Recent additions

  • Finite element simulation of ductile fracture in polycrystalline materials using a regularized porous crystal plasticity model 

    Khadyko, Mikhail; Frodal, Bjørn Håkon; Hopperstad, Odd Sture (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-18)
    In the present study, a hypoelastic–plastic formulation of porous crystal plasticity with a regularized version of Schmid’s law is proposed. The equation describing the effect of the voids on plasticity is modified to allow for an explicit analytical solution for the effective resolved shear stress. The regularized porous crystal plasticity model is implemented as a material model in a finite element ...
  • Modeling of Pressure and Temperature Profiles for the Flow of CO2 through a Restriction 

    Leyli, Amir Nadem; Jackson, Steven; Khawaja, Hassan; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-19)
    CO<sub>2</sub> emissions due to massive industrialization have led to several environmental issues. Carbon Capture and Storage (CCS) is one of the most important technologies that can be used to reduce anthropogenic CO<sub>2</sub> emissions worldwide. CCS projects mainly involve three processes: carbon capture, transportation, and storage. In the transportation process, the modeling of the flow in ...
  • Solving a Real-World Urban Postal Service Network Redesign Problem 

    Yu, Hao; Sun, Xu; Solvang, Wei Deng; Laporte, Gilbert (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-28)
    Due to recent technological advancements, more diversified customer demand, and increasingly harder competition, traditional postal service systems have experienced significant changes all over the world. In Norway, through a strategic reform called post-in-shop, undertaken in 2013, most postal services are now provided at postal service counters located in retailer stores in order to improve ...
  • Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard 

    Dreyer, Joshua; Partamies, Noora; Whiter, Daniel; Ellingsen, Pål Gunnar; Baddeley, Lisa; Buchert, Stephan C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-04)
    This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). An all-sky camera captured these FAEs on three separate occasions in 2015 and 2017 at the Kjell Henriksen Observatory near the arctic town of Longyearbyen, Svalbard, Norway. A total of 305 FAE candidates were identified. They seem to appear ...
  • Recognizing Potential of LiDAR for Comprehensive Measurement of Sea Spray Flux for Improving the Prediction of Marine Icing in Cold Conditions - A Review 

    Dhar, Sushmit; Khawaja, Hassan (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-06)
    Marine icing phenomenon depends on multiple variables like vessel characteristics and uncertain factors like environmental parameters, developing an accurate model for its forecasting, evaluation, and estimation is very challenging. Commonly, most severe ice accretion is caused due to sea spray. The past attempts to measure impinging sea spray flux were carried out on specific parts of the spray ...
  • Path planning and collision avoidance for autonomous surface vehicles I: a review 

    Vagale, Anete; Oucheikh, Rachid; Bye, Robin Trulssen; Osen, Ottar Laurits; Fossen, Thor I. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-29)
    Autonomous surface vehicles are gaining increasing attention worldwide due to the potential benefits of improving safety and efficiency. This has raised the interest in developing methods for path planning that can reduce the risk of collisions, groundings, and stranding accidents at sea, as well as costs and time expenditure. In this paper, we review guidance, and more specifically, path planning ...
  • Path planning and collision avoidance for autonomous surface vehicles II: a comparative study of algorithms 

    Vagale, Anete; Bye, Robin Trulssen; Oucheikh, Rachid; Osen, Ottar; Fossen, Thor I. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-06)
    Artificial intelligence is an enabling technology for autonomous surface vehicles, with methods such as evolutionary algorithms, artificial potential fields, fast marching methods, and many others becoming increasingly popular for solving problems such as path planning and collision avoidance. However, there currently is no unified way to evaluate the performance of different algorithms, for example ...
  • Investigating the affordances of a flipped mathematics classroom from an activity theoretical perspective 

    Fredriksen, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-20)
    Flipped Classroom as a pedagogical framework has gained popularity at secondary and tertiary levels of mathematics education, but there is a lack of research based on a solid theoretical foundation. This article considers the flipped mathematics classroom from the perspective of affordances and cultural–historical activity theory. The empirical background is based on semi-structured interview data ...
  • Using Deep Learning Methods to Monitor Non-Observable States in a Building 

    Tangrand, Kristoffer; Bremdal, Bernt Arild (Peer reviewed; Conference object; Konferansebidrag, 2020-02-06)
    This paper presents results from ongoing research with a goal to use a combination of time series from non-intrusive ambient sensors and deep recurrent neural networks to predict room usage at a university campus. Training data was created by collecting measurements from ambient sensors measuring room CO2, humidity, temperature, light, motion and sound, while the ground-truth counts was created ...
  • Exploring Realistic Mathematics Education in a Flipped Classroom Context at the Tertiary Level 

    Fredriksen, Helge (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-01)
    Flipped classroom (FC) pedagogical frameworks have recently gained considerable popularity, especially at secondary school levels. However, there are rich opportunities to explore FC at tertiary levels, but progress on the area requires instructors’ attention to well-designed tasks for students’ collaborative learning. Realistic Mathematics Education (RME) provides a foundation for the development ...
  • User-Friendly MES Interfaces: Recommendations for an AI-Based Chatbot Assistance in Industry 4.0 Shop Floors 

    Mantravadi, Soujanya; Jansson, Andreas Dyrøy; Møller, Charles (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-04)
    The purpose of this paper is to study an Industry 4.0 scenario of ‘technical assistance’ and use manufacturing execution systems (MES) to address the need for easy information extraction on the shop floor. We identify specific requirements for a user-friendly MES interface to develop (and test) an approach for technical assistance and introduce a chatbot with a prediction system as an interface layer ...
  • Frequency Support of Fast-Multi-Energy Storage Systems in Low Rotational Inertia Scenarios 

    Ersdal, Anne Mai; Acosta Montalvo, Martha Nohemi; Gonzalez-Longatt, Francisco; Torres, José Luis Rueda; Palenski, Peter (Peer reviewed; Chapter, 2020-11-10)
    Modern power systems are increasing the connection of power electronic converters (PECs), and new inertia-less technologies displace the synchronous generation units. Therefore, the total rotational system inertia is reduced, creating new problems related to the system frequency control and stability. Several mechanisms to enable the PECs with frequency sensible control loops have been proposed in ...
  • Proactive Learning for Intelligent Maintenance in Industry 4.0 

    Noureddine, Rami; Solvang, Wei Deng; Johannessen, Espen; Yu, Hao (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-03)
    Manufacturing companies require efficient maintenance practices in order to improve business performance, ensure equipment availability and reduce process downtime. With the advent of new technology, manufacturing processes are evolving from the traditional ways into digitalized manufacturing. This transformation enables systems and machines to be connected in complex networks as a collaborative ...
  • Solving the Location Problem of Printers in a University Campus Using p-Median Location Model and AnyLogic Simulation 

    Sun, Xu; Yu, Hao; Solvang, Wei Deng (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-03)
    The location decision on service facilities is of significant importance in determining the accessibility of the service provided. Due to this reason, it has been extensively focused over the past decades by both researchers and practitioners. This paper investigates a novel two-phase hybrid method combining both optimization model and agent-based simulation in order to solve the location problem ...
  • A Stochastic Closed-Loop Supply Chain Network Optimization Problem Considering Flexible Network Capacity 

    Yu, Hao; Solvang, Wei Deng; Sun, Xu (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-03)
    Nowadays, due to the concern of environmental challenges, global warming and climate change, companies across the globe have increasingly focused on the sustainable operations and management of their supply chains. Closed-loop supply chain (CLSC) is a new concept and practice, which combines both traditional forward supply chain and reverse logistics in order to simultaneously maximize the utilization ...
  • An Introduction of the Role of Virtual Technologies and Digital Twin in Industry 4.0 

    Azarian, Mohammad; Yu, Hao; Solvang, Wei Deng; Shu, Beibei (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-03)
    It is inevitable that technological improvements have affected human’s life in any aspect to a large extent. Automation, artificial intelligence, robotics, etc., are some advances contributed to the fourth industrial revolution: Industry 4.0. Despite there are still many arguments, Internet of Things (IoT) and Cyber Physical Systems (CPS) have been widely acknowledged as the main fundaments of ...
  • Sensitivity Analysis and Case Studies for CO2 Transportation Energy Consumption 

    Jackson, Steven (Journal article; Tidsskriftartikkel; Peer reviewed, 2020)
    The transportation of CO2 is important to all Carbon Capture and Storage (CCS) projects. Both the infrastructure costs – compressors, pipelines, tanker ships, etc. – and the energy consumed in the compression or liquefaction of CO2 are significant. Understanding how the size, capacity and energy consumption of transportation alternatives varies between projects is therefore important. Modelling ...
  • Optimization study of heat pumps using refrigerant blends – Ejector versus expansion valve systems 

    Brodal, Eivind; Eiksund, Oddmar (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-19)
    This article investigates tap water heating systems to highlight an ongoing debate. Some report that CO2-based transcritical heat pumps with an ejector have the best coefficient of performance (COP), while others report that blend-based refrigerant systems (without an ejector) are better. In the literature, however, these systems are only compared with conventional heat pump designs, and not against ...
  • Mathematical modelling of bioenergy systems for stability analysis and parametric sensitivity 

    Das, Subhashis (Doctoral thesis; Doktorgradsavhandling, 2021-03-19)
    <p>This thesis presents a research study on bioreactor design and biochemical processes for conversion of biomass into bioenergy and develops mathematical models that can be used for designing better reactors and control systems. Good design of the bioreactors and understanding of the biochemical process is essential to control the process for maximizing the yield. Improving the performance efficiency ...
  • Conjugate Heat Transfer Model Based on SIMPLE and Coupled Energy and Heat Equations 

    Leyli, Amir Nadem; Andleeb, Zahra; Khawaja, Hassan; Messahel, Ramzi; Kanna, Rajesh; Moatamedi, Mojtaba (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-28)
    In this study, a numerical weak coupling strategy for the modeling of a conjugate heat transfer phenomenon is considered. Where the incompressible Navier-Stokes equations are solved using the Semi-Implicit Method for Pressure Linked Equations (SIMPLE) as a first step, and then the heat conduction equation for solid is solved in a second step considering the convective velocity field resulting from ...

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