963-8687, E-ISSN 1873-1198, Vol. 23, no 1, p. 45-61Article in journal (Refereed)
    Abstract [en]

    Information systems (IS) are strategic in so far as they are used to realize strategic intent. Yet, while much has been said about aligning IS functionality with the strategic intent and how to organizationally implement strategically aligned systems, less is known of how to successfully implement strategic change associated with system use – a truly critical challenge within strategic IS implementation. Drawing on a strategy-as-practice perspective we address this gap by developing a multi-dimensional view of IS strategy, conceptualizing three key challenges in the IS strategy process, to explain how and why a paper mill, despite successfully implementing a strategic production management system, failed to produce intended strategic change. We call this outcome strategy blindness: organizational incapability to realize the strategic intent of implemented, available system capabilities. Using a longitudinal case study we investigate how cognitive rigidity of key actors and fixed, interrelated practices shaped the implementation of the new production system. We also identify core components and dynamics that constitute a richer multi-dimensional view of the IS strategy implementation (alignment) process. In particular, we identify three salient factors that contribute to strategy blindness – mistranslation of intent, flexibility of the IT artifact and cognitive entrenchment – and discuss how they affect strategic implementation processes. We conclude by discussing implications of our findings for IS strategy theory and practice, especially the contribution of strategy-as-practice to this stream of research.

  • 61.
    Aslani, Ehsan
    et al.
    Umeå University, Faculty of Social Sciences, Informatics.
    Fredriksson, Johan
    Umeå University, Faculty of Social Sciences, Informatics.
    Reklamfilm av nyskapande och kreativ karaktär2008Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This paper consists of a comprehensive look at the advertising industry as a whole and communication mould various guises in the context of technology development. It also describes a production in the form of a commercial for a network of ten companies called The Lodge. The result is discussed based on questions on the subject communications and marketing. The discussions of this work will then be transferred to a proposal for further research.

  • 62.
    Asp, Simon
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Reducing Food Waste with a Sustainable Lunch Concept: A Service Design Project2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Environmental problems such as pollution and overconsumption is something that is mentioned often in the news as this thesis is written. Food waste is a problem that causes valuable resources to be lost, as on average one third of all food globally is being wasted. The food chain is complicated, from the farm to the table, and innovations in all parts of the chain could help reduce the waste. We have aimed our scope to the end of the chain, when food is made at a restaurants to be served to customers. Figures say that about 23% of food in the restaurant business in Sweden is being wasted. To try to solve this problem, we have turned to service design and the methodologies presented there, to find a potential solution that could help reduce food waste.

    An extensive service design process was made with many interviews with restaurants to find where a solution could be made. The whole design process is presented in the report, and the final concept resolves around a sustainable lunch dish that can be made out of ingredients that would otherwise be thrown out. The dish would be sold at lunch restaurants for a reduced price since it is cheap to make, and would make more people act sustainable. A concept test was made to evaluate the the sustainable dish concept with the help from the public. The main question was:

    Is this concept something that could be adopted by people who buy lunch on a regular basis in Sweden?

    The concept test resulted in 165 respondents that were asked what they would choose to eat from a given menu. 32% chose the sustainable dish, and although biases were believed to have played a role in the decision, the concept was deemed successful. A website was then designed, aimed towards restaurants that wanted to adopt the concept and to get started in an easy way.

  • 63.
    Ataei, Mehrnaz
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    ME|EMO: Application concept for sharing emotions through non-verbal communication2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    ME|EMO provides a method to help users to express, visualize and share emotions through digital nonverbal communication. This application will enable the users to map their emotions to colors and encourage users to paint their feelings. A canvas with uncolored images and a color palette with color coded emotions creates an environment for expressing and visualizing the feelings. The result is an image file in the form of a simple piece of modern art with the possibility of sharing it through social networks, or to record the emotions and save precious moments of life. Technology development, new ways of communication, digital tools, apps, social media, have helped people to have a better life by giving people the opportunity to communicate easier with loved ones and friends. ME|EMO tries to enhance the way of modern communication (digital text-based) such as social networks or modern healthcare systems, by supporting the emotional side of communications. 

  • 64.
    Augustian, Midhumol
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sandvig, Axel
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Norwegian University of Science and Technology (NTNU), Norway.
    Kotikawatte, Thivra
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Yongcui, Mi
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Evensmoen, Hallvard Røe
    Norwegian University of Science and Technology (NTNU), Norway.
    EEG Analysis from Motor Imagery to Control a Forestry Crane2018In: Intelligent Human Systems Integration (IHSI 2018) / [ed] Karwowski, Waldemar, Ahram, Tareq, 2018, Vol. 722, p. 281-286Conference paper (Refereed)
    Abstract [en]

    Brain-computer interface (BCI) systems can provide people with ability to communicate and control real world systems using neural activities. Therefore, it makes sense to develop an assistive framework for command and control of a future robotic system which can assist the human robot collaboration. In this paper, we have employed electroencephalographic (EEG) signals recorded by electrodes placed over the scalp. The human-hand movement based motor imagery mentalization is used to collect brain signals over the motor cortex area. The collected µ-wave (8–13 Hz) EEG signals were analyzed with event-related desynchronization/synchronization (ERD/ERS) quantification to extract a threshold between hand grip and release movement and this information can be used to control forestry crane grasping and release functionality. The experiment was performed with four healthy persons to demonstrate the proof-of concept BCI system. From this study, it is demonstrated that the proposed method has potential to assist the manual operation of crane operators performing advanced task with heavy cognitive work load.

  • 65.
    Augustsson, Nils-Petter
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Persson, Tomas
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Stolterman, Erik
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    The character of a VR -visualization2003In: Proceedings of the 26th International Systems Research in Scandinavia (IRIS)Conference, 2003Conference paper (Refereed)
    Abstract [en]

    When we humans are dealing with complex things in our daily lives, for example an artifact, we tend to ascribe different characters to it. This is our way of getting a quick overview of the artifact and makes it understandable to us. The ascribing of character is not based on thorough examination of the object at hand though, but rather on a certain thing, i.e. a characteristic that catches our attention. This characteristic gives us a certain feeling about the artifact and makes it possible for us to make a judgment about it, even if it is a snap one. With this as a starting point we try to identify the different characteristics, which constitute the overall character, i.e. realism. In many visualisations with this objective, realism is juxtaposed with copying static structures, i.e. buildings and streets. This is also a strong contributor to the realism character in the Botnia-track visualisation. In our opinion this is not enough to get a realistic character. We have identified a few other prominent characteristics that also are important contributors to the realism character, for example landmarks, sound, moving objects and narrator voice. Our main conclusion is that if a realistic character is desirable, more than visualisation of static structures is necessary. We found at least five additional characteristics that influence people’s perception of a virtualisation; landmarks, sound, moving objects and narrator voice. In our opinion, all of these are important for a realistic character to emerge and something that designers have to take in to consideration to reach the intended goal.

  • 66. Awid, Kamil
    et al.
    Cleophas, Loek
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Watson, Bruce W.
    Using Human Computation in Dead-zone based 2D Pattern Matching2016In: Prague Stringology Conference 2016 / [ed] Holub, J Zdarek, J, CZECH TECHNICAL UNIV PRAGUE , 2016, p. 22-32Conference paper (Other academic)
    Abstract [en]

    This paper examines the application of human computation (HC) to two-dimensional image pattern matching. The two main goals of our algorithm are to use turks as the processing units to perform an efficient pattern match attempt on a subsection of an image, and to divide the work using a version of dead-zone based pattern matching. In this approach, human computation presents an alternative to machine learning by outsourcing computationally difficult work to humans, while the dead-zone search offers an efficient search paradigm open to parallelization-making the combination a powerful approach for searching for patterns in two-dimensional images.

  • 67.
    Axelsson, Lenny
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Exploring HCI-issues within error- sensitive intensive healthcare systems: An Ethnographic case study2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    People are used to working routines that are taught and transferred from one to another, routines such as how to interact with an information system and how to use it in a specific context. While user experience and usability have been two issues of interest within the field of HCI, there is a lack of research exploring usage and behavior while interacting with complex error-sensitive systems, in so much as an action that couldn’t be undone once performed. This thesis explores the error-sensitive aspects of complexity within interactions of the administering of medical prescription activities at an intensive healthcare unit. The aim is to investigate the interactions of computer-supported cooperative work environments used for information transformation activities for medical prescriptions. The results reveal a number of HCI-related issues in which clinicians socially bypass system interactions by making incomplete data inputs while assuming a given level of understanding of other employees. 

  • 68.
    Backman, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Bodin, Kenneth
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Bucht, Gösta
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Janlert, Lars-Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Maxhall, Marcus
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Pederson, Thomas
    Innovative Communication Group, IT University of Copenhagen.
    Sjölie, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Sondell, Björn
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Surie, Dipak
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    easyADL – Wearable Support System for Independent Life despite Dementia2006In: ACM CHI 2006 Workshop onDesigning Technology for People with Cognitive Impairments, 2006Conference paper (Refereed)
    Abstract [en]

    This position paper outlines the easyADL project, a two-year project investigating the possibility of using wearable technology to assist people suffering the dementia disease in performing Activities of Daily Living (ADL). An introduction to the egocentric interaction modeling framework is provided and the virtual reality based development methodology is discusssed.

  • 69. Backman, Anders
    et al.
    Bodin, Kenneth
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Lacoursière, Claude
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Servin, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Democratizing CAE with Interactive Multiphysics Simulation and Simulators2012Conference paper (Other academic)
  • 70. Badariah Asan, Noor
    et al.
    Hassan, Emadeldeen
    Umeå University, Faculty of Science and Technology, Department of Computing Science. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Velander, Jacob
    Redzwan Mohd Shah, Syaiful
    Noreland, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Blokhuis, Taco J.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Voigt, Thiemo
    Augustine, Robin
    Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 9, article id 2752Article in journal (Refereed)
    Abstract [en]

    In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7–2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.

  • 71. Bae, Seung-Hee
    et al.
    Halperin, Daniel
    West, Jevin
    Rosvall, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Howe, Bill
    Scalable Flow-Based Community Detection for Large-Scale Network Analysis2013In: 2013 IEEE 13TH INTERNATIONAL CONFERENCE ON DATA MINING WORKSHOPS (ICDMW) / [ed] Ding, W Washio, T Xiong, H Karypis, G Thuraisingham, B Cook, D Wu, X, IEEE, 2013, p. 303-310Conference paper (Refereed)
    Abstract [en]

    Community-detection is a powerful approach to uncover important structures in large networks. Since networks often describe flow of some entity, flow-based community-detection methods are particularly interesting. One such algorithm is called Infomap, which optimizes the objective function known as the map equation. While Infomap is known to be an effective algorithm, its serial implementation cannot take advantage of multicore processing in modern computers. In this paper, we propose a novel parallel generalization of Infomap called RelaxMap. This algorithm relaxes concurrency assumptions to avoid lock overhead, achieving 70% parallel efficiency in shared-memory multicore experiments while exhibiting similar convergence properties and finding similar community structures as the serial algorithm. We evaluate our approach on a variety of real graph datasets as well as synthetic graphs produced by a popular graph generator used for benchmarking community detection algorithms. We describe the algorithm, the experiments, and some emerging research directions in high-performance community detection on massive graphs.

  • 72. Ballesteros, S.
    et al.
    Peter, C.
    Waterworth, Eva L.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Waterworth, John A.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    The role of ICT and networking in healthy ageing2012In: Proceedings of the 5th International Conference on PErvasive Technologies Related to Assistive Environments, ACM Digital Library, 2012Conference paper (Refereed)
    Abstract [en]

    In this paper, we report the results from the psychologicalassessment conducted using a test battery composed of cognitiveand social wellbeing tests and questionnaires performed by usersand controls that participated in the AGNES project in Spain,Sweden and Greece at the beginning of the study and after thedeployment of the first prototype. The project carries out noveltechnological interventions in an emerging area in ageingresearch. The main innovation is the integration of differenttechnological components and social networking to provide anovel solution to the ageing population living at home. Themotivation was based on relevant findings on the psychology ofageing and the need for technologies to support the ageingpopulation. End-users have been heavily involved, providingdesign input, continuum evaluation and feedback. Theprojectfocuses on improving the mental and physical wellbeing ofelderly people living at home, who often suffer the effects ofsocial and physical isolation including cognitive decline, lowactivity levels and poor mood states. The main results were thatthe users but not the control participants improved cognitiveperformance andthe feeling of being treated with respect, beingindependent, self-realization and greater achievement.

  • 73.
    Balog, Rodica
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Streamlined "Purchase to Payment" process2008Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 74.
    Bashir, Muhammad Shahid
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Zakaria, Mohd Zalmy
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Hesitation on adoption Self-Service Technologies (SSTs): A case study on self payment machine2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Self service providers are making such systems which offer faster and more flexible service to the user. Most of us are familiar about self service technologies such as Kiosk, Auto Teller Machine, Self Check in machine, Self payment machine etc. Unfortunately, users are not using these SSTs commonly as advancement has been occurring in SSTs. Sometimes, people look annoyed and feel fear to use such kind of technology at public spaces. Generally, these systems need interaction between users and technology to create service outcome instead of interacting with a service personnel. These technological interfaces have been called Self-service technologies (SSTs). Yet, not all users choose to use the new technologies and they still feel some hesitations to adopt this technologies in this case SSTs. This study investigated the factors that make users hesitate to use and adopt SSTs.

  • 75.
    Baskar, Jayalakshmi
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Adaptive human-agent dialogues for reasoning about health2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this research is to develop new theories, methods and technology, which enables adaptive and personalised dialogues between a human and a software agent, to handle everyday queries about health that are perceived as meaningful and useful to the human. Some of the challenges to build such human-agent dialogue system are the following. The agent needs to have knowledge about the human, the topic of the dialogue, the knowledge domain of the topic, and also about the physical and social environment. Moreover, the agent must know about itself, its role, purpose and limitations. It must know how to be cooperative and be able to behave and express with empathy while conducting a dialogue activity. In some situations, it needs to reason and make decisions about a topic together with the human and about its own behavior. To be able to do this, it needs the capability to evaluate its behavior in the context in which the dialogue takes place. These challenges are addressed by developing formal semantic models to provide the agent with tools to build their knowledge and to be able to reason and make decisions. These models were developed based on literature studies, theories of human activity, argumentation theory, personas and scenarios.

    The models were formalised and implemented using Semantic Web technology, and integrated into a human-agent dialogue system. The system was evaluated with a group of therapists and a group of elderly people, who showed curiosity and interest in having dialogues with a software agent on various topics.

    The formal models that the agent constructs are adapted to the specific situation and to the human actor participating in a dialogue. They are based on four models: a model with knowledge about the human actor, a model of itself, a domain model, and a dialogue activity model. The dialogue activity is based on argumentation schemes, which function as patterns of reasoning and for the dialogue execution. These models allow the agent and the human actor to conduct flexible and nested sub-dialogues with different purposes within a main dialogue about a topic. The agent can adapt its moves to the human actor's trail of reasoning, to the human's priorities and goals, and to some human's emotional state. A method for the agent to be able to evaluate its behavior was also developed and evaluated. The proportion of appropriate moves in relation to the local context of earlier moves in the dialogue was 90% in the pilot study, which indicates that the agent's strategies for selecting moves can be improved.

    Future research will focus on further development of reasoning methods, learning and assessment methods, and interface design. The results will be applied to additional knowledge domains to test its domain independence and will be evaluated with different groups of potential users.

  • 76.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Janols, Rebecka
    Umeå University, Faculty of Science and Technology, Department of Computing Science. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation.
    Guerrero, Esteban
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Nieves, Juan Carlos
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    A Multipurpose Goal Model for Personalised Digital Coaching2017In: Agents and Multi-Agent Systems for Health Care: 10th International Workshop, A2HC 2017, São Paulo, Brazil, May 8, 2017, and International Workshop, A-HEALTH 2017, Porto, Portugal, June 21, 2017, Revised and Extended Selected Papers, Springer, 2017, Vol. 10685, p. 94-116Conference paper (Refereed)
    Abstract [en]

    Supporting human actors in daily living activities for improving health and wellbeing is a fundamental goal for assistive technology. The personalisation of the support provided by assistive technology in the form of digital coaching requires user models that handle potentially conflicting goals and motives. The aim of this research is to extend a motivational model implemented in an assistive technology, into a multipurpose motivational model for the human actor who is to be supported, which can be translated into a multipurpose goal model for a team of assistive agents. A team of assistive agents is outlined with supplementary goals following the human’s different properties. A method for generating multipurpose arguments relating to different motives were developed, and implemented in a human-agent dialogue system. The results are exemplified based on a use case from an earlier pilot user study of the assistive technology. Future work includes user studies to validate the model.

  • 77.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Cognitive Architecture of an Agent for Human-Agent Dialogues2014In: Highlights of Practical Applications of Heterogeneous Multi-Agent Systems: the PAAMS Collection, Springer, 2014, Vol. 430, p. 89-100Conference paper (Refereed)
    Abstract [en]

    This paper proposes a cognitive architecture of an intelligent agent that can have a dialogue with a human agent on health-related topics. This architecture consists of four main components, namely, the Belief Base, the Dialogue Manager, the Task Manager and the Plan Generator. Each component has sub-components that perform a set of tasks for the purpose to enable the agent to be enrolled in a dialogue. In this paper the particular sub-component of the Dialogue Manager, the Dialogue Strategy has been discussed in detail. A notion of scheme is introduced, which functions as a template with variables that are instantiated each time a state is entered. The agent’s dialogue strategy is implemented as a combination of the schemes and the state transitions that the agent makes in response to the human’s request. We used a combination of finite-state and agent-based dialogue strategies for dialogue management. This combined dialogue strategy enables a multi-topic dialogue between a human and an agent.

  • 78.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Human-Agent Dialogues and Their Purposes2017In: Proceedings of the European Conference on Cognitive Ergonomics 2017, New York, NY, USA: ACM Digital Library, 2017, p. 101-104Conference paper (Refereed)
    Abstract [en]

    A common conversation between an older adult and a nurse about health-related issues includes topics such as troubles with sleep, reasons for walking around nighttime, pain conditions, etc. Such a dialogue can be regarded as a "natural" dialogue emerging from the participating agents' lines of thinking, their roles, needs and motives, while switching between topics as the dialogue unfolds. The purpose of this work is to define a generic conceptual model of purposeful human-agent dialogue activity including different types of argumentation dialogues, suitable for health-related topics. This is done based on analyses of a scenario, persona and models of human behaviour. The model will be shared between the human and the agent, allowing for adaptation to the human's reasoning, needs and motives.

  • 79.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Semantic model for adaptive human-agent dialogues2014Manuscript (preprint) (Other academic)
    Abstract [en]

    A common conversation between an older adult and a nurse about health-related issues includes topics such as troubles with sleep, reasons for walking around nighttime, pain conditions, etc. Such a dialogue can be regarded as a "natural" dialogue emerging from the participating agents' lines of thinking, their roles, needs and motives, while switching between topics as the dialogue unfolds. The purpose of this work is to define a generic model of purposeful human-agent dialogues suitable for health-related topics. This is done based on analyses of scenarios, personas and models of human behavior. The results include four models, which need to be included in a software agent's belief base; i) a user model, ii) a model of the domain knowledge related to the topic of the dialogue, iii) an agent model, and iv) a dialogue activity model. The models were implemented into a prototype system for human-agent dialogues, which was evaluated by therapists and a group of older adults.

  • 80.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Towards personalised support for monitoring and improving health in risky environments2013In: VIII Workshop on Agents Applied in Health Care (A2HC), 2013, p. 93-104Conference paper (Refereed)
  • 81.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Surie, Dipak
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Yan, Chunli
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Yekeh, Farahnaz
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Personalisation and user models for support in daily living2012In: The 27th annual workshop of the Swedish Artificial Intelligence Society (SAIS), 14–15 May 2012 / [ed] Lars Karlsson, Julien Bidot, 2012, p. 7-16Conference paper (Refereed)
    Abstract [en]

    In recent years, the interest in developing personalised applications for home environment has grown since it has a wide reach in helping people in their daily activities. However, for our purposes the concept activities of daily living also need to include work and leisure activities not necessarily performed in home environments. In this article, we describe an ongoing effort to develop a generic framework for assessing ability and tailoring of support applications in the health domain. We also give an overview of the approaches that have been adopted for personalisation and user modelling to various application areas. Suggestions of future development are provided.

  • 82.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Yan, Chunli
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    User's control of personalised intelligent environments supporting health2013In: Intelligent Environments (IE), 2013 9th International Conference on, IEEE Computer Society, 2013, p. 270-273Conference paper (Refereed)
    Abstract [en]

    This research project aims at supporting workers in the mining and construction industries and older adults at home, in monitoring the risks of their daily work or living situation. A goal is to create awareness in the individual about risks and how to decrease risks. Methods and knowledge-based applications are developed, which synthesise knowledge about the user, the user’s activities, the environment and generic domain knowledge for the purpose of providing tailored support and advice to individuals. This knowledge is also what the user can relate to, interact with and control through different methods. In this paper we investigate different approaches to user control of intelligent environments and propose a dialogue-based method for user control.

  • 83.
    Baskar, Jayalakshmi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Yan, Chunli
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lindgren, Helena
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Instrument-Oriented Approach to Detecting and Representing Human Activity for Supporting Executive Functions and Learning2017In: Proceedings of the European Conference on Cognitive Ergonomics 2017, New York, NY, USA: ACM Digital Library, 2017, p. 105-112Conference paper (Refereed)
    Abstract [en]

    The goal of this study is to develop a computer-interpretable model for activity detection and representation, based on existing informal models of how humans perform activity. Appropriate detection of purposeful human activity is an essential functionality of active assistive technology aiming at providing tailored support to individuals for improving activity performance and completion. The main contribution is the design of a model for detection and representation of human activities based on three categories of instruments, which is implemented as two generic and supplementary terminology models: an event ontology and a core ontology. The core ontology is extended for each new knowledge domain into a domain ontology. The model builds the base for personalization of services generated by the cooperative reasoning performed by a human collaborating with an intelligent and social software agent. Ongoing and future work includes user studies in the different application domains.

  • 84.
    Baudin, Joel
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Boman, Andre
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Webben och dess nya invånare: Vilka krav kan vi ställa på framtiden2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The current state of our web is one where users can create and distribute information freely and without constraining limitations of knowledge. It’s as easy as making a Facebook status update or sending out a Tweet to make contributions to the web and we’re all doing it. Web-Giants like Facebook and Google deinate the web because they have such massive user amounts and therfore they control the information their users see. This is a problem because we’re hidden from the entire information amount that is the web in the 21st century. Today we limit ourself unknowingly by using these sites who implements a personalization approach which tries to show us the information it thinks we want to see. The next generation of the web seeks to open up the web to computers that makes it easier for them to understand and analyse the information on the web. Then they can help us by giving more relevant answers to the questions we ask them and show us what we actually want to see. This papers focus is in how these questions affect the daily life of the digital natives 2.0. What is their views on a web-based life now and in the future. We then go on to use these islands of information to render forth a list of demands one should be able to ask of a web-application in the future we know as Web 3.0.

  • 85. Baum, Seth D.
    et al.
    Armstrong, Stuart
    Ekenstedt, Timoteus
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Häggström, Olle
    Hanson, Robin
    Kuhlemann, Karin
    Maas, Matthijs M.
    Miller, James D.
    Salmela, Markus
    Sandberg, Anders
    Sotala, Kaj
    Torres, Phil
    Turchin, Alexey
    Yampolskiy, Roman V.
    Long-term trajectories of human civilization2019In: Foresight, ISSN 1463-6689, E-ISSN 1465-9832, Vol. 21, no 1, p. 53-83Article in journal (Refereed)
    Abstract [en]

    Purpose: This paper aims to formalize long-term trajectories of human civilization as a scientific and ethical field of study. The long-term trajectory of human civilization can be defined as the path that human civilization takes during the entire future time period in which human civilization could continue to exist.

    Design/methodology/approach: This paper focuses on four types of trajectories: status quo trajectories, in which human civilization persists in a state broadly similar to its current state into the distant future; catastrophe trajectories, in which one or more events cause significant harm to human civilization; technological transformation trajectories, in which radical technological breakthroughs put human civilization on a fundamentally different course; and astronomical trajectories, in which human civilization expands beyond its home planet and into the accessible portions of the cosmos.

    Findings: Status quo trajectories appear unlikely to persist into the distant future, especially in light of long-term astronomical processes. Several catastrophe, technological transformation and astronomical trajectories appear possible.

    Originality/value: Some current actions may be able to affect the long-term trajectory. Whether these actions should be pursued depends on a mix of empirical and ethical factors. For some ethical frameworks, these actions may be especially important to pursue.

  • 86.
    Bayuh Lakew, Ewnetu
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Xu, Lei
    Hernandez-Rodriguez, Francisco
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Pahl, Claus
    A Tree-based Protocol for Enforcing Quotas in Clouds2014In: 2014 IEEE WORLD CONGRESS ON SERVICES (SERVICES), 2014, p. 279-286Conference paper (Refereed)
    Abstract [en]

    Services are increasingly being hosted on cloud nodes to enhance their performance and increase their availability. The virtually unlimited availability of cloud resources enables service owners to consume resources without quantitative restrictions, paying only for what they use. To avoid cost overruns, resource consumption must be controlled and capped when necessary. We present a distributed tree-based protocol for managing quotas in clouds that minimizes communication overheads and reduces the time required to determine whether a quota has been exhausted. Experimental evaluation shows that our protocol reduces communication costs by 42% relative to a distributed baseline solution and is up to 15 times faster.

  • 87.
    Becher, Marina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Börlin, Niclas
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Measuring soil motion with terrestrial close range photogrammetry in periglacial environments2014In: EUCOP 4: Book of Abstracts / [ed] Gonçalo Vieira, Pedro Pina, Carla Mora and António Correia, University of Lisbon and the University of Évora , 2014, p. 351-351Conference paper (Other academic)
    Abstract [en]

    Cryoturbation plays an important role in the carbon cycle as it redistributes carbon deeper down in the soil where the cold temperature prevents microbial decomposition. This contribution is also included in recent models describing the long-term build up of carbon stocks in artic soils. Soil motion rate in cryoturbated soils is sparsely studied. This is because the internal factors maintaining cryoturbation will be affected by any excavation, making it impossible to remove soil samples or install pegs without changing the structure of the soil. So far, mainly the motion of soil surface markers on patterned ground has been used to infer lateral soil motion rates. However, such methods constrain the investigated area to a predetermined distribution of surface markers that may result in a loss of information regarding soil motion in other parts of the patterned ground surface.

    We present a novel method based on terrestrial close range (<5m) photogrammetry to calculate lateral and vertical soil motion across entire small-scale periglacial features, such as non-sorted circles (frost boils). Images were acquired by a 5-camera calibrated rig from at least 8 directions around a non-sorted circle. During acquisition, the rig was carried by one person in a backpack-like portable camera support system. Natural feature points were detected by SIFT and matched between images using the known epipolar geometry of the calibrated rig. The 3D coordinates of points matched between at least 3 images were calculated to create a point cloud of the surface of interest. The procedure was repeated during two consecutive years to be able to measure any net displacement of soil and calculate rates of soil motion. The technique was also applied to a peat palsa where multiple exposures where acquired of selected areas.

    The method has the potential to quantify areas of disturbance and estimate lateral and vertical soil motion in non-sorted circles. Furthermore, it should be possible to quantify peat erosion and rates of desiccation crack formations in peat palsas. This tool could provide new information about cryoturbation rates that could improve existing soil carbon models and increase our understanding about how soil carbon stocks will respond to climate change.

  • 88. Beco, S
    et al.
    Maraschini, A
    Pacini, F
    Biran, O
    Breitgand, O
    Meth, K
    Rochwerger, B
    Salant, E
    Silvera, E
    Tal, S
    Wolfsthal, Y
    Yehuda, M
    Caceres, J
    Hierro, J
    Emmerich, W
    Galis, A
    Edblom, Lennart
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Henriksson, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hernandez, Francisco
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Tordsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hohl, A
    Levy, E
    Sampaio, A
    Scheuermann, B
    Wusthoff, M
    Latanicki, J
    Lopez, G
    Marin-Frisonroche, J
    Dorr, A
    Ferstl, F
    Huedo, E
    Llorente, I
    Montero, R
    Massonet, P
    Naqvi, S
    Dallons, G
    Pezz, M
    Puliafito, A
    Ragusa, C
    Scarpa, M
    Muscella, S
    Cloud Computing and RESERVOIR project2009In: Nuovo Cimento C, ISSN ISSN 1124-1896, Vol. 32, no 2, p. 99-103Article in journal (Refereed)
  • 89. Belabbaci, Ahlem
    et al.
    Cherroun, Hadda
    Cleophas, Loek
    Umeå University, Faculty of Science and Technology, Department of Computing Science. FASTAR Research Group, Stellenbosch University, South Africa.
    Ziadi, Djelloul
    Tree pattern matching from regular tree expressions2018In: Kybernetika (Praha), ISSN 0023-5954, E-ISSN 1805-949X, Vol. 54, no 2, p. 221-242Article in journal (Refereed)
    Abstract [en]

    In this work we deal with tree pattern matching over ranked trees, where the pattern set to be matched against is defined by a regular tree expression. We present a new method that uses a tree automaton constructed inductively from a regular tree expression. First we construct a special tree automaton for the regular tree expression of the pattern E, which is somehow a generalization of Thompson automaton for strings. Then we run the constructed automaton on the subject tree t. The pattern matching algorithm requires an O(vertical bar t vertical bar vertical bar E vertical bar) time complexity, where vertical bar t vertical bar is the number of nodes of t and vertical bar E vertical bar is the size of the regular tree expression E. The novelty of this contribution besides the low time complexity is that the set of patterns can be infinite, since we use regular tree expressions to represent patterns.

  • 90. Ben Yehuda, M.
    et al.
    Biran, O.
    Breitgand, D.
    Meth, K.
    Rochwerger, B.
    Salant, E.
    Silvera, E.
    Tal, S.
    Wolfsthal, Y.
    Cáceres, J.
    Hierro, J.
    Emmerich, W.
    Galis, A.
    Edblom, Lennart
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Henriksson, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hernández, Francisco
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Tordsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hohl, A.
    Levy, E.
    Sampaio, A.
    Scheuermann, B.
    Wusthoff, M.
    Latanicki, J.
    Lopez, G.
    Marin-Frisonroche, J.
    Dörr, A.
    Ferstl, F.
    Beco, S.
    Pacini, F.
    Llorente, I.
    Montero, R.
    Huedo, E.
    Massonet, P.
    Naqvi, S.
    Dallons, G.
    Pezzé, M.
    Puliato, A.
    Ragusa, C.
    Scarpa, M.
    Muscella, S.
    RESERVOIR: An ICT Infrastructure for Reliable and Effective Delivery of Services as Utilities2008Report (Other academic)
  • 91.
    Bensch, Suna
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Graph Transformation for Incremental Natural Language Analysis.2014Other (Other academic)
  • 92.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Björklund, Henrik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Drewes, Frank
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Algorithmic properties of Millstream systems2010In: Developments in Language Theory: 14th International Conference, DLT 2010 / [ed] Sheng Yu, Springer Berlin/Heidelberg, 2010, p. 54-65Conference paper (Refereed)
    Abstract [en]

    Millstream systems have recently been proposed as a formalization of the linguistic idea that natural language should be described as a combination of different modules related by interfaces. In this paper we investigate algorithmic properties of Millstream systems having regular tree grammars as modules and MSO logic as interface logic. We focus on the so-called completion problem: Given trees generated by a subset of the modules, can they be completed into a valid configuration of the Millstream system?

  • 93.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Bordihn, Henning
    Information, codes and languages: Essays dedicated to Helmut Jürgensen on the occassion of his 75th birthday – Preface2018In: Journal of Automata, Languages and Combinatorics, ISSN 1430-189X, Vol. 23, no 1–3, p. 2p. 3-4Article in journal (Refereed)
    Abstract [en]

    This special issue is dedicated to Professor Helmut Jürgensen on the occasion of his 75th birthday and in appreciation of his scientific work and his impact as teacher, mentor, and person. The sixteen papers in this special issue were submitted by invitation of the guest editors. Each paper was reviewed by at least two referees. The authors of the papers in this special issue are collaborators, co-authors, or scientific descendents of Helmut Jürgensen.

  • 94.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Bordihn, Henning
    Institut für Informatik, Universität Potsdam.
    Holzer, Markus
    Institut für Informatik, Universität Giessen.
    Kutrib, Martin
    Institut für Informatik, Universität Giessen.
    On input-revolving deterministic and nondeterministic finite automata2009In: Information and Computation, ISSN 0890-5401, E-ISSN 1090-2651, Vol. 207, p. 1140-1155Article in journal (Refereed)
    Abstract [en]

    We introduce and investigate input-revolving finite automata, which are (nondeterministic) finite state automata with additional ability to shift the remaining part of the input. Three different modes of shifting are considered, namely revolving to the left, revolving to the right, and circular-interchanging. We investigate the computational capacities of these three types of automata and their deterministic variants, comparing any of the six classes of automata with each other and with further classes of well-known automata. In particular, it is shown that nondeterminism is better than determinism, that is, for all three modes of shifting there is a language accepted by the nondeterministic model but not accepted by any determinstic automaton of the same type. Concerning the closure properties most of the deterministic language families studied are not closed under standard operations. For example, we show that the family of languages accepted by deterministic right-revolving finite automata is an anti-AFL which is not closed under reversal and intersection.

  • 95.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Drewes, Frank
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Millstream Systems: a formal model for linking language modules by interfaces2010In: Proc. ACL 2010 Workshop on Applications of Tree Automata in Natural Language Processing (ATANLP 2010), The Association for Computer Linguistics , 2010Conference paper (Refereed)
  • 96.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Drewes, FrankUmeå University, Faculty of Science and Technology, Department of Computing Science.
    Proceedings of Umeå's 16th student conference in computing science: USCCS 20132013Conference proceedings (editor) (Other academic)
  • 97.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Drewes, FrankUmeå University, Faculty of Science and Technology, Department of Computing Science.Freund, RudolfTechnical University Vienna.Otto, FriedrichTechnical University Kassel.
    Fifth Workshop on Non-Classical Models for Automata and Applications - NCMA 2013, Umeå, Sweden, August 13 - August 14, 2013, Proceedings2013Conference proceedings (editor) (Refereed)
  • 98.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Drewes, Frank
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hellström, Thomas
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Grammatical Inference of Graph Transformation Rules2015In: Proceedings of the 7th Workshop on Non-Classical Modelsof Automata and Applications (NCMA 2015), Austrian Computer Society , 2015, p. 73-90Conference paper (Refereed)
  • 99.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Drewes, FrankUmeå University, Faculty of Science and Technology, Department of Computing Science.Hirvensalo, MikaOtto, Friedrich
    Fundamenta Informaticae: special issue2015Conference proceedings (editor) (Other academic)
  • 100.
    Bensch, Suna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Drewes, Frank
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Jürgensen, Helmut
    Department of Computer Science, The University of Western Ontario, London, Canada.
    van der Merwe, Brink
    Department of Computer Science, Stellenbosch University, South Africa.
    Correct readers for the incremental construction of Millstream configurations by graph transformation2012Report (Other academic)
    Abstract [en]

    Millstream systems have been proposed as a non-hierarchical method for modelling natural language. Millstream congurations represent and connect multiple structural aspects of sentences. We present a method by which the Millstream congurations corresponding to a sentence are constructed. The construction is incremental, that is, it proceeds as the sentence is being read and is complete when the end of the sentence is reached. It is based on graph transformations and a lexicon which associates words with rules for the graph transformations.

1234567 51 - 100 of 1944
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