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  • 1.
    Aagaard, Sebastian
    Örebro University, School of Science and Technology.
    Demonstrating customer and business value through the implementation of a Design for Reliability Program2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It is widely assumed within industry that implementation of a Design for Reliability (DfR) Program can reduce warranty costs, increase customer value and reduce Total Cost of Ownership (TCO) when applied within both product development and product improvement projects. DfR is the set of tools and related product development processes for improvement in the reliability of a product, over time through changes in the product design and the manufacturing process. This research activity aimed at demonstrating the customer and business value of implementing a DfR Program at Epiroc Surface Division. This wasinvestigated from the perspective of selected projects and product development activities focused on the Epiroc SmartROC D65 drilling rig, which has actively worked with the reliability tools.The study has concluded that implementing the DfR Program has yielded tangible business value. The enhanced Early-Life Reliability report now allows for better evaluation of business value. This value has primarily been derived from the ability to analyze reductions in warranty costs and improvements in Mean Time Between Events (MTBE), a subset of Mean Time between Failures (MTBF). A method has been developed to determine business value in terms of cost savings. From a customer perspective, when considering the TCO, it could be demonstrated that working actively with the reliability tools during product development positively affects the mechanical availability and productivity of the equipment resulting in TCO improvements. The primary tools employed in the study include the enhanced Early-Life Reliability report, and risk management tools employed during product development for early identification of potential failure modes.The study has concluded that the most significant opportunities for improving the DfR Program is by an increased collection of relevant data from the equipment’s useful life and not limited to the early life during the warranty period. Additionally, recording and reporting actual MTBFdata would be desirable to gain a broader perspective than what MTBE currently provides. Improving the quality and reliability of the input data used in tools like the Early-Life Reliability report would significantly enhance the output of this asset. It has been proven that the data can be utilized effectively. The enhanced version of the tool is not available for widespread use within the organization. However, once released, it could be a great opportunity to improve DfR in conjunction with the developed method for prioritizing efforts and demonstrating customer and business value.

  • 2.
    Aarseth Larsson, Kim
    Örebro University, School of Science and Technology.
    Chemical Characterisation of Nitrocellulose2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nitrocellulose is the main component in many types of ammunition, propellants and explosives. The principles of production for nitrocellulose have not changed much since the 19th century when it started being industrially produced for this purpose. The character of the nitrocellulose has a large effect on the end products abilities. The aim of this study was to develop a method that would be able to characterise and distinguish between nitrocellulose from different manufacturers to be able to relate the character of the nitrocellulose to the properties of ammunition, propellants and explosives. Samples were dissolved in acetone and analysed by GC/MS and data were then analysed by multivariable statistics. FTIR was also used to characterise the nitrocellulose. Results from both methods showed very small differences when chromatograms and spectra were analysed. This study shows that GC/MS and FTIR are not suitable for this type of characterisation. The differences between the data were not sufficient to be able to separate the samples from each other.

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  • 3.
    Aarseth Larsson, Kim
    Örebro University, School of Science and Technology.
    Inhibition of SIRT1 Alters Apoptotic and Sex Related Genes in Zebrafish (Danio rerio)2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide - dependent deacetylase that belongs to the sirtuin protein family. The protein has been linked to both cancer through its effect on p53 and age related illnesses through its effect on peroxisome proliferator-activated receptor gamma (PPAR-γ). Recent data have shown a correlation between SIRT1, male fertility and spermatogenesis. Because the mechanism of sex differentiation in zebrafish is still not wellunderstood the sirt1 gene is an attractive target to study in order to improve our understanding of this topic. Zebrafish of different age were exposed to various concentrations of EX-527 toinhibit the SIRT1 protein. This was followed by qRT-PCR analysis of apoptotic and sex-related genes. Both apoptotic and sex-related gene expression levels were affected by the exposure. There were differences in genes that were affected, both between the concentrations of EX-527, and between the ages of the exposed zebrafish. The male- specific gene sexdetermining region Y box 9A (sox9a) was down-regulated at both studied EX-527 concentrations in both zebrafish larvae and juveniles. The exposure of the EX-527 resulted in no significant difference in sex-ratio. Further studies are required to describe the pathway for SIRT1 gene regulation in zebrafish.

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  • 4.
    Abad, Esteban
    et al.
    CSIC, Institute of Environmental Assessment and Water Research, Laboratory of Dioxins, Barcelona, Spain.
    Abalos, Manuela
    CSIC, Institute of Environmental Assessment and Water Research, Laboratory of Dioxins, Barcelona, Spain.
    Fiedler, Heidelore
    Örebro University, School of Science and Technology.
    Air monitoring with passive samplers for dioxin-like persistent organic pollutants in developing countries (2017-2019)2021In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 287, no Pt 1, article id 131931Article in journal (Refereed)
    Abstract [en]

    As part of the global monitoring plan on persistent organic pollutants (GMP) under the Stockholm Convention passive air samplers equipped with polyurethane foam disks (PUFs) were applied to monitor dioxin-like POPs. For sampling, toluene-pretreated PUFs were exposed for three months during two years. Chemical analysis was performed in one accredited expert laboratory using internationally accepted methods; for comparison, all results were normalized to one PUF and 3 month exposure. Total TEQs, using WHO2005-TEFs, were lowest in the Pacific Islands countries (PAC) and had similar mean values in Africa (16.8 pg TEQ/PUF), Asia (16.9 pg TEQ/PUF), and Latin American and Caribbean countries (GRULAC, 13.3 pg TEQ/PUF). Using median values, Asia (13.4 pg TEQ/PUF) and GRULAC (13.1 pg TEQ/PUF) had higher amounts than Africa (6.1 pg TEQ/PUF) and PAC (2.1 pg TEQ/PUF). The contribution of PCDD/PCDF to the total TEQ was 2-3-times higher than from the dl-PCB. Mono-ortho PCB did not play a role in any of the samples. The previous 40 samples during 2010/2011 and the present 195 samples from 2017/2018 did not show a statistical difference (p value = 0.3), only for GRULAC, a downward trend was identified. It is recommended combining 4 PUFs to ‘annual’ samples.

  • 5.
    Abalos, M.
    et al.
    MTM Research Center, Örebro University, Örebro, Sweden.
    Abad, E.
    Laboratory of Dioxins, Mass Spectrometry Laboratory, Environmental Chemistry Dept., IDÆA-CSIC, Barcelona, Spain.
    van Leeuwen, S. P. J.
    Institute for Environmental Studies (IVM), Vrije University, Amsterdam, Netherlands; RIKILT-Institute of Food Safety, Wageningen, Netherlands.
    Lindström, Gunilla
    Örebro University, School of Science and Technology.
    Fiedler, Heidelore
    UNEP Chemicals, Châtelaine GE, Switzerland.
    de Boer, J.
    Institute for Environmental Studies (IVM), Vrije University, Amsterdam, Netherlands.
    van Bavel, Bert
    Results for PCDD/PCDF and dl-PCBs in the first round of UNEPs biennial global interlaboratory assessment on persistent organic pollutants2013In: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 46, p. 98-109Article in journal (Refereed)
    Abstract [en]

    The first worldwide interlaboratory assesment on persistent organic pollutants (POPs) under the Stockholm Convention was organized in the Asian/Pacific, Latin American and African regions during 2009-11.

    A relatively large number of laboratories reported data for the PCDDs/PCDFs and dioxin-like PCBs, especially in the Asian region. Within the Asian region, several participants used high-resolution GC/high-resolution MS systems optimized for dioxin analysis. The availibility of High-resolution mass spectrometer instrumentation is limited in the Latin America and African regions, although recently several new laboratories for dioxins have started in the Latin American region.

  • 6.
    Abbas, Malak
    et al.
    Örebro University, School of Science and Technology.
    Al-Falahi, Diana
    Örebro University, School of Science and Technology.
    Digitala lärresurser i matematikundervisning2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Society is highly digitalized and digital learning resources have been given a large space at school in almost all grades. The purpose of using digital learning resources is to support students in their learning and development. Digital learning resources have another purpose, which is to facilitate the teacher's work. In this study, a systematic literature study will be done to investigate what previous research that has focused on digital learning resources in mathematics education will be compiled. digital learning resources in mathematics teaching. The purpose of this literature study is to investigate the use of digital learning resources during mathematics teaching and how it can promote student learning. The study will also considerthe use of digital learning resources based on the socio-cultural perspective. The results of the compiled research showed that digital learning resources of various kinds can promote students' learning in different ways. Among other things, it promotes motivation for learning, commitment, problem-solving skills, algebraic thinking, number calculations and pattern recognition. The results also show that a large part of the underlying aspects that can prevent students' learning from being promoted through digital learning resources is the teachers' lack of knowledge regarding the use of the material

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  • 7.
    Abderhim, Walid Tajeddinn
    Örebro University, School of Science and Technology.
    Morphological Analysis of β-catenin and E-cadherin in Colorectal Cancer2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 8.
    Abdirazak Mohamed, Warsame
    et al.
    Örebro University, School of Science and Technology.
    Sultan, Ahmed
    Örebro University, School of Science and Technology.
    Fallstudier i IDA ICE2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Case studies have been performed on a room, of which the U-values, the outer wall orientation and the ventilation system are adjusted, to study how such measures affect the energy usage of said room. The aim is to create a frame of reference that can be used to give quick answers to questions regarding the amount of energy that could be saved by applying the methods discussed in this thesis. During said studies, the U-value of a simulated room’s outer wall has been decreased from 0,15 to 0,11, and the U-value of the windows of the same room has been decreased from 1,2 to 0,9. The room has been moved so that the outer wall would face west, south, east and north respectively. Finally, the simulated room’s energy and heat balance have been simulated in two cases for a person load of 20 persons, of which the first case presents a room with a CAV (Constant Air Volume) ventilation system, and the second case presents a room with a VAV (Varied Air Volume) ventilation system. The following results are obtained from the simulations: Choosing a window with a U-value of 0.9 instead of 1.2 W/m2Kdecreases the room’s energy usage by 15 %. Choosing an outer wall with a U-value of 0.11 instead of 0.15W/m2K decreases the room’s energy usage by 9 %. Choosing a VAV ventilation system instead of a CAV ventilation system decreases the room’s energy usage by up to 16 %. Constructing the outer wall to face south decreases the room’s energy usage by 14-29 %.

  • 9.
    Abdishakour Hussein, Nassim
    et al.
    Örebro University, School of Science and Technology.
    Hassen, Abubaker Jemal
    Örebro University, School of Science and Technology.
    Lagring och transport av anläggningsmassor ur ett livscykelperspektiv2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden's population is constantly increasing, and this means that people are moving more in larger cities, which is straining traffic, among other things. The Swedish Government's vision is that by 2045 the country will achieve net zero greenhouse gas emissions. In view of this, the Swedish Transport Administration has developed climate requirements and guidelines on how to carry out and design the country's infrastructure to reduce greenhouse gas emissions. To achieve the long-term goal, climate neutrality 2045, the Swedish Transport Administration has set milestones. According to Trafikverket (2020) by 2020, 2025 and 2030 climate emissions will subsequently be reduced by 15%, 30% and 50%. The purpose of the report was to investigate how bulk materials can be stored to reduce the climate impact by using a life cycle analysis so that Veidekke Sverige AB and Implenia Sverige AB, which have been commissioned to build Förbifart Stockholm (Trafikplats Hjulsta Södra), will reach future climate requirements. The report is limited to the investigation of how much CO2 eq can be saved by storing/reusing bulk materials instead of transporting them away, to be used in the project's Climate Calculation. To carry out this study, it was important to identify the fuels used in the transport of bulk materials, the weight of bulk materials and how far the bulk materials were transported. In addition, the difference was mapped from an environmental perspective if the bulk materials were stored compared to if they are transported away. The results showed that from a climate perspective it pays to handle bulk materials by storing and that the trucks use HVO as fuel. Trucks powered by HVO emit 4.045 tons of CO2 eq. When transporting bulk materials to facilities, these trucks emit approximately 78.204 tons of CO2 eq. This shows that a climate saving of about 74 tons of CO2 eq is made when storing bulk materials, which is 18 times less than if the bulk materials are transported away. In addition, the study highlights that if the transport distance had been reduced by 25%, emissions would be reduced by 19.5 tons of CO2 eq. The conclusion of this study is that storage of bulk materials and HVO as a fuel is most beneficial from an environmental perspective when handling bulk masses because climate-impacting emissions are reduced by 610% compared to diesel. However,

  • 10.
    Abdolahpur Monikh, Fazel
    et al.
    Institute of Environmental Sciences (CML), Leiden University, Leiden, Netherlands; Department of Environmental & Biological Sciences, University of Eastern Finland, Joensuu, Finland.
    Chupani, Latifeh
    Örebro University, School of Science and Technology. University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Vodňany, Czech Republic.
    Vijver, Martina G.
    Institute of Environmental Sciences (CML), Leiden University, Leiden, Netherlands.
    Peijnenburg, Willie J. G. M.
    Institute of Environmental Sciences (CML), Leiden University, Leiden, Netherlands; National Institute of Public Health and the Environment (RIVM), Center for Safety of Substances and Products, Bilthoven, Netherlands.
    Parental and trophic transfer of nanoscale plastic debris in an assembled aquatic food chain as a function of particle size2021In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 269, article id 116066Article in journal (Refereed)
    Abstract [en]

    The existing limitations in analytical techniques for characterization and quantification of nanoscale plastic debris (NPD) in organisms hinder understanding of the parental and trophic transfer of NPD in organisms. Herein, we used iron oxide-doped polystyrene (PS) NPD (Fe-PS-NPD) of 270 nm and Europium (Eu)-doped PS-NPD (Eu-PS-NPD) of 640 nm to circumvent these limitations and to evaluate the influence of particle size on the trophic transfer of NPD along an algae-daphnids food chain and on the reproduction of daphnids fed with NPD-exposed algae. We used Fe and Eu as proxies for the Fe-PS-NPD and Eu-Ps-NPD, respectively. The algae cells (Pseudokirchinella subcapitata) were exposed to 4.8 × 1010 particles/L of Fe-PS-NPD or Eu-PS-NPD for 72 h. A high percentage (>60%) of the NPD was associated with algal cells. Only a small fraction (<11%) of the NPD, however, was transferred to daphnids fed for 21 days on the NPD-exposed algae. The uptake and trophic transfer of the 270 nm Fe-PS-NPD were higher than those for the 640 nm Eu-PS-NPD, indicating that smaller NPD are more likely to transfer along food chains. After exposure to Fe-PS-NPD, the time to first brood was prolonged and the number of neonates per adult significantly decreased compared to the control without any exposure and compared to daphnids exposed to the Eu-Ps-NPD. The offspring of daphnids exposed to Eu-PS-NPD through algae, showed a traceable concentration of Eu, suggesting that NPD are transferred from parents to offspring. We conclude that NPD can be transferred in food chains and caused reproductive toxicity as a function of NPD size. Studies with prolonged exposure and weathered NPD are endeavored to increase environmental realism of the impacts determined.

  • 11.
    Abdul Khaliq, Ali
    et al.
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Point-to-point safe navigation of a mobile robot using stigmergy and RFID technology2016In: 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Institute of Electrical and Electronics Engineers (IEEE), 2016, p. 1497-1504, article id 7759243Conference paper (Refereed)
    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.

  • 12.
    Abdulkareem, Ahmed
    et al.
    Örebro University, School of Science and Technology.
    Al-Radi, Omar
    Örebro University, School of Science and Technology.
    Evaluating the measured grip stiffness of different carton board material properties and geometries2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This candidate thesis reports the findings of a study on an objective method for measuring grip stiffness in carton board packages with different geometries and material properties. Syntouch Biotac and a tensile tester were used as an objective method for measuring grip stiffness. In this project tests were carried out on packages with three different grammages and two different geometries. For each grammage and geometry, ten packages were tested.

    The study identifies that the applied method for the measurement of grip stiffness works to measure the change in grip stiffness regardless of where a load was applied on a package. Furthermore, the method demonstrates reasonable results. Finally, the study concluded that the objective testing method could distinguish between different material properties and geometries of the cartons being measured.

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    Evaluating the measured grip stiffness of different carton board material properties and geometries
  • 13.
    Abdullaev, F. Kh.
    et al.
    Physical-Technical Institute, Uzbek Academy of Sciences, Tashkent, Uzbekistan; Theoretical Physics Department, National University of Uzbekistan, Tashkent, Uzbekistan.
    Yuldashev, J. S.
    Physical-Technical Institute, Uzbek Academy of Sciences, Tashkent, Uzbekistan; Theoretical Physics Department, National University of Uzbekistan, Tashkent, Uzbekistan.
    Ögren, Magnus
    Örebro University, School of Science and Technology. Hellenic Mediterranean University, Heraklion, Greece.
    Management of solitons in medium with competing cubic and quadratic nonlinearities2023In: Optik (Stuttgart), ISSN 0030-4026, E-ISSN 1618-1336, Vol. 274, article id 170545Article in journal (Refereed)
    Abstract [en]

    Management of solitons in media with competing quadratic and cubic nonlinearities is investigated. Two schemes, using rapid modulations of a mismatch parameter, and of the Kerr nonlinearity parameter are studied. For both cases, the averaged in time wave equations are derived. In the case of mismatch management, the region of the parameters where stabilization is possible is found. In the case of Kerr nonlinearity management, it is shown that the effective chi(2) nonlinearity depends on the intensity imbalance between fundamental (FH) and second (SH) harmonics. Predictions obtained from the averaged equations are confirmed by numerical simulations of the full PDE’s.

  • 14.
    Abdullaev, F. Kh.
    et al.
    Physical-Technical Institute, Uzbek Academy of Sciences, Tashkent, Uzbekistan; Theoretical Physics Department, National University of Uzbekistan, Tashkent, Uzbekistan.
    Yuldashev, J. S.
    Physical-Technical Institute, Uzbek Academy of Sciences, Tashkent, Uzbekistan; Theoretical Physics Department, National University of Uzbekistan, Tashkent, Uzbekistan.
    Ögren, Magnus
    Örebro University, School of Science and Technology. HMU Research Center, Institute of Emerging Technologies, Heraklion, Greece.
    Nonlinearity managed vector solitons2023In: Physics Letters A, ISSN 0375-9601, E-ISSN 1873-2429, Vol. 491, article id 129206Article in journal (Refereed)
    Abstract [en]

    The evolution of vector solitons under nonlinearity management is studied. The averaged over strong and rapid modulations in time of the inter-species interactions vector Gross-Pitaevskii equation (GPE) is derived. The averaging gives the appearance of the effective nonlinear quantum pressure depending on the population of the other component. Using this system of equations, the existence and stability of the vector solitons under the action of the strong nonlinearity management (NM) is investigated. Using a variational approach the parameters of NM vector solitons are found. The numerical simulations of the full time-dependent coupled GPE confirms the theoretical predictions. 

  • 15.
    Abdullaev, F Kh
    et al.
    Physical-Technical Institute, Uzbekistan Academy of Sciences, Tashkent, Uzbekistan.
    Ögren, M
    Örebro University, School of Science and Technology.
    Yuldashev, J
    Physical-Technical Institute, Uzbekistan Academy of Sciences, Tashkent, Uzbekistan.
    Matter waves in atomic-molecular BEC with Feshbach resonance management2021In: OSA Nonlinear Optics 2021 / [ed] R. Boyd; C. Conti; D. Christodoulides; P. Rakich, Optical Society of America, 2021, article id NTh3A.17Conference paper (Refereed)
    Abstract [en]

    Dynamics of matter waves in the atomic to molecular condensate transition with a time modulated atomic scattering length is investigated. The conditions for dynamical suppression of association of atoms into the molecular field are obtained.

  • 16.
    Abdullaev, Fatkhulla
    et al.
    Physical-Technical Institute, Uzbek Academy of Sciences, Tashkent, Uzbekistan; CNH, Universidade Federal do ABC, Santo André, Brazil.
    Ögren, Magnus
    Örebro University, School of Science and Technology. Nano Science Center, Department of Chemistry, University of Copenhagen, København, Denmark.
    Sørensen, Mads-Peter
    Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark.
    Collective dynamics of Fermi-Bose mixtures with an oscillating scattering length2019In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 99, no 3, article id 033614Article in journal (Refereed)
    Abstract [en]

    Collective oscillations of superfluid mixtures of ultra cold fermionic and bosonic atoms are investigated while varying the fermion-boson scattering length. We study the dynamics with respect to excited center of mass modes and breathing modes in the mixture. Parametric resonances are also analyzed when the scattering length varies periodically in time, by comparing partial differential equation (PDE) models and ordinary differential equation (ODE) models for the dynamics. An application to the recent experiment with fermionic Li-6 and bosonic Li-7 atoms, which approximately have the same masses, is discussed.

  • 17.
    Abdullaev, Fatkhulla
    et al.
    Physical-Technical Institute, Uzbek Academy of Sciences, Tashkent, Uzbekistan; Theoretical Physics Department, National University of Uzbekistan, Tashkent, Uzbekistan.
    Ögren, Magnus
    Örebro University, School of Science and Technology. Hellenic Mediterranean University, Heraklion, Greece.
    Yuldashev, Jasur
    Physical-Technical Institute, Uzbek Academy of Sciences, Tashkent, Uzbekistan; Theoretical Physics Department, National University of Uzbekistan, Tashkent, Uzbekistan.
    Matter waves in atomic-molecular condensates with Feshbach resonance management2021In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 104, no 2, article id 024222Article in journal (Refereed)
    Abstract [en]

    The dynamics of matter waves in the atomic to molecular condensate transition with a time-modulated atomic scattering length is investigated. Both the cases of rapid and slow modulations are studied. In the case of rapid modulations, the average over oscillations for the system is derived. The corresponding conditions for dynamical suppression of the association of atoms into the molecular field, or of second-harmonic generation in nonlinear optical systems, are obtained. For the case of slow modulations, we find resonant enhancement in the molecular field. We then illustrate chaos in the atomic-molecular BEC system. We suggest a sequential application of the two types of modulations, slow and rapid, when producing molecules.

  • 18.
    Abdullah, Aram
    et al.
    Örebro University, School of Science and Technology.
    Oktay, Samuel
    Örebro University, School of Science and Technology.
    Översyn av arbetstidsförläggning2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to keep up with the construction industry development it is important to be competitive. Many building contractors strive short construction times, which some- times can be difficult to achieve. In order to achieve short construction times you have to find clever solutions and a good production technic that ultimately gives a good re- sult. Shorter construction time contributes to lower costs for contractors.

    Something that is rare in today's construction industry is an extended working time this is something untried in Örebro. In the current situation a construction site opens about 07.00 and closes again for the day at 16.00, Monday to Friday. After 16.00 the construc- tion is stopped. This contributes to an inefficient use of the expenses found at a con- struction site. By extending the current working time with a few hours per day, it will hopefully contribute to a more efficiency use of the costs found at a construction site and also that the number of construction days decreases.

    In the current situation construction workers in PEAB se an extended working time negatively. According to PEAB this is because they do not understand their position in a business way within the company. PEAB argue that construction workers "permanent employment" is not a particularly secure employment. They argue that the only way to get a secure job is to PEAB in partnership with their employees can go get new jobs and deliver results together with their workers. The question then is how PEAB will be able to distinguish themselves from all other construction companies and gain a competitive advantage. According to Fredrik Ahl, Project Manager at PEAB, the solution is an ex- tended working time.

    This report aims to examine how a change in the current working time will affect the cost of a construction site. We also examined the reactions that occur among workers and officials when working hours are changing. 

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  • 19.
    Abdullah, Muhammad
    Örebro University, School of Science and Technology.
    Mobile Robot Navigation using potential fields andmarket based optimization2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A team of mobile robots moving in a shared area raises the problem of safe and autonomous navigation. While avoiding static and dynamic obstacles, mobile robots in a team can lead to complicated and irregular movements. Local reactive approaches are used to deal with situations where robots are moving in dynamic environment; these approaches help in safe navigation of robots but do not give optimal solution. In this work a 2-D navigation strategy is implemented, where a potential field method is used for obstacle avoidance. This potential field method is improved using fuzzy rules, traffic rules and market based optimization (MBO). Fuzzy rules are used to deform repulsive potential fields in the vicinity of obstacles. Traffic rules are used to deal situations where two robots are crossing each other. Market based optimization (MBO) is used to strengthen or weaken repulsive potential fields generated by other robots based on their importance. For the verification of this strategy on more realistic vehicles this navigation strategy is implemented and tested in simulation. Issues while implementing this method and limitations of this navigation strategy are also discussed. Extensive experiments are performed to examine the validity of MBO navigation strategy over traditional potential field (PF) method.

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  • 20.
    AbdulWahab, Atqah
    et al.
    Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar; Weill Cornell Medicine‑Qatar, Doha, Qatar.
    Zahraldin, Khalid
    Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar.
    Sid Ahmed, Mazen
    Örebro University, School of Science and Technology. Department of Laboratory Medicine and Pathology, Microbiology Division, Hamad Medical Corporation, Doha, Qatar.
    Abu Jarir, Sulieman
    Departments of Internal Medicine, Hamad Medical Corporation, Doha, Qatar.
    Muneer, Mohammed
    Plastic Surgery, Hamad Medical Corporation, Doha, Qatar.
    Mohamed, Shehab F.
    Departments of Internal Medicine, Hamad Medical Corporation, Doha, Qatar.
    Hamid, Jemal M.
    Department of Laboratory Medicine and Pathology, Microbiology Division, Hamad Medical Corporation, Doha, Qatar.
    Hassan, Abubaker A. I.
    Departments of Internal Medicine, Hamad Medical Corporation, Doha, Qatar.
    Ibrahim, Emad Bashir
    Weill Cornell Medicine‑Qatar, Doha, Qatar; Department of Laboratory Medicine and Pathology, Microbiology Division, Hamad Medical Corporation, Doha, Qatar.
    The emergence of multidrug-resistant Pseudomonas aeruginosa in cystic fibrosis patients on inhaled antibiotics2017In: Lung India, ISSN 0970-2113, E-ISSN 0974-598X, Vol. 34, no 6, p. 527-531Article in journal (Refereed)
    Abstract [en]

    Introduction: Multidrug-resistant Pseudomonas aeruginosa (MDR-PA) is an important and growing issue in the care of patients with cystic fibrosis (CF), and a major cause of morbidity and mortality.

    Objective: The objective of the study was to describe the frequency of MDR-PA recovered from the lower respiratory samples of pediatric and adult CF patients, and its antibiotic resistance pattern to commonly used antimicrobial agents including beta-lactams, aminoglycosides, and fluoroquinolones.

    Materials and Methods: The lower respiratory isolates of P. aeruginosa were obtained from inpatients and outpatients CF clinics from a tertiary care teaching hospital for the period from October 2014 to September 2015. The identification and antimicrobial susceptibility for all the isolates were performed by using the BD Phoenix (TM) and E-test in compliance with Clinical and Laboratory Standards Institute (CLSI) guidelines.

    Results: A total of 61 P. aeruginosa samples were isolated from thirty CF patients from twenty families. Twelve sputum samples were positive for MDR-PA (seven nonmucoid and five mucoid isolates) from five CF patients (five families) with moderate-to-very severe lung disease given MDR-PA frequency of 19.7%. The median age of the study group was 20 (range 10-30) years. Three CF patients were on chronic inhaled tobramycin and two on nebulized colistin. The antimicrobial patterns of isolates MDR-PA showed the highest rate of resistance toward each gentamycin, amikacin, and cefepime (100%), followed by 91.7% to ciprofloxacin, 75% to tobramycin, 58.3% to meropenem, and 50% to piperacillin-tazobactam. None of the isolates were resistant to colistin during the study period.

    Conclusion: The study results emphasize that the emergence of a significant problem in the clinical isolates of P. aeruginosa in CF patients that dictate appropriate attention to the antibiotic management after proper surveillance.

  • 21.
    Abraham, Kaleb
    et al.
    Örebro University, School of Science and Technology.
    Lust, Andreas
    Örebro University, School of Science and Technology.
    JÄMFÖRELSE AV KLIMATPÅVERKANFÖR GLASULL OCH POLYURETAN: MPARISON OF CLIMATE IMPACT FOR GLASS WOOL AND POYURETHANE2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study examines the climate impact of the thermal insulation materials, glass wool and polyurethane. Two wall constructions with a size of one square meter are used in the study to compare their carbon footprints and determine which material has the lowest environmental impact. For the walls to be comparable, they need to have the same U-value. The study will be limited to only examining the materials from a cradle-to-gate perspective. Literature searches will be conducted for data collection. For the calculation of environmental impact, the study will examine Life Cycle Assessment (LCA), Environmental Product Declarations (EPDs), and the Boverket’s Climate Declaration.Environmental data for building materials is calculated using LCA, and from this, EPDs can be generated, which contain summarized environmental data. This study collects environmental data from EPDs Boverket’s Climate Database. U-values are calculated using the U- and λ-value method, and then the mean value is derived. Subsequently, the quantities of the materials are determined, and the walls' total Global Warming Potential (GWP) is calculated.According to the results of the study, walls with polyurethane and glass wool insulation show a significant difference in their carbon footprints. GWP calculations show that the wall with polyurethane insulation emits approximately 33 kg CO2e (carbon dioxide equivalents), while the wall with glass wool insulation emits around 17 kg CO2e. The results also indicate that the insulation layers alone exhibit a significant difference in carbon footprint, approximately 20 kg CO2e for polyurethane and 4.0 kg CO2e for glass wool. The significant difference may be attributed to the oil-based production of polyurethane. The study also found that the manufacturing stage contributes the most to the climate impact for both insulation materials.When selecting insulation materials, other material properties also need to be investigated, such as fire resistance, acoustic performance, and more. The economic aspect also plays a significant role in the selection process.From an environmental perspective, the conclusion indicates that glass wool insulation is the better choice.

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  • 22.
    Abrahamsson, Linda
    et al.
    Örebro University, School of Science and Technology.
    Anwar, Hama
    Örebro University, School of Science and Technology.
    Kvinnor i byggproduktion2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A lack of work environment and development opportunities for women in the construction production sector might lead to loss of valuable skills. It has been noted that the construction production is imprinted by an older maleculture. The construction industry is generally a male dominated industry and the gender distribution is most uneven within the construction production where there is a shortage of women.Women who work in construction production often choose to leave their role for another within the industry after a couple of years. The ambition with this study is through surveys map how women experience and have experienced their work in construction production. The goal is to find factors and patterns that later on can be used by the construction industry in effort on the matter of attracting and retaining more women in construction production. This essay has partially been written with the construction company NCC Building Örebro/Värmland. Through the results of this essay, NCC wants to be able to compare and weigh up how far they as a company have come in the gender equality issues compared to the rest of the construction production sector. In order to find answers to the essays questions a literature study and data collection was done. Multiple surveys were sent out to both women and men with different roles in the construction production. The respondents had the opportunity to answer with different alternatives and in some of the questions write comments. The surveys were sent out to women employed at NCC Örebro/värmland and to women in the industry at different workplaces and locations around Sweden. A survey was also sent out to a group of men at NCC Örebro/Värmland in order to make a comparison on equivalent questions that were asked both to women and men. The results indicate that women in the construction production do not always have the same possibilities as men. When a comparison was carried out between women at NCC Örebro/Värmland and other women with experience in the construction industry it shows a small percentage difference in certain matters that NCC has a more prosperous workplace for women.Keywords:

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  • 23.
    Abu Baker Karim, Aria
    et al.
    Örebro University, School of Science and Technology.
    Schnelzer, Anna
    Örebro University, School of Science and Technology.
    Optimering av glidlager och utveckling av dess konstruktion2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We have in this project become engrossed in a plain bearing design that is located in a screw press. The screw press compact an unknown mass that is confidential. Robustus have a suggestion to over dimensioning the present plain bearing. The aim of this project was to analyze and to do an optimization on some plain bearings and compare them to the present bearing and to take the choice of material and the environment where the bearing is located into account. The analysis and the optimizations showed that the current plain bearing had the best geometry but not the optimal material selection. The project is in an early state and it needs some geometrical changes. The most important of everything is that the problem has been identified with the help of the wrecked plain bearing and with an excel model.

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  • 24.
    Abuabaid, Hanan
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Mattias
    Örebro University, School of Science and Technology.
    Scherbak, Nikolai
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    Jass, Jana
    Örebro University, School of Science and Technology.
    Probiotic Lactobacillus rhamnosus alters inflammatory responses of bladder epithelial and macrophage-like cells in co-cultureManuscript (preprint) (Other academic)
  • 25. Ackum, Susanne
    et al.
    Borg, Tor
    Braunerhjelm, Pontus
    Calmfors, Lars
    Institutet för näringslivsforskning, Stockholm, Sweden.
    Eklund, Klas
    Hansson, Åsa
    Lunds Universitet, Institutet för näringslivsforskning, Lund, Sweden.
    Hultkrantz, Lars
    Örebro University, Örebro University School of Business.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Nordström Skans, Oskar
    Wetterstrand, Maria
    Vi tar fram en handfast plan för en omstart av Sverige2020In: Dagens Nyheter, ISSN 1101-2447, no 27 aprilArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Det är /.../ fullt möjligt att tänka strategiskt och systematiskt även i brinnande kris. Omstartskommissionen hoppas kunna bidra till fokus, analys och konkreta policyförslag för att stödja Sveriges långsiktiga inriktning. Vi kommer att under våren och sommaren anordna seminarier och hearings om vårt arbete, delrapporter ska läggas fram – och när budgetarbetet börjar och Riksdagen öppnar, vill vi kunna bidra med en rejäl och handfast plan för hur vi omstartar Sverige.

  • 26.
    Adayson, Christian
    et al.
    Örebro University, School of Science and Technology.
    Ashor, Denkha
    Örebro University, School of Science and Technology.
    Analysering av förbättringsförslag till byggproduktion - En studie baserad på Lean2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In recent years, production in the construction industry has evolved into a costlier construction. It has become poorer productivity and increased construction defect attributed to scientific development. They can include notes that 40% of employees time at work goes to value-added work. Construction industry is inefficient in comparison to other manufacturing industries which has 65-75% in value-added work. It is also clear that the costs in the construction sector can be reduced by 30-35%. The authorities in the various reports conveyed its current troubles and that the renovation industry needs.

    The study was done with the help of interviews and a questionnaire analysis on several construction sites to investigate if the problem persists. We chose to focus on four different construction companies working on similar sized projects. By this is obtained a greater overview of the practical work steps.

    The aim is to offer suggestions for improvement using Lean to building production.

    The work delineated on studying waste, orderliness, and continuous improvement.

    The work began with a thorough literature search and through scientific articles. This was done in order to get an overall picture of Lean and also to analyze the problem in the construction industry.

    Lean is about making work more efficiently by managing resources properly. It aims to eliminate unnecessary waste and making continuous improvements. It is an approach that has been used in manufacturing and have been designed by Toyota Automotive Group. Given its present situation in the construction industry want to study, explore opportunities Lean can bring in terms of efficiency and reduction of costs of production.

    It can be ascertained is that workplaces are still gaps in the understanding of what waste is. They are not sufficiently informed and prioritize sometimes the wrong kind of waste. During the interviews it became apparent major gaps in knowledge on the issue. Wrong priorities result that it becomes a messy workplace, which in turn makes it less environmentally friendly and can thus cause injuries.

    Through that process and maintain order in the workplace, it provides the opportunity for a larger workspace that is more flexible, higher quality of performance, employee ergonomics are better and there is less risk of injury.

  • 27.
    Adediran, Gbotemi A.
    et al.
    Department of Chemistry, Umeå University, Umeå, Sweden.
    Liem-Nguyen, Van
    Örebro University, School of Science and Technology. Department of Chemistry, Umeå University, Umeå, Sweden.
    Song, Yu
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Schaefer, Jeffra K.
    Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey, United States.
    Skyllberg, Ulf
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Björn, Erik
    Department of Chemistry, Umeå University, Umeå, Sweden.
    Microbial Biosynthesis of Thiol Compounds: Implications for Speciation, Cellular Uptake, and Methylation of Hg(II)2019In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, no 14, p. 8187-8196Article in journal (Refereed)
    Abstract [en]

    Cellular uptake of inorganic divalent mercury (Hg(II)) is a key step in microbial formation of neurotoxic methylmercury (MeHg), but the mechanisms remain largely unidentified. We show that the iron reducing bacterium Geobacter sulfurreducens produces and exports appreciable amounts of low molecular mass thiol (LMM-RSH) compounds reaching concentrations of about 100 nM in the assay medium. These compounds largely control the chemical speciation and bioavailability of Hg(II) by the formation of Hg(LMM-RS)<INF><INF><INF>2</INF></INF> </INF>complexes (primarily with cysteine) in assays without added thiols. By characterizing these effects, we show that the thermodynamic stability of Hg(II)-complexes is a principal controlling factor for Hg(II) methylation by this bacterium such that less stable complexes with mixed ligation involving LMM-RSH, OH<SUP>-</SUP>, and Cl<SUP>-</SUP> are methylated at higher rates than the more stable Hg(LMM-RS)<INF>2</INF> complexes. The Hg(II) methylation rate across different Hg(LMM-RS)<INF>2</INF> compounds is also influenced by the chemical structure of the complexes. In contrast to the current perception of microbial uptake of Hg, our results adhere to generalized theories for metal biouptake based on metal complexation with cell surface ligands and refine the mechanistic understanding of Hg(II) availability for microbial methylation.

  • 28.
    Adolfsson, Daniel
    Örebro University, School of Science and Technology.
    Robust large-scale mapping and localization: Combining robust sensing and introspection2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The presence of autonomous systems is rapidly increasing in society and industry. To achieve successful, efficient, and safe deployment of autonomous systems, they must be navigated by means of highly robust localization systems. Additionally, these systems need to localize accurately and efficiently in realtime under adverse environmental conditions, and within considerably diverse and new previously unseen environments.

    This thesis focuses on investigating methods to achieve robust large-scale localization and mapping, incorporating robustness at multiple stages. Specifically, the research explores methods with sensory robustness, utilizing radar, which exhibits tolerance to harsh weather, dust, and variations in lighting conditions. Furthermore, the thesis presents methods with algorithmic robustness, which prevent failures by incorporating introspective awareness of localization quality. This thesis aims to answer the following research questions:

    How can radar data be efficiently filtered and represented for robust radar odometry? How can accurate and robust odometry be achieved with radar? How can localization quality be assessed and leveraged for robust detection of localization failures? How can self-awareness of localization quality be utilized to enhance the robustness of a localization system?

    While addressing these research questions, this thesis makes the following contributions to large-scale localization and mapping: A method for robust and efficient radar processing and state-of-the-art odometry estimation, and a method for self-assessment of localization quality and failure detection in lidar and radar localization. Self-assessment of localization quality is integrated into robust systems for large-scale Simultaneous Localization And Mapping, and rapid global localization in prior maps. These systems leverage self-assessment of localization quality to improve performance and prevent failures in loop closure and global localization, and consequently achieve safe robot localization.

    The methods presented in this thesis were evaluated through comparative assessments of public benchmarks and real-world data collected from various industrial scenarios. These evaluations serve to validate the effectiveness and reliability of the proposed approaches. As a result, this research represents a significant advancement toward achieving highly robust localization capabilities with broad applicability.

    List of papers
    1. Oriented surface points for efficient and accurate radar odometry
    Open this publication in new window or tab >>Oriented surface points for efficient and accurate radar odometry
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    2021 (English)Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents an efficient and accurate radar odometry pipeline for large-scale localization. We propose a radar filter that keeps only the strongest reflections per-azimuth that exceeds the expected noise level. The filtered radar data is used to incrementally estimate odometry by registering the current scan with a nearby keyframe. By modeling local surfaces, we were able to register scans by minimizing a point-to-line metric and accurately estimate odometry from sparse point sets, hence improving efficiency. Specifically, we found that a point-to-line metric yields significant improvements compared to a point-to-point metric when matching sparse sets of surface points. Preliminary results from an urban odometry benchmark show that our odometry pipeline is accurate and efficient compared to existing methods with an overall translation error of 2.05%, down from 2.78% from the previously best published method, running at 12.5ms per frame without need of environmental specific training. 

    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:oru:diva-108799 (URN)
    Conference
    Radar Perception for All-Weather Autonomy - Half-Day Workshop at 2021 IEEE International Conference on Robotics and Automation (ICRA 2021), Xi'an, China, May 30 - June 5, 2021
    Funder
    Knowledge FoundationEU, Horizon 2020, 732737
    Available from: 2023-10-09 Created: 2023-10-09 Last updated: 2024-01-02Bibliographically approved
    2. CFEAR Radarodometry - Conservative Filtering for Efficient and Accurate Radar Odometry
    Open this publication in new window or tab >>CFEAR Radarodometry - Conservative Filtering for Efficient and Accurate Radar Odometry
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    2021 (English)In: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2021), IEEE, 2021, p. 5462-5469Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents the accurate, highly efficient, and learning-free method CFEAR Radarodometry for large-scale radar odometry estimation. By using a filtering technique that keeps the k strongest returns per azimuth and by additionally filtering the radar data in Cartesian space, we are able to compute a sparse set of oriented surface points for efficient and accurate scan matching. Registration is carried out by minimizing a point-to-line metric and robustness to outliers is achieved using a Huber loss. We were able to additionally reduce drift by jointly registering the latest scan to a history of keyframes and found that our odometry method generalizes to different sensor models and datasets without changing a single parameter. We evaluate our method in three widely different environments and demonstrate an improvement over spatially cross-validated state-of-the-art with an overall translation error of 1.76% in a public urban radar odometry benchmark, running at 55Hz merely on a single laptop CPU thread.

    Place, publisher, year, edition, pages
    IEEE, 2021
    Series
    IEEE International Conference on Intelligent Robots and Systems. Proceedings, ISSN 2153-0858, E-ISSN 2153-0866
    Keywords
    Localization SLAM Mapping Radar
    National Category
    Computer Vision and Robotics (Autonomous Systems)
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:oru:diva-94463 (URN)10.1109/IROS51168.2021.9636253 (DOI)000755125504051 ()9781665417143 (ISBN)9781665417150 (ISBN)
    Conference
    IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2021), Prague, Czech Republic, (Online Conference), September 27 - October 1, 2021
    Funder
    Knowledge FoundationEU, Horizon 2020, 732737
    Available from: 2021-09-20 Created: 2021-09-20 Last updated: 2024-01-02Bibliographically approved
    3. Lidar-Level Localization With Radar? The CFEAR Approach to Accurate, Fast, and Robust Large-Scale Radar Odometry in Diverse Environments
    Open this publication in new window or tab >>Lidar-Level Localization With Radar? The CFEAR Approach to Accurate, Fast, and Robust Large-Scale Radar Odometry in Diverse Environments
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    2023 (English)In: IEEE Transactions on robotics, ISSN 1552-3098, E-ISSN 1941-0468, Vol. 39, no 2, p. 1476-1495Article in journal (Refereed) Published
    Abstract [en]

    This article presents an accurate, highly efficient, and learning-free method for large-scale odometry estimation using spinning radar, empirically found to generalize well across very diverse environments—outdoors, from urban to woodland, and indoors in warehouses and mines—without changing parameters. Our method integrates motion compensation within a sweep with one-to-many scan registration that minimizes distances between nearby oriented surface points and mitigates outliers with a robust loss function. Extending our previous approach conservative filtering for efficient and accurate radar odometry (CFEAR), we present an in-depth investigation on a wider range of datasets, quantifying the importance of filtering, resolution, registration cost and loss functions, keyframe history, and motion compensation. We present a new solving strategy and configuration that overcomes previous issues with sparsity and bias, and improves our state-of-the-art by 38%, thus, surprisingly, outperforming radar simultaneous localization and mapping (SLAM) and approaching lidar SLAM. The most accurate configuration achieves 1.09% error at 5 Hz on the Oxford benchmark, and the fastest achieves 1.79% error at 160 Hz.

    Place, publisher, year, edition, pages
    IEEE, 2023
    Keywords
    Radar, Sensors, Spinning, Azimuth, Simultaneous localization and mapping, Estimation, Location awareness, Localization, radar odometry, range sensing, SLAM
    National Category
    Computer Sciences Computer Vision and Robotics (Autonomous Systems) Robotics
    Research subject
    Computer and Systems Science; Computer Science
    Identifiers
    urn:nbn:se:oru:diva-103116 (URN)10.1109/tro.2022.3221302 (DOI)000912778500001 ()2-s2.0-85144032264 (Scopus ID)
    Available from: 2023-01-16 Created: 2023-01-16 Last updated: 2023-10-18
    4. BFAR – Bounded False Alarm Rate detector for improved radar odometry estimation
    Open this publication in new window or tab >>BFAR – Bounded False Alarm Rate detector for improved radar odometry estimation
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    2021 (English)Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper presents a new detector for filtering noise from true detections in radar data, which improves the state of the art in radar odometry. Scanning Frequency-Modulated Continuous Wave (FMCW) radars can be useful for localisation and mapping in low visibility, but return a lot of noise compared to (more commonly used) lidar, which makes the detection task more challenging. Our Bounded False-Alarm Rate (BFAR) detector is different from the classical Constant False-Alarm Rate (CFAR) detector in that it applies an affine transformation on the estimated noise level after which the parameters that minimize the estimation error can be learned. BFAR is an optimized combination between CFAR and fixed-level thresholding. Only a single parameter needs to be learned from a training dataset. We apply BFAR tothe use case of radar odometry, and adapt a state-of-the-art odometry pipeline (CFEAR), replacing its original conservative filtering with BFAR. In this way we reduce the state-of-the-art translation/rotation odometry errors from 1.76%/0.5◦/100 m to 1.55%/0.46◦/100 m; an improvement of 12.5%.

    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:oru:diva-108800 (URN)
    Conference
    ICRA
    Funder
    Knowledge Foundation
    Available from: 2023-10-09 Created: 2023-10-09 Last updated: 2024-01-02Bibliographically approved
    5. CorAl – Are the point clouds Correctly Aligned?
    Open this publication in new window or tab >>CorAl – Are the point clouds Correctly Aligned?
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    2021 (English)In: 10th European Conference on Mobile Robots (ECMR 2021), IEEE, 2021, Vol. 10Conference paper, Published paper (Refereed)
    Abstract [en]

    In robotics perception, numerous tasks rely on point cloud registration. However, currently there is no method that can automatically detect misaligned point clouds reliably and without environment-specific parameters. We propose "CorAl", an alignment quality measure and alignment classifier for point cloud pairs, which facilitates the ability to introspectively assess the performance of registration. CorAl compares the joint and the separate entropy of the two point clouds. The separate entropy provides a measure of the entropy that can be expected to be inherent to the environment. The joint entropy should therefore not be substantially higher if the point clouds are properly aligned. Computing the expected entropy makes the method sensitive also to small alignment errors, which are particularly hard to detect, and applicable in a range of different environments. We found that CorAl is able to detect small alignment errors in previously unseen environments with an accuracy of 95% and achieve a substantial improvement to previous methods.

    Place, publisher, year, edition, pages
    IEEE, 2021
    National Category
    Computer Vision and Robotics (Autonomous Systems)
    Identifiers
    urn:nbn:se:oru:diva-94464 (URN)10.1109/ECMR50962.2021.9568846 (DOI)000810510000059 ()
    Conference
    10th European Conference on Mobile Robots (ECMR 2021), Bonn, Germany, (Online Conference), August 31 - September 3, 2021
    Funder
    Knowledge FoundationEU, Horizon 2020, 732737 101017274
    Available from: 2021-09-22 Created: 2021-09-22 Last updated: 2024-01-02Bibliographically approved
    6. CorAl: Introspection for robust radar and lidar perception in diverse environments using differential entropy
    Open this publication in new window or tab >>CorAl: Introspection for robust radar and lidar perception in diverse environments using differential entropy
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    2022 (English)In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 155, article id 104136Article in journal (Refereed) Published
    Abstract [en]

    Robust perception is an essential component to enable long-term operation of mobile robots. It depends on failure resilience through reliable sensor data and pre-processing, as well as failure awareness through introspection, for example the ability to self-assess localization performance. This paper presents CorAl: a principled, intuitive, and generalizable method to measure the quality of alignment between pairs of point clouds, which learns to detect alignment errors in a self-supervised manner. CorAl compares the differential entropy in the point clouds separately with the entropy in their union to account for entropy inherent to the scene. By making use of dual entropy measurements, we obtain a quality metric that is highly sensitive to small alignment errors and still generalizes well to unseen environments. In this work, we extend our previous work on lidar-only CorAl to radar data by proposing a two-step filtering technique that produces high-quality point clouds from noisy radar scans. Thus, we target robust perception in two ways: by introducing a method that introspectively assesses alignment quality, and by applying it to an inherently robust sensor modality. We show that our filtering technique combined with CorAl can be applied to the problem of alignment classification, and that it detects small alignment errors in urban settings with up to 98% accuracy, and with up to 96% if trained only in a different environment. Our lidar and radar experiments demonstrate that CorAl outperforms previous methods both on the ETH lidar benchmark, which includes several indoor and outdoor environments, and the large-scale Oxford and MulRan radar data sets for urban traffic scenarios. The results also demonstrate that CorAl generalizes very well across substantially different environments without the need of retraining.

    Place, publisher, year, edition, pages
    Elsevier, 2022
    Keywords
    Radar, Introspection, Localization
    National Category
    Computer Vision and Robotics (Autonomous Systems)
    Identifiers
    urn:nbn:se:oru:diva-100756 (URN)10.1016/j.robot.2022.104136 (DOI)000833416900001 ()2-s2.0-85132693467 (Scopus ID)
    Funder
    Knowledge FoundationEuropean Commission, 101017274Vinnova, 2019-05878
    Available from: 2022-08-24 Created: 2022-08-24 Last updated: 2024-01-02Bibliographically approved
    7. TBV Radar SLAM - Trust but Verify Loop Candidates
    Open this publication in new window or tab >>TBV Radar SLAM - Trust but Verify Loop Candidates
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    2023 (English)In: IEEE Robotics and Automation Letters, E-ISSN 2377-3766, Vol. 8, no 6, p. 3613-3620Article in journal (Refereed) Published
    Abstract [en]

    Robust SLAM in large-scale environments requires fault resilience and awareness at multiple stages, from sensing and odometry estimation to loop closure. In this work, we present TBV (Trust But Verify) Radar SLAM, a method for radar SLAM that introspectively verifies loop closure candidates. TBV Radar SLAM achieves a high correct-loop-retrieval rate by combining multiple place-recognition techniques: tightly coupled place similarity and odometry uncertainty search, creating loop descriptors from origin-shifted scans, and delaying loop selection until after verification. Robustness to false constraints is achieved by carefully verifying and selecting the most likely ones from multiple loop constraints. Importantly, the verification and selection are carried out after registration when additional sources of loop evidence can easily be computed. We integrate our loop retrieval and verification method with a robust odometry pipeline within a pose graph framework. By evaluation on public benchmarks we found that TBV Radar SLAM achieves 65% lower error than the previous state of the art. We also show that it generalizes across environments without needing to change any parameters. We provide the open-source implementation at https://github.com/dan11003/tbv_slam_public

    Place, publisher, year, edition, pages
    IEEE, 2023
    Keywords
    SLAM, localization, radar, introspection
    National Category
    Computer Vision and Robotics (Autonomous Systems)
    Identifiers
    urn:nbn:se:oru:diva-106249 (URN)10.1109/LRA.2023.3268040 (DOI)000981889200013 ()2-s2.0-85153499426 (Scopus ID)
    Funder
    Vinnova, 2021-04714 2019-05878
    Available from: 2023-06-13 Created: 2023-06-13 Last updated: 2024-01-17Bibliographically approved
    8. Localising Faster: Efficient and precise lidar-based robot localisation in large-scale environments
    Open this publication in new window or tab >>Localising Faster: Efficient and precise lidar-based robot localisation in large-scale environments
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    2020 (English)In: 2020 IEEE International Conference on Robotics and Automation (ICRA), IEEE, 2020, p. 4386-4392Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper proposes a novel approach for global localisation of mobile robots in large-scale environments. Our method leverages learning-based localisation and filtering-based localisation, to localise the robot efficiently and precisely through seeding Monte Carlo Localisation (MCL) with a deeplearned distribution. In particular, a fast localisation system rapidly estimates the 6-DOF pose through a deep-probabilistic model (Gaussian Process Regression with a deep kernel), then a precise recursive estimator refines the estimated robot pose according to the geometric alignment. More importantly, the Gaussian method (i.e. deep probabilistic localisation) and nonGaussian method (i.e. MCL) can be integrated naturally via importance sampling. Consequently, the two systems can be integrated seamlessly and mutually benefit from each other. To verify the proposed framework, we provide a case study in large-scale localisation with a 3D lidar sensor. Our experiments on the Michigan NCLT long-term dataset show that the proposed method is able to localise the robot in 1.94 s on average (median of 0.8 s) with precision 0.75 m in a largescale environment of approximately 0.5 km 2.

    Place, publisher, year, edition, pages
    IEEE, 2020
    Series
    IEEE International Conference on Robotics and Automation (ICRA), ISSN 1050-4729, E-ISSN 2577-087X
    Keywords
    Gaussian processes, learning (artificial intelligence), mobile robots, Monte Carlo methods, neural nets, optical radar, path planning, recursive estimation, robot vision, SLAM (robots), precise lidar-based robot localisation, large-scale environments, global localisation, Monte Carlo Localisation, MCL, fast localisation system, deep-probabilistic model, Gaussian process regression, deep kernel, precise recursive estimator, Gaussian method, deep probabilistic localisation, large-scale localisation, largescale environment, time 0.8 s, size 0.75 m, Robots, Neural networks, Three-dimensional displays, Laser radar, Kernel
    National Category
    Robotics
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:oru:diva-88030 (URN)10.1109/ICRA40945.2020.9196708 (DOI)000712319503010 ()2-s2.0-85092712554 (Scopus ID)978-1-7281-7396-2 (ISBN)978-1-7281-7395-5 (ISBN)
    Conference
    2020 IEEE International Conference on Robotics and Automation (ICRA), Paris, France, May 31 - August 31, 2020
    Funder
    EU, Horizon 2020, 732737
    Note

    Funding agency:

    UK Research & Innovation (UKRI)

    Engineering & Physical Sciences Research Council (EPSRC) EP/M019918/1

    Available from: 2021-01-31 Created: 2021-01-31 Last updated: 2024-01-02Bibliographically approved
    9. NDT-Transformer: Large-Scale 3D Point Cloud Localisation using the Normal Distribution Transform Representation
    Open this publication in new window or tab >>NDT-Transformer: Large-Scale 3D Point Cloud Localisation using the Normal Distribution Transform Representation
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    2021 (English)In: 2021 IEEE International Conference on Robotics and Automation (ICRA), IEEE, 2021Conference paper, Published paper (Refereed)
    Abstract [en]

    3D point cloud-based place recognition is highly demanded by autonomous driving in GPS-challenged environments and serves as an essential component (i.e. loop-closure detection) in lidar-based SLAM systems. This paper proposes a novel approach, named NDT-Transformer, for real-time and large-scale place recognition using 3D point clouds. Specifically, a 3D Normal Distribution Transform (NDT) representation is employed to condense the raw, dense 3D point cloud as probabilistic distributions (NDT cells) to provide the geometrical shape description. Then a novel NDT-Transformer network learns a global descriptor from a set of 3D NDT cell representations. Benefiting from the NDT representation and NDT-Transformer network, the learned global descriptors are enriched with both geometrical and contextual information. Finally, descriptor retrieval is achieved using a query-database for place recognition. Compared to the state-of-the-art methods, the proposed approach achieves an improvement of 7.52% on average top 1 recall and 2.73% on average top 1% recall on the Oxford Robotcar benchmark.

    Place, publisher, year, edition, pages
    IEEE, 2021
    Series
    IEEE International Conference on Robotics and Automation (ICRA), ISSN 1050-4729, E-ISSN 2577-087X
    National Category
    Computer Vision and Robotics (Autonomous Systems)
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:oru:diva-96652 (URN)10.1109/ICRA48506.2021.9560932 (DOI)000765738804041 ()2-s2.0-85124680724 (Scopus ID)9781728190778 (ISBN)9781728190785 (ISBN)
    Conference
    2021 IEEE International Conference on Robotics and Automation (ICRA 2021), Xi'an, China, May 30 - June 5, 2021
    Funder
    EU, Horizon 2020, 732737
    Note

    Funding agencies:

    UK Research & Innovation (UKRI)

    Engineering & Physical Sciences Research Council (EPSRC) EP/R026092/1  

    Royal Society of London European Commission RGS202432

    Available from: 2022-01-24 Created: 2022-01-24 Last updated: 2024-01-02Bibliographically approved
    10. Improving Localisation Accuracy using Submaps in warehouses
    Open this publication in new window or tab >>Improving Localisation Accuracy using Submaps in warehouses
    2018 (English)Conference paper, Oral presentation with published abstract (Other academic)
    Abstract [en]

    This paper presents a method for localisation in hybrid metric-topological maps built using only local information that is, only measurements that were captured by the robot when it was in a nearby location. The motivation is that observations are typically range and viewpoint dependent and that a map a discrete map representation might not be able to explain the full structure within a voxel. The localisation system uses a method to select submap based on how frequently and where from each submap was updated. This allow the system to select the most descriptive submap, thereby improving the localisation and increasing performance by up to 40%.

    National Category
    Robotics
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:oru:diva-71844 (URN)
    Conference
    IEEE/RSJ Int. Conf. on Intelligent Robots and Systems (IROS), Workshop on Robotics for Logistics in Warehouses and Environments Shared with Humans, Madrid, Spain, October 5, 2018
    Projects
    Iliad
    Available from: 2019-01-28 Created: 2019-01-28 Last updated: 2024-01-02Bibliographically approved
    11. A Submap per Perspective: Selecting Subsets for SuPer Mapping that Afford Superior Localization Quality
    Open this publication in new window or tab >>A Submap per Perspective: Selecting Subsets for SuPer Mapping that Afford Superior Localization Quality
    Show others...
    2019 (English)In: 2019 European Conference on Mobile Robots (ECMR), IEEE, 2019Conference paper, Published paper (Refereed)
    Abstract [en]

    This paper targets high-precision robot localization. We address a general problem for voxel-based map representations that the expressiveness of the map is fundamentally limited by the resolution since integration of measurements taken from different perspectives introduces imprecisions, and thus reduces localization accuracy.We propose SuPer maps that contain one Submap per Perspective representing a particular view of the environment. For localization, a robot then selects the submap that best explains the environment from its perspective. We propose SuPer mapping as an offline refinement step between initial SLAM and deploying autonomous robots for navigation. We evaluate the proposed method on simulated and real-world data that represent an important use case of an industrial scenario with high accuracy requirements in an repetitive environment. Our results demonstrate a significantly improved localization accuracy, up to 46% better compared to localization in global maps, and up to 25% better compared to alternative submapping approaches.

    Place, publisher, year, edition, pages
    IEEE, 2019
    National Category
    Computer Sciences
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:oru:diva-79739 (URN)10.1109/ECMR.2019.8870941 (DOI)000558081900037 ()2-s2.0-85074443858 (Scopus ID)978-1-7281-3605-9 (ISBN)
    Conference
    European Conference on Mobile Robotics (ECMR), Prague, Czech Republic, September 4-6, 2019
    Funder
    EU, Horizon 2020, 732737Knowledge Foundation
    Available from: 2020-02-03 Created: 2020-02-03 Last updated: 2024-01-02Bibliographically approved
    12. Incorporating Ego-motion Uncertainty Estimates in Range Data Registration
    Open this publication in new window or tab >>Incorporating Ego-motion Uncertainty Estimates in Range Data Registration
    Show others...
    2017 (English)In: 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1389-1395Conference paper, Published paper (Refereed)
    Abstract [en]

    Local scan registration approaches commonlyonly utilize ego-motion estimates (e.g. odometry) as aninitial pose guess in an iterative alignment procedure. Thispaper describes a new method to incorporate ego-motionestimates, including uncertainty, into the objective function of aregistration algorithm. The proposed approach is particularlysuited for feature-poor and self-similar environments,which typically present challenges to current state of theart registration algorithms. Experimental evaluation showssignificant improvements in accuracy when using data acquiredby Automatic Guided Vehicles (AGVs) in industrial productionand warehouse environments.

    Place, publisher, year, edition, pages
    Institute of Electrical and Electronics Engineers (IEEE), 2017
    Series
    Proceedings of the ... IEEE/RSJ International Conference on Intelligent Robots and Systems, ISSN 2153-0858, E-ISSN 2153-0866
    National Category
    Robotics
    Research subject
    Computer Science
    Identifiers
    urn:nbn:se:oru:diva-62803 (URN)10.1109/IROS.2017.8202318 (DOI)000426978201108 ()2-s2.0-85041958720 (Scopus ID)978-1-5386-2682-5 (ISBN)978-1-5386-2683-2 (ISBN)
    Conference
    IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2017), Vancouver, Canada, September 24–28, 2017
    Projects
    Semantic RobotsILIAD
    Funder
    Knowledge FoundationEU, Horizon 2020, 732737
    Available from: 2017-11-24 Created: 2017-11-24 Last updated: 2024-01-02Bibliographically approved
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    Robust large-scale mapping and localization: Combining robust sensing and introspection
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  • 29.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Castellano-Quero, Manuel
    Örebro University, School of Science and Technology.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    CorAl: Introspection for robust radar and lidar perception in diverse environments using differential entropy2022In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 155, article id 104136Article in journal (Refereed)
    Abstract [en]

    Robust perception is an essential component to enable long-term operation of mobile robots. It depends on failure resilience through reliable sensor data and pre-processing, as well as failure awareness through introspection, for example the ability to self-assess localization performance. This paper presents CorAl: a principled, intuitive, and generalizable method to measure the quality of alignment between pairs of point clouds, which learns to detect alignment errors in a self-supervised manner. CorAl compares the differential entropy in the point clouds separately with the entropy in their union to account for entropy inherent to the scene. By making use of dual entropy measurements, we obtain a quality metric that is highly sensitive to small alignment errors and still generalizes well to unseen environments. In this work, we extend our previous work on lidar-only CorAl to radar data by proposing a two-step filtering technique that produces high-quality point clouds from noisy radar scans. Thus, we target robust perception in two ways: by introducing a method that introspectively assesses alignment quality, and by applying it to an inherently robust sensor modality. We show that our filtering technique combined with CorAl can be applied to the problem of alignment classification, and that it detects small alignment errors in urban settings with up to 98% accuracy, and with up to 96% if trained only in a different environment. Our lidar and radar experiments demonstrate that CorAl outperforms previous methods both on the ETH lidar benchmark, which includes several indoor and outdoor environments, and the large-scale Oxford and MulRan radar data sets for urban traffic scenarios. The results also demonstrate that CorAl generalizes very well across substantially different environments without the need of retraining.

  • 30.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Mattias
    MRO Lab of the AASS Research Centre, Örebro University, Örebro, Sweden.
    Kubelka, Vladimír
    Örebro University, School of Science and Technology.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    TBV Radar SLAM - Trust but Verify Loop Candidates2023In: IEEE Robotics and Automation Letters, E-ISSN 2377-3766, Vol. 8, no 6, p. 3613-3620Article in journal (Refereed)
    Abstract [en]

    Robust SLAM in large-scale environments requires fault resilience and awareness at multiple stages, from sensing and odometry estimation to loop closure. In this work, we present TBV (Trust But Verify) Radar SLAM, a method for radar SLAM that introspectively verifies loop closure candidates. TBV Radar SLAM achieves a high correct-loop-retrieval rate by combining multiple place-recognition techniques: tightly coupled place similarity and odometry uncertainty search, creating loop descriptors from origin-shifted scans, and delaying loop selection until after verification. Robustness to false constraints is achieved by carefully verifying and selecting the most likely ones from multiple loop constraints. Importantly, the verification and selection are carried out after registration when additional sources of loop evidence can easily be computed. We integrate our loop retrieval and verification method with a robust odometry pipeline within a pose graph framework. By evaluation on public benchmarks we found that TBV Radar SLAM achieves 65% lower error than the previous state of the art. We also show that it generalizes across environments without needing to change any parameters. We provide the open-source implementation at https://github.com/dan11003/tbv_slam_public

    The full text will be freely available from 2025-06-01 00:00
  • 31.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Lowry, Stephanie
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Improving Localisation Accuracy using Submaps in warehouses2018Conference paper (Other academic)
    Abstract [en]

    This paper presents a method for localisation in hybrid metric-topological maps built using only local information that is, only measurements that were captured by the robot when it was in a nearby location. The motivation is that observations are typically range and viewpoint dependent and that a map a discrete map representation might not be able to explain the full structure within a voxel. The localisation system uses a method to select submap based on how frequently and where from each submap was updated. This allow the system to select the most descriptive submap, thereby improving the localisation and increasing performance by up to 40%.

    Download full text (pdf)
    Improving Localisation Accuracy using Submaps in warehouses
  • 32.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Lowry, Stephanie
    Örebro University, School of Science and Technology.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    A Submap per Perspective: Selecting Subsets for SuPer Mapping that Afford Superior Localization Quality2019In: 2019 European Conference on Mobile Robots (ECMR), IEEE, 2019Conference paper (Refereed)
    Abstract [en]

    This paper targets high-precision robot localization. We address a general problem for voxel-based map representations that the expressiveness of the map is fundamentally limited by the resolution since integration of measurements taken from different perspectives introduces imprecisions, and thus reduces localization accuracy.We propose SuPer maps that contain one Submap per Perspective representing a particular view of the environment. For localization, a robot then selects the submap that best explains the environment from its perspective. We propose SuPer mapping as an offline refinement step between initial SLAM and deploying autonomous robots for navigation. We evaluate the proposed method on simulated and real-world data that represent an important use case of an industrial scenario with high accuracy requirements in an repetitive environment. Our results demonstrate a significantly improved localization accuracy, up to 46% better compared to localization in global maps, and up to 25% better compared to alternative submapping approaches.

    Download full text (pdf)
    A Submap per Perspective - Selecting Subsets for SuPer Mapping that Afford Superior Localization Quality
  • 33.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Alhashimi, Anas
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    CFEAR Radarodometry - Conservative Filtering for Efficient and Accurate Radar Odometry2021In: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2021), IEEE, 2021, p. 5462-5469Conference paper (Refereed)
    Abstract [en]

    This paper presents the accurate, highly efficient, and learning-free method CFEAR Radarodometry for large-scale radar odometry estimation. By using a filtering technique that keeps the k strongest returns per azimuth and by additionally filtering the radar data in Cartesian space, we are able to compute a sparse set of oriented surface points for efficient and accurate scan matching. Registration is carried out by minimizing a point-to-line metric and robustness to outliers is achieved using a Huber loss. We were able to additionally reduce drift by jointly registering the latest scan to a history of keyframes and found that our odometry method generalizes to different sensor models and datasets without changing a single parameter. We evaluate our method in three widely different environments and demonstrate an improvement over spatially cross-validated state-of-the-art with an overall translation error of 1.76% in a public urban radar odometry benchmark, running at 55Hz merely on a single laptop CPU thread.

    Download full text (pdf)
    CFEAR Radarodometry - Conservative Filtering for Efficient and Accurate Radar Odometry
  • 34.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Alhashimi, Anas
    Örebro University, Örebro, Sweden; Computer Engineering Department, University of Baghdad, Baghdad, Iraq.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Lidar-Level Localization With Radar? The CFEAR Approach to Accurate, Fast, and Robust Large-Scale Radar Odometry in Diverse Environments2023In: IEEE Transactions on robotics, ISSN 1552-3098, E-ISSN 1941-0468, Vol. 39, no 2, p. 1476-1495Article in journal (Refereed)
    Abstract [en]

    This article presents an accurate, highly efficient, and learning-free method for large-scale odometry estimation using spinning radar, empirically found to generalize well across very diverse environments—outdoors, from urban to woodland, and indoors in warehouses and mines—without changing parameters. Our method integrates motion compensation within a sweep with one-to-many scan registration that minimizes distances between nearby oriented surface points and mitigates outliers with a robust loss function. Extending our previous approach conservative filtering for efficient and accurate radar odometry (CFEAR), we present an in-depth investigation on a wider range of datasets, quantifying the importance of filtering, resolution, registration cost and loss functions, keyframe history, and motion compensation. We present a new solving strategy and configuration that overcomes previous issues with sparsity and bias, and improves our state-of-the-art by 38%, thus, surprisingly, outperforming radar simultaneous localization and mapping (SLAM) and approaching lidar SLAM. The most accurate configuration achieves 1.09% error at 5 Hz on the Oxford benchmark, and the fastest achieves 1.79% error at 160 Hz.

    Download full text (pdf)
    Lidar-level localization with radar? The CFEAR approach to accurate, fast and robust large-scale radar odometry in diverse environments
  • 35.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Alhashimi, Anas
    School of Science and Technology, Örebro University, Örebro, Sweden.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Oriented surface points for efficient and accurate radar odometry2021Conference paper (Refereed)
    Abstract [en]

    This paper presents an efficient and accurate radar odometry pipeline for large-scale localization. We propose a radar filter that keeps only the strongest reflections per-azimuth that exceeds the expected noise level. The filtered radar data is used to incrementally estimate odometry by registering the current scan with a nearby keyframe. By modeling local surfaces, we were able to register scans by minimizing a point-to-line metric and accurately estimate odometry from sparse point sets, hence improving efficiency. Specifically, we found that a point-to-line metric yields significant improvements compared to a point-to-point metric when matching sparse sets of surface points. Preliminary results from an urban odometry benchmark show that our odometry pipeline is accurate and efficient compared to existing methods with an overall translation error of 2.05%, down from 2.78% from the previously best published method, running at 12.5ms per frame without need of environmental specific training. 

  • 36.
    Adolfsson, Daniel
    et al.
    Örebro University, School of Science and Technology.
    Magnusson, Martin
    Örebro University, School of Science and Technology.
    Liao, Qianfang
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    CorAl – Are the point clouds Correctly Aligned?2021In: 10th European Conference on Mobile Robots (ECMR 2021), IEEE, 2021, Vol. 10Conference paper (Refereed)
    Abstract [en]

    In robotics perception, numerous tasks rely on point cloud registration. However, currently there is no method that can automatically detect misaligned point clouds reliably and without environment-specific parameters. We propose "CorAl", an alignment quality measure and alignment classifier for point cloud pairs, which facilitates the ability to introspectively assess the performance of registration. CorAl compares the joint and the separate entropy of the two point clouds. The separate entropy provides a measure of the entropy that can be expected to be inherent to the environment. The joint entropy should therefore not be substantially higher if the point clouds are properly aligned. Computing the expected entropy makes the method sensitive also to small alignment errors, which are particularly hard to detect, and applicable in a range of different environments. We found that CorAl is able to detect small alignment errors in previously unseen environments with an accuracy of 95% and achieve a substantial improvement to previous methods.

    Download full text (pdf)
    CorAl – Are the point clouds Correctly Aligned?
  • 37.
    Adolfsson, Josefine
    et al.
    Örebro University, School of Science and Technology.
    Trinh, Madeleine
    Örebro University, School of Science and Technology.
    Effektivisering av produktionsflöde för lageravdelningen2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project has taken place at Martin G Anderson in Örebro, a company that manufactures window glasses. The company has problems with the last step of the process which is the warehouse, where big volume of glass and overtime working hours affects the workers. Purposes of the project is to find additional grounds for improvement suggestions increasing the efficiency of the production in the warehouse. As a part of the project, relevant data is collected to be able to describe the status report at the company. The status reports cover a process description and process mapping. To be able to find possible solutions to improve the current situation, the problems of the warehouse must be investigated. This is accomplished by a status analysis where relevant analytic tools as 5 Whys and 7+1 wastes of Lean production are used. The project plans are to maintain the PDCA cycle where the focus is to approach the phase Plan. The remaining phases of PDCA can thereafter be resumed by the company. The results show multiple wastes in the company, where parts of the wastes are non-value-added activities. The improvement suggestions are therefore aimed at eliminating or reducing these activities and in that way streamline the production flow in the warehouse department. One of the suggestions was theoretically analysed to determine if the suggestion was feasible or not, which resulted in it being possible to implement. Other suggestions are general ideas for the company in order to strive for a more standardised way of working. For continued work, Martin G Anderson should resume the PDCA cycle where the improvement suggestions will be implemented, evaluated and maintained a standard if the suggestions prove to have a good impact. Prerequisites are given in order to be able to attack other problem areas on the basis of this report.

  • 38.
    Afram, Christian
    et al.
    Örebro University, School of Science and Technology.
    Demir, Kamil
    Örebro University, School of Science and Technology.
    UTVECKLINGEN AV EN JÄMSTÄLLD REKRYTERINGHur påverkar olika stora aktörer rekryteringen i byggbranschen: THE DEVELOPMENT OF AN EQUAL RECRUITMENTHow do different large actors affect recruitment in the construction industry2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The construction industry has been the least gender equal and most male-dominated in Sweden and it is important to analyze the problem and the underlying causes. Statistics show that 99 % of all craftsmen were men in 2020. The recruitment process plays an important role in the gender equality issue considering that it is where corporations show their position on both gender equality and how they work with the gender equality issues they face.  The purpose of this study is to investigate the gender equality challenges in recruitment and how major operators work with this process.  The method used is literature studies and qualitative studies. Interview studies have been key to answering our questions. We have six interviewed operators with different turnover. Respondents selected by the individuals who recruit construction related personnel to their corporation.  The results show that different large corporations with different turnovers decide how they implement gender equality in their recruitment companies in the construction industry. It has also shown a clear connection with the fact that the large corporations with the most turnover have a much better grasp of the gender equality issue and work with constant improvements and challenges, which also shows a clear structure in gender equality work within recruitment in the corporation 

    Download full text (pdf)
    fulltext
  • 39.
    Aghaie Azghandi, Mohammed Ali
    et al.
    Örebro University, School of Science and Technology.
    Ahmad, Omar
    Örebro University, School of Science and Technology.
    Byggföretagens hantering av fuktsäkerhetsprojektering – med fokus på projektörer2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Moisture damage usually occurs due to incorrect planning, design and execution throughout the construction process. These inaccuracies result in large cost of action that can be minimized or even eliminated if the moisture safety work is done properly. The design phase is an important stage and a properly implemented moisture safety design can be of great importance for the moisture safety work during the construction process. The planners’ role at this stage is to carry out a moisture safety work based on the requirements of the developer. The purpose of this exam is to find out the choice of method made by the planners’ in the implementation of moisture safety design and to review the need of competence development among the planners’ about moisture.    The two methods that have been used to achieve the purpose of this exam are interviews and literature studies. The target group in this exam is the construction companies in Sweden. The way of how the companies handle of moisture safety design is being reviewed in the design stage.  Of all involved actors in the design phase, the focus is on the planners'. Three out of five planners' are dissatisfied with their own moisture competence, which is in line with the opinion of the experts' of moisture about the planners' competence.   During the interviews, several experts' of moisture have pointed out the need for increased moisture competence among the planners'. The lack competence means that the planners' cannot consider or detect possible moisture risks during the moisture safety design. The method that is used by 80% of the planners' during moisture safety design is the ByggaF method. The planners' knowledge of ByggaF is still low according to the experts' of moisture and for this reason the planners' cannot apply entirely the ByggaF method. The tools that planners' need to have with them is knowledge and experience. In order to discover what is wrong, you need to have both the knowledge and experience about what is right.  Based on the response from both the building committee and the participants, a review of the documentation regarding the moisture safety work is not always requested by the building committee.  The conclusion is that projectors must acquire competence in both moisture and the ByggaF method.   

    Download full text (pdf)
    fulltext
  • 40.
    Aghazadeh, David
    Örebro University, School of Science and Technology.
    Utvärdering av tidsplaneringsverktyg för universitet2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Scheduling is most often a problem that occurs at schools and universities. Scheduling is a task where all activities must be assigned to time and space with the right resources. When scheduling is done manually, the task takes a long time and is difficult to solve. The time it takes to solve the task can take a large amount of time. With the help of the right tools, time can be shortened, a better schedule can be created, and the workforce can be placed elsewhere. Scheduling at Örebro University is done manually by the administration. The purpose of the project is to generate a ground for making decisions about tools that can be facilitating. The project's focus is on the timetabling problem for universities, not for schools or production planning. During the project, scheduling tools have been found and selected, with the requirement that they have open source code. For evaluation, I set out criteria I applied as the basis for comparison. The experiment design consisted of creating three different sample data to experiment on the tools. The purpose of the three different test data was to produce an assessment according to the points of the criteria. The tools that were most convincing were those that got the best results according to the assessment criteria.

  • 41.
    Agusi, Mejrema
    Örebro University, School of Science and Technology.
    Aspekter för framgång i matematik– Viktiga aspekter för att främja elevernas intresse för matematik.2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Students who find mathematics difficult and complicated can lose their confidence in their abilities after the first years of school to cope with mathematical tasks and gradually give up all efforts to learn mathematics. This systematic literature study aims to shed light on the teacher's role in developing students' interest in mathematics. The goal is to point out important aspects that can strengthen the teacher's teaching to arouse and create a positive interest in the students in their teaching. The result is research on different perceptions from different continents in the world about essential aspects that teachers can work from to promote students' interest in the mathematical subject. The most central aspect focuses on the importance of the teacher's knowledge of the students. Half of the articles that form the basis of this study also shed light on the importance of the current mathematics classroom. Finally, there are themes about communication and creating self-confidence through feedback.

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  • 42.
    Ahari, Elias
    et al.
    Örebro University, School of Science and Technology.
    Eliasson, Erik
    Örebro University, School of Science and Technology.
    UNDERSÖKNING AV OMSTÄLLNINGSTIDER OCH VARIATIONER VID KARTONGMASKIN 2: EN FALLSTUDIE PÅ IGGESUND PAPERBOARD AB, IGGESUND2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Iggesund Mill manufactures bleached board that is used in exclusive packaging. Iggesund Mill is a part of the Holmen Groupand is located almost 30 scandinavian miles north of Stockholm. A strategic initiative has been launched at Iggesund Mill, which includes improving the working environment, increasing participation and increasing the ability to produce high quality board.

    In this study, changeovers and the variations that occur on the board machine 2 (KM2)have been investigated. This work has been conducted as a qualitative case study where interviews and observations have been analyzed with theoretical support. Early in the study it proved difficult to determine the changeover times at KM2. This may be due to an uncertainty regarding how to report changeovers, which creates a misleading picture of the changeover problems. The conclusion of this is that Iggesund Mill should clearly define the term "Changeover". The variety of products also leads to a lot of changeovers which leads to variations in the process that adversely affect the productivity. A recommendation for a continued work is to investigate whether the product variety can be reduced or the possibility to run larger production cycles.

  • 43.
    Ahlinder, Jenny
    Örebro University, School of Science and Technology.
    Drav som ingrediens i framtidens bröd2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Drav är en biprodukt från ölbryggning som årligen produceras i stora volymer och som huvudsakligen består av skalrester från olika sädesslag. Att berika bröd med drav skulle potentiellt kunna öka möjligheterna att använda olika näringspåståenden vid profilering av brödprodukter, såsom högt fiberinnehåll och proteinkälla. Vissa konsumenter är benägna att betala mer för en produkt som innehåller höga halter av ett visst näringsämne, vilket kan vara betydelsefullt ur ett försäljningsperspektiv för innovativa aktörer inom livsmedelssystemet. Denna litteraturstudie syftar till att granska och sammanfatta vetenskaplig litteratur som undersöker dravens bidrag och påverkan på näringsvärdet och de sensoriska egenskaperna vid tillsats i bröd. Studien är utförd enligt systematisk metodik som kännetecknas av hög transparens och en kritisk granskning. Resultatet visar att draven innehåller rikligt av protein (31.4g per 100g), kolhydrater (49.9g per 100g) och fiber (42.6g per 100g) (Neylon et al., 2021). Detta bidrar således till ett ökat innehåll av dessa näringsämnen vid tillsats i bröd. Tillsatsen verkar även möjliggöra användandet av vissa näringspåståenden vid profilering av brödet, såsom fiberkälla. Vid en tillsats över 10% drav i förhållande till mängden mjöl, verkar de sensoriska egenskaperna påverkas negativt. Genom att tillsätta drav i bröd bakat på fullkornsvetemjöl verkar dock risken för negativ påverkan på de sensoriska egenskaperna minska. Det beror på att tillsatsen blir mindre tydlig eftersomfullkornsvetemjöl redan innehåller rikligt med fibrer i jämförelse med bröd bakat på enbart vetemjöl. Framtida forskning bör undersöka möjligheterna att använda och bearbeta drav ur ett storskaligt och industriellt perspektiv, i syfte att öka möjligheterna att använda drav som en livsmedelsingrediens i framtiden.

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  • 44.
    Ahmad, Abrar
    Örebro University, School of Science and Technology.
    Kras and Braf mutation analysis in colon cancer by pyrosequencing2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 45.
    Ahmed, Farouq
    Örebro University, School of Science and Technology.
    Utökad automatisering av e-handel med shopify API2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Competition among sellers is rapidly increasing within e-commerce due to the decreasing barrier of entry. In order for a seller to be relevant, effectiveness is a requirement that can be achieved by using different methods and tools that result in a successful and profitable online store. One of the methods that sellers use is drop shipping which allows sale of goods without inventory holding. This is done by ordering the products from a third part that ships to the customer the moment an order is placed, instead of purchasing the products in advance. This leads to cheaper and more effective trade for new and already existing sellers.Despite the good opportunities that drop shipping allows, it is a time consuming task that requires a high level of accuracy due to the many repetitive tasks that are performed during the sales process. This is a problem that can hinder sellers from using the drop shipping model. In order to make it easier for sellers to utilize this method, a program can perform the manual tasks automatically.In this report, different software architectural patterns are studied to build the base of a prototype program that could perform the manual tasks with a satisfactory level of automation.

  • 46.
    Ahmed, Mobyen Uddin
    et al.
    Örebro University, School of Science and Technology.
    Banaee, Hadi
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Health monitoring for elderly: an application using case-based reasoning and cluster analysis2013In: ISRN Artificial Intelligence, ISSN 2090-7435, E-ISSN 2090-7443, Vol. 2013, no 2013, p. 1-11Article in journal (Refereed)
    Abstract [en]

    This paper presents a framework to process and analyze data from a pulse oximeter which measures pulse rate and blood oxygen saturation from a set of individuals remotely. Using case-based reasoning (CBR) as the backbone to the framework, records are analyzed and categorized according to how well they are similar. Record collection has been performed using a personalized health profiling approach where participants wore a pulse oximeter sensor for a fixed period of time and performed specific activities for pre-determined intervals. Using a variety of feature extraction in time, frequency and time-frequency domains, and data processing techniques, the data is fed into a CBR system which retrieves most similar cases and generates alarm and flag according to the case outcomes. The system has been compared with an expert's classification and 90% match is achieved between the expert's and CBR classification. Again, considering the clustered measurements the CBR approach classifies 93% correctly both for the pulse rate and oxygen saturation. Along with the proposed methodology, this paper provides a basis for which the system can be used in analysis of continuous health monitoring and be used as a suitable method as in home/remote monitoring systems.

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  • 47.
    Ahmed, Mobyen Uddin
    et al.
    Örebro University, School of Science and Technology.
    Banaee, Hadi
    Örebro University, School of Science and Technology.
    Rafael-Palou, Xavier
    Barcelona Digital Technology Centre, Barcelona, Spain.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Intelligent Healthcare Services to Support Health Monitoring of Elderly2015In: INTERNET OF THINGS: USER-CENTRIC IOT, PT I, Springer, 2015, Vol. 150, p. 178-186Conference paper (Refereed)
    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.

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  • 48.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalen University, Västerås, Sweden.
    Fotouhi, Hossein
    Mälardalen University, Västerås, Sweden.
    Köckemann, Uwe
    Örebro University, School of Science and Technology.
    Lindén, Maria
    Mälardalen University, Västerås, Sweden.
    Tomasic, Ivan
    Mälardalen University, Västerås, Sweden.
    Tsiftes, Nicolas
    RISE SICS, Stockholm, Sweden.
    Voigt, Thiemo
    RISE SICS, Stockholm, Sweden.
    Run-Time Assurance for the E-care@home System2018In: Internet of Things (IoT) Technologies for HealthCare (HealthyIoT 2017) / [ed] Ahmed, MU; Begum, S; Fasquel, JB, Springer, 2018, Vol. 225, p. 107-110Conference paper (Refereed)
    Abstract [en]

    This paper presents the design and implementation of the software for a run-time assurance infrastructure in the E-care home system. An experimental evaluation is conducted to verify that the run-time assurance infrastructure is functioning correctly, and to enable detecting performance degradation in experimental IoT network deployments within the context of E-care home.

  • 49.
    Ahmed, Mobyen Uddin
    et al.
    Örebro University, School of Science and Technology.
    Islam, Asif Moinul
    Örebro University, Örebro, Sweden.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    A case-based patient identification system using pulseoximeter and a personalized health profile2012Conference paper (Refereed)
    Abstract [en]

    This paper proposes a case-based system framework in order to identify patient using their health parameters taken with physiological sensors. It combines a personalized health profiling protocol with a Case-Based Reasoning (CBR) approach. The personalized health profiling helps to determine a number of individual parameters which are important inputs for a clinician to make the final diagnosis and treatment plan. The proposed system uses a pulse oximeter that measures pulse rate and blood oxygen saturation. The measurements are taken through an android application in a smart phone which is connected with the pulseoximeter and bluetooth communication. The CBR approach helps clinicians to make a diagnosis, classification and treatment plan by retrieving the most similar previous case. The case may also be used to follow the treatment progress. Here, the cases are formulated with person’s contextual information and extracted features from sensor signal measurements. The features are extracted considering three domain analysis:1) time domain features using statistical measurement, 2) frequency domain features applying Fast Fourier Transform (FFT), and 3) time-frequency domain features applying Discrete Wavelet Transform (DWT). The initial result is acceptable that shows the advancement of the system while combining the personalized health profiling together with CBR.

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  • 50.
    Ahmed, Mobyen Uddin
    et al.
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Physical Activity Classification for Elderly based on Pulse Rate2013Conference paper (Refereed)
    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%.

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