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  • 1.
    Andler, Sten F
    et al.
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Brohede, Marcus
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Gustavsson, Sanny
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    DeeDS NG: Architecture, Design, and Sample Application Scenario2007In: Handbook of Real-Time and Embedded Systems, CRC Press, 2007Chapter in book (Other academic)
  • 2.
    Atif, Yacine
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Stylianos, Sergis
    University of Piraeus, Athens, Greece.
    Demetrios, Sampson
    Curtin University, Perth, Australia.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    A Cyberphysical Learning Approach for Digital Smart Citizenship Competence Development2017In: WWW '17: Proceedings of the 26th International Conference on World Wide Web Companion, ACM Digital Library, 2017, p. 397-405Conference paper (Refereed)
    Abstract [en]

    Smart Cities have emerged as a global concept that argues for the effective exploitation of digital technologies to drive sustainable innovation and well-being for citizens. Despite the large investments being placed on Smart City infrastructure, however, there is still very scarce attention on the new learning approaches that will be needed for cultivating Digital Smart Citizenship competences, namely the competences which will be needed by the citizens and workforce of such cities for exploiting the digital technologies in creative and innovative ways for driving financial and societal sustainability. In this context, this paper introduces cyberphysical learning as an overarching model of cultivating Digital Smart Citizenship competences by exploiting the potential of Internet of Things technologies and social media, in order to create authentic blended and augmented learning experiences.

  • 3.
    Bae, Juhee
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Havsol, Jesper
    AstraZeneca, Gothenburg, Sweden.
    Karpefors, Martin
    AstraZeneca, Gothenburg, Sweden.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Short Text Topic Modeling to Identify Trends on Wearable Bio-sensors in Different Media Types2019In: Proceedings - 6th International Symposium on Computational and Business Intelligence, ISCBI 2018, IEEE Computer Society, 2019, p. 89-93Conference paper (Refereed)
    Abstract [en]

    The technology and techniques for bio-sensors are rapidly evolving. Accordingly, there is significant business interest to identify upcoming technologies and new targets for the near future. Text information from internet reflects much of the recent information and public interests that help to understand the trend of a certain field. Thus, we utilize Dirichlet process topic modeling on different media sources containing short text (e.g., blogs, news) which is able to self-adapt the learned topic space to the data. We share the observations from the domain experts on the results derived from topic modeling on wearable biosensors from multiple media sources over more than eight years. We analyze the topics on wearable devices, forecast and market analysis, and bio-sensing techniques found from our method. 

  • 4.
    Ding, Jianguo
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Lindström, Birgitta
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Andler, Sten F.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Towards Threat Modeling for CPS-based Critical Infrastructure Protection2015In: Proceedings of the International Emergency Management Society (TIEMS), 22nd TIEMS Annual Conference: Evolving threats and vulnerability landscape: new challenges for the emergency management / [ed] Snjezana Knezic & Meen Poudyal Chhetri, Brussels: TIEMS, The International Emergency Management Society , 2015, Vol. 22Conference paper (Refereed)
    Abstract [en]

    With the evolution of modern Critical Infrastructures (CI), more Cyber-Physical systems are integrated into the traditional CIs. This makes the CIs a multidimensional complex system, which is characterized by integrating cyber-physical systems into CI sectors (e.g., transportation, energy or food & agriculture). This integration creates complex interdependencies and dynamics among the system and its components. We suggest using a model with a multi-dimensional operational specification to allow detection of operational threats. Embedded (and distributed) information systems are critical parts of the CI where disruption can lead to serious consequences. Embedded information system protection is therefore crucial. As there are many different stakeholders of a CI, comprehensive protection must be viewed as a cross-sector activity to identify and monitor the critical elements, evaluate and determine the threat, and eliminate potential vulnerabilities in the CI. A systematic approach to threat modeling is necessary to support the CI threat and vulnerability assessment. We suggest a Threat Graph Model (TGM) to systematically model the complex CIs. Such modeling is expected to help the understanding of the nature of a threat and its impact on throughout the system. In order to handle threat cascading, the model must capture local vulnerabilities as well as how a threat might propagate to other components. The model can be used for improving the resilience of the CI by encouraging a design that enhances the system's ability to predict threats and mitigate their damages. This paper surveys and investigates the various threats and current approaches to threat modeling of CI. We suggest integrating both a vulnerability model and an attack model, and we incorporate the interdependencies within CI cross CI sectors. Finally, we present a multi-dimensional threat modeling approach for critical infrastructure protection.

  • 5.
    Helldin, Tove
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Steinhauer, H. Joe
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Situation Awareness in Telecommunication Networks Using Topic Modeling2018In: 2018 21st International Conference on Information Fusion, FUSION 2018, IEEE, 2018, p. 549-556Conference paper (Refereed)
    Abstract [en]

    For an operator of wireless telecommunication networks to make timely interventions in the network before minor faults escalate into issues that can lead to substandard system performance, good situation awareness is of high importance. Due to the increasing complexity of such networks, as well as the explosion of traffic load, it has become necessary to aid human operators to reach a good level of situation awareness through the use of exploratory data analysis and information fusion techniques. However, to understand the results of such techniques is often cognitively challenging and time consuming. In this paper, we present how telecommunication operators can be aided in their data analysis and sense-making processes through the usage and visualization of topic modeling results. We present how topic modeling can be used to extract knowledge from base station counter readings and make design suggestions for how to visualize the analysis results to a telecommunication operator.

  • 6.
    Karlsson, Alexander
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Duarte, Denio
    Campus Chapecó, Federal University of Fronteira sul, Chapecó, Brazil.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Bae, Juhee
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Evaluation of the dirichlet process multinomial mixture model for short-text topic modeling2018In: Proceedings - 6th International Symposium on Computational and Business Intelligence, ISCBI 2018, USA: Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 79-83, article id 8638311Conference paper (Refereed)
    Abstract [en]

    Fast-moving trends, both in society and in highly competitive business areas, call for effective methods for automatic analysis. The availability of fast-moving sources in the form of short texts, such as social media and blogs, allows aggregation from a vast number of text sources, for an up to date view of trends and business insights. Topic modeling is established as an approach for analysis of large amounts of texts, but the scarcity of statistical information in short texts is considered to be a major problem for obtaining reliable topics from traditional models such as LDA. A range of different specialized topic models have been proposed, but a majority of these approaches rely on rather strong parametric assumptions, such as setting a fixed number of topics. In contrast, recent advances in the field of Bayesian non-parametrics suggest the Dirichlet process as a method that, given certain hyper-parameters, can self-adapt to the number of topics of the data at hand. We perform an empirical evaluation of the Dirichlet process multinomial (unigram) mixture model against several parametric topic models, initialized with different number of topics. The resulting models are evaluated, using both direct and indirect measures that have been found to correlate well with human topic rankings. We show that the Dirichlet Process Multinomial Mixture model is a viable option for short text topic modeling since it on average performs better, or nearly as good, compared to the parametric alternatives, while reducing parameter setting requirements and thereby eliminates the need of expensive preprocessing. 

  • 7.
    Mathiason, Gunnar
    University of Skövde, School of Humanities and Informatics.
    A Simulation Approach for Evaluating Scalability of a Virtually Fully Replicated Real-time Database2006Report (Other academic)
    Abstract [en]

    We use a simulation approach to evaluate large scale resource usage in a distributed real-time database. Scalability is often limited by that resource usage is higher than what is added to the system when a system is scaled up. Our approach of Virtual Full Replication (VFR) makes resource usage scalable, which allows large scale real-time databases. In this paper we simulate a large scale distributed real-time database with VFR, and we compare it to a fully replicated database (FR) for a selected set of system parameters used as independent variables. Both VFR and FR support local timeliness of transactions by ensuring local availability for data objects accessed by transactions. The difference is that VFR has a scalable resource usage due to lower bandwidth usage for data update replication. The simulation shows that a simulator has several advantages for studying large scale distributed real-time databases and for studying scalability in resource usage in such systems.

  • 8.
    Mathiason, Gunnar
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Virtual Full Replication for Scalable Distributed Real-Time Databases2009Doctoral thesis, monograph (Other academic)
    Abstract [en]

    A fully replicated distributed real-time database provides high availability and predictable access times, independent of user location, since all the data is available at each node. However, full replication requires that all updates are replicated to every node, resulting in exponential growth of bandwidth and processing demands with the number of nodes and objects added. To eliminate this scalability problem, while retaining the advantages of full replication, this thesis explores Virtual Full Replication (ViFuR); a technique that gives database users a perception of using a fully replicated database while only replicating a subset of the data.

    We use ViFuR in a distributed main memory real-time database where timely transaction execution is required. ViFuR enables scalability by replicating only data used at the local nodes. Also, ViFuR enables flexibility by adaptively replicating the currently used data, effectively providing logical availability of all data objects. Hence, ViFuR substantially reduces the problem of non-scalable resource usage of full replication, while allowing timely execution and access to arbitrary data objects.

    In the thesis we pursue ViFuR by exploring the use of database segmentation. We give a scheme (ViFuR-S) for static segmentation of the database prior to execution, where access patterns are known a priori. We also give an adaptive scheme (ViFuR-A) that changes segmentation during execution to meet the evolving needs of database users. Further, we apply an extended approach of adaptive segmentation (ViFuR-ASN) in a wireless sensor network - a typical dynamic large-scale and resource-constrained environment. We use up to several hundreds of nodes and thousands of objects per node, and apply a typical periodic transaction workload with operation modes where the used data set changes dynamically. We show that when replacing full replication with ViFuR, resource usage scales linearly with the required number of concurrent replicas, rather than exponentially with the system size.

  • 9.
    Mathiason, Gunnar
    University of Skövde, School of Humanities and Informatics.
    Virtual Full Replication for Scalable Distributed Real-Time Databases2006Report (Other academic)
    Abstract [en]

    Distributed real-time systems increase in size an complexity, and the nodes in such systems become difficult to implement and test. In particular, communication for synchronization of shared information in groups of nodes becomes complex to manage. Several authors have proposed to using a distributed database as a communication subsystem, to off-load database applications from explicit communication. This lets the task for information dissemination be done by the replication mechanisms of the database. With increasingly larger systems, however, there is a need for managing the scalability for such database approach. Furthermore, timeliness for database clients requires predictable resource usage, and scalability requires bounded resource usage in the database system. Thus, predictable resource management is an essential function for realizing timeliness in a large scale setting.

    We discuss scalability problems and methods for distributed real-time databases in the context of the DeeDS database prototype. Here, all transactions can be executed timely at the local node due to main memory residence, full replication and detached replication of updates. Full replication contributes to timeliness and availability, but has a high cost in excessive usage of bandwidth, storage, and processing, in sending all updates to all nodes regardless of updates will be used there or not. In particular, unbounded resource usage is an obstacle for building large scale distributed databases. For many application scenarios it can be assumed that most of the database is shared by only a limited number of nodes. Under this assumption it is reasonable to believe that the degree of replication can be bounded, so that a bound also can be set on resource usage.

    The thesis proposal identifies and elaborates research problems for bounding resource usage in large scale distributed real-time databases. One objective is to bound resource usage by taking advantages of pre-specified data needs, but also by detecting unspecified data needs and adapting resource management accordingly. We elaborate and evaluate the concept of virtual full replication, which provides an image of a fully replicated database to database clients. It makes data objects available where needed, while fulfilling timeliness and consistency requirements on the data.

    In the first part of our work, virtual full replication makes data available where needed by taking advantages of pre-specified data accesses to the distributed database. For hard real-time systems, the required data accesses are usually known since such systems need to be well specified to guarantee timeliness. However, there are many applications where a specification of data accesses can not be done before execution. The second part of our work extends virtual full replication to be used with such applications. By detecting new and changed data accesses during execution and adapt database replication, virtual full replication can continuously provide the image of full replication while preserving scalability.

    One of the objective of the thesis work is to quantify scalability in the database context, so that actual benefits and achievements can be evaluated. Further, we find out the conditions for setting bounds on resource usage for scalability, under both static and dynamic data requirements.

  • 10.
    Mathiason, Gunnar
    et al.
    University of Skövde, School of Humanities and Informatics.
    Amirijoo, Medhi
    Linköping University.
    Real-time Communication Through a Distributed Resource Reservation Approach2004Report (Other academic)
    Abstract [en]

    Bandwidth reservation for real-time networks offers an approach for real-time networking in a switched Ethernet or IP setting. In a switched network, switches prevent from indeterministic back-off times at collisions and here bandwidth reservation limits send rates to protects from overallocation of link bandwidth. The work in this paper aims at avoiding problems with a centralized bandwidth broker for resource reservation for bandwidth in a throttled real-time network. A centralized broker (such as a ’GlobeThrottle’) is a single point of failure in a distributed system and is also a hot-spot resource, which all nodes of the system use for registering new real-time channels. To avoid both these problems we propose a distributed algorithm to be used instead of a central bandwidth broker. Also, the GlobeThrottle approach uses TCP/IP communication for channel allocation, which gives indeterministic time channel allocation. However, this problem is not addressed in this paper.

    In the proposed solution, Real-time Communication Through a Distributed Resource Reservation Approach (STRUTS), real-time channels are throttled and the throttle level for each sending node is agreed between all nodes. The agreement must be atomic to avoid transitional bandwidth over-usage due to temporary inconsistencies between nodes (’mutual inconsistencies’) in throttling level information for different nodes. In this paper we use two-phase-commit (2PC) for atomic node agreements, where changes in channels information will be visible at the same time instant at all nodes. Thus, the throttling based on the agreed channel information will guarantee that the maximal bandwidth is not exceeded. Using a distributed agreement avoids the problems of a single point of failure and hot-spot behavior, and is thus scalable to some extent. However, 2PC commitment incurs other problems with scalability since it requires that the network is not partitioned and also that nodes are locked during the agreement process, which prevents other nodes from allocating channels for the same node concurrently. When using 2PC for agreement it is not possible to have deterministic channel allocation time when there are no guarantees for the maximum locking time on the channel data. We have through experimental results verified that by using STRUTS, we avoid overallocation of links.

  • 11.
    Mathiason, Gunnar
    et al.
    University of Skövde, School of Humanities and Informatics.
    Andler, Sten F.
    University of Skövde, School of Humanities and Informatics.
    Jagszent, Daniel
    Institute for Program Structures and Data Organization, University of Karlsruhe.
    Virtual full replication by static segmentation for multiple properties of data objects2005In: RTiS 2005: proceedings of Real time in Sweden 2005, the 8th Biennal SNART Conference on Real-Time Systems / [ed] Sten F. Andler, Anton Cervin, Skövde: Skövde University , 2005, p. 11-18Conference paper (Refereed)
    Abstract [en]

    We implement Virtual full replication for a distributed real-time database by segmenting the database on multiple data properties. Virtual full replication provides an image to the application of full replication in a partially replicated database, by replicating data to meet the actual data needs of the users of the data. This is useful since fully replicated real-time databases, that allow updates at all nodes, do not scale well as updates must be replicated to every other node for replica consistency, also to nodes where only a small share of the database will ever be used. We propose an algorithm that segments the database on multiple data properties without causing a combinatorial problem. We show, by analysis and an implementation, that scalability for such a system can be improved due to scalable resource usage, while application semantics of full replication is unchanged.

  • 12.
    Mathiason, Gunnar
    et al.
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Andler, Sten F.
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Kang, Woochul
    University of Virginia, USA.
    Exploring a Multi-Tiered Whiteboard Infrastructure for Information Fusion in Wireless Sensor Networks2008In: Proceedings of the second Skövde Workshop on Information Fusion Topics (SWIFT 2008) / [ed] H. Boström, R. Johansson, Joeri van Laere, Skövde: University of Skövde , 2008, p. 63-66Conference paper (Refereed)
    Abstract [en]

     It is important for the life time of a wireless sensor network (WSN) to reduce the amount of data transferred through the network. As a typical approach, sensor data is filtered before propagating updates, to a node at the edge of a network, where it can be fused. Information Fusion inside the network can reduce the amount of data propagated, by fusing data before and in propagation, without losing the information value in it. We explore infrastructures for distributed fusion, with fusion nodes located at strategic nodes inside the network, as an approach of structured distributed fusion for WSNs. We propose an infrastructure for a white-board approach that uses a distributed real-time database with virtual full replication. With such an approach, both raw and fused data are logically available at all nodes and physically available where used, such that only used data will be propagated and use resources. The actual resource usage will be relative to the actual demand for data, rather than to the amount of data published at the white-board. We present an exploration of such an infrastructure, and points out future key research questions for such a white-board approach.

  • 13.
    Mathiason, Gunnar
    et al.
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Andler, Sten F
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Son, S H
    University of Virginia.
    Virtual Full Replication by Adaptive Segmentation2007In: 13th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2007), IEEE Computer Society, 2007, p. 327-337Conference paper (Refereed)
    Abstract [en]

    We propose virtual full replication by adaptive segmentation (ViFuR-A), and evaluate its ability to maintain scalability in a replicated real-time database. With full replication and eventual consistency, transaction timeliness becomes independent of network delays for all transactions. However, full replication does not scale well, since all updates must be replicated to all nodes, also when data is needed only at a subset of the nodes. With virtual full replication that adapts to actual data needs, resource usage can be bounded and the database can be made scalable. We propose a scheme for adaptive segmentation that detects new data needs and adapts replication. The scheme includes an architecture, a scalable protocol and a replicated directory service that together maintains scalability. We show that adaptive segmentation bounds the required storage at a significantly lower level compared to static segmentation, for a typical workload where the data needs change repeatedly. Adaptation time can be kept constant for the workload when there are sufficient resources. Also, the storage is constant with an increasing amount of nodes and linear with an increasing rate of change to data needs.

  • 14.
    Mathiason, Gunnar
    et al.
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Andler, Sten F
    University of Skövde, School of Humanities and Informatics. University of Skövde, The Informatics Research Centre.
    Son, Sang H
    University of Virginia.
    Virtual Full Replication for Scalable and Adaptive Real-Time Communication in Wireless Sensor Networks2008In: Proceedings of the Second International Conference on Sensor Technologies and Applications (SENSORCOMM 2008), IEEE Computer Society , 2008, p. 55-64Conference paper (Refereed)
    Abstract [en]

     

    Sensor networks have limited resources and often support large-scale applications that need scalable propagation of sensor data to users. We propose a white-board style of communication in sensor networks using a distributed real-time database supporting Virtual Full Replication with Adaptive Segmentation. This allows mobile client nodes to access, transparently and efficiently, any sensor data at any node in the network. We present a two-tiered wireless architecture, and an adaptation protocol, for scalable and adaptive white-board communication in large-scale sensor networks. Sensor value readings at nodes of the sensor tier are published at nodes of the database tier as database updates to objects in a distributed real-time database. The search space of client nodes for sensor data is thus limited to the number of database nodes. With this scheme, we can show scalable resource usage and short adaptation times for several hundreds of database nodes and up to 50 moving clients.

     

  • 15.
    Mathiason, Gunnar
    et al.
    University of Skövde, School of Humanities and Informatics.
    Andler, Sten F
    University of Skövde, School of Humanities and Informatics.
    Son, Sang H.
    University of Virginia.
    Selavo, Leo
    University of Virginia.
    Virtual Full Replication for Wireless Sensor Networks2007In: Proceedings work-in-progress session of the 19th Euromicro conference on Real-Time Systems (ECRTS 2007), 4-6 July, 2007, Pisa, Italy, Skövde: Högskolan i Skövde , 2007, p. 4-Chapter in book (Other academic)
    Abstract [en]

    We propose to use a distributed real-time database with Virtual Full Replication by Adaptive Segmentation, for whiteboard communication in a sensor network with mobile sink nodes. Sensor networks are large scale applications with limited resources, so they need scalable propagation of sensor data, both to the users inside the network and to the network edges. Virtual full replication enables scalable and adaptive propagation of sensor data, by bounding resource usage to the current data needs. We use a two-tiered wireless sensor network, where each sensor value is published in the distributed database at gateways of the upper tier. Mobile users search for sensor data only at the gateways, which limits the search space.

  • 16.
    Rose, Jeremy
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Berndtsson, Mikael
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Larsson, Peter
    Advectas, Göteborg, Sweden.
    The advanced analytics Jumpstart: definition, process model, best practices2017In: Journal of Information Systems and Technology Management, ISSN 1809-2640, E-ISSN 1807-1775, Vol. 14, no 3, p. 339-360Article in journal (Refereed)
  • 17.
    Steinhauer, H. Joe
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Helldin, Tove
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Topic Modeling for Situation Understanding in Telecommunication Networks2017In: 2017 27th International Telecommunication Networks and Applications Conference (ITNAC), IEEE, 2017, p. 73-78Conference paper (Refereed)
  • 18.
    Steinhauer, H. Joe
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Helldin, Tove
    University of Skövde, The Informatics Research Centre. University of Skövde, School of Informatics.
    Mathiason, Gunnar
    University of Skövde, The Informatics Research Centre. University of Skövde, School of Informatics.
    Spatio-Temporal Awareness for Wireless Telecommunication Networks2018In: Working Papers and Documents of the IJCAI-ECAI-2018 Workshop on Learning and Reasoning: Principles & Applications to Everyday Spatial and Temporal Knowledge, 2018, p. 49-50Conference paper (Refereed)
  • 19.
    Steinhauer, H. Joe
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Helldin, Tove
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Anomaly Detection in Telecommunication Networks using Topic Models2018Conference paper (Refereed)
  • 20.
    Steinhauer, H. Joe
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Helldin, Tove
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Topic modeling for anomaly detection in telecommunication networks2019In: Journal of Ambient Intelligence and Humanized Computing, ISSN 1868-5137, E-ISSN 1868-5145, p. 1-12Article in journal (Refereed)
    Abstract [en]

    To ensure reliable network performance, anomaly detection is an important part of the telecommunication operators’ work. This includes that operators need to timely intervene with the network, should they encounter indications of network performance degradation. In this paper, we describe the results of an initial experiment for anomaly detection with regard to network performance, using topic modeling on base station run-time variable data collected from live Radio Access Networks (RANs). The results show that topic modeling clusters semantically related data in the same way as human experts would and that the anomalies in our test cases could be identified in latent Dirichlet allocation (LDA) topic models. Our experiment further reveals which information provided by the topic model is particularly usable to support human anomaly detection in this application domain.

  • 21.
    Steinhauer, H. Joe
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Helldin, Tove
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Root-Cause Localization using Restricted Boltzmann Machines2016In: 2016 19th International Conference on Information Fusion Proceedings, IEEE Computer Society, 2016, p. 248-255Conference paper (Refereed)
  • 22.
    Ståhl, Niclas
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Falkman, Göran
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Boström, Jonas
    Department of Medicinal Chemistry, CVMD iMED, AstraZeneca, Mölndal, Sweden.
    Deep Convolutional Neural Networks for the Prediction of Molecular Properties: Challenges and Opportunities Connected to the Data2018In: Journal of Integrative Bioinformatics, E-ISSN 1613-4516, Vol. 16, no 1Article in journal (Refereed)
    Abstract [en]

    We present a flexible deep convolutional neural network method for the analysis of arbitrary sized graph structures representing molecules. This method, which makes use of the Lipinski RDKit module, an open-source cheminformatics software, enables the incorporation of any global molecular (such as molecular charge and molecular weight) and local (such as atom hybridization and bond orders) information. In this paper, we show that this method significantly outperforms another recently proposed method based on deep convolutional neural networks on several datasets that are studied. Several best practices for training deep convolutional neural networks on chemical datasets are also highlighted within the article, such as how to select the information to be included in the model, how to prevent overfitting and how unbalanced classes in the data can be handled.

  • 23.
    Ståhl, Niclas
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Falkman, Göran
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Boström, Jonas
    Medicinal Chemistry, Early Cardiovascular, Renal and Metabolism, R&D BioPharmaceuticals , AstraZeneca , Mölndal , Sweden.
    Deep Reinforcement Learning for Multiparameter Optimization in de novo Drug Design2019In: Journal of Chemical Information and Modeling, ISSN 1549-9596, E-ISSN 1549-960X, Vol. 59, no 7, p. 3166-3176Article in journal (Refereed)
    Abstract [en]

    In medicinal chemistry programs it is key to design and make compounds that are efficacious and safe. This is a long, complex, and difficult multiparameter optimization process, often including several properties with orthogonal trends. New methods for the automated design of compounds against profiles of multiple properties are thus of great value. Here we present a fragment-based reinforcement learning approach based on an actor-critic model, for the generation of novel molecules with optimal properties. The actor and the critic are both modeled with bidirectional long short-term memory (LSTM) networks. The AI method learns how to generate new compounds with desired properties by starting from an initial set of lead molecules and then improving these by replacing some of their fragments. A balanced binary tree based on the similarity of fragments is used in the generative process to bias the output toward structurally similar molecules. The method is demonstrated by a case study showing that 93% of the generated molecules are chemically valid and more than a third satisfy the targeted objectives, while there were none in the initial set.

  • 24.
    Ståhl, Niclas
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Falkman, Göran
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Boström, Jonas
    Department of Medicinal Chemistry, CVMD iMED, AstraZeneca, Sweden.
    Improving the use of deep convolutional neural networks for the prediction of molecular properties2019In: Practical Applications of Computational Biology and Bioinformatics, 12th International Conference / [ed] Florentino Fdez-Riverola, Mohd Saberi Mohamad, Miguel Rocha, Juan F. De Paz, Pascual González, Cham: Springer, 2019, Vol. 803, p. 71-79Conference paper (Refereed)
    Abstract [en]

    We present a flexible deep convolutional neural network method for the analyse of arbitrary sized graph structures representing molecules. The method makes use of RDKit, an open-source cheminformatics software, allowing the incorporation of any global molecular (such as molecular charge) and local (such as atom type) information. We evaluate the method on the Side Effect Resource (SIDER) v4.1 dataset and show that it significantly outperforms another recently proposed method based on deep convolutional neural networks. We also reflect on how different types of information and input data affect the predictive power of our model. This reflection highlights several open problems that should be solved to further improve the use of deep learning within cheminformatics.

  • 25.
    Ståhl, Niclas
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Falkman, Göran
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    A self-organizing ensemble of deep neural networks for the classification of data from complex processes2018In: INFORMATION PROCESSING AND MANAGEMENT OF UNCERTAINTY IN KNOWLEDGE-BASED SYSTEMS: APPLICATIONS, IPMU 2018, PT III / [ed] Medina, J., Ojeda-Aciego, M., Verdegay, J.L., Perfilieva, I., Bouchon-Meunier, B., Yager, R.R., 2018, Vol. 855, p. 248-259Conference paper (Refereed)
    Abstract [en]

    We present a new self-organizing algorithm for classification of a data that combines and extends the strengths of several common machine learning algorithms, such as algorithms in self-organizing neural networks, ensemble methods and deep neural networks. The increased expression power is combined with the explanation power of self-organizing networks. Our algorithm outperforms both deep neural networks and ensembles of deep neural networks. For our evaluation case, we use production monitoring data from a complex steel manufacturing process, where data is both high-dimensional and has many nonlinear interdependencies. In addition to the improved prediction score, the algorithm offers a new deep-learning based approach for how computational resources can be focused in data exploration, since the algorithm points out areas of the input space that are more challenging to learn.

  • 26.
    Ståhl, Niclas
    et al.
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Mathiason, Gunnar
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Falkman, Göran
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Karlsson, Alexander
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Using recurrent neural networks with attention for detecting problematic slab shapes in steel rolling2019In: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 70, p. 365-377Article in journal (Refereed)
    Abstract [en]

    The competitiveness in the manufacturing industry raises demands for using recent data analysis algorithms for manufacturing process development. Data-driven analysis enables extraction of novel knowledge from already existing sensors and data, which is necessary for advanced manufacturing process refinement involving aged machinery. Improved data analysis enables factories to stay competitive against newer factories, but without any hefty investment. In large manufacturing operations, the dependencies between data are highly complex and therefore very difficult to analyse manually. This paper applies a deep learning approach, using a recurrent neural network with long short term memory cells together with an attention mechanism to model the dependencies between the measured product shape, as measured before the most critical manufacturing operation, and the final product quality. Our approach predicts the ratio of flawed products already before the critical operation with an AUC-ROC score of 0.85, i.e., we can detect more than 80 % of all flawed products while having less than 25 % false positive predictions (false alarms). In contrast to previous deep learning approaches, our method shows how the recurrent neural network reasons about the input shape, using the attention mechanism to point out which parts of the product shape that have the highest influence on the predictions. Such information is crucial for both process developers, in order to understand and improve the process, and for process operators who can use the information to learn how to better trust the predictions and control the process.

1 - 26 of 26
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