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  • 1.
    Abdul Khaliq, Ali
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Pecora, Federico
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Saffiotti, Alessandro
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Point-to-point safe navigation of a mobile robot using stigmergy and RFID technology2016Inngår i: 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Institute of Electrical and Electronics Engineers (IEEE), 2016, 1497-1504 s., 7759243Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Reliable autonomous navigation is still a challenging problem for robots with simple and inexpensive hardware. A key difficulty is the need to maintain an internal map of the environment and an accurate estimate of the robot’s position in this map. Recently, a stigmergic approach has been proposed in which a navigation map is stored into the environment, on a grid of RFID tags, and robots use it to optimally reach predefined goal points without the need for internal maps. While effective,this approach is limited to a predefined set of goal points. In this paper, we extend this approach to enable robots to travel to any point on the RFID floor, even if it was not previously identified as a goal location, as well as to keep a safe distance from any given critical location. Our approach produces safe, repeatable and quasi-optimal trajectories without the use of internal maps, self localization, or path planning. We report experiments run in a real apartment equipped with an RFID floor, in which a service robot either reaches or avoids a user who wears slippers equipped with an RFID tag reader.

  • 2.
    Agélii Genlott, Annika
    et al.
    Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Grönlund, Åke
    Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Closing the gaps: Improving literacy and mathematics by ict-enhanced collaboration2016Inngår i: Computers and education, ISSN 0360-1315, E-ISSN 1873-782X, Vol. 99, 68-80 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Literacy and mathematics are necessary skills that for different reasons unfortunately not everybody acquires sufficiently. In OECD countries there is also a gender gap; boys lag behind girls in literacy but often outperform girls in mathematics (OECD, 2012). ICT (Information and communication technologies) may contribute useful tools to address both these problems but in order to effectively create better educational conditions there is yet a need to develop effective methods that combine ICT with key factors for learning. This research contributes to this by measuring effects of the “Write to Learn” (WTL) method. WTL lets children from 1st grade use several ICT tools to write texts and subsequently discuss and refine them together with classmates and teachers using digital real-time formative feedback and assessment. The central learning factor addressed, in mathematics as well as in literacy, is the written communication allowing the learners to interact with peers and teachers. WTL draws on methods from socio-cultural theory, including continuous social interaction and written real-time formative feedback among peers, using shared electronic forums for collaboration, thereby providing social meaning and increased learning of literacy and mathematics, among both boys and girls.

    The study uses quantitative methods and two control groups, one using traditional method (no ICT) and one using technology individually (without integrated social interaction and formative feedback), to compare results from 502 students in grade 3 national tests in mathematics and literacy. WTL yields by far best results; higher average score both in literacy and mathematics, smaller gender gap, and significantly better results for the under-achievers. The ITU method performs worst, which shows that ICT use must be well integrated into the pedagogy to be useful.

  • 3.
    Ahmed, Mobyen Uddin
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Banaee, Hadi
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Rafael-Palou, Xavier
    Barcelona Digital Technology Centre, Barcelona, Spain.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Intelligent Healthcare Services to Support Health Monitoring of Elderly2015Inngår i: INTERNET OF THINGS: USER-CENTRIC IOT, PT I, Springer, 2015, Vol. 150, 178-186 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper proposed an approach of intelligent healthcare services to support health monitoring of old people through the project named SAAPHO. Here, definition and architecture of the proposed healthcare services are presented considering six different health parameters such as: 1) physical activity, 2) blood pressure, 3) glucose, 4) medication compliance, 5) pulse monitoring and 6) weight monitoring. The outcome of the proposed services is evaluated in a case study where total 201 subjects from Spain and Slovenia are involved for user requirements analysis considering 1) end users, 2) clinicians, and 3) field study analysis perspectives. The result shows the potentiality and competence of the proposed healthcare services for the users.

  • 4.
    Ahmed, Mobyen Uddin
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Physical Activity Classification for Elderly based on Pulse Rate2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Physical activity is one of the key components for elderly in order to be actively ageing. However, it is difficult to differentiate and identify the body movement and actual physical activity using only accelerometer measurement. Therefore, this paper presents an application of case-based retrieval classification scheme to classify the physical activity of elderly based on pulse rate measurements. Here, case-based retrieval approach used the features extracted from both time and frequency domain. The evaluation result shows the best accuracy performance while considering the combination of time and frequency domain features. According to the evaluation result while considering the control measurements, the sensitivity, specificity and overall accuracy are achieved as 95%, 96% and 96% respectively. Considering the test dataset, the system was succeeded to identify 13 physical activities out of 16 i.e. the percentage of the correctness was 81%.

  • 5.
    Ahmed, Mobyen Uddin
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Physical activity identification using supervised machine learning and based on pulse rate2013Inngår i: International Journal of Advanced Computer Sciences and Applications, ISSN 2158-107X, E-ISSN 2156-5570, Vol. 4, nr 7, 210-217 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Physical activity is one of the key components for elderly in order to be actively ageing. Pulse rate is a convenient physiological parameter to identify elderly’s physical activity since it increases with activity and decreases with rest. However, analysis and classification of pulse rate is often difficult due to personal variation during activity. This paper proposed a Case-Based Reasoning (CBR) approach to identify physical activity of elderly based on pulse rate. The proposed CBR approach has been compared with the two popular classification techniques, i.e. Support Vector Machine (SVM) and Neural Network (NN). The comparison has been conducted through an empirical experimental study where three experiments with 192 pulse rate measurement data are used. The experiment result shows that the proposed CBR approach outperforms the other two methods. Finally, the CBR approach identifies physical activity of elderly 84% accurately based on pulse rate

  • 6.
    Ahmed, Rehan M.
    et al.
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Ananiev, Anani V.
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Compliant motion control for safe human robot interaction2009Inngår i: Robot motion and control 2009 / [ed] Krzysztof R. Kozłowski, Berlin: Springer , 2009, 265-274 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Robots have recently been foreseen to work side by side and share workspace with humans in assisting them in tasks that include physical human-robot (HR) interaction. The physical contact with human tasks under uncertainty has to be performed in a stable and safe manner [6]. However, current industrial robot manipulators are still very far from HR coexisting environments, because of their unreliable safety, rigidity and heavy structure. Besides this, the industrial norms separate the two spaces occupied by a human and a robot by means of physical fence or wall [9]. Therefore, the success of such physical HR interaction is possible if the robot is enabled to handle this interaction in a smart way to prevent injuries and damages.

  • 7.
    Ahmed, Rehan M.
    et al.
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Modeling of magneto rheological fluid actuator enabling safe human-robot interaction2008Inngår i: IEEE International Conference on Emerging Technologies and Factory Automation, 2008. ETFA 2008, 2008, 974-979 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Impedance control and compliant behavior for safe human-robot physical interaction of industrial robots normally can be achieved by using active compliance control of actuators based on various sensor data. Alternatively, passive devices allow controllable compliance motion but usually are mechanically complex. We present another approach using a novel actuation mechanism based on magneto-rheological fluid (MRF) that incorporates variable stiffness directly into the joints. In this paper, we have investigated and analyzed principle characteristics of MRF actuation mechanism and presented the analytical-model. Then we have developed the static and dynamic model based on experimental test results and have discussed three essential modes of motion needed for human-robot manipulation interactive tasks.

  • 8.
    Ahtiainen, Juhana
    et al.
    Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland.
    Stoyanov, Todor
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Saarinen, Jari
    GIM Ltd., Espoo, Finland.
    Normal Distributions Transform Traversability Maps: LIDAR-Only Approach for Traversability Mapping in Outdoor Environments2017Inngår i: Journal of Field Robotics, ISSN 1556-4959, E-ISSN 1556-4967, Vol. 34, nr 3, 600-621 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Safe and reliable autonomous navigation in unstructured environments remains a challenge for field robots. In particular, operating on vegetated terrain is problematic, because simple purely geometric traversability analysis methods typically classify dense foliage as nontraversable. As traversing through vegetated terrain is often possible and even preferable in some cases (e.g., to avoid executing longer paths), more complex multimodal traversability analysis methods are necessary. In this article, we propose a three-dimensional (3D) traversability mapping algorithm for outdoor environments, able to classify sparsely vegetated areas as traversable, without compromising accuracy on other terrain types. The proposed normal distributions transform traversability mapping (NDT-TM) representation exploits 3D LIDAR sensor data to incrementally expand normal distributions transform occupancy (NDT-OM) maps. In addition to geometrical information, we propose to augment the NDT-OM representation with statistical data of the permeability and reflectivity of each cell. Using these additional features, we train a support-vector machine classifier to discriminate between traversable and nondrivable areas of the NDT-TM maps. We evaluate classifier performance on a set of challenging outdoor environments and note improvements over previous purely geometrical traversability analysis approaches.

  • 9.
    Albitar, Houssam
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    In-water surface cleaning robot: concept, locomotion and stability2014Inngår i: International Journal of Mechatronics and Automation, ISSN 2045-1067, Vol. 4, nr 2, 104-115 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper introduces a new concept of flexible crawling mechanism in the design ofindustrial in-water cleaning robot, which is evaluated from the viewpoint of work and operationon an underwater surface. It enables the scanning and cleaning process performed by water jets,while keeping stable robot position on the surface by its capacity to bear and compensate the jetreactions. Such robotic platform can be used for cleaning and maintenance of various underwatersurfaces, including moving ships in the open sea. The designed robot implements its motions bycontraction and expansion of legged mechanism using standard motors and suction cupstechnology. In this study we focus at the conditions for achieving enough adhesion for keepingcontinuous contact between the robot and the surface and robot stability in different situations forthe basic locomotions.

  • 10.
    Albitar, Houssam
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    New concept of in-water surface cleaning robot2013Inngår i: Mechatronics and Automation (ICMA), 2013 IEEE International Conference onDate 4-7 Aug. 2013, IEEE conference proceedings, 2013, 1582-1587 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper introduces a new concept of flexible crawling mechanism to design an industrial underwater cleaning robot, which is evaluated from the viewpoint of the capability to work underwater, scanning the desired surface, and bearing the reactions. This can be used as a robotic application in underwater surface cleaning and maintenance. We designed a robot that realizes the motion by contraction and extraction using DC-motors and vacuum technology. In this study we first focused on realizing the adhesion, bearing reactions, and achieving a stable locomotion on the surface.

  • 11.
    Albitar, Houssam
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Stability study of underwater crawling robot on non-horizontal surface2014Inngår i: Mobile Service Robotics: Clawar 2014: 17th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines: Poznan, Poland 21 - 23 July 2014, Singapore: World Scientific, 2014, 511-519 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper introduces a study of a concept of exible crawling mechanism todesign an industrial underwater cleaning robot, which is evaluated from theviewpoint of the capability to work underwater, scanning the desired surface,and bearing the reactions. This can be used as a robotic application in under-water surface cleaning and maintenance. In this study we focused on realizingthe adhesion on the surface in stationary and in motion, bearing reactions,enabling the needed locomotion types for scanning, and achieving the stabilityin dierent situations on the surface.

  • 12.
    Albitar, Houssam
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Dandan, Kinan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Layered mission control architecture and strategy for crawling underwater cleaning robot2015Inngår i: International Journal of Mechatronics and Automation, ISSN 2045-1059, Vol. 5, nr 2/3, 114-124 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the mechanical design and the control system architecture of anunderwater robot, developed for bio-fouling cleaning surfaces. The robotic system presented herehas been designed to improve the productivity, reduce the environmental impacts, and excludethe hazards for the operators. The control system has a layered structure which is distributed intotwo blocks: cleaning robot, and on-board base station connected with power and control cablesand a water hose, to facilitate different modes of operations and to increase the system reliability.A low level control has been implemented on the robotic platform. The onboard station designedto be in different layers of the control system: manual, semiautonomous and autonomous modes.A scaled prototype has been implemented and tested to prove the concept, and to make certainthat the mechanical design and the chosen control system are perfectly suited to the mainfunctions of the robotic system.

  • 13.
    Albitar, Houssam
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Dandan, Kinan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Underwater Robotics: Surface Cleaning Technics, Adhesion and Locomotion Systems2016Inngår i: International Journal of Advanced Robotic Systems, ISSN 1729-8806, E-ISSN 1729-8814, Vol. 13, 7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Underwater robots are being developed for various applications ranging from inspection to maintenance and cleaning of submerged surfaces and constructions. These platforms should be able to travel on these surfaces. Furthermore, these platforms should adapt and reconfigure for underwater environment conditions and should be autonomous. Regarding the adhesion to the surface, they should produce a proper attaching force using a light-weight technics. Taking these facts into consideration, this paper presents a survey of different technologies used for underwater cleaning and the available underwater robotics solutions for the locomotion and the adhesion to surfaces.

  • 14.
    Aldammad, Mohamad
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Current collector for heavy vehicles on electrified roads2014Inngår i: Proceedings of the 14th Mechatronics Forum International Conference, Mechatronics 2014 / [ed] Leo J De Vin and Jorge Solis, Karlstad: Karlstad University , 2014, 436-441 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a prototype of a novel current collector manipulator that can be mounted beneath a road vehicle between the front and rear wheels to collect electric power from road embedded power lines. The ground-level power supply concept for road vehicles is described and the kinematic model of this two degree of freedom manipulator is detailed. Finally, the power line detection, based on an array of inductive sensors, is discussed.

  • 15.
    Aldammad, Mohamad
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Center for Applied Autonomous Sensor Systems, Örebro University, Örebro, Sweden.
    Current Collector for Heavy Vehicles on Electrified Roads: Field Tests2016Inngår i: Journal of Asian Electric Vehicles, ISSN 1348-3927, Vol. 14, nr 1, 1751-1757 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the field tests and measurements performed on a novel current collector manipulator to be mounted beneath a heavy vehicle to collect electric power from road embedded power lines. We describe the concept of the Electric Road System (ERS) test track being used and give an overview of the test vehicle for testing the current collection. The emphasis is on the field tests and measurements to evaluate both the vertical accelerations that the manipulator’s end-effector is subject to during operation and the performance of the detection and tracking of the power line.

  • 16.
    Aldammad, Mohamad
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Current collector for heavy vehicles on electrified roads: kinematic analysisInngår i: International Journal of Electric and Hybrid Vehicles, ISSN 1751-4088Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a prototype of a novel current collector manipulator to be be mounted beneath a heavy vehicle to collect electric power from road-embedded power lines. We describe the concept of the ground-level power supply system for heavy vehicles and its main components. The main requirements and constraints, such as safety, robustness to harsh road and weather operational conditions, ambient environment aspects and dynamic properties, are introduced. The emphasis is on the developed kinematic model, which provides the base for further development of the control system. We propose and derive an alternative approach for representing the inverse kinematics by a two-dimensional polynomial approximation that avoids the usage of complicated non-linear equations. Its simplicity is demonstrated by a numerical example with the basic parameters of the prototype. The basic motion sequences of the current collector and the way to control them are outlined. 

  • 17.
    Aldammad, Mohamad
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ananiev, Anani
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kalaykov, Ivan
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Current Collector for Heavy Vehicles on Electrified Roads: Motion Control2015Inngår i: Journal of Asian Electric Vehicles, ISSN 1348-3927, Vol. 13, nr 2, 1725-1732 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the adopted motion control schemes of a novel current collector manipulator to be mounted beneath a heavy hybrid electric vehicle to collect electric power from road embedded power lines. We describe our approach of power line detection and tracking based on an array of inductive proximity sensors. The emphasis is on the adopted motion control logic for sequential and closed loop motions to detect and track the power line respectively. We implement the sliding mode control approach for the closed loop control scheme as straightforward solution given the binary nature of the inductive proximity sensors being used. The overall architecture of the entire motion control system is presented. Finally, the implementation of the entire control logic in a form of a state machine is discussed.

  • 18.
    Aleotti, Jacopo
    et al.
    Örebro universitet, Institutionen för teknik.
    Skoglund, Alexander
    Örebro universitet, Institutionen för teknik.
    Duckett, Tom
    Örebro universitet, Institutionen för teknik.
    Position teaching of a robot arm by demonstration with a wearable input device2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes the first prototype of a "Programming by demonstration" (PbD) system for position teaching of a robot manipulator. A new approach for enabling PbD using supervised learning is presented, by connecting a wearable input device for sensing human arm movements to the software controller of a robot arm. The method does not require analytical modelling of either the human arm or robot, and can be customised for different users and robots. Initial experiments on some simple movements tasks are presented.

  • 19.
    Alfredsson, Anders
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Larsson, Gustav
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lokalisering och visualisering av område: En smartphone-applikation för en ökad trygghetskänsla2016Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Rapporten handlar om olika metoder för att lokalisera smartphones och skapandet av en Androidapplikation. Applikationen skulle visualisera Campusområdet vid Örebro universitet för att öka medvetenheten och säkerhetskänslan för personer som är där kvällar och nätter. Implementationen av systemet beskrivs tillsammans med de problem som uppstod, samt dess lösningar.

  • 20.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Klugl, Franziska
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Knowing without telling: integrating sensing and mapping for creating an artificial companion2016Inngår i: Proceedings of the 24th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, New York, NY, USA: Association for Computing Machinery (ACM), 2016, 11:1-11:4 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper depicts a sensor-based map navigation approach which targets users, who due to disabilities or lack of technical knowledge are currently not in the focus of map system developments for personalized information. What differentiates our approach from the state-of-art mostly integrating localized social media data, is that our vision is to integrate real time sensor generated data that indicates the situation of dfferent phenomena (such as the physiological functions of the body) related to the user. The challenge hereby is mainly related to knowledge representation and integration. The tentative impact of our vision for future navigation systems is re ected within a scenario.

  • 21.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Automatic annotation of sensor data streams using abductive reasoning2013Inngår i: Automatic Annotation of Sensor Data Streams using AbductiveReasoning, SCITEPRESS, 2013, 345-354 s.Konferansepaper (Fagfellevurdert)
  • 22.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Ontology alignment for classification of low level sensor data2012Konferansepaper (Fagfellevurdert)
  • 23.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Reasoning for sensor data interpretation: an application to air quality monitoring2015Inngår i: Journal of Ambient Intelligence and Smart Environments, ISSN 1876-1364, E-ISSN 1876-1372, Vol. 7, nr 4, 579-597 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper we introduce a representation and reasoning model for the interpretation of time-series signals of a gas sensor situated in a sensor network. The interpretation process includes inferring high level explanations for changes detected over the gas signals. Inspired from the Semantic Sensor Network (SSN), the ontology used in this work provides an adaptive way of modelling the domain-related knowledge. Furthermore, exploiting (Incremental) Answer Set Programming (ASP) enables a declarative and automatic way of rule definition. Converting the ontology concepts and relations into ASP logic programs, the interpretation process defines a logic program whose answer sets are considered as eventual explanations for the detected changes in the gas sensor signals. The proposed approach is tested in a kitchen environment which contains several objects monitored by different sensors. The contextual information provided by the sensor network together with high level domain knowledge are used to infer explanations for changes in the ambient air detected by the gas sensors.

  • 24.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Towards Automatic Ontology Alignmentfor Enriching Sensor Data Analysis2013Inngår i: Communications in Computer and Information Science, ISSN 1865-0929, E-ISSN 1865-0937, Vol. 415, 179-193 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work ontology alignment is used to align an ontology comprising high level knowledge to a structure representing the results of low-level sensor data classification. To resolve inherent uncertainties from the data driven classifier, an ontology about application domain is aligned to the classifier output and the result is recommendation system able to suggest a course of action that will resolve the uncertainty. This work is instantiated in a medical application domain where signals from an electronic nose are classified into different bacteria types. In case of misclassifications resulting from the data driven classifier, the alignment to an ontology representing traditional microbiology tests suggests a subset of tests most relevant to use. The result is a hybrid classification system (electronic nose and traditional testing) that automatically exploits domain knowledge in the identification process.

  • 25.
    Alirezaie, Marjan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Längkvist, Martin
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kiselev, Andrey
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Open GeoSpatial Data as a Source of Ground Truth for Automated Labelling of Satellite Images2016Inngår i: SDW 2016: Spatial Data on the Web, Proceedings / [ed] Krzysztof Janowicz et al., CEUR Workshop Proceedings , 2016, 5-8 s.Konferansepaper (Fagfellevurdert)
  • 26.
    Almqvist, Håkan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Magnusson, Martin
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kucner, Tomasz Piotr
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lilienthal, Achim
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Learning to detect misaligned point clouds2017Inngår i: Journal of Field Robotics, ISSN 1556-4959, E-ISSN 1556-4967Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Matching and merging overlapping point clouds is a common procedure in many applications, including mobile robotics, three-dimensional mapping, and object visualization. However, fully automatic point-cloud matching, without manual verification, is still not possible because no matching algorithms exist today that can provide any certain methods for detecting misaligned point clouds. In this article, we make a comparative evaluation of geometric consistency methods for classifying aligned and nonaligned point-cloud pairs. We also propose a method that combines the results of the evaluated methods to further improve the classification of the point clouds. We compare a range of methods on two data sets from different environments related to mobile robotics and mapping. The results show that methods based on a Normal Distributions Transform representation of the point clouds perform best under the circumstances presented herein.

  • 27.
    Almqvist, Håkan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Magnusson, Martin
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lilienthal, Achim J.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Improving Point Cloud Accuracy Obtained from a Moving Platform for Consistent Pile Attack Pose Estimation2014Inngår i: Journal of Intelligent and Robotic Systems, ISSN 0921-0296, E-ISSN 1573-0409, Vol. 75, nr 1, 101-128 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a perception system for enabling automated loading with waist-articulated wheel loaders. To enable autonomous loading of piled materials, using either above-ground wheel loaders or underground load-haul-dump vehicles, 3D data of the pile shape is needed. However, using common 3D scanners, the scan data is distorted while the wheel loader is moving towards the pile. Existing methods that make use of 3D scan data (for autonomous loading as well as tasks such as mapping, localisation, and object detection) typically assume that each 3D scan is accurate. For autonomous robots moving over rough terrain, it is often the case that the vehicle moves a substantial amount during the acquisition of one 3D scan, in which case the scan data will be distorted. We present a study of auto-loading methods, and how to locate piles in real-world scenarios with nontrivial ground geometry. We have compared how consistently each method performs for live scans acquired in motion, and also how the methods perform with different view points and scan configurations. The system described in this paper uses a novel method for improving the quality of distorted 3D scans made from a vehicle moving over uneven terrain. The proposed method for improving scan quality is capable of increasing the accuracy of point clouds without assuming any specific features of the environment (such as planar walls), without resorting to a “stop-scan-go” approach, and without relying on specialised and expensive hardware. Each new 3D scan is registered to the preceding using the normal-distributions transform (NDT). After each registration, a mini-loop closure is performed with a local, per-scan, graph-based SLAM method. To verify the impact of the quality improvement, we present data that shows how auto-loading methods benefit from the corrected scans. The presented methods are validated on data from an autonomous wheel loader, as well as with simulated data. The proposed scan-correction method increases the accuracy of both the vehicle trajectory and the point cloud. We also show that it increases the reliability of pile-shape measures used to plan an efficient attack pose when performing autonomous loading.

  • 28.
    Almqvist, Håkan
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Magnusson, Martin
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Stoyanov, Todor
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lilienthal, Achim J.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Improving Point-Cloud Accuracy from a Moving Platform in Field Operations2013Inngår i: 2013 IEEE International Conference on Robotics and Automation (ICRA), IEEE conference proceedings, 2013, 733-738 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a method for improving the quality of distorted 3D point clouds made from a vehicle equipped with a laser scanner moving over uneven terrain. Existing methods that use 3D point-cloud data (for tasks such as mapping, localisation, and object detection) typically assume that each point cloud is accurate. For autonomous robots moving in rough terrain, it is often the case that the vehicle moves a substantial amount during the acquisition of one point cloud, in which case the data will be distorted. The method proposed in this paper is capable of increasing the accuracy of 3D point clouds, without assuming any specific features of the environment (such as planar walls), without resorting to a "stop-scan-go" approach, and without relying on specialised and expensive hardware. Each new point cloud is matched to the previous using normal-distribution-transform (NDT) registration, after which a mini-loop closure is performed with a local, per-scan, graph-based SLAM method. The proposed method increases the accuracy of both the measured platform trajectory and the point cloud. The method is validated on both real-world and simulated data.

  • 29.
    Alzghoul, Ahmad
    et al.
    Department of Information Technology, Division of Computing Science, Uppsala, Sweden.
    Backe, Björn
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Löfstrand, Magnus
    Department of Information Technology, Division of Computing Science, Uppsala, Sweden.
    Byström, Arne
    Bosch Rexroth Mellansel AB, Mellansel, Sweden.
    Liljedahl, Bengt
    Bosch Rexroth Mellansel AB, Mellansel, Sweden.
    Comparing a knowledge-based and a data-driven method in querying data streams for system fault detection: A hydraulic drive system application2014Inngår i: Computers in industry (Print), ISSN 0166-3615, E-ISSN 1872-6194, Vol. 65, nr 8, 1126-1135 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The field of fault detection and diagnosis has been the subject of considerable interest in industry. Fault detection may increase the availability of products, thereby improving their quality. Fault detection and diagnosis methods can be classified in three categories: data-driven, analytically based, and knowledge-based methods.

    In this work, we investigated the ability and the performance of applying two fault detection methods to query data streams produced from hydraulic drive systems. A knowledge-based method was compared to a data-driven method. A fault detection system based on a data stream management system (DSMS) was developed in order to test and compare the two methods using data from real hydraulic drive systems.

    The knowledge-based method was based on causal models (fault trees), and principal component analysis (PCA) was used to build the data-driven model. The performance of the methods in terms of accuracy and speed, was examined using normal and physically simulated fault data. The results show that both methods generate queries fast enough to query the data streams online, with a similar level of fault detection accuracy. The industrial applications of both methods include monitoring of individual industrial mechanical systems as well as fleets of such systems. One can conclude that both methods may be used to increase industrial system availability.

  • 30.
    Alzghoul, Ahmad
    et al.
    Department of Information Technology, Division of Computing Science, Uppsala, Sweden.
    Löfstrand, Magnus
    Department of Information Technology, Division of Computing Science, Uppsala, Sweden.
    Addressing concept drift to improve system availability by updating one-class data-driven models2015Inngår i: Evolving Systems, ISSN 1868-6478, E-ISSN 1868-6486, Vol. 6, nr 3, 187-198 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Data-driven models have been used to detect system faults, thereby increasing industrial system availability. The ability to search data streams while dealing with concept drift are challenges for data-driven models. The objective of this work is to demonstrate a general method to manage concept drift when using one-class data-driven models. The method has been used to develop an automatically retrained and updated polygon-based model. In this paper, the available industrial data allowed for use of one-class data-driven models, and the polygon-based model was selected because it has previously been successful. Possible scenarios that allow one-class data-driven models to be retrained or updated were identified. Based on the identified scenarios, a method to automatically update a polygon-based model online is proposed. The method has been tested and verified using data collected from a Bosch Rexroth Mellansel AB hydraulic drive system. Data representing relevant faults was inserted into the data set in close collaboration with engineers from the company. The results show that the developed polygon-based model method was able to address the concept drift issue and was able to significantly improve the classification accuracy compared to the static polygon-based model. Thereby, the model could significantly improve industrial system availability when applied in the relevant production process. This paper shows that the developed polygon-based model requires small memory space while its updating procedure is simple and fast. Finally, the identified scenarios may be helpful as input for supporting other one-class data-driven models to cope with concept drift, thus increasing the generalizability of the results.

  • 31.
    Alzghoul, Ahmad
    et al.
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Löfstrand, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Increasing availability of industrial systems through data stream mining2011Inngår i: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 60, nr 2, 195-205 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Improving industrial product reliability, maintainability and thus availability is a challenging task for many industrial companies. In industry, there is a growing need to process data in real time, since the generated data volume exceeds the available storage capacity. This paper consists of a review of data stream mining and data stream management systems aimed at improving product availability. Further, a newly developed and validated grid-based classifier method is presented and compared to one-class support vector machine (OCSVM) and a polygon-based classifier.

    The results showed that, using 10% of the total data set to train the algorithm, all three methods achieved good (>95% correct) overall classification accuracy. In addition, all three methods can be applied on both offline and online data.

    The speed of the resultant function from the OCSVM method was, not surprisingly, higher than the other two methods, but in industrial applications the OCSVMs' comparatively long time needed for training is a possible challenge. The main advantage of the grid-based classification method is that it allows for calculation of the probability (%) that a data point belongs to a specific class, and the method can be easily modified to be incremental.

    The high classification accuracy can be utilized to detect the failures at an early stage, thereby increasing the reliability and thus the availability of the product (since availability is a function of maintainability and reliability). In addition, the consequences of equipment failures in terms of time and cost can be mitigated.

  • 32.
    Alzghoul, Ahmad
    et al.
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Löfstrand, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Backe, Björn
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Data stream forecasting for system fault prediction2012Inngår i: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 62, nr 4, 972-978 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Competition among today’s industrial companies is very high. Therefore, system availability plays an important role and is a critical point for most companies. Detecting failures at an early stage or foreseeing them before they occur is crucial for machinery availability. Data analysis is the most common method for machine health condition monitoring. In this paper we propose a fault-detection system based on data stream prediction, data stream mining, and data stream management system (DSMS). Companies that are able to predict and avoid the occurrence of failures have an advantage over their competitors. The literature has shown that data prediction can also reduce the consumption of communication resources in distributed data stream processing. In this paper different data-stream-based linear regression prediction methods have been tested and compared within a newly developed fault detection system. Based on the fault detection system, three DSM algorithms outputs are compared to each other and to real data. The three applied and evaluated data stream mining algorithms were: Grid-based classifier, polygon-based method, and one-class support vector machines (OCSVM). The results showed that the linear regression method generally achieved good performance in predicting short-term data. (The best achieved performance was with a Mean Absolute Error (MAE) around 0.4, representing prediction accuracy of 87.5%). Not surprisingly, results showed that the classification accuracy was reduced when using the predicted data. However, the fault-detection system was able to attain an acceptable performance of around 89% classification accuracy when using predicted data.

  • 33.
    Alzghoul, Ahmad
    et al.
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Löfstrand, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Karlsson, Lennart
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Karlberg, Magnus
    Division of Computer Aided Design, Luleå University of Technology, Luleå, Sweden.
    Data stream mining for increased functional product availability awareness2011Inngår i: Functional Thinking for Value Creation: Proceedings of the 3rd CIRP International Conference on Industrial Product Service Systems, Technische Universität Braunschweig, Braunschweig, Germany, May 5th - 6th, 2011 / [ed] Hesselbach, J. & Herrmann, C., Springer Berlin/Heidelberg, 2011, 237-241 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Functional Products (FP) and Product Service Systems (PSS) may be seen as integrated systems comprising hardware and support services. For such offerings, availability is key. Little research has been done on integrating Data Stream Management Systems (DSMS) for monitoring (parts of) a FP to improve system availability. This paper introduces an approach for how data stream mining may be applied to monitor hardware being part of a Functional Product. The result shows that DSMS have the potential to significantly support continuous availability awareness of industrial systems, especially important when the supplier is to supply a function with certain availability.

  • 34.
    Amato, G.
    et al.
    ISTI-CNR, Pisa, Italy.
    Bacciu, D.
    Università di Pisa, Pisa, Italy.
    Broxvall, Mathias
    Örebro Universitet, Örebro, Sweden.
    Chessa, S.
    Università di Pisa, Pisa, Italy.
    Coleman, S.
    University of Ulster, Ulster, UK.
    Di Rocco, Maurizio
    Örebro Universitet, Örebro, Sweden.
    Dragone, M.
    Trinity College Dublin, Dublin, Ireland.
    Gallicchio, C.
    Università di Pisa, Pisa, Italy.
    Gennaro, C.
    ISTI-CNR, Pisa, Italy.
    Lozano, H.
    Tecnalia, Madrid, Spain.
    McGinnity, T. M.
    University of Ulster, Ulster, UK.
    Micheli, A.
    Università di Pisa, Pisa, Italy.
    Ray, A. K.
    University of Ulster, Ulster, UK.
    Renteria, A.
    Tecnalia, Madrid, Spain.
    Saffiotti, Alessandro
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Swords, D.
    University College Dublin, Dublin, Ireland.
    Vairo, C.
    ISTI-CNR, Pisa, Italy.
    Vance, P.
    University of Ulster, Ulster, UK.
    Robotic Ubiquitous Cognitive Ecology for Smart Homes2015Inngår i: Journal of Intelligent and Robotic Systems, ISSN 0921-0296, E-ISSN 1573-0409, Vol. 80, S57-S81 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Robotic ecologies are networks of heterogeneous robotic devices pervasively embedded in everyday environments, where they cooperate to perform complex tasks. While their potential makes them increasingly popular, one fundamental problem is how to make them both autonomous and adaptive, so as to reduce the amount of preparation, pre-programming and human supervision that they require in real world applications. The project RUBICON develops learning solutions which yield cheaper, adaptive and efficient coordination of robotic ecologies. The approach we pursue builds upon a unique combination of methods from cognitive robotics, machine learning, planning and agent-based control, and wireless sensor networks. This paper illustrates the innovations advanced by RUBICON in each of these fronts before describing how the resulting techniques have been integrated and applied to a proof of concept smart home scenario. The resulting system is able to provide useful services and pro-actively assist the users in their activities. RUBICON learns through an incremental and progressive approach driven by the feedback received from its own activities and from the user, while also self-organizing the manner in which it uses available sensors, actuators and other functional components in the process. This paper summarises some of the lessons learned by adopting such an approach and outlines promising directions for future work.

  • 35.
    Amnå, Erik
    et al.
    Örebro universitet, Samhällsvetenskapliga institutionen.
    Halleröd, Björn
    Umeå universitet.
    Hallqvist, Johan
    Karolinska Institutet.
    Lundberg, Ingvar
    Uppsala universitet.
    Sundqvist, Jan
    Karolinska Institutet.
    Theorell, Töres
    Karolinska Institutet.
    Thorslund, Mats
    Karolinska Institutet.
    Vingård, Eva
    Uppsala universitet.
    Wall, Stig
    Umeå universitet.
    Åkerstedt, Torbjörn
    Karolinska Institutet.
    Östergren, Per Olof
    Lunds universitet.
    En halv miljard av statens pengar riskerar att slösas bort2007Inngår i: Göteborgs-Posten, Vol. 2007-09-13, 47-47 s.Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Minskade anslag gör att den årliga undersökningen om våra levnadsförhållanden hotas att halveras. Det kan drabba redan svaga grupper som äldre, invandrare och ensamstående föräldrar.

  • 36.
    Amouzgar, Kaveh
    et al.
    Product Development Department, School of Engineering, Jönköping University, Jönköping, Sweden; School of Engineering Science, University of Skövde, Skövde, Sweden.
    Strömberg, Niclas
    Örebro universitet, Institutionen för naturvetenskap och teknik. Department of Mechanical Engineering.
    Radial Basis Functions as Surrogate Models with A Priori Bias in Comparison with a Posteriori Bias2017Inngår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 55, nr 4, 1453-1469 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to obtain a robust performance, the established approach when using radial basis function networks (RBF) as metamodels is to add a posteriori bias which is defined by extra orthogonality constraints. We mean that this is not needed, instead the bias can simply be set a priori by using the normal equation, i.e. the bias becomes the corresponding regression model. In this paper we demonstrate that the performance of our suggested approach with a priori bias is in general as good as, or even for many test examples better than, the performance of RBF with a posteriori bias. Using our approach, it is clear that the global response is modelled with the bias and that the details are captured with radial basis functions. The accuracy of the two approaches are investigated by using multiple test functions with different degrees of dimensionality. Furthermore, several modeling criteria, such as the type of radial basis functions used in the RBFs, dimension of the test functions, sampling techniques and size of samples, are considered to study their affect on the performance of the approaches. The power of RBF with a priori bias for surrogate based design optimization is also demonstrated by solving an established engineering benchmark of a welded beam and another benchmark for different sampling sets generated by successive screening, random, Latin hypercube and Hammersley sampling, respectively. The results obtained by evaluation of the performance metrics, the modeling criteria and the presented optimal solutions, demonstrate promising potentials of our RBF with a priori bias, in addition to the simplicity and straight-forward use of the approach.

  • 37.
    Andersson, Robin
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Franzén, Simon
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Realtidsuppdaterad dashboard2017Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna rapport kommer täcka utvecklingen av en Realtidsuppdaterad Dashboardför Flex Applications. Dashboarden kan ses som en interaktiv anslagstavla,ochär en ny moduli Flex Applications befintliga personaladministrationssystem.

    Under utvecklingen haräven en fördjupning inom ämnet informationsöverbelastninggjorts, då detta har relevans till designen av gränssnittet. Resultatet av detta visar på att det inte finns en given lösning utan snarare riktlinjer för hur designen bör se ut.

    Applikationen som skrevs till Dashboarden skapades med hjälp av språket TypeScript samt ramverket Angular 2. Applikationen skrevs först självständigt, avskiljt från Flex redan befintliga system.Dettaför att få en förståelse för hur TypeScript och Angular 2ska hanteras, och ävendärför att behovet av en direkt koppling till systemet ej behövdes från start.

    Applikationen kopplades sedansamman med det befintliga systemet för att kunna visualisera faktisk data. Detta blev lyckat och visade på att den valda systemdesignen fungerade som tänkt.

  • 38.
    Andreasson, Henrik
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Camera based navigation by mobile robots: local visual feature based localisation and mapping2009Bok (Annet vitenskapelig)
    Abstract [en]

    The most important property of a mobile robot is the fact that it is mobile. How to give a robot the skills required to navigate around its environment is therefore an important topic in mobile robotics. Navigation, both for robots and humans, typically involves a map. The map can be used, for example, to estimate a pose based on observations (localisation) or determine a suitable path between to locations. Maps are available nowadays for us humans with few exceptions, however, maps suitable for mobile robots rarely exists. In addition, to relate sensor readings to a map requires that the map content and the observation is compatible, i.e. different robots may require different maps for the same area. This book addresses some of the fundamental problems related to mobile robot navigation (registration, localisation and mapping) using cameras as the primary sensor input. Small salient regions (local visual features) are extracted from each camera image, where each region can be seen as a fingerprint. Many fingerprint matches implicates a high likelihood that they corresponding images originate from a similar location, which is a central property utilised in this work.

  • 39.
    Andreasson, Henrik
    Örebro universitet, Institutionen för teknik.
    Local visual feature based localisation and mapping by mobile robots2008Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    This thesis addresses the problems of registration, localisation and simultaneous localisation and mapping (SLAM), relying particularly on local visual features extracted from camera images. These fundamental problems in mobile robot navigation are tightly coupled. Localisation requires a representation of the environment (a map) and registration methods to estimate the pose of the robot relative to the map given the robot’s sensory readings. To create a map, sensor data must be accumulated into a consistent representation and therefore the pose of the robot needs to be estimated, which is again the problem of localisation.

    The major contributions of this thesis are new methods proposed to address the registration, localisation and SLAM problems, considering two different sensor configurations. The first part of the thesis concerns a sensor configuration consisting of an omni-directional camera and odometry, while the second part assumes a standard camera together with a 3D laser range scanner. The main difference is that the former configuration allows for a very inexpensive set-up and (considering the possibility to include visual odometry) the realisation of purely visual navigation approaches. By contrast, the second configuration was chosen to study the usefulness of colour or intensity information in connection with 3D point clouds (“coloured point clouds”), both for improved 3D resolution (“super resolution”) and approaches to the fundamental problems of navigation that exploit the complementary strengths of visual and range information.

    Considering the omni-directional camera/odometry setup, the first part introduces a new registration method based on a measure of image similarity. This registration method is then used to develop a localisation method, which is robust to the changes in dynamic environments, and a visual approach to metric SLAM, which does not require position estimation of local image features and thus provides a very efficient approach.

    The second part, which considers a standard camera together with a 3D laser range scanner, starts with the proposal and evaluation of non-iterative interpolation methods. These methods use colour information from the camera to obtain range information at the resolution of the camera image, or even with sub-pixel accuracy, from the low resolution range information provided by the range scanner. Based on the ability to determine depth values for local visual features, a new registration method is then introduced, which combines the depth of local image features and variance estimates obtained from the 3D laser range scanner to realise a vision-aided 6D registration method, which does not require an initial pose estimate. This is possible because of the discriminative power of the local image features used to determine point correspondences (data association). The vision-aided registration method is further developed into a 6D SLAM approach where the optimisation constraint is based on distances of paired local visual features. Finally, the methods introduced in the second part are combined with a novel adaptive normal distribution transform (NDT) representation of coloured 3D point clouds into a robotic difference detection system.

  • 40.
    Andreasson, Henrik
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Bouguerra, Abdelbaki
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Åstrand, Björn
    Högskolan i Halmstad, CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Rögnvaldsson, Thorsteinn
    Högskolan i Halmstad, CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Gold-Fish SLAM: An Application of SLAM to Localize AGVs2014Inngår i: Field and Service Robotics: Results of the 8th International Conference / [ed] Yoshida, Kazuya; Tadokoro, Satoshi, Heidelberg, Germany: Springer Berlin/Heidelberg, 2014, 585-598 s.Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The main focus of this paper is to present a case study of a SLAM solution for Automated Guided Vehicles (AGVs) operating in real-world industrial environments. The studied solution, called Gold-fish SLAM, was implemented to provide localization estimates in dynamic industrial environments, where there are static landmarks that are only rarely perceived by the AGVs. The main idea of Gold-fish SLAM is to consider the goods that enter and leave the environment as temporary landmarks that can be used in combination with the rarely seen static landmarks to compute online estimates of AGV poses. The solution is tested and verified in a factory of paper using an eight ton diesel-truck retrofitted with an AGV control system running at speeds up to 3 m/s. The paper includes also a general discussion on how SLAM can be used in industrial applications with AGVs

  • 41.
    Andreasson, Henrik
    et al.
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Bouguerra, Abdelbaki
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Åstrand, Björn
    Rögnvaldsson, Thorsteinn
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Gold-fish SLAM: an application of SLAM to localize AGVs2012Inngår i: Proceedings of the International Conference on Field and Service Robotics (FSR), July 2012., 2012Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The main focus of this paper is to present a case study of a SLAM solution for Automated Guided Vehicles (AGVs) operating in real-world industrial environ- ments. The studied solution, called Gold-fish SLAM, was implemented to provide localization estimates in dynamic industrial environments, where there are static landmarks that are only rarely perceived by the AGVs. The main idea of Gold-fish SLAM is to consider the goods that enter and leave the environment as temporary landmarks that can be used in combination with the rarely seen static landmarks to compute online estimates of AGV poses. The solution is tested and verified in a factory of paper using an eight ton diesel-truck retrofitted with an AGV control sys- tem running at speeds up to 3 meters per second. The paper includes also a general discussion on how SLAM can be used in industrial applications with AGVs.

  • 42.
    Andreasson, Henrik
    et al.
    Örebro universitet, Institutionen för teknik.
    Duckett, Tom
    University of Lincoln.
    Lilienthal, Achim J.
    A Minimalistic Approach to Appearance-Based Visual SLAM2008Inngår i: IEEE Transactions on Robotics, ISSN 1552-3098, Vol. 24, nr 5, 991-1001 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a vision-based approach to SLAM in indoor / outdoor environments with minimalistic sensing and computational requirements. The approach is based on a graph representation of robot poses, using a relaxation algorithm to obtain a globally consistent map. Each link corresponds to a relative measurement of the spatial relation between the two nodes it connects. The links describe the likelihood distribution of the relative pose as a Gaussian distribution. To estimate the covariance matrix for links obtained from an omni-directional vision sensor, a novel method is introduced based on the relative similarity of neighbouring images. This new method does not require determining distances to image features using multiple view geometry, for example. Combined indoor and outdoor experiments demonstrate that the approach can handle qualitatively different environments (without modification of the parameters), that it can cope with violations of the “flat floor assumption” to some degree, and that it scales well with increasing size of the environment, producing topologically correct and geometrically accurate maps at low computational cost. Further experiments demonstrate that the approach is also suitable for combining multiple overlapping maps, e.g. for solving the multi-robot SLAM problem with unknown initial poses.

  • 43.
    Andreasson, Henrik
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Saarinen, Jari
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Cirillo, Marcello
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Stoyanov, Todor
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lilienthal, Achim
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Drive the Drive: From Discrete Motion Plans to Smooth Drivable Trajectories2014Inngår i: Robotics, E-ISSN 2218-6581, Vol. 3, nr 4, 400-416 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Autonomous navigation in real-world industrial environments is a challenging task in many respects. One of the key open challenges is fast planning and execution of trajectories to reach arbitrary target positions and orientations with high accuracy and precision, while taking into account non-holonomic vehicle constraints. In recent years, lattice-based motion planners have been successfully used to generate kinematically and kinodynamically feasible motions for non-holonomic vehicles. However, the discretized nature of these algorithms induces discontinuities in both state and control space of the obtained trajectories, resulting in a mismatch between the achieved and the target end pose of the vehicle. As endpose accuracy is critical for the successful loading and unloading of cargo in typical industrial applications, automatically planned paths have not been widely adopted in commercial AGV systems. The main contribution of this paper is a path smoothing approach, which builds on the output of a lattice-based motion planner to generate smooth drivable trajectories for non-holonomic industrial vehicles. The proposed approach is evaluated in several industrially relevant scenarios and found to be both fast (less than 2 s per vehicle trajectory) and accurate (end-point pose errors below 0.01 m in translation and 0.005 radians in orientation).

  • 44.
    Andreasson, Henrik
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Saarinen, Jari
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Cirillo, Marcello
    Örebro universitet, Institutionen för naturvetenskap och teknik. SCANIA AB, Södertälje, Sweden.
    Stoyanov, Todor
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lilienthal, Achim
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Fast, continuous state path smoothing to improve navigation accuracy2015Inngår i: IEEE International Conference on Robotics and Automation (ICRA), 2015, IEEE Computer Society, 2015, 662-669 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Autonomous navigation in real-world industrial environments is a challenging task in many respects. One of the key open challenges is fast planning and execution of trajectories to reach arbitrary target positions and orientations with high accuracy and precision, while taking into account non-holonomic vehicle constraints. In recent years, lattice-based motion planners have been successfully used to generate kinematically and kinodynamically feasible motions for non-holonomic vehicles. However, the discretized nature of these algorithms induces discontinuities in both state and control space of the obtained trajectories, resulting in a mismatch between the achieved and the target end pose of the vehicle. As endpose accuracy is critical for the successful loading and unloading of cargo in typical industrial applications, automatically planned paths have not be widely adopted in commercial AGV systems. The main contribution of this paper addresses this shortcoming by introducing a path smoothing approach, which builds on the output of a lattice-based motion planner to generate smooth drivable trajectories for non-holonomic industrial vehicles. In real world tests presented in this paper we demonstrate that the proposed approach is fast enough for online use (it computes trajectories faster than they can be driven) and highly accurate. In 100 repetitions we achieve mean end-point pose errors below 0.01 meters in translation and 0.002 radians in orientation. Even the maximum errors are very small: only 0.02 meters in translation and 0.008 radians in orientation.

  • 45.
    Andreasson, Henrik
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Stoyanov, Todor
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Real time registration of RGB-D data using local visual features and 3D-NDT registration2012Inngår i: Proc. of International Conference on Robotics and Automation (ICRA) Workshop on Semantic Perception, Mapping and Exploration (SPME), IEEE, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Recent increased popularity of RGB-D capable sensors in robotics has resulted in a surge of related RGBD registration methods. This paper presents several RGB-D registration algorithms based on combinations between local visual feature and geometric registration. Fast and accurate transformation refinement is obtained by using a recently proposed geometric registration algorithm, based on the Three-Dimensional Normal Distributions Transform (3D-NDT). Results obtained on standard data sets have demonstrated mean translational errors on the order of 1 cm and rotational errors bellow 1 degree, at frame processing rates of about 15 Hz.

  • 46.
    Andreasson, Henrik
    et al.
    Örebro universitet, Institutionen för teknik.
    Treptow, André
    University of Tübingen.
    Duckett, Tom
    Örebro universitet, Institutionen för teknik.
    Localization for mobile robots using panoramic vision, local features and particle filter2005Inngår i: Proceedings of the 2005 IEEE International Converence on Robotics and Automation: ICRA - 2005, 2005, 3348-3353 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we present a vision-based approach to self-localization that uses a novel scheme to integrate featurebased matching of panoramic images with Monte Carlo localization. A specially modified version of Lowe’s SIFT algorithm is used to match features extracted from local interest points in the image, rather than using global features calculated from the whole image. Experiments conducted in a large, populated indoor environment (up to 5 persons visible) over a period of several months demonstrate the robustness of the approach, including kidnapping and occlusion of up to 90% of the robot’s field of view.

  • 47.
    Andreasson, Henrik
    et al.
    Örebro universitet, Institutionen för teknik.
    Triebel, Rudolph
    University of Friburg.
    Burgard, Wolfram
    University of Friburg.
    Improving plane extraction from 3D data by fusing laser data and vision2005Inngår i: 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2005. (IROS 2005): IROS 2005 IEEE/RSJ, 2005, 2656-2661 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The problem of extracting three-dimensional structures from data acquired with mobile robots has received considerable attention over the past years. Robots that are able to perceive their three-dimensional environment are envisioned to more robustly perform tasks like navigation, rescue, and manipulation. In this paper we present an approach that simultaneously uses color and range information to cluster 3d points into planar structures. Our current system also is able to calibrate the camera and the laser based on the remission values provided by the range scanner and the brightness of the pixels in the image. It has been implemented on a mobile robot equipped with a manipulator that carries a range scanner and a camera for acquiring colored range scans. Several experiments carried out on real data and in simulations demonstrate that our approach yields highly accurate results also in comparison with previous approaches

  • 48.
    Arafat, Yeasin
    et al.
    Office of the President of the General Assembly United Nations, New York.
    Hellström, Thomas
    Umeå universitet.
    Rashid, Jayedur
    Örebro universitet, Akademin för naturvetenskap och teknik.
    Parameterized sensor model and an approach for measuring goodness of robotic maps2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Map building is a classical problem in mobile and au tonomous robotics, and sensor models is a way to interpret raw sensory information, especially for building maps. In this paper we propose a parameterized sensor model, and optimize map goodness with respect to these parameters. A new approach, measuring the goodness of maps without a handcrafted map of the actual environment is introduced and evaluated. Three different techniques; statistical anal ysis, derivative of images, and comparison of binary maps have been used as estimates of map goodness. The results show that the proposed sensor model generates better maps than a standard sensor model. However, the proposed ap proach of measuring goodness of maps does not improve the results as much as expected.

  • 49.
    Arain, Muhammad Asif
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Cirillo, Marcello
    Örebro universitet, Institutionen för naturvetenskap och teknik. Scania AB, Granparksvagen 10, SE-15187 Södertälje, Sweden.
    Hernandez Bennetts, Victor
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Schaffernicht, Erik
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Trincavelli, Marco
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lilienthal, Achim J.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Efficient Measurement Planning for Remote Gas Sensing with Mobile Robots2015Inngår i: 2015 IEEE International Conference on Robotics and Automation (ICRA), Washington, USA: IEEE Computer Society, 2015, 3428-3434 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The problem of gas detection is relevant to manyreal-world applications, such as leak detection in industrialsettings and surveillance. In this paper we address the problemof gas detection in large areas with a mobile robotic platformequipped with a remote gas sensor. We propose a novelmethod based on convex relaxation for quickly finding anexploration plan that guarantees a complete coverage of theenvironment. Our method proves to be highly efficient in termsof computational requirements and to provide nearly-optimalsolutions. We validate our approach both in simulation andin real environments, thus demonstrating its applicability toreal-world problems.

  • 50.
    Arain, Muhammad Asif
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Fan, Han
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Hernandez Bennetts, Victor
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Schaffernicht, Erik
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Lilienthal, Achim J.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Improving Gas Tomography With Mobile Robots: An Evaluation of Sensing Geometries in Complex Environments2017Inngår i: 2017 ISOCS/IEEE International Symposium on Olfaction andElectronic Nose (ISOEN 2017) Proceedings, 2017, 7968895Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An accurate model of gas emissions is of high importance in several real-world applications related to monitoring and surveillance. Gas tomography is a non-intrusive optical method to estimate the spatial distribution of gas concentrations using remote sensors. The choice of sensing geometry, which is the arrangement of sensing positions to perform gas tomography, directly affects the reconstruction quality of the obtained gas distribution maps. In this paper, we present an investigation of criteria that allow to determine suitable sensing geometries for gas tomography. We consider an actuated remote gas sensor installed on a mobile robot, and evaluated a large number of sensing configurations. Experiments in complex settings were conducted using a state-of-the-art CFD-based filament gas dispersal simulator. Our quantitative comparison yields preferred sensing geometries for sensor planning, which allows to better reconstruct gas distributions.

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